The UnMuseum: Ask the Curator

Moon's Strange Orbit - Does the moon revolve the Earth directly above equator? If yes, does it mean that people in upper northern hemisphere will be see it on the horizon? - Anonymous

Our moon, unlike most moons in our solar system, does not follow a path directly above its planet's equator. Instead, our moon follows an orbital path very much closer to Earth's ecliptic plane. Earth's ecliptic is the path Earth follows as it orbits the Sun.

The earth's equator is tilted off its ecliptic by a little more than 23 degrees. This angle is what gives us the seasons as the northern hemisphere is more tilted toward the sun during the summer and away from the sun in the winter (The opposite is true for the southern hemisphere where the seasons there are reversed).

This tilt also explains why the moon traces a different path across the sky depending on the season. Like the sun, during the winter it is closer to the horizon. In fact, further north than the Arctic Circle the moon will not be visible for 14 days at a time as it passes out of sight behind the tilt of our planet for half of its orbit. Or course when it does re-emerge it rises and stays up for fourteen days (The same is true at the Antarctic Circle).

The fact that the moon orbits close to the Earth's ecliptic plane has been used as evidence against the theory that the moon was created at the same time the Earth. In this theory, most of the spinning material in the region of Earth was pulled together by gravity to form our planet, but some of pulled together to form the moon. If that was the case, however, we would expect out moon to be orbiting along the equator. The current leading theory as to the creation of the moon is that a body the size of Mars hit Earth throwing massive amounts of material into orbit. Over the course of the next century this material was drawn together by gravity to form our moon.

Please how old is the Earth? Biblically it is accurately about 6042 to 7000 years and scientifically it counts on millions. Should we believe in God's wisdom or mere knowledge of man? - Cheta A

There has been a dispute going on in some circles between some biblical fundamentalists, who argue that science is wrong about the age of the planet because the Bible says that the Earth is only 10,000 years old; and some scientists who claim that the Bible must be inaccurate because clearly the Earth is millions of years old. There are, however, a number of people who hold the views that these differences are not irreconcilable. Though I am not a theologian, I will endeavor to give you the highlights of some of these ideas.

Age/Day View - One of the major reasons that science doesn't seem to match up with the Bible is the creation story in Genesis that seems make the universe and the earth appear in only 6 literal days. This view says that the days mentioned in Genesis are not 24 hour days, but "ages." These "ages" might have lasted millions of years or even billions of years and may have also overlapped. Though some critics argue that a "day" in this context in the Bible must only be 24-hours long, others argue that this alternate interpretation is not really inconsistent with some Biblical understandings of the word "day."

At least one author, Israeli physicist and Genesis scholar Gerald L. Schroeder, argues that depending how you define "time" these days could be both 24 hours and millions or billions of years long. For more information on this idea check out his book The Science of God: The Convergence of Scientific and Biblical Wisdom.

Mature Creation - Another view is that the Earth and Universe were created in seven days 10,000 years ago, but they have been given a whole consistent history of billions of years. This idea isn't really inconsistent with other parts of the Bible. For example, Adam is created as an adult man without the usual 20 years or so need to grow from baby to mature human under the usual laws of nature. Perhaps the earth and universe were also created in a relatively short amount of time without the 15 billion years that might normally be needed for such a process.

If you accept this view then for theological reasons the world is 10,000 years old, but for purposes of science the world is some 4.5 billion years.

Some argue that this seems somewhat disingenuous of God to create a false history. However, it isn't any more dishonest then creating Atom, calling him a man, though he never went through the normal human creation process. Indeed in our own poor attempts to create worlds and universes inside computers (i.e. video games like "The Sims") we always apply this method and it never seems dishonest to us within that context.

This isn't meant to be a complete discussion on the subject - just a starting point. Debates over this subject have already filled thousands of web pages, so I recommend you take a look at what has already been written about these ideas across the internet.

Vital Vitamins - What is a "vitamin", and how can sunlight make vitamin D? - John

A vitamin is an organic compound needed by a human or animal in tiny amounts in order to stay healthy. Usually a compound is only called a vitamin when the animal is unable to make it by itself, but must get it by eating it. This means that some compounds are vitamins for some animals but not really for others. For example, vitamin D is not really a vitamin in the human diet because we create it ourselves when sunlight hits our skin. It is a vitamin for most fish, however, who must get it by eating algae (Or by eating other fish who have eaten algae). The algae in turn create when they float in shallow waters under the sun.

For many years scientists suspected that certain foods contained tiny amounts of some substances needed for health, but they didn't know what those substances were. For example, in 1749, the Scottish surgeon James Lind discovered that citrus foods helped prevent scurvy, a particularly deadly disease often suffered by sailors who did not get fresh fruit in their diet. As it turns out the sailors were not getting vitamin C - otherwise known as ascorbic acid - which is found in the fruits. Though Lind didn't exactly know what the missing ingredient was, he recommended eating lemons and limes to avoid scurvy, an idea which was adopted by the British Royal Navy and led to their nickname "Limies".

In 1881, Russian doctor Nikolai Lunin did an experiment where he gave one group of mice milk and the other group an artificial mixture of all the separate parts of milk known at that time: proteins, fats, carbohydrates, and salts. The mice that got the regular milk were fine, but those which got just the parts got sick and died. This told Lunin that there was something in the milk that science was unaware of that was needed for the mice to stay healthy. The first scientist to extract one of these micronutrients was Japanese researcher Umetaro Suzuki in 1910. He named his discovery aberic acid. It would later become known as vitamin B1.

-The world "vitamin" is a blend of the words "vital" and "amine" where amine is a specific sort of organic compound. However, as other vitamins were found, not all turned out to be amines, but the name stuck.

-Often an animals will have to eat the vitamins they need every day because their bodies will not store the vitamins for any length of time.

Vitamin D is produced photo-chemically when ultra-violet light interacts with the substance 7-dehydrocholesterol. In the case of humans the creation of the Vitamin D takes place in the epidermis, the top layer of our skin, when light from the sun penetrates it and hits the 7-dehydrocholesterol our bodies put there. How much and how quickly you make your Vitamin D depends on how much sun light you get and the color of your skin. People with darker skin produce it more slowly than people with lighter skin.

For mammals with fur, who can't get sunlight to their skin at all, the Vitamin D is synthesized in oily secretions that are deposited onto the fur. As those oils sit on the fur and are exposed to the sun, the vitamin D is created. The animal then must lick the oils off and swallow them to get the Vitamin D into their systems.

Glowing Arthropods - Why do scorpions fluoresce under a UV light? - Warren

This is a subject that scientists don't know a great deal about, but let's start with some basic facts. Some materials when hit by a light with a wave-length shorter than humans can see will absorb that light energy and then radiate back light within the visible spectrum so when a person looks at the object, it seems to glow. This process is called fluorescence.

There is a substance in the epicuticle (sometimes called the hyaline layer) of the scorpion's exoskeleton that fluoresces when exposed to ultra-violet light. Nobody knows exactly what this stuff is but some scientists speculate it is a complex of mucosaccharides (a simple form of sugar) and proteins. Also �-Carboline, a trytophan derivative, is known to play an important part.

Nobody really knows how the fluorescence gets there either. Baby scorpions aren't born with it and scorpions that have just molted don't have it. This has leads some people to suggest that it is either secreted by the scorpion over time, a side effect of the animal's exoskeleton as it is tanned by the sun or the result of chemical reactions as the new exoskeleton hardens. The fact that some scorpions that live their entire lives in dark caves and still fluoresce, however, leads some people to think that it unlikely to be the tanning process.

Finally we also don't know what advantage this gives the scorpion. Some have speculated that this property somehow helps the scorpion with their ultra-violet light sensitivity, but studies have shown that different levels of UV light seem to have little effect on the animal's behavior.

We do know that scorpions have had this characteristic for a very long time. This kind of fluorescence has even been seen in some of the fossils of ancient scorpions. We also know it is not unique to scorpions as some sow bugs, millipedes, centipedes, solfugids and a few beetles also will glow in ultra-violet light. We also know that with each molting the effect grows stronger so that older scorpions glow brighter than young ones. The amount a scorpion glows is also connected the particular species. Some glow brightly, others hardly at all.

Whatever it is, this characteristic has been a boon to scientists and scorpion enthusiasts. A small camping lamp can have its fluorescent bulb replaced with one that produces ultra-violet (or "black") light that will cause scorpions to glow a soft blue or green at a distance of one or two feet. This is a great aid in finding the small animals. Scientists can then easily use tongs to collect specimens and many new species have been found this way. A flashlight that produces UV light can also be useful when camping in scorpion habitats to check your sleeping back to make sure you are not crawling in with one of the tiny critters.

Air on the moon - Is it possible to channel a pipe from Earth to Moon and pump in some of earth's atmosphere so as to support free life? - Cheta A.

Construction of a pipeline from the Earth to the Moon would be a difficult and probably impossible construction problem. Though scientists think it might be feasible to build an elevator that would lift people and materials in earth orbit, the space station that the elevator would be connected to would rotate in sync with our planet so it would always be directly overhead. The moon orbits the earth once a month, however, while our planet spins every 24 hours, so a pipeline from earth to moon would quickly get twisted and tangled.

