Life on Mars: the search continues.Startling star·tle v. star·tled, star·tling, star·tles v.tr. 1. To cause to make a quick involuntary movement or start. 2. To alarm, frighten, or surprise suddenly. See Synonyms at frighten. Evidence of Past Life on Mars Scientists have long speculated about the possibility of life on Mars owing to the planet's proximity and similarity to Earth. It remains an open question whether life exists on Mars now, or existed there in the past. Rocks the Science World." Those were the headlines last August when astronomers announced they'd found "fossils" of ancient life forms in a potato-sized rock from the "Red Planet." Now NASA NASA: see National Aeronautics and Space Administration. NASA in full National Aeronautics and Space Administration Independent U.S. is sending a fleet of 10 robotic spacecraft--the first since Viking landers explored Mars' surface in 1976--to "dig" for more evidence. NASA scientists had planned the first two missions well before last summer's big discovery. The Mars Global Surveyor The Mars Global Surveyor (MGS) was a US spacecraft developed by NASA and the Jet Propulsion Laboratory and launched November 1996. It began the United States's return to Mars after a 20-year absence. is set for launch next month. By next September, it will begin orbiting Mars, taking detailed photos of the planet's surface. The Mars Pathfinder, due to launch in December, will land on Martian soil on July 4, 1997. If these two missions-- or others that follow--dig up proof of life, we will know for the first time that life, we will know for the first time that life is not unique to Earth. And we'll have real reasons to believe we may not be alone in the universe! FORMIDABLE PLANET Anyone who's ever read or watched science fiction has probably dreamed about life on Mars. But when the Viking landers explored the Red Planet's surface 20 years ago, they found a cold and barren world--and no signs of life. "Mars is a very inhospitable place now," says NASA scientist David McKay, who is a member of the Mars research team. The big challenges to life on Mars include: * No atmospheric oxygen--the gas most living things Living Things may refer to:
* No protective ozone layer ozone layer or ozonosphere, region of the stratosphere containing relatively high concentrations of ozone, located at altitudes of 12–30 mi (19–48 km) above the earth's surface. to screen out the Sun's harmful ultraviolet (UV) rays. * No liquid water. Very low atmospheric pressure atmospheric pressure or barometric pressure Force per unit area exerted by the air above the surface of the Earth. Standard sea-level pressure, by definition, equals 1 atmosphere (atm), or 29.92 in. (760 mm) of mercury, 14.70 lbs per square in., or 101. and an average temperature of -53[degrees]C (-64[degrees]F) mean all the water on Mars Psychedelic rock and electronic music group from Quebec City (Québec, Canada), Water on Mars (WOM) is the instrument of its leader Philippe Navarro, guitarist, vocalist, arranger, producer and principal author and composer of the trio. today is either frozen or floating around the atmosphere as water vapor. "Liquid water is a basic requirement for life as we know it Life As We Know It is an American television drama on the ABC network during the 2004-2005 season. It was created by Gabe Sachs and Jeff Judah. The series was based on the novel Doing It by British writer Melvin Burgess. ," says NASA scientist Jack D. Farmer. Without it, not even cells--the building blocks of life--can exist! But Mars may not always have been so inhospitable. Photos of Mars' surface reveal what look like dried lake and stream beds. These suggest that liquid water once gushed across the planet. And now, evidence found inside Martian meteorites--rocky chunks of Mars that fell to Earth--implies the existence of water . . . and much more! BLASTS FROM THE PAS! Over the past 20 years or so, scientists have discovered about a dozen rocky chunks of Mars here on Earth. They know the rocks are from Mars because gases trapped inside are identical to those detected in Mars' atmosphere by the Viking spacecraft. Millions of years ago, says geologist Allan Treiman, who has studied the Martian meteorites Meteorites See also astronomy. aerolithology the science of aerolites, whether meteoric stones or meteorites. Also called aerolitics. astrolithology the study of meteorites. Also called meteoritics. , "large asteroids This is a list of numbered minor planets, nearly all of them asteroids, in sequential order. As of late September 2007 there are 164,612 numbered minor planets, and many more not yet numbered. Most asteroids are ordinary and not particularly noteworthy. hit Mars and bounced these pieces off into space." Some chunks escaped Mars' gravity and orbited the Sun for millions of years. Eventually--thousands of years ago--some crashed into Earth, Treiman says. Inside the oldest Mars chunk, one that's 3.6 billion years old, scientists now say they've found signs of ancient Martian life! LITTLE GREEN MEN? "We are not talking about little green men," says NASA Administer Daniel Goldin Daniel Saul Goldin (born July 23, 1940) served as the 9th