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  1. How Jupiter Got Big


    How did the largest planet in our solar system form?

    The traditional view is that Jupiter first formed a rocky core, several times the size of Earth, which then attracted a still larger outer envelope of gas. This process is known as “accretion.”

    But there are problems with this model. The major problem is that if the large, gaseous planet did form by the gradual accretion of material, it would have taken a very long time to develop. Current estimates range between 10 million and 1 billion years. However, recent observations of distant stars suggest that planets have at ...

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  1. Unpuzzling Proteins


    Based on a press release from NASA Ames Research Center

    Thanks to a new supercomputer, scientists may be a step closer to understanding one of nature’s more difficult puzzles. Scientists at NASA Ames Research Center are using the SGI 512-processor Origin 3000, the most powerful parallel supercomputer of its kind, to try to determine the structure of proteins.

    Proteins play a fundamental role in living cells, acting as catalysts for all chemical reactions. Proteins also act as a kind of “nervous system” for a cell, transmitting signals from the outside environment. They assist in transporting nutrients into the cell, and ...

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  1. Space Weather on Mars


    Based on a Science @ NASA story by Dr. Tony Phillips

    Alien planets have alien weather.

    Take Mars, for example. A morning weather report on the Red Planet might sound like this:

    “Good morning, Martians! It looks like another solar storm heading our way. An X-class solar flare exploded this morning and proton counts have soared 1000-fold. More of the deadly particles are en route, so don’t leave shelter today without your radiation suit!”

    “Coming up next, the sunspot report, right after this word from our sponsor: Levi’s Relaxed Fit LeadPants.”

    It doesn’t sound much like the forecasts we ...

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  1. Reflections From a Warm Little Pond


    Back in 1953, Jim Kasting said, scientists thought they had the origin of life figured out. Chemists Stanley Miller and Harold Urey at the University of Chicago had simulated that crucial instant around 3.9 billion years ago when a batch of simple inorganic molecules, zapped by a bolt of lightning (or maybe just the sun’s warmth during a break in the clouds), fell together to form the prototypes for the complex organic compounds that life is made from.

    Now that was a moment. Remember it on Star Trek? The muddy puddle of ooze on the edge of Nowheresville? The ...

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  1. Keeping "Cool" at Deep-Sea Vents


    Adapted from a University of Delaware press release

    Using a novel detector attached to a submarine, a research team led by University of Delaware marine scientists has determined that water chemistry controls the location and distribution of two species of weird worms that inhabit deep-sea hydrothermal vent sites. The study, which is the first to demonstrate through real-time measurements how different chemical compounds control the biology at the vents, is reported in the April 12 edition of the journal Nature.

    The interdisciplinary research team included chemists, biologists, and marine engineers from the UD Graduate College of Marine Studies and the ...

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  1. Was Johnny Appleseed a Comet?


    Based on a Science @ NASA press release

    Four billion years ago Earth was bombarded by a hail of comets and asteroids. The shattering collisions rendered our planet uninhabitable during a period scientists call the Late Heavy Bombardment (LHB).

    It surely sounds like the LHB was an awful time for the beleaguered young planet — but perhaps the pelting was a good thing after all, say researchers. Kamikaze comets could have delivered important organic molecules to Earth — sowing the seeds for life.

    Genesis by comets is a controversial idea, but it’s just received an important boost. A NASA-supported experiment ...

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  1. Roses for the Red Planet


    It has been nearly 25 years since NASA sent biological experiments to Mars. Chris McKay, a planetary scientist with the Space Sciences Division of NASA’s Ames Research Center and a member of the NASA Astrobiology Institute, thinks it’s time to try again.

    McKay helped organize a NASA conference last year on what it might take to make Mars fit for human habitation. While the general tone of the conference was speculative—all of the participants agreed that humans aren’t likely to begin terraforming the Red Planet any time soon—McKay maintains that it was important nonetheless to begin now ...

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  1. Oily Fossils Provide Clues to the Evolution of Flowers


    Text based on a Stanford University press release
    Daffodils, tulips, roses and other flowers are so much a part of our daily lives that we take them for granted. Yet, how and when flowering plants appeared on Earth remains a mystery, a question that has gone unanswered by evolutionary scientists for more than a century.
    According to the fossil record, mosses were the first plants to emerge on land, some 425 million years ago, followed by ferns, firs, ginkgoes, conifers and several other varieties. Then, it seems, about 130 million years ago flowering plants abruptly appeared out of nowhere.
    Where ...

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  1. Focus on Europa


    Four decades of space exploration have taught us a great deal about the nine planets and dozens of moons that comprise our solar system. Yet Earth remains the only world on which we know for certain that life exists.

    Scientists and science fiction writers alike have long speculated on that Mars might also harbor life. But images of Jupiter’s moon Europa sent back by NASA’s Galileo spacecraft have led planetary geologists and biologists alike to seriously consider adding that ice-covered world to the list of possible habitats for life.

    Chris Chyba, who holds the Carl Sagan Chair for the ...

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  1. Twenty Thousand Leagues Under the Sea


    Miles below the ocean surface exist some of the most fascinating habitats for life on Earth. Here, where sunlight never reaches, live complex ecosystems that can appear and disappear within a matter of decades. What provides the thermal and chemical energy that fuels these ecosystems are deep-sea hydrothermal vents, one of the unofficial wonders of the natural world.

    These vents occur at oceanic “spreading centers,” mountainous ridges where magma from deep within the Earth’s crust forces its way up to the ocean floor, creating new ocean crust and pushing the old crust out of the way. This is ...

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  1. Life's Chemical Fingerprints


    Perhaps in 2008, a rover on Mars will press its robotic arm against a rock. A probe at the end of the arm will scan the rock, repeatedly zapping the surface with a microscopically thin laser beam, probably green or ultraviolet.

    As the laser light hits the rock, it will “scatter” (be deflected) in random directions. Most of that light will stay the same color, but a tiny fraction will be shifted just slightly to a different color, a phenomenon called the Raman effect. That slight shift will reveal whether the rock harbors the chemical signatures of life, either microbes ...

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  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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Astrobiology Magazine