There would be little point in building one, anyway, in an attempt to pressurize the moon and give it a breathable atmosphere. The moon already has an atmosphere, (mostly created by out gassing from the underground chemical reactions) but the atmosphere is so thin it almost does not exist. The gravity of the moon, only one-sixth that of Earth is too weak to hold any significant amount of gas on the surface. Most of it drifts into space to be swept away by the solar wind.

Of course we still might have an interest in putting stations and maybe even cities on the moon. (These would probably be airtight and partly or completely underground. By putting a couple of meters of rock above the habitations you can protect life from the stray radiation that often bombards the lunar surface) If we do build underground cities we will need air for the inhabitants to breath. Rather than pipe it up, or even bring it up in large cargo spaceships, it would much more efficient to create it from materials already on the surface. There is plenty of oxygen and nitrogen (to major components of air) locked up in lunar rocks and soil. Getting these out of the rocks will require energy, but there is plenty of that on the moon. It gets lots of sunlight (no cloudy days) that can be turned into electrical power. For that reason NASA is thinking of locating the first lunar stations near the poles so they can get an almost continuous exposure to energy from the sun.

Using Magnets for Traveling Through Space - I'm wondering if it's possible to use the principles of magnetism for travel (besides Maglev). For example, could a ship with a highly focused electromagnet aim and pull itself to a planet's magnetic field, or to the heavy metal core of an asteroid? Could this same idea be used to create a flying car, by pushing or pulling off more than one point at the same time? Thanks - Maxwell

While magnets and magnetic forces are very important in present and future transportation designs, the type of arrangement you suggest - focusing a magnetic field toward a distant object to pull yourself toward it seems an unlikely mechanism to be used. The problem is that magnetic fields lose their strength very quickly over long distances. So if you attempted to build a ship using this principal to pull yourself toward to a distant object you would need an impractically large magnetic field requiring a tremendous amount of energy. You would also have the problem that your engine would be attracting every piece of ferrite material (those attracted to a magnet) within miles -the wrenches in you tool kit, you belt buckle, other ships near you etc... You vessel would soon be covered with loose ferrite objects.

A train using Maglev does not have this same difficulty. The train uses magnetism to float just above its rails (often less than an inch) so that distance is not a problem. By changing the poles on the magnets involved the train can be not only pushed upward by the magnetic field but also down the track to give the vehicle forward speed.

A magnetic flying car might be workable, but only if it was levitating above a special magnetic road. Like the Maglev train it would be limited to "flying" just a few inches above the ground.

Of course many engines used in transportation now use magnets to operate. Almost every electric motor uses magnetic fields to generate movement and some advanced space probes use magnetic fields to shoot particles out the of the back of the probe at high speeds to push the device forward.

The only example of a magnetic transportation system that I could find that was similar to your design was a satellite engine being developed in conjunction with NASA. While details of the design are limited, the engine would interact with Earth magnetic field to allow satellites to maneuver while in orbit. Last year a model of the engine exploded during testing, but the inventors of the engine think they have worked out the bugs and are hopeful that they will be able to try a test in space in the next few years.

Geostationary Satellites - Is it true that for a satellite to hold the same position over the earth it can only be over the equator? - John

The type of satellite you are talking about is called a geostationary satellite and the idea for it was first proposed by Herman Potonik, a Slovenen rocket engineer, in 1928. Most people connect the idea, however, with famed science fiction writer Arthur C. Clarke. Clarke wrote an article about the idea for Wireless World in 1945.

The speed with which a satellite in orbit circles the Earth is dependent upon how high above the Earth's surface it is. Objects in low Earth orbit circle the globe much faster than those in higher orbits. For example, the space shuttle orbits the earth at a height of between 115 and 380 miles and will circle the Earth about 16 times in a 24 hour period. If an object is placed in orbit at a much higher level, say 22,300 miles, it will circle the globe only once in a 24 hour period. This makes it the object a geosynchronous satellite orbiting at the same rate the planet turns.

However, unless the satellite is also in an orbit over the Earth's equator, it will appear to move back and forth in the sky along a north to south line during the course of the day. To be a geostationary satellite the object needs to be in a circular orbit directly over the equator at the height of 22,300 miles (This is sometimes refered to as the "Clarke orbit"). Only then will it appear to be fixed in a single location in the sky.

There are many uses for geostationary satellites including communications (for example, the dish television broadcast satillite I get my TV on) and weather observation. Since they do not move in the sky, geostationary satellites allow receivers on the ground to use a simple fixed antennal to point to them and pickup broadcasts. Because the satellites are over Earth's equator, however, any northern hemisphere location wishing to point an antenna at them must have a clear view of the southern sky. The opposite is true in the southern hemisphere.

The demise of movie star/martial arts expert /cultural icon Bruce Lee in 1973, at 32 years of age, has inspired more conspiracy theories than almost any other death in modern times. The list possible culprits include:

Kung Fu traditionalists - They resented Lee's open portrayal of their sect's secret arts on the screen.

Japanese Ninjas - Who were angry about how the Japanese were portrayed in Lee's films.

The Triad (Chinese "Mafia") - They had him killed because he did not bow to their extortion claims on his motion picture salary.

American Mafia - Lee refused their offer to be made an American movie star choosing instead to return to Hong Kong.

An unnamed prostitute - Lee had taken a powerful aphrodisiac which had caused him to become very violent. The prostitute, fearing for her life, hit him over the head with a glass ashtray.

Vengeful spirit - The Lee family was cursed and this accounted for his death and the death of his son, Brandon Lee (Brandon Lee was killed in an accident involving a gun on a set in 1993 while filming the movie "Crow").

Of course, not all of these can be true and it is likely that not any of them are true. However, there are some strange circumstances surrounding his death that have allowed these rumors to flourish:

The first indication that not all was well with Lee occurred on when the actor collapsed at Golden Harvest studios in Hong Kong on May 10th of 1973. He was rushed to the hospital were doctors determined he had cerebral edema - swelling of the brain. He was successfully treated at the hospital and released.

Over two months later on July 20 he was again in Hong Kong visiting the apartment of actress Betty Ting to go over a script when he felt ill. Ting gave him a tablet of Equagesic (a combination aspirin and muscle relaxant) and he lay down for a nap. Later on Ting and producer Raymond Chow were unable to wake him and called a doctor. The doctor examined him but was unable to help him and he died. The body was sent to Queen Elizabeth Hospital.

The autopsy showed that Lee had died from a cerebral edema similar to the one he had experienced back in May. The official report called it "death by misadventure." The only foreign substance found in Lee's body was the Equagesic and trace amounts of cannabis in his stomach. It seems likely that Lee's brain had swollen because of a rare allergic reaction to some substance. However, there was no evidence that Lee had taken Equagesic before the May incident and the amount of cannabis is his system seemed far too small for that to be the cause. Most doctors who reviewed the case, however, feel that he most have died of a hypersensitivity to the Equagesic, or the cannabis, or some combination of the two.

Conspiracy theorists have suggested that someone murdered Lee by giving him some substance that caused the swelling. They contend that the poison either did not show up on the toxicology tests used or officials were bribed to suppress the evidence.

No real proof of any murder conspiracy has ever surfaced and the death remains a sad end to a promising life. Lee, at age 32, was incredibly popular at the time of his death and many of his fans refused to believe Lee - who many considered the fittest man on the planet at the time - was dead. Others blame his death on over training, though there is also no evidence of this either.

Have Laser Gun, Will Travel - Hey, you know laser guns? Could they even exist? - J. Smith

Laser guns have long been a popular device used in Science Fiction literature. Probably the first story to describe something that appears to be laser cannon was H.G. Well's heat-ray from the 1898 book War of the Worlds. When actual lasers first became available in the early 1960's weapons seemed like a natural application. Several Sci-fi TV shows from the period including Lost in Space and the pilot for Star Trek, featured characters using laser pistols.

The problem that real weapons designers soon found themselves confronted with was the how much energy was needed to power such a weapon. A laser capable of projecting enough energy to due significant damage could not be powered with battery small enough to be carried by a man. The same was true for more powerful laser cannons that might be mounted on a truck or a tank. The power source was too heavy to really make the weapon easily mobile, especially if you consider a laser's effectiveness when compared to more conventional and cheaper rockets, bullets or bombs.

Even so lasers have become a major part of the military's inventory. Usually they are used to guide missiles or bombs to their targets. The target is "painted" with a laser beam by an observer and the bomb or missile then flies to the laser light reflected off the target.

The military hasn't given up on using laser for more than just guiding weapons, however. Currently there is joint development program by the U.S. and Israel on a device known as the Tactical High-Energy Laser or THEL. THEL is designed to knock out airborne weapons from a fixed location or mobile platform (like a truck or tank). Critics argue that counter measures, such as equipping the target with a mirror-like surface to reflect the laser, will make the system ineffective.

The U.S. Air Force is also experimenting with a plane based chemical laser system that would vaporize a ground target. This might be more advantageous in some situation than using a missile or bomb as it avoids damage to the places immediately adjacent to the target.

