If you have been to the movies in the past couple of years, you might have seen such blockbusters as Independence Day, Contact, or Men in Black. Hollywood is constantly releasing films that deal with the subject of outer space, and in particular the idea of other life in outer space. Why?

It turns out that the mind of the human being is fascinated by the possibility of other life in the universe. As early as the fifth century B.C., the Greeks discussed the possibility that life existed elsewhere. Being the imaginative humans that we are, almost everyone has guessed at one time or another what life elsewhere in the universe might look like. However, scientists who look for signs of life outside of the planet earth probably have a much different idea of what these life forms might look like. They aren't looking for little green men running around with space guns as you might have seen in Mars Attacks, but instead are looking for something quite different.

In 1958, the United States Congress created the National Aeronautics and Space Administration, or NASA. Its purpose was to coordinate and conduct all aeronautical and space activities for the United States of America, except those of the military. Among the many programs which NASA now runs, one is the search for life outside our home planet. NASA is currently examining our neighbor planet Mars for signs of life, as well as the moons of other planets in our solar system. It has also developed highly advanced technology for the search of life outside of our own solar system, such as special radars and infrared telescopes.

For decades, debates have been common and fierce as to whether life existed on our closest neighboring planet, Mars. Many believed that other beings, Martians, did indeed exist, and were highly intelligent. Others claimed that there was no proof of this, and that life as we know it was, in fact, not possible due to the extreme conditions of the Martian environment. In 1976, NASA sent two landers, Viking I and Viking II, to the surface of Mars to determine if life did indeed exist. However, when these landers executed their experiments, they showed rather convincingly that there were no organic compounds above the one part per billion level in the upper few centimeters of the surface. The landers also reported on the extreme environment of Mars, with temperatures falling to 120o Fahrenheit (48.9oC) below 0 at night. So, for a while the debate subsided surrounding the existence of life on Mars.

In 1996, a meteor was found in Allan Hills, Antarctica. Upon examination, it was discovered that this meteor, which is 4.5 billion years old, fell to the earth 13,000 years ago, and possibly contained evidence of life on Mars. Inside the meteor, along tiny cracks, scientists found evidence of what many believe to be ancient bacteria.There are four main clues which bring some scientists to this conclusion. One is that the meteorite is definitely of Martian origin and that it contains carbonate globules. The second is the presence of polycyclic aromatic compounds, which are complex organic molecules. The third piece of evidence is the presence of iron and other compounds which appear to be like those made by bacteria. The last, and perhaps most intriguing , is the pictures of the possible fossilized bacteria themselves. When taken separately, these pieces of evidence probably wouldn't amount to much. But what is compelling is that all of these pieces of evidence occur within millimeters of each other.

However, skeptics still remain. Some simply aren't sure, while others are certain that this meteorite contains no evidence of former life.. However, all agree that convincing evidence would contain proof that the fossils had cell walls, that the cells had been divided, and that chemicals more closely related to living organisms as we know them be found. And so, the debates continue. While these debates over ALH84001 occur, the science community continues its pursuit in finding signs of life, extant or extinct, on Mars.

On July 4, 1997, a small spacecraft dropped onto Mars and tumbled to a stop. This pod, sent by the Jet Propulsion Laboratory in Pasadena, California, will be examining and doing tests on the Mars surface. This pod, called Pathfinder, will be sending signals back to Earth concerning the atmosphere and soil. It has also deployed a small land rover, similar to radio controlled cars.
This rover, called Sojourner, has been testing the Martian rocks for their minerals. In 2002, testing will be done on a different Mars probe to see if organic compounds or amino acids are present.If it finds amino acids buried in the surface, it will be testing to determine the chirality of the molecules. If they are homo chiral, then that would be strong evidence that life existed at one point on Mars. If the amino acids are racemized, then it will be difficult to determine if they originated from life. In the next several years, NASA will be sending more space craft to Mars, to continue in its quest for extraterrestrial life.

Hot links to NASA, NSCORT, SIO, Hughes Aircraft Company, Amgen, JPL.