1. Return to the Red Planet

    The Mars Global Surveyor (MGS) currently orbiting Mars has sent back a wealth of new information. It has revealed an enticing sample of the martian surface at a level of detail never previously achieved from orbit. It has shown us layered sedimentary deposits in crater basins. It has discovered what appear to be seepage gullies caused by recently running water, in regions of Mars believed to be far too cold for liquid water to flow.

    As is often the case, these discoveries have led to new questions. For example, if there are so many places where the martian landscape appears ...

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  1. Taking the Temperature of a Martian Meteorite

    Inside martian meteorite ALH84001 may lie the fossilized remains of ancient bacteria. Some scientists have suggested that other martian meteorites could have seeded the early Earth with primitive forms of life. Others argue that any asteroid or comet that impacted Mars with sufficient force to eject material into interplanetary space would have superheated the ejecta, and that bacteria could not have survived.

    New research by Benjamin Weiss and his colleagues at the California Institute of Technology indicates that at least one such meteorite — ALH84001 — didn’t get all that hot. Weiss’s team believes that the interior of ...

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  1. Can Liquid Water Exist on Present-Day Mars?

    In 1998, NASA’s Associate Administrator Wesley Huntress, Jr., stated, “Wherever liquid water and chemical energy are found, there is life. There is no exception.”

    Could there, then, be life on Mars? In the mid-1970s, the Viking Lander mission’s Gas Exchange Experiment detected strong chemical activity in the martian soil. Liquid water seems to be the one element needed for the equation of life on Mars. The presence of water there, however, is still hotly contested.

    Many scientists believe that liquid water does not and cannot exist on the surface of Mars today. Although surface water may have been ...

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  1. NASA Astrobiology Institute Announces New Teams

    Text based on a NASA Ames Press Release

    NASA has selected four new teams to become part of the agency’s Astrobiology Institute (NAI), a national and international research consortium that studies the origin, evolution, distribution and future of life on Earth and in the universe.

    After a highly competitive peer-review process, teams from Michigan State University (MSU), East Lansing; the University of Rhode Island (URI), Kingston; the University of Washington (UW), Seattle; and NASA’s Jet Propulsion Laboratory (JPL), Pasadena, CA, today were notified of their selection.

    These new teams of researchers will bring specialized expertise to the institute, allowing ...

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  1. Evo Devo Learns a Larval Lesson

    In Ridley Scott’s 1979 slimy monster masterpiece, “Alien,” the extraterrestrial life form discovered by Sigourney Weaver and crew goes through two startlingly different phases after it hatches. Is such a change during the life of an animal mere SciFi license? Not really. In fact, many earthlings go through similar drastic changes in form. Think, for example, of the caterpillar and butterfly, or the tadpole and adult frog.

    Scientists have studied the life history of animals, part of a field called development, for many decades. Other scientists have studied how life arose and evolved on Earth. But for the first ...

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  1. An Astronomy First: Telescopes Double-Team Hawaiian Night Sky

    Text based on a NASA Press Release

    Proving that two telescopes are better than one, NASA astronomers have gathered the first starlight obtained by linking two Hawaiian 10-meter telescopes.

    This successful test at the W.M. Keck Observatory on Mauna Kea makes the linked telescopes, which together are called the Keck Interferometer, the world’s most powerful optical telescope system. The project will eventually search for planets around nearby stars and help NASA design future space-based missions that can search for habitable, Earthlike planets.

    “Successfully combining the light from the two largest telescopes on Earth is a fabulous technical advancement for ...

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  1. Through Thick or Thin: Exploring Europa's Outer Layer of Ice

    When NASA’s Galileo spacecraft sent back images and data of the Jovian moon Europa, scientists began thinking seriously that life just might exist on this enigmatic, frozen world.

    Europa appears to have all the conditions necessary for the emergence of life: liquid water, organic chemicals, and energy. A layer of ice covers Europa, but there is strong evidence – the most convincing comes from Galileo’s magnetometer – that a salty ocean may lie underneath. Organic chemicals are prevalent throughout the universe and could have been deposited on Europa by comets and meteors. Tidal forces exerted by Jupiter could provide ...

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  1. Looking for Signs of Life in Acid-Washed Rocks

    Extraordinary clues to the history of biological evolution on Earth often come from something as mundane as rocks. To better understand the close connection between life and geology—and how one affects the other—new laboratory methods are being developed to tease out the information that ancient rocks contain.