Lasers may actually turn out to be more useful in the end as non-lethal weapons. The U.S. military has been working on a low powered laser gun that could be carried by a man that would temporary blind his opponents.

FDR Assassinated?- I've read a couple of short articles about the idea that FDR was actually assassinated. Is there any evidence or proof to this? Who thought of this theory? - Thanks, Frank

On April 12th, 1945, Franklin Delano Roosevelt died at the "Little White House" in Warm Springs, Georgia. According to the history books he had a massive cerebral hemorrhage (bleeding in the brain).

What seems to have made some people suspicious of this explanation was that the President was buried with a closed casket. According to some stories not even close family members were allowed to view his body. This eventually led to two rumors. A) That he was assassinated and the body was disfigured (shot in the face with a .45 pistol) or B) that he didn't actually die, but was spirited off somewhere by people unhappy with his policies.

The assassination rumor appears to have gained some popularity in the 50's when a group called the Christian Nationalist Crusade(CNC) put out a pamphlet entitled "The Roosevelt Death: A Super Mystery." In the anonymous handout (written by "Mr. X") the group suggested that FDR had been murdered (or maybe driven to suicide) by an international secret organization for whom he worked. The organization supposedly found that his accelerating illness was making him more of a liability than an asset. The CNC pamphlet alleged that this secret organization was controlled by the Jews and/or Communists. These CNC claims aren't much of a surprise, however, as the group was known to have antisemitic, racist, and anti-communist views.

No real hard evidence for this story has been ever found. Another rumor was that FDR was poisoned, not shot. This story, however, would seem to undermine the one fact that might support the assassination theory: The closed casket. A closed casket would not be needed if the cause of death was poison.

There seems no real reason to question Roosevelt's death given the poor state of his health. He had been struck down by polio when he was young and lived as an invalid for many years. He was also an extremely heavy smoker with emphysema, very high blood-pressure, atherosclerosis (hardening of the arteries) and angina. You can add to this more than a dozen years of stress from running the country during the Great Depression and World War II and you begin to wonder how he lived as long as he did. In fact, a prominent pathologist, Dr. Emanuel Libman, after seeing Roosevelt's image in newsreels in 1943 prophetically said, "It doesn't matter whether Roosevelt is re-elected or not, he'll die of a cerebral hemorrhage within 6 months."

Libman wasn't the only one who questioned FDR's longevity. When Roosevelt ran for elections for a fourth time in 1944 many of the members of his party did not expect to see him live to the end of his term. They were so concerned that they insisted that Vice-President Henry A. Wallace (who was thought to be soft on communism) be dropped from the ticket. He was replaced by Harry Truman.

Still conspiracy theories linger on. There were certainly people who might have wanted to do him harm and he had already survived an attempt on his life in 1933 while he was President-Elect. Here are some places you can check these theories out: Bill Hanson's book entitled "Closely Guarded Secrets" supports the poisoning hypothesis. You can also read an excerpt from "The Roosevelt Death: A Super Mystery" which can be found on archive.org.

Tension on the Surface - I often see drops of water hanging but not falling. Gravity is pulling on them, so what's holding them up? - John

The effect you are referring to is known as surface tension. Surface tension is responsible for many of the strange things we see liquids do, but are so familiar we don't usually even think about them. Surface tension is caused by forces in nature that pull the tiny particles that make up substances (molecules) together. A general name for these is intermolecular forces and they are only effective at a very short range. So short that the molecules have to be practically touching for them to take effect.

Intermolecular forces tend to pull molecules of the same substance together more strongly than molecules of substances of different types. This is what causes water to form into beads on a waxed surface. The wax does not attract the water molecules as much as other water molecules do, so they pull themselves together into a sphere shape which allows the most volume of water with the smallest surface area letting the water molecules to get as close to each other as they can. Because gravity is also acting on the water sphere, however, it tends to flatten out a bit forming into a bead.

What does this have to do with hanging water? Let's take the example of a droplet hanging from a leaking facet. The water forms into half sphere to get as close as possible to each other. Even though the metal of the facet doesn't attract the water molecules as much as other water molecules do, there is still enough attraction to counteract gravity and keep the half sphere from falling or turning into a full sphere.

As more water from the leak flows into the droplet, however, it gets bigger and heavier until it weighs so much that the surface tension of the droplet to the facet isn't enough to keep it attached. The droplet becomes elongated with less and less of the water touching the metal. As less and less of the water touches the metal the surface tension drops even more until the droplet falls free.

One in the air the droplet, now free from the attraction to the facet, can form into a perfect sphere to minimize the distance between the water molecules. Rain drops, contrary to popular belief, are spheres. They only appear to be shaped with an elongated tail because that's the way our eyes see them as they zoom by us on the way to the ground.

Surface tension also explains why water droplets on wax paper pull together when brought close to each other. Again the water molecules are trying to get as close to each other as they can by minimizing the outside area and maximize the volume. Surface tension also explains how a bug like the water strider can walk on the surface of a pond. The bug so light his weight is not enough to push the water molecules apart so his foot can sink in.

End of Life on Earth - With recent news about global warming and the slow depletion of the Earth's natural resources due to mining, hunting, killing of plants and animals to make way for modernization, is it possible for man to render the Earth virtually un-inhabitable? If yes, how do you think this will happen, how fast, and given the current state of the Earth, how long until it will happen. - Harris

You didn't mention in your email if you meant virtually un-inhabitable by just humans or almost any living thing. Given the choice let's go for the big enchilada! Could man end life on Earth entirely? Probably not given we know there are bacteria that live two miles underground getting their energy not from the sun but from radiation in the rock. These things would be very hard for us to get at, let alone kill. However, we might be able to do in just about everything else on the planet, including ourselves, if we let our most advanced technology get into the wrong hands.

The best (or perhaps worse) scenario for this would be the deliberate misuse of nanotechnology. Nanotechnology will allow us to produce machines as small as or even smaller than bacteria. The positive uses of this technology include the ability to make a tiny robot that would live in a human body and hunt down cancer cells. Such a thing seems like science fiction, but researchers and engineers are thinking about ways to do this now, and multi-millions of dollars are being poured into this technology both in the United States and abroad.

Imagine the danger though if someone were to reprogram that tiny robot to kill all living cells. A handful of those nano robots might not be that dangerous to large populations, but suppose that these robots also had the ability to self-replicate. The result would be a plague would spread across the earth killing all life.

Another possibility is creating a self-reproducing nano-robot that would enter plants and disrupt photosynthesis. A plant that cannot carry out photosynthesis (create food from sunlight) is a dead plant. Without plants to provide food, life would soon vanish from the earth (with the exception of those bacteria we mentioned before that live off radiation instead of sunlight).

Of course no sane man (or woman) would build such a robot, but the world is filled with crazy people and terrorist groups. Suppose they got a hold of this technology? People thinking about this problem have already coined a term for it: Nanoterrorism. Nobody is quite sure at this point how difficult it will be to build such a robot. Obviously nature has already engineered some organic self-reproducing machines in the form of bacteria. At some point in our future - perhaps in the next decade or two - we will be able to do the same thing. Our machines, unlike bacteria, will be programmed to do specific functions of our own design. Some of them will give us great benefits (think of a self-reproducing nano-robot that be dropped into the ocean to clean up an oil spill), while others may bode of great danger.

I'm not saying here we should blindly panic and start burning down laboratories that work with nano-technology, however. What we do need to do is carefully think how the technology should be used and what safeguards should be in place.

Baghdad Battery for Electric Cars? - "Has the Babylon battery on your site ever been tested out for a power source for cars? How about lamps etc.?" - Sheryl Skoglund

In 1938 the German archeologist Wilhelm Konig discovered an object in the Baghdad museum's collection that looked to him like it might be the remains of a battery: a clay jar which seemed to have an iron bar running from the top surrounded by a copper cylinder (http://www.unmuseum.org/bbattery.htm). Other scientists disagreed with his idea claiming the jars might have been used to contain scrolls or have some other purpose, but Konig published his conjecture in 1940 and people have been fascinated with the possibility ever since.

Several people have actually made replicas of the Baghdad Battery and tried it on different applications. The voltage produced is pretty low compared to modern batteries. Perhaps a half volt. (Your everyday AAA battery produces one and one half volts.) This might be sufficient to light a LED bulb, but given the size of the ancient battery, it really has no modern practical use. It has been suggested that the ancients might have used it to electroplate objects.

What is amazing about the battery - if that is truly what it is - is that it exists at all. It was thought the discovery of how to make electricity though a chemical reaction was not discovered until beginning of the 19th century. The battery, and other devices like the Antikythera Mechanism (http://www.unmuseum.org/amechanism.htm), which is a mechanical computer used to predict the movement of the stars, suggest that the ancients knew a lot more about technology that we originally appreciated.