and longest-tenured Administrator of NASA from April 1, 1992, to November 17, 2001. He was appointed by President George H. W. Bush and served under three presidential administrations. . Rather, the scientists say they've detected chemical and fossil remains of microscopic, bacteria-like organisms. The chemicals include traces of carbon compounds that are the basis of life. The rock also contains mineral samples that are known to be the by-products of bacteria, says McKay. Even more startling are the electron-microscope images of the rock's interior. These reveal tubelike structures, which the researchers say could be fossils of ancient Martian bacteria. These tiny "Martians" are less than one-hundredth the width of a human hair! These chemicals and fossils are only evidence--not proof--that life existed on Mam "It is very difficult to prove life existed 3.6 billion years ago on Earth, let alone on Mars," says Stanford University Stanford University, at Stanford, Calif.; coeducational; chartered 1885, opened 1891 as Leland Stanford Junior Univ. (still the legal name). The original campus was designed by Frederick Law Olmsted. David Starr Jordan was its first president. chemist Richard Zare Richard N. Zare (born November 19, 1939 in Cleveland, Ohio) is an American chemist. He is currently Professor of Chemistry at Stanford University. He earned his B.A. in 1961 and his Ph.D. , who is part of the Mars-meteorite investigative team. But the fact that these chemicals and fossils were clustered inside the meteorite meteorite, meteor that survives the intense heat of atmospheric friction and reaches the earth's surface. Because of the destructive effects of this friction, only the very largest meteors become meteorites. is compelling evidence, he suggests. If the chemicals and fossils were, instead, contaminants from Earth, they would have been found at higher concentrations outside the rock. Still, the findings will have to stand the test of further experiments. J. William Schopf, a scientist at the University of California The University of California has a combined student body of more than 191,000 students, over 1,340,000 living alumni, and a combined systemwide and campus endowment of just over $7.3 billion (8th largest in the United States). already has an idea of some tests he'd like to do on the Mardan fossils. "We've got to look inside these things, see if they have cell walls [as many bacteria do], . . . see if they are composed of organic material." THE NEXT MISSION Others will want more evidence from Mars itself. This year's missions could dig up the first clues. The Mars Pathfinder with land in what NASA scientists call a "grab bag" site--the mouth of an ancient water channel. When water flowed on Mars 2 to 4 million years ago, many different kinds of rocks probably washed down from upstream. The Pathfinder's six-wheeled robotic land rover will analyze the elements in these rocks, and transmit the information back to Earth. Meanwhile, cameras aboard the Mars Global Surveyor with scout out good sites for future landers. The spacecraft will orbit 378 kilometers (235 miles) above the planet, taking detailed photos of ancient lake basins and thermal springs. Subsequent landers will scoop up soil and conduct detailed on-site chemical analyses. But in order for scientists on Earth to duplicate their life-searching studies, one of these missions will have to bring some samples of Mars back to Earth.... Or, the scientists will have to go to Mars. Maybe by the time today's teens are old enough to be astronauts, it will happen, says Allan Treiman. Would you want to go look for life on Mars? Check out the Mars Exploration Program Web site at: http://www.jpl.nasa.gov/mars/ index.html RELATED ARTICLE: THE MEANING OF LIFE So what if there were bacteria-like "critters living on Mars 3.6 billion years ago? Does that mean aliens like Marvin the Martian This page is about the cartoon character. See Marv The Marsh for the English rapper. Marvin the Martian (or Marvin Martian) is a fictional character appearing in the Looney Tunes cartoons. and Star Trek's Worf are roaming the universe, too? Well . . . Scientists say finding signs of any form of alien life--even primitive microbes--greatly increases the likelihood that other extraterrestial life forms exist. For one thing, if life developed on two planets within our own solar system (Earth and Mars), "it greatly increases the probability that this could happen somewhere else," says Jack D. Farmer, a Mars expert at NASA. * Think about it: Mars is merely our planetary next-door neighbor. What might we find if we looked beyond our solar system, to the countless planets that orbit the billions of stars in the billions of galaxies of the universe? Perhaps lots of microbes ... or maybe something else. After all, scientists think all the life forms that live on Earth today evolved from primitive microbes. It's possible that simple life forms evolved into thinking beings elsewhere too. Maybe some of these creatures are even smarter than humans. If they do exist, what do you think they look like? And what would they think of us? |
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