    Pioneering one such method is Dr. Frances Westall, paleobiologist for the Lunar and Planetary Institute and member of the NASA Astrobiology Institute. She and her colleagues are using acid vapor to isolate the remains of tiny microbial life forms. These fossils, entombed within ancient sedimentary fossil structures known as stromatolites, were ...

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  1. TNA World

    DNA is the building block for life on Earth. But it is a highly complex molecule, and could not have arranged itself spontaneously. What did it develop from? Astrobiologists examine possible ancestors of DNA: nucleic acids called PNA, p-RNA, and TNA.

    We all know that DNA (Figure 1) makes up the building blocks for life on Earth. But DNA – deoxyribonucleic acid – is highly complex. It could not have appeared spontaneously; it must have evolved from a simpler form.

    Scientists have put forth the theory that RNA – ribonucleic acid (Figure 2) – was the predecessor to DNA ...

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  1. Ganymede's Liquid Past

    Based on a NASA Ames Research Center press release

    Long swaths of bright, flat terrain on the surface of Jupiter’s icy moon Ganymede may testify that water or slush emerged there about a billion years ago, say planetary scientists. NASA scientists have combined stereo images from NASA’s Galileo and Voyager missions to examine these provocative features on the moon.

    This bright terrain, long since frozen over, lies uniformly in troughs about one kilometer (a little over a half mile) lower than Ganymede’s older, darker, cratered terrain.

    Ganymede is the largest moon in the solar system and larger than the ...

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  1. Some Like It Hot

    Most people who visit Yellowstone National Park go there to take in the scenery and to catch a glimpse of the park’s iconic Old Faithful geyser. But not Jack Farmer. When he ventures out to Yellowstone, he goes in search of clues to what life might have been like on Earth – and Mars – some four billion years ago.

    Farmer is an astrobiologist who heads the Arizona State University Lead Team of the NASA Astrobiology Institute (NAI). What fascinates him about Yellowstone are the microscopic organisms that inhabit the boiling waters of its hot springs. He refers to these ...

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  1. A Shortage of Planets

    At an age of about 10 billion years, globular clusters contain some of the oldest stars in the Milky Way. Scientists study these ancient, densely packed star systems to learn about the lives of stars, the formation of galaxies, and the evolution of the universe. By searching for planets in globular clusters, it is also possible to discover whether planets formed when our galaxy was relatively young.

    Astronomer Ronald Gilliland of the Space Telescope Science Institute in Baltimore, Maryland, and his team searched for planets in the globular cluster 47 Tucanae, a crowded group of stars located about 15,000 ...

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  1. Two Rovers in Search of a Landing Site

    In the spring of 2003, NASA will launch two spacecraft on 35-million-mile journeys to Mars. Each craft will carry a small rover, equipped with a set of robotic geologic tools designed to search out mineral evidence within Martian rocks that water was once present on Earth’s neighboring planet.

    The Mars Explorer Rovers, as they are tentatively dubbed, are larger and more-advanced descendants of the Sojourner rover that roamed the Martian surface in July 1997. Both MERs will arrive at the Red Planet early in 2004, but they will go to different, widely separated locations.

    The question NASA is trying ...

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  1. Scientists Find Evidence of Ancient Microbial Life on Mars

    (Text based on a NASA Ames Research Center Press Release)

    An international team of researchers has discovered compelling evidence that the magnetite crystals in the martian meteorite ALH84001 are of biological origin.

    The researchers found that the magnetite crystals embedded in the meteorite are arranged in long chains, which they say could have been formed only by once-living organisms. Their results are reported in the February 27 Proceedings of the National Academy of Sciences.

    “The chains we discovered are of biological origin,” said Dr. Imre Friedmann, an NRC senior research fellow at NASA’s Ames Research Center in ...

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  1. Apocalypse Then

    (From Science@NASA)

    New findings provide evidence that Earth’s most severe mass extinction – an event 250 million years ago that wiped out 90 percent of the life on Earth – was triggered by a collision with a comet or asteroid.

    Over 90 percent of all marine species and 70 percent of land vertebrates perished as a result, according to the NASA-funded research team, led by Dr. Luann Becker of the University of Washington (UW), Seattle. The team’s findings will be published in today’s issue of the journal Science.

    The collision wasn’t directly responsible for the extinction, but rather ...

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Astrobiology Magazine