People Too Heavy for the Earth? - This may be a very stupid question, but I have been curious about this for a long time. When the earth was first formed, there were no people inhabiting the earth. Now there are over 6 1/2 billion people on the earth (along with all the animals now roaming the earth). I realize living things consume the resources of earth but why has not the weight of 6 1/2 billion people affected the orbit or tilt of the earth? It is an incredible amount of weight on earth that was not there before. - Diane

There are a few reasons why this weight does not affect earth's orbit. If we take the average weight of a human being as 150lbs and multiply it by 6.5 billion, then converte it to kilograms by dividing by 2.2, we get an approximate mass for all the human life on our planet as 443.19 billion kilograms (this is probably an over-estimate as the much of the world's population are children which would lower the average weight). This seems like a large number until you compare it with the mass of the earth, however, which is 6,000,000,000,000,000 billion kilograms. We are only a tiny, tiny fraction of the planet's total mass.

Accurate estimates of the planet's total biomass (all plants and animals) are hard to come by, but one often cited figure is 69,181 billion kilograms. Still only a tiny fraction of earth's total mass.

Even if people did represent a large percentage of the earth's weight our growth in numbers on the planet would not represent a change in the planets total mass. Why? Because all that we are was once part of the earth. For example 80% percent of our bodies are water. The water was here before people were on the earth; it was just located in the lakes, rivers and oceans of our planet. As a human body grows it takes on this water that was already on the planet. The water is shifted from sitting on the surface of the earth to inside your body, but the mass does not change. This is the same for all the other materials in your body and for all life.

The only way to significantly increase the weight of our planet would be for it to be hit by a large object (by large I mean planet-sized). If such a collision occurred, however, the impact would probably wipe out all life on the planet and any modifications to the orbit would be a moot point as far as human beings were concerned.

DNA vs GENES - I would like to know the difference between DNA and genes. - Kamini

DNA stands for deoxyribonucleic acid. It is a double-stranded, helical nucleic acid molecule that encodes information hereditary information for almost all living organisms. A gene is one section of the DNA that controls a specific function or characteristic.

DNA is arranged like a twisted ladder with the up and down rails composed of sugar molecules and phosphate molecules connected to rungs made of either adenine and thymine or guanine and cytosine. One section of rail and a half rung is called a nucleotide and each nucleotide can be connected with others to make both sides of the ladder and to make the ladder longer. Because the half rungs (called bases) can be either adenine, thymine, guanine or cytosine, there are four different types of nucleotides. The order of the nucleotides on the ladder is important as this is how information is encoded into the DNA. It is not unlike the zeros and ones that encode information for computer program.

A group of consecutive nucleotides on the ladder that composes the instructions necessary to make one protein is called a gene. The protein molecule that the gene makes may control characteristics like a person's eye color, hair color, etc. On average a gene includes 3000 nucleotides, but for some simple proteins only a few dozen may be needed. Not all DNA nucleotides are part of a gene. There are lengthy intergenic regions in between most genes that either have no function or a regulatory function the scientists are only yet beginning to understand.

Humans are believed to have about 20,000 - 25,000 genes. More than ninety-nine percent of these genes are shared by all humans with only less than a percent involved in giving us all those traits that make use individuals. (In fact chimps, our closet biological relatives, have the 96% of the same DNA we do). Human DNA is also split up into unconnected sections called chromosomes. Humans have 23 pairs of chromosomes. A child gets one half of each pair from their mother and the other half from their father which is why a child might have their father's wide set eyes, but their mother's eye color. Chromosome number 23 is known as the sex chromosome because females carry two X types and males carry one Y and one X.

The DNA in a gene is divided up into two components. A "non-coding" section that simply indicates whether the gene is "on" or "off" (sometimes referred to the gene being "expressed" or not) and a "coding" section which contains the instructions to build the protein. The DNA does not build the protein itself but transcribes the information to RNA (Ribonucleic acid) to do the work. RNA looks and acts a lot like DNA, but is made up of only one half of the twisted ladder and uses a few alternate materials. In a few cases gene may not make a protein at all, but just RNA which is then used in another part of the protein synthesis operation.

Every cell in our body carries a copy of our DNA and parts of that DNA are very specific to each person, which is why it has become as important as fingerprinting to establish identity. Just a few cells left behind at a crime scene through a strand of hair can be enough to let police positively identify someone as the perpetrator. DNA can also predict if a person will get certain disease. For example, Tay-Sachs, which is a fatal disease often afflicting Eastern European Jews, has been shown to be the result a mutated and non-functioning HEXA gene. Other genes may not directly cause a disease, but increase the likelihood of a person getting ill. For example, researchers have shown that people with a nonfunctioning CREB gene are at an increased risk for anxiety and alcoholism.

The DNA actually looks like a super-tiny thread and is impossible to see without the use of an electron microscope. Typically it is curled up on itself so it can fit inside a microscopic cell. If you were to uncurl the DNA in a single cell, however, it would stretch out to about three feet in length and contain three billion base pairs.

Vall�e and Bostrom - Is the idea that we are all just living in a big computer simulation related to what Jacques Vall�e and people like that are talking about when they try to explain UFO's as not extraterrestrial craft but "control devices" and so on? That is, do they mean that the ones behind the UFO's are the programmers of this big simulation we're living in, who are doing experiments on us by sending these weird, anomalous phenomena and seeing how we deal with them? I never really understood what Vall�e was getting at till I read the article on the world as a computer simulation in the current edition of the Museum of Unnatural Mystery. Thanks. - Alan Meyers

Dr. Jacques F. Vall�e, a computer scientist, venture capitalist and former astronomer, has long been one of the "deep thinkers" in the arena of Ufology. Born in France in 1939 he became interested in the subject when he observed a UFO in 1955. At first Vall�e was convinced that UFOs were extraterrestrial spacecraft and published his ideas in his book Anatomy of a phenomenon: unidentified objects in space--a scientific appraisal. By 1969, however, his thinking had changed and he began to see UFOs and alien abduction reports as part of a much larger phenomenon that included other paranormal events. He outlined his thinking for this in his book Passport to Magonia: From Folklore to Flying Saucers. Vall�e suggested in his book that flying saucers and alien visitors might not be from other planets, but from other dimensions or even different time periods. These ideas did not sit well with many UFO enthusiasts and Vall�e soon found himself an outcast among their ranks, or as he put it a "heretic among heretics".

Vall�e sees one possible explanation of the UFO phenomenon as that of a "control mechanism " with incidents as deceptions created to manipulate people and society. Sometimes this is done by other humans. For example, we know the US Air Force encouraged UFO reports to hide the flights of SR-71 Blackbird spy aircraft in the 80's. The Soviet Union also did the same thing to cover the launch of rockets that were not in compliance with the SALT treaty they had signed.

Much of the social manipulation caused by UFOs reports, however, Vall�e suggests are done by non-human entities who have an agenda of which we are totally unaware. Vall�e's initial thinking was that these entities were from another dimension, and were not operators of a simulated world that we are living in (See last month article on Living in a Video Game). "There is a distinction to be made between a Matrix-like virtual world and what I first proposed in 'Messengers,' [Messengers of Deception: UFO Contacts and Cults his 1979 book] namely an information multiverse with fully physical manifestations" said Vall�e, in an interview with SUB ROSA online magazine.

The multiverse he is thinking about is related to some of the interpretations of quantum theory which suggest that reality consists of many nearly parallel universes. If beings from one universe successfully figured out how to cross to another universe we might interpret them as extra terrestrials. A visitor moving from one quantum parallel universe to another also might be jumping in time also leading to the suggestion that flying saucers are our ancestors' attempts to manipulate their past.

Even though Vall�e initial ideas with control mechanisms didn't involve our living in a simulated universe, in my opinion the idea that UFO incidents (and other paranormal experiences) are attempts by those outside the simulation to influence our society seem to make just as much sense as the multi-dimensional approach. Remember Vall�e's initial thinking on this subject was published in 1979 long before Bostrom's 2002 paper on the simulation argument came out. Perhaps Vall�e, after pondering Bostrom's thinking, will address this possibility directly in some future book.

BC, AD, BCE, and CE- Why are the years are called by BC and AD and how exactly did the year change to BC to AD'? Did ancient people follow this? - Gajendra K.

The B.C./A.D. numbering system is based on the presumed year of the birth of Jesus Christ. Years before his birth are given the abbreviation B.C. ("Before Christ") designation and are numbered backwards so the further back in time you go in time the higher the number. For example, the Great Pyramid is thought to have been built 2560 years before Christ was born which would be expressed as 2560 B.C..

The A.D. stands for "Anno Domini" which is Latin for "In the year of our Lord." All recent dates are expressed in the number of years after Jesus's birth. This year is A.D. 2008 which translates to "The year of our Lord 2008" or 2008 years after Christ was born. Technically the A.D. abbreviation should go before the number, but more recently it has become common to put it either at the beginning or the end, for example "2008 A.D.".

Some people prefer to use the designation C.E. (for "Common Era") instead of A.D. so there is no religious connection (though C.E. can also thought of as "Christian Era."). The same thing can be done changing B.C. - Before Christ - to B.C.E which means "Before Common Era."

This dating system wasn't invented until A.D. 525, and was not commonly used until the 8th century. Before then dates were typically numbered years based on the start of the reign of the current king. For example, Babylon was established as the center of the Babylonian Empire during the 30th year of King Hammurabi's reign. In some cases dates were not established by the beginning of the reign of the current king, but the beginning of the dynasty of kings to which he belonged.

A few early calendars (like the Hebrew Calendar) tried to base their dates of the number of years since the world was created, but given that different religious scholars disagreed about when this occurred, the number system was never universal.

While previous number systems were adequate in ancient times when there were few contacts between different peoples and little shared history, as interactions between cultures spread, it became difficult to constantly match the years of different king's reigns together to establish correct dates. The A.D. system first became popular in Western Europe and is now the defacto standard though out most of the world. Its popularity can also be attributed to the success of the Gregorian calendar (our system of months and days) to which it has been closely tied.

Historical re-examination of the birth of Christ in the last century suggests Jesus was actually born several years before A.D. 1, but given that the system is now so well established there has been no attempt to fix it. Another quirk with the system is that there is no "year zero." This means that if you go one year backwards from A.D. 1 you will find yourself at 2 B.C.. Incidentally some people incorrectly attribute the A.D. to the abbreviation of "After [Christ's] Death" but this is incorrect as it would yield dates 33 years too low - The length of Jesus' life.

Cleopatra of Egypt - We studied Ancient Egypt and I was absent when we studied Queen Cleopatra. Who is she? - Samantha

There are several Cleopatra's in Egyptian history, but the most famous one was Cleopatra VII. She was the last Pharaoh of Egypt, at a time just before the country was completely taken over by the Rome. Cleopatra herself was not of Egyptian heritage, but Greek. In 331BC Alexander the Great (who was from a section of Greece) liberated Egypt when he defeated the Persian Empire. After Alexander's death in 232BC, Egypt fell under control of one of Alexander's generals, Ptolemy. The Ptolemy family kept power there until Cleopatra was born to her father, Ptolemy XII, in 69BC. Cleopatra showed great interest in the traditions of Egypt and was the only member of her family in 300 years that bothered to learn the language. She followed the Egyptian beliefs and while she ruled she was considered the re-incarnation and embodiment of, Isis, the Egyptian goddess of wisdom.

When her father died in 51 BC, a 17 year-old Cleopatra and her 12-year-old brother, Ptolemy XIII, took over. In addition to be siblings, Cleo and her brother were married (a common trick used to keep power in the family back then). Cleo attempted to push her husband/bother into the background and get sole control of the kingdom, but lost the battle and was forced to flee Egypt.

Cleopatra's chance to get back into power came in 48BC when a political miscalculation by her brother got the Roman ruler Julius Caesar angry with him. Cleopatra took advantage of this situation: It is said that she had her servants bring an expensive Persian carpet to Caesar as a gift. When it was unrolled, Cleopatra tumbled out. Caesar, age 50, enchanted by her beauty and youth (she was only 21) and fell in love with her. He helped her returned her to the Egyptian throne which led to Ptolemy XIII's death. Caesar and Cleo had a son, Caesarion, together. It was Caesar's plan to have Caesarion rule Egypt after his death and leave Rome to grand-nephew, Octavian. Cleopatra, however, wished her son to be heir to all of Rome.

When Caesar was killed by members of the Roman Senate in 44BC, Cleopatra made Caesarion her co-regent and successor. Later she allied herself with Mark Anthony, one of the three men ruling Rome after Caesar's death. They married and had children. It is likely that Cleopatra had plans to take on Rome and make herself and her son rulers of the known world, but the Romans, under Octavian, attacked first. Anthony and Cleopatra's forces were defeated at the naval battle off the coast of Actium. Soon the armies of Rome were marching through Egypt and Anthony was mortally wounded in battle. Cleopatra was held under house arrest and commited suicide (legend has it that she killed herself by letting a deadly Asp snake bite her) in 30BC at the age of 39.

Cleopatra is remembered for her immense beauty and even more immense ambition. She ruled in a time when Greek women were expected to be submissive to their husbands. Instead of taking a back seat to men, however, she cleverly used her charms to gain political advantages over her enemies and was nearly successful in ruling the known world.

Tesla's "Death Beam" - I'm wondering about Tesla's Death Ray. Did anyone ever try to build one after his death? Was it ever proven as a viable weapon? - Frank

Nikola Tesla, the almost forgotten genius of electricity, hated war and for years searched for a way to put an end to it. In 1934, at age 78, Tesla thought he had found it. He had an idea for a death beam based on sending a concentrated stream of charged particles though the air. The beam would carry tremendous energy and would disrupt or melt whatever it hit. The weapon, he thought, could be used to down any hostile airplane approaching a country's borders. The beam could only be sent in a straight line and would not follow the curve of the earth, so it only had a range of only a couple of hundred miles. Because of this, Tesla felt that his invention could be used only as a defensive weapon to prevent aggression.

He failed to get much interest in it until he wrote a technical paper entitled "New Art of Projecting Concentrated Non-Dispersive Energy Through Natural Media" and mailed it to a number of Allied nations including the United States, Canada, England, France, the Soviet Union, and Yugoslavia. According to him the weapon would be "capable of destroying 10,000 enemy airplanes at a distance of 250 miles." The nation that showed the greatest interest in it was the Soviet Union, which tested one stage of the weapon in 1939 and sent Tesla a check for $25,000.

Tesla's design was clever. One the problems with a charged particle weapon is that the particles need to be accelerated in a vacuum, but then must be able to emerge from the weapon into the atmosphere to make the beam. To keep the interior of the weapon a vacuum Tesla devised a gateway for the particles that consisted of a blast of high-speed air blowing across the weapon's barrel. The blowing air helped maintain the vacuum, but would not hinder the beam.

Despite this, experts say his exact design appears unworkable. However, after his death some of his papers appeared to have gone missing and then, during the "cold war" both the United States and the Soviet Union tried to developed "charged particle" weapons similar in principal to Tesla's designs. Conspiracy theorists suggest this is more than a coincidence. Later a similar weapon was designed to be put aboard a rocket as part of the SDI ("Star Wars") program to down approaching missiles, but the idea was never implemented. Currently one company is experimenting with a charged particle beam weapon code named MEDUSA which they hope can be used to defend against planes and light tanks. So far, however, no charged particle weapon seems to have made it into the standard defense inventory of any nation.

The Zapotec's Little Tunnels - I've heard of tunnels found in buildings from the Zapotec empire, somewhere in Central or South America. These tunnels, as I have heard, were too small for adults or normal-sized children to enter, but still had little staircases carved into them, and ceremonial-type items were found in them. I can't find much information on them- are they real? Are people still trying to explore them? Any idea what they were used for? Many thanks - Tango.

The Zapotec Empire of central American (now Mexico) existed from about 500 BC to 700 AD, and reached peak population of around 16,500 around 500 AD. At this point in time they abandoned their old capital and built a new one, Monte Alb�n, atop a high plateau in the valley of Oaxaca. Beneath the central plaza of this city runs a labyrinth of small tunnels. The tunnels, many only a foot high, are - as you note - too small for adults and most children. Some appear to have steps and are connected chambers containing artifacts like human skeletons and funerary objects. Despite Monte Alb�n being one of the most studied archeological sites in the Americans, the reason behind the tunnels is unknown, but ideas have been proposed ranging from water drainage to a transportation system for diminutive aliens. One explanation seems to be that the tubes were used for sighting the different positions of the sun, moon and stars as they moved across the sky, but the existence of the chambers snd artifacts seems to also suggest a ritual connection.

This, by far, is not the only mystery about Monte Alb�n. On the north side of the site is an area called "The Gallery of Dancers" with many stone tablets carved with reliefs of human figures in contorted positions. Nobody is exactly sure what these figures mean, except that they are not really dancers. The leading theory is that they may be human sacrifices.

Perhaps we could understand more about the city and its strange features if we could read the Zapotec hieroglyphics that cover city walls. While the language is still spoken in Mexico, the meanings of the glyphs have been lost and only a handful are now known. Without a key, like the Rosetta Stone which allowed Egyptian script to be deciphered, the translation of these texts may never be known. For a look at the plaza and the tunnels check:

Additional pictures can be seen here including the entrance to a tunnel that might have been used to site the planet Venus:

The "Big Crunch" is one of several theories about how the universe will end. Probably everybody is now familiar with the leading theory about how the universe started, the so called "Big Bang." According to the Big Bang theory, at the beginning of the universe all matter and energy was compressed into an infinity small point with infinite density and temperature. Then followed a period of rapid inflation and expansion (the Bang). Matter in the universe cooled and coalesced into stars, planets and galaxies. The expansion continues today as each of the local groups of galaxies, including ours, grows further apart from each other.

For many years scientists pondered what would happen at the end of the universe. While the expansion continues, gravity is trying to reverse the process and pull all matter back together. Scientists figured that either gravity would be too weak and the expansion would continue forever while just getting slower and slower, or gravity would be strong enough to bring all the matter and energy back together in a "Big Crunch."

Scientists also speculated if the universe did come back into a "Big Crunch" it might precipitate another "Big Bang" which would create another universe. Ours, they suggested, might be just one in an unending series of universes.

Initial measurements suggested the amount of gravity and the speed of the expansion were very nearly balanced. This meant that scientists had to impatiently wait for decades until better technology was available so that more accurate studies could be made and they could find out what the fate of the universe was.

In one of those moments that proved that Sir Arthur Eddington was right when he said "not only is the universe stranger than we imagine, it is stranger than we can imagine," the results came back showing that the expansion wasn't slowing at all. It was - much to the shock of almost everybody - accelerating. Scientists have decided that the reason for the acceleration must be something they've dubbed "dark energy," but they have almost no idea what this energy might be and how it works.

If the expansion continues at the current rate the universe may end in "The Big Rip." At some point about 50 billion years in the future the expansion will become so great that everything will be ripped apart. Galaxies will fly apart as individual solar systems go their own way. Later stars will lose their planets and eventually everything down to the subatomic level will be torn asunder.

Although a "Big Crunch" seems unlikely due to this most recent finding, because scientists know almost nothing about what "dark energy" is, they can't rule out that it might suddenly reverse and cause a rapid collapse of the universe. When this might happen is also a mystery. If there is a Big Crunch, the universe would end as all matter was sucked into black holes, then the black holes were pulled together to create a single massive black hole. Scientists have no idea whether this singularity might lead to a new universe and a new expansion or not.

Up a Well - If a person is in a deep well in the daytime and he looks straight up will he be able to see the stars? - M. Matthews

The notion that you can see the stars during daylight hours from the bottom of a deep well or chimney has been around a long time. The ancient Greek philosopher Aristotle mentions it as does the 19th century author Charles Dickens. However, any theoretical or practical evidence for this seems lacking. The British astronomer Rev. W.F.A. Ellison tried it from the bottom of a bottom of a colliery 900 feet below the surface and found the he wasn't struck by the sight of stars, but the brilliant blue of the sky when compared the darkened tube he was looking up through.

We cannot see the stars in the sky during the day because of the sunlight is scattering off gas molecules in the air, sending light in all directions - including into our eyes. (Blue is scattered more than the other colors so that is why the sky is blue). The light radiating this way during day is much brighter than most stars. A few extremely bright stars, like Sirius, are visible in the day if you know where to look, though they do not stand out against the day sky like they do at night. If you were at the bottom of a well shaft, and Sirius was directly overhead during the day, the well shaft might reduce the glare from the sun enough to make the star more visible. It would not, however, allow you to see the fainter stars and the real world chance of Sirius being exactly over your shaft would be extremely small.

Similarly planets, like Venus, can be seen in the daylight and viewing them from a well or chimney might reduce the Sun's glare and make them more visible, but you could probably get the same effect by using the cardboard cylinder from a roll of paper towels that you hold up to your eye.

Expansion of Universe vs. Speed of Light - I read "K-Pax IV," a fictional book, and an alien character suggested that light only travels because the universe is expanding. She suggests that light cannot exceed the speed of light because that's the speed of the expanding universe and if the light exceeds that speed then it's going out of the universe's bounds. Is this somewhat true or completely fictional? - Melqui

In reviewing the literature on this subject I see no credible theories that connect the expansion of the universe, as we know it, to the speed of light. Usually when we talk about the "expansion of the universe" we are referring to the way things in the universe get farther away from each other over the course of time. This started with the "Big Bang" and continues today. Recently this speed was measured to be about 71 (km/s)/megaparsec. That means that if two objects in the universe are a megaparsec apart (3261.5 light years) they will be moving away from each other at 71 kilometers a second.

This speed is well below that of light so there doesn't seem to be a direct connection. In addition, the effect is additive so that at great distances - billions of megaparsecs apart - two objects can actually be moving away from each other at more that the speed of light. This would seem to defy Einstein's Theory, but remember that the movement of these objects is because they are just being carried along by the expansion of space, not because the objects themselves have been accelerated.

There is also recent evidence that the rate that the universe is expanding is increasing for some unknown reason. This is also unlike that speed of light which almost all scientists believe is a constant. Even the few people that suggest light speed may not be a constant speculate that it is slowing down, not speeding up.

Some future theory may find a connection between the speed of light and the expansion of the universe, but it is not obvious at point in time. Still, we do not know everything about the universe - in fact we do not even know what we don't know - so there is always the possibility of new discovery over the horizon that would change everything.

A WOW in SETI - What do you know about the WOW signal, and have scientists found any possible source (other than aliens)? Could it have even been faked? Or is it more likely to be a genuine signal from aliens? If that's the case, why haven't we heard any more? - Jonathan .

This signal (called the "WOW" signal because that's what the scientist who first saw the data wrote on the printout) was observed by the "Big Ear" radio telescope at Ohio State University on August 15, 1977. The Big Ear was part of a SETI (Search for Extraterrestrial Intelligence) project run by the college for almost 30 years. The signal was the closest thing to an alien contact that the project - or anybody else involved in SETI - has ever found.

There are several things that make the signal so interesting. The first is the strength. It is extremely high: The most powerful signal ever received from space from an unknown source. Second is its duration. Almost exactly 72 seconds. This is significant because the Big Ear was a fixed radio antenna which swept the sky as the earth turned and 72 seconds was exactly the length of time it would take for the antenna to sweep by a pinpoint source in space. Also the growth and decay pattern of the signal is exactly what one would expect for a fixed celestial source, making it unlikely it was an earthbound transmitter. Third is its frequency: It is very near the frequency of hydrogen and very concentrated. The hydrogen "line" is considered to be by most scientists the logical frequency to choose if you where trying to broadcast to another civilization. The fact that that signal did not extend much above or below that frequency is a strong indication that the broadcast was artificial, as natural sources a rarely so concentrated.

Another intriguing aspect of this signal is that is that it was only observed from one of the Big Ear's two "horns" but not the other. They scanned the same section of sky about two minutes apart, so in that short period something, or somebody, stopped the transmission.

As fascinating as the signal was, it has never been found again despite many researchers revisiting that location in the sky using, in many cases, much more sensitive equipment. This both deepens the mystery and makes it almost impossible to hope for a solution. The follow up surveys have almost eliminated the possibly of some weird natural source. However, the lack of any additional signals also makes it seem very unlikely that aliens are trying to contact us. Most scientists believe that they definitely would try more than once (although we ourselves have only sent a sent an outbound signal once). The only way we may have missed their additional signals, if they exist, is if they are being repeated at very long intervals (at least 14 hours apart).

In science, unless something is repeatable, it doesn't count for much. Some have suggested that the signal may have been a man-made space probe that the SETI team wasn't aware of, but there is no way of proving that one way or another. So, the mystery continues. We can only hope that if E.T. was trying to contact us, he tries to phone again, soon.

Time Speeding Up? - Someone just said to me she thinks the last 3 years have aged everyone more than in the past because the actual minute itself (the unit of time) is speeding up. Can this be possible? - Jennifer E.

I suspect your friend is referring to the insertion of "leap seconds" into the calendar in the last few years. If this is the case, it isn't so much that time itself is speeding up, but that the earth's rotation is slowing down.

Of course, how you look at it depends on how you define time. We casually define our days as one rotation of our planet, hours as one 24th the length of that day, minutes as one 60th of the length of that hour and seconds as one 60th the length of that minute. If the Earth rotation slows (which it does due to the pull of the moon and sun's gravity on our oceans which create friction between the water and land) the days get longer by a few fractions of a second each year.

While this tiny difference is unimportant to most people, it is of great concern to scientists who need to measure things carefully down to the thousandths of a second for many scientific experiments. If the length of a second is changing as the earth slows down it can't be used to compare the results of one experiment with a similar one done years earlier. To solve this problem scientists invented the "physics second." A physics second is length that the second was according to the rotation of our planet in 1900. Scientists then use atomic clocks (that measure time as a function of the change of states in the element cesium) to track time without having to refer to the earth rotation. When the atomic clocks slip out of sync with the rotation of the earth by about a second a "leap second" is inserted into the clocks tracking to keep it aligned with the astronomical day.

If you thought of the real value of time as the length of the day, then indeed you might come to the conclusion that time is going faster - after all we are inserting extra fractions of a second into those days so time must have sped up, right? Well, not really. It is probably more accurate to think that time has stayed the same, but our days are getting longer.

Weird Findings - What do you do if you find pieces of a creature unlike that of anything of this earth? - Charlie

Probably your best bet, when trying to identify an unknown animal (extraterrestrial or not) is to contact a biologist professor at a local college or university. They will be familiar with animals in your area and can eliminate some possibilities of an unusual, but earthly species. Most scientists would jump at the chance to identify a new species (even an earthly one) if given the chance. If they find one, they get to write a paper on it and they become famous (at least within the biology world).

This goes for fossils too. If you find a fossil, which you think might be something significant you can contact a geologist or paleontologist at a local college or university. It could be an important find. It has happened before:

In 1974 a contractor working on a housing development in South Dakota came across some strange bones. His son, who was a college student, recognized them as fossils and contacted a university. Scientists came out and examined the location and immediately discovered the remains of at least four Columbian Mammoths. Later excavations revealed that the location was an ancient sinkhole which had trapped mammoths for centuries and was a treasure trove of important fossils. The housing project was abandoned and a museum built on the location: The South Dakota Mammoth Site near Hot Springs. It's great place to learn about mammoths while visiting South Dakota.

The Berkeley Horror - I have a book by Daniel Cohen called Worlds Most Famous Ghosts. In it is a chapter on something called the "Berkeley Square Horror" in London. It is something about a room at 50 Berkeley Square that if anyone stays one night in there they will either be dead or have gone insane. Supposedly this has happened several times. I have searched several sights including wikipedia.com and I have found nearly no info. It would be much appreciated if you could help me out. - Frank

There are multiple stories about 50 Berkeley Square, many of them contradictory. The house was constructed in 1740 and for a number of years was the home to British Prime Minister George Canning. The source of the haunting stories starts around 1830 with either young woman who committed suicide by jumping from the top floor, or a Mr. Myers was preparing the house for the just new bride and went insane after he was jilted. Or maybe the haunting really comes from a Mr. Dupre, who confined his insane brother in an upper story room. Or maybe the story about the little girl who was tortured to death by a sadistic servant is what started it. Well, take your pick. According to the story after Mr. Myers/Dupre/young woman/little girl was gone and a new family had moved in, a maid was found in a third floor bedroom screaming and muttering she has seen something "horrible" there. The story continues next with a Captain Kenfeild, fianc�e, to the family's daughter (In other versions this is a young aristocrat named Robert Warboys) who decides to challenge the apparition by staying in the room overnight. He sees something that either kills him with fright (in some versions) or leaves him crazed.

Another tale connected with the house brings the story into the 20th century with two sailors in 1943 who break into the long empty house to stay overnight and encounter a monstrous, shapeless, oozing mass in the third floor room. One sailor escapes to tell the tale while the other jumps out the window to his death (speared on the points of an iron railing) to avoid the horror.

The house became famous for these stories and by the beginning of the 20th century and was listed by some authors as "the most haunted place in Britain." The current owners still get visitors from time to time curious about the house. The stories were also an inspiration for a 1947 movie "The Ghosts of Berkeley Square."

As far as I am aware nobody has carefully researched the history of the house to determine if any of the 18th century stories are real. This could probably be done by checking records to see who owned the house, who died there, and going though police reports associated with the house, etc. Clearly there are problems with the 1943 story as it indicates the house was empty, but history shows that in 1938 Maggs Brothers Rare Books moved into the location. The company reports no ghostly incidents since they have been there even though there were many all-night fire watches held during the Second World War.

You can visit the building, even the supposedly haunted 3rd floor, by going to the Maggs Brothers website and taking a virtual tour. So far nobody has reported any virtual horrors. http://www.maggs.com/maggstour/0/exterior.asp

Elongated Night Reflections - If you look at the reflection of a street light from across a body of water, it appears long in one direction but not the other? Why? - Tariq

Water, under the right conditions, reflects light just like mirror. Of course, a mirror is a usually composed of solid material (most commonly glass with a silver backing) and water is liquid. As long as the water is perfectly still and flat the image reflected is almost mirror-like, but should a breeze start to ripple the water, strange things start to happen.

The ripples cause the shape of the surface of the water to change into a series of up and down curves. This means that the light normal reflected by the surface doesn't come straight to the viewer, but is distorted much like in a fun house mirror. While fun house mirrors are usually static - either making you look tall and thin or short and fat - the many ripples in the water are always moving and changing giving the reflected image a vibrating quality.

Because a lake might have thousand of ripples between the viewer and a distant object on the other side of the lake each ripple as it moves is capable of picking a tiny bit of the light coming from the object and reflecting it back to the viewer (see diagram) making it look like the object is in thousands of different locations.

During the day when everything is evenly lighted these bits of light are overwhelmed by all the other reflections involved and only contribute to the overall reflected image by making it look fuzzy. At night, however, when the most of the background is dark, all these tiny reflection become visible. They tend to appear to elongate the lighted object in the direction where the ripples appear spaced closely together from the viewer's perspective. That is vertically as you have observed. It is possible to see some spreading horizontally, however, depending on what direction the wind is blowing the ripples.

Before Big Bang - I'm a 60 year old scientist and I have a rock-solid understanding of the concept of entropy, including the idea of life as a temporary bump in the overall decline of order and organization in a system. All I want before I die is to know if there is any credible scientific theory about how the spring originally got wound 14-or-so billion years ago - Bob W.

Let me re-phrase you question as, "What was there before the Big-Bang and where did all the energy it requires come from?" At this point I don't believe there are any "credible" theories to explain this as none of the ideas scientists have about this area can be tested by experimentation. In fact, there is not likely to be anything testable until scientists can first create a Grand Unified theory of everything combining Einstein's General Relativity with Quantum Physics. That quest, which has been pursued by physicists like the Holy Grail for almost a century, so far does not seem near a conclusion.

So the best I can do is to throw out one of the more intriguing ideas floating around cosmology circles these days. This particular model comes out of string theory (One possible candidate for the Grand Unified Theory that says all energy and matter is composed of super-small vibrating loops of strings.) This idea was worked out by Paul Steinhardt (Princeton University) and Neil Turok (Cambridge University). They suggest our universe is part of a much larger universe. The model says that our universe exists on a three dimensional membrane ( or "Brane" in string theory lingo) and there are other branes close to ours, only millimeters away, but invisible.

Every trillion years or so these branes are drawn together and when they collide a huge amount of energy is released making a "Big Bang" that creates a universe on the brane (other universes can be created at other locations of the brane that may collide at other times) This process of collision Steinhardt and Turok named ekpyrosis which is the Greek word for conflagration. In addition to creating a smaller universe, ekpyrosis also pushes the branes apart.

Over the life of the universe some of the big bang energy turns into matter which becomes stars, galaxies and, of course, us. Eventually the energy involved in our universe spreads out as stars burn out and the universe grows cold. According to this idea, however, the branes which still contain the energy, and they are drawn back together again to collide and create another universe in an eternal cycle.

They only problem with this, and alternate theories like it, is that there is no way to test these theories experimentally to know if there is any evidence that they are true. Even if this idea is true, however, we may have just moved the question back a little bit further: What created that greater universe and where did all its energy come from?

Big Packaderm vs. Little Sport Device - Could an elephant have the same momentum as a golf ball? - Anonymous.

The easiest way of thinking about momentum is the force necessary to stop a moving object. It involves both the mass of the object and speed of the object. Technically, in classical physics, this can be expressed as the mass of the object mulitpled by its velocity. The formula is:

If we had and elephant that weighed 7200 Kg (about 15840 pounds) running at 1 meter per second, the elephant would have:

That means that 7200kg is the mass, 1 meter/second (m/s) is the velocity and 7200 kg m/s ("kilogram meters per second") is the momentum.

It is easy to see a trivial situation where any two objects, no matter the size of their mass, would have the same momentum. Any object that has no veolocity has no momentum. So both an elephant and a golf ball would have the same momentum if neither were moving.

There are also cases where the elephant and the golf ball could have the momentum even if they were both moving. Imagine our 7200 kilograms elephant from above and a golf ball weighing .046 kilograms. If we set up the equation with the elephant on the left and the golf ball on the right:

We can see that an elephant running along at 1 meter per second has the same momentum as a golf ball moving at 156,521 meters per second (around 351,000 miles per hour). So an heavy elephant moving along at a trot would have the same momentum as small golf ball going very, very fast.

Now, a couple of additional considerations. This is the formula for momentum under classical (Newtonian physics). The formala under relativistic physics is slightly different and allows for objects like photons, which have no mass, to still have momentum. Also a complete description of momentum for an object includes the direction (or vector) of the motion.

Zero on the Kelvin temperature scale is often referred to as absolute zero. To get an idea of what absolute zero is, we first need to know a little bit about heat and temperature. All atoms and molecules "vibrate" with thermal energy. The more vibration, the more heat the atom or molecule has. As the atoms and molecules of a material are cooled, the vibration slows down and the energy decreases. The point at which all heat energy has been removed from a material is called absolute zero. This is approximately -459.67 �F on the Fahrenheit scale or 0� on the Kelvin scale.

According to the third law of Thermodynamics you can never completely achieve absolute zero but only approach it, but scientists have come darn close. In September of 2003 scientists at MIT managed to get a small group of sodium atoms down to 240 millionths of a degree above absolute zero. Larger objects are harder to cool, but another group at MIT managed to get a mirror about the size of a dime down to just 0.8 �K above absolute zero. They did this by shooting laser pulses at it to "trap" and "damp" the molecular motion.

These laboratory temperatures are just a bit colder than any reported in nature. The coldest known place is about 5,000 light years away from Earth in the Boomerang Nebula located in the constellation Centaurus. Astronomers think the temperatures there run around 1�K. If you ever visit it, better bring a jacket.

Scientists are very interested in the behavior of objects very close to absolute zero. It may give them the chance to observe quantum physics effects that normally are too small to see because the are lost in the heat motion of the material. Just a final note: There is also something called a negative temperature (less then absolute zero on the Kelvin scale) but negative temperatures are actually hotter then absolute zero.

Quantum Physics Weirdness - I noticed on your site that quantum physics is mentioned often. I was wondering if you could explain its origins and why it's considered more reliable than the physics used prior to its emergence? (If that is so) - Robert D.

Quantum Mechanics is one of the two great physics theories of the 20th century that replaced classical (Newtonian) physics. The other was General Relativity. Interestingly both were fathered by the same man: Albert Einstein. While he loved the one child the other was disliked. Einstein never felt comfortable with Quantum Physics.

General Relativity is mostly used to describe how the world of big things work: The movement of planets, stars, rockets, etc. Everything down to about the size of an atom. Below that size scientists almost always use quantum physics to do their calculations. Both were needed as classical physics created by Issac Newton in 17th century couldn't predict how the things worked when dealing with extremely large objects (like planets and stars) or extremely small objects (like photons and electrons).

While the rules of general relativity seem to make some kind of sense to us, the rules involved with quantum physics are bizarre and challenge our understanding of reality. Little in this realm is for certain. Everything is based on the probability of something happening. This is one of the reasons Einstein disliked it. He has often been quoted as saying, "He [God] does not play dice" with the universe.

One illustration of the strangeness of quantum theory is the dual nature of light. Is light a particle or a wave? The experiment that scientists used to find this out is called the double-slit experiment. A barrier with two narrow slits is placed between a light source and a screen. If light is a stream of particles we could expect to see each particle pass through one slit or the other and create two separate lines of light on the screen behind it. This isn't what occurs, however. We see a pattern of light and dark lines all across the screen. This, known as an interference pattern, is the result of waves of light passing through the two slits, then interacting as they hit the screen with the wave crests reinforcing each other to make the light lines and the wave troughs making the dark lines.

So I guess light is a wave them, huh? If you close one of slits, though, suddenly light starts behaving like a particle again. We see it piling up behind the open slit. Well, maybe light only behaves like a wave when a lot of light particles are moving together. Unfortunately this is not the case. When the double slit experiment is performed sending only one photon (light particle) though the barrier at a time the photon doesn't show up behind the slits. It can show up anywhere on the screen. In fact, as you send more and more photons though the experiment one at a time the interference pattern slowly builds up, just as before. Does that mean that each individual photon is a wave that interferes with itself? Yep. Does this mean that the photon passed through both slits at the same time? Indeed, this seems to be the case.

When scientists have placed photon detectors at each slit to see which side the photon goes though a strange thing happens. Suddenly the interference pattern disappears and there are just two lines of light one behind each slit. The detector has somehow forced the photon to stop behaving as a wave and act like a particle again. Even if the detector is placed on the opposite side of the barrier, after the photon passes though the slits, the photon still acts like a particle. How did it know that there was going to be a photon detector on the opposite side of the barrier so it would behave like a particle and not a wave when it passed though the barrier?

In the end, light is both a wave and a particle at the same time. If you think that doesn't make sense, you are right. However, that doesn't change the fact that it is true. If you can explain why all this happens and support your ideas with experimental proof, you're probably on your way to a Nobel prize.

This is just the tip of the iceberg when it comes to Quantum Physics weirdness. As you get deeper and deeper into it what you find seems to make less and less common sense. You might try to argue that scientists simply have gotten the thing wrong except that quantum theory is one of the most successful theories of all time and is used in the design of such everyday things as TVs and cell phones. Experiments show that not just light is both a particle and a wave, so are electrons, protons and atoms. These maybe small things too, but remember we are just made of atoms. At some level are we just waves too?

Scientists have grappled to figure out what this means in the real world. Some interpretations include the ideas like "nothing is real until it is observed" or that there are countless "multiple universes" each differing just slightly from the one next to it. There isn't room here to discuss all the ramifications of quantum theory, so I'm going to give you a couple links that may help. Prepare to see the world in a different light after reading these, or at least have an awful headache:

End of Magnetism? - If the earth's magnetic field collapsed would there still be magnets? - Anonymous

Magnetism is one of those funny things we see everyday - use everyday - but never know how it works. As it turns out, it is the result of moving electric charges. Almost everybody has done the experiment of wrapping a wire around an iron nail in a spiral pattern, then connecting the wires to a battery to product a crude electromagnet. The current flowing though the wire (in the form of electrons) creates the magnetic field. This field then influences the iron nail to become a magnet also, adding to the strength of the effect, though it would work even without the nail.

If you need a moving electric charge to make a magnetic field, how do permanent magnets work? After all there is no battery involved and no apparent electric charge. Well there actually is, however, a moving electric charge at the atomic level. The electrons orbit around the nucleus of each atom in the material. The electrons also have a quantum-mechanical property called "spin" which looks like a moving electrical charge. These two effects produce a tiny magnetic field for each atom.

In most materials the magnetic fields of each atom are aligned in no particular order so they cancel each other out. In some special materials, however, the fields line up (or can be made to line up) in a particular pattern so that their strength adds up. That's why the nail in the electromagnet experiment above becomes a magnet when exposed to a magnetic field. The field created by the moving electric charges in the wire lines up the nail's fields properly and then those fields can add their own strength to the overall effect.

If you want to see this at home take a paper clip and hang it from a permanent magnet. The paper clip isn't a magnet in itself, but will become a temporary magnet in the presence of a magnetic field. You can then hang a second paper clip from the first one and it will also become a magnet because of the field of the one before it. It is easy to construct a whole chain of paper clips this way. Detach the first one from the permanent magnet, however, and the whole chain falls apart as each of the magnetic fields fall apart one after another.

For centuries scientists have puzzled about why Earth has a strong magnetic field. (The magnetic field of Venus is barely detectable.) They still don't understand the details, but they do know that the outer core of the Earth is mostly molten iron that moves in a convection pattern due to heat at the core. This movement, along with the Earth's spin seems to make the Earth into a big electromagnet. The magnetic field of our planet isn't as stable as we might think, however. There is evidence that the poles of this gigantic magnet have moved, changed intensity, and even reversed many times in past.

If the magnetic field of the Earth went away would we still have magnets? Yes, because each magnet generates its own magnetic field independently. The Earth is just a big version of our experiment with the wire and the nail. A collapse in the Earth's magnetic field, however, would mean that compasses (which are just little magnets in the form of pointers that align with the Earth's magnetic field) would not point the right direction. This would cause problem not only for humans who depend on compasses for navigation, but also for animals that have developed internal compasses in their bodies for use in migration.

Fortunately, though the Earth's magnetic field has weakened in the past 150 years, it looks like it will many centuries before a full collapse and reversal. In fact it may be just as likely that nothing will happen at all in the near future and the original orientation will regain its strength.

The End of the Universe - Our small Earth and other planets are in space. It's a big area; can you tell me the total size of space? Will it have a beginning and an end? - J.R.

One of the fundamental questions scientists have struggled with over the years is the size, shape and destiny of the universe. The prevailing theory is that the universe came into being about 13.7 billion years ago in what has been whimsically called "The Big Bang." It has been expanding (some people use the term "inflating") ever since. Gravity - the force that pulls all forms of matter toward each other - is working against the expansion. For a long time scientists debated over whether there was enough matter in the universe given its size (what we call the density) to bring the expansion to a halt and eventually reverse it. If there isn't, gravity will just slow down the expansion but never stop it. If the universe came back together it would end in a "Big Crunch." If it continued with a slow expansion it would just sort of slowly die out as all energy was expended and evenly distributed through out all of space.

The scientists were blown away when recent observations showed that the universe is unlikely to either be pulled back together or just slowed down. The universe's expansion actually appears to be accelerating, for some unknown reason. Scientists have speculated that is due to an unknown force we can't detect which they have dubbed "dark energy." If this is the case, if the universe is accelerated enough it may end when it is actually ripped apart at the atomic level in some distance future.

The shape of the universe is related to its density because higher density means more gravity. If the density is beyond a certain critical value, space, as seen in four dimensions, will be rolled up into the shape of a ball. If the density is just at the critical value, it will be as if the surface of the ball had been flattened out into a sheet. If the density falls below that critical point, it will be as if the sheet had been bent down on two sides and up on the other two forming a "saddle" shape.

The shape of the universe, in turn, has an impact on theories about how large it is. For example, the observable universe (that is the part we can see) is about 92-94 billion light-years across. If the universe were a closed sphere, however, it could actually be quite a bit smaller than this because light traveling in a "straight line" would eventually follow the curve of the sphere and come back to its starting point. This means that if you used a telescope to look at a distance galaxy, you might be actually be looking at your own galaxy from the other side. It might seem that it would be easy to look at a distant part of space and see if the galaxies there matched up with any galaxies in opposite direction, but an experiment like this is extremely difficult to do. In reality the great distances involved mean that we are seeing the galaxies at different times in their history, so they may not look the same or be in the same position.

Recent data from the Wilkinson Microwave Anisotropy Probe (WMAP) NASA launched in 2001 suggests that the shape of the universe - at least the observable universe - is nearly "flat" with a minimum size of around 78 billion light years. However it is more likely that it is quite larger and may indeed be infinite. For comparison the diameter of the orbit of Neptune, our outer most planet, is a little more than one thousandth of a light year wide.

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