1. The USA Returns to Mars

    Based on a NASA press release

    The United States returned to Mars last night as NASA’s 2001 Mars Odyssey fired its main engine at 7:26 p.m. Pacific time on Oct. 23rd (0226 UT on Oct. 24th) and was captured into orbit around the red planet.

    At 7:55 p.m. Pacific time, flight controllers at the Deep Space Network station in Goldstone, Calif., and Canberra, Australia, picked up the first radio signal from the spacecraft as it emerged from behind the planet Mars.

    “Early information indicates everything went great,” said Matt Landano, the Odyssey project manager ...

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  1. The Three Domains of Life

    When scientists first started to classify life, everything was designated as either an animal or a plant. But as new forms of life were discovered and our knowledge of life on Earth grew, new categories, called ‘Kingdoms,’ were added. There eventually came to be five Kingdoms in all – Animalia, Plantae, Fungi, Protista, and Bacteria.

    The five Kingdoms were generally grouped into two categories called Eukarya and Prokarya. Eukaryotes represent four of the five Kingdoms (animals, plants, fungi and protists). Eukaryotes are organisms whose cells have a nucleus — a sort of sack that holds the cell’s DNA. Animals, plants ...

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  1. Titan: Biological Birthplace?

    Saturn’s giant moon Titan, cloaked in a thick nitrogen atmosphere laced with hydrocarbons, could provide a laboratory in the sky for scientists seeking insight into the origins of life. With the Cassini-Huygens mission, scheduled for a 2004 rendezvous with Saturn and Titan, scientists hope to find evidence for primitive organic chemistry, preserved in the extreme cold of the moon’s icy surface. For while “Titan is not a place where life began or could flourish,” says planetary scientist Jonathan Lunine, it is a good place to look for biomolecules.

    Titan is a Mercury-sized world comprised of a 50-50 ...

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  1. Photosynthesis: Take It or Leave It

    The Supposition

    Cindy L. VanDover, a biologist and hydrothermal vent expert at the College of William and Mary in Williamsburg, VA. wondered if photosynthetic bacteria might live near hydrothermal vents. This was a striking speculation, considering that such vent systems lie thousands of feet deep in the ocean, well below the depth to which sunlight penetrates. The ecosystems surrounding such vents survive because of bacteria that garner energy from hydrogen sulfide, not from light.

    But water emerges from hydrothermal vents at hundreds of degrees, kept from boiling only by the intense pressure. The hot water, and perhaps hot rocks, VanDover ...

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  1. Carbonaceous Clues to the Early Solar System

    Adapted from an Arizona State University press release

    Scientists have conducted an organic analysis of the Tagish Lake meteorite, a rare, carbon-rich meteorite classified as a carbonaceous chondrite. The meteorite fell on a frozen Canadian lake in January 2000, and is the most pristine carbonaceous chondrite specimen ever studied.

    The analysis suggests there can be a different outcome for the evolution of organic chemicals in space than from what has been observed in other carbonaceous meteorites. This difference could be due to the possibility that the Tagish Lake meteorite contains carbon molecules that may have accumulated during the formation and ...

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  1. Space Bones

    Based on an Science@NASA press release by Doug Hullander and Patrick L. Barry

    Everybody knows space is dangerous. Some of the perils are obvious: hard vacuum, extreme cold, and unpredictable blasts of radiation from the Sun.

    Other perils are less conspicuous. The effects of prolonged weightlessness on the human body, for example, can be slow and subtle — yet no less dangerous if astronauts fail to take proper precautions.

    Weakening of the bones due to the progressive loss of bone mass is a particularly serious effect of extended spaceflight. Studies of cosmonauts and astronauts who spent many months on ...

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  1. Finding Distant Worlds

    We know that there are at least 75 planets outside our own solar system, orbiting their distant stars. The rate of planet discovery has sped up recently, and many more planets will likely be discovered in the weeks and years to come.

    And yet, we have never seen any of these planets with our own eyes. Planets do not glow like a star – they only reflect light. That makes them a lot harder to see from far away. Any light reflecting off a planet also tends to be overwhelmed by the brightness of the host star.

    So how do ...

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  1. Evolution’s Double Take

    Based on a Netherlands Organization for Scientific Research press release

    The Eukarya domain is broken down into four Kingdoms: animals, plants, fungi, and protists. All eukaryotes are characterized by having their DNA enclosed within a cell nucleus. In most eukaryotes, mitochondria act as the powerhouses of the cell. Mitochondria convert food into energy through the respiration of oxygen.

    But not all eukaryotes rely on mitochondria for their energy. For instance, the cells of plants and some protists also contain plastids, where photosynthesis takes place and provides the organism with food. Organisms that live in environments without oxygen, such as anaerobic ...

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  1. Cometary Closeup

    Based on a NASA/JPL press release

    In a risky flyby, NASA’s ailing Deep Space 1 spacecraft successfully navigated past a comet, giving researchers the best look ever inside the glowing core of icy dust and gas.

    The space probe’s close encounter with comet Borrelly provided the best-resolution pictures of the comet to date. The already-successful Deep Space 1, without protection from the little-known comet environment, whizzed by just 2,200 kilometers (1,400 miles) from the rocky, icy nucleus of the 10-kilometer-long (more than 6-mile-long) comet.

    Exceeding the team’s expectations of how this elderly spacecraft would perform, the ...

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  1. Making the Moon

    Based on a Southwest Research Institute press release

    The “giant impact” theory, first proposed in the mid-1970s to explain how the Moon formed, has now received a major boost. New computer simulations demonstrate how a single impact could yield the current Earth-Moon system. According to these new results, which appeared in the August 16 issue of Nature, the Moon is a chip off of the terrestrial block.

    The Earth-Moon system is unusual in several respects. The Moon has an abnormally low density compared to the terrestrial planets (Mercury, Venus, Earth, and Mars), indicating that it lacks high-density iron. While the ...

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  1. A Greener Planetary Greenhouse

    Based on a Science @ NASA news story

    For more than two decades, northern hemisphere vegetation has become gradually more lush, according to new research based on NASA satellite data.

    Researchers confirm that plant life seen above 40 degrees north latitude, which represents a line stretching from New York to Madrid to Beijing, has been growing more vigorously since 1981. One possible cause is rising temperatures, linked perhaps to the buildup of greenhouse gases in our atmosphere.

    The area of northern vegetation has not actually expanded, but it has increased in density. The growing season has also increased by several days ...

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  1. Genomics Meets Geology

    The last third of the last century could be called the decades of molecular biology. Biologists turned the spotlight of chemistry on biological black boxes and began to understand how cells and inheritance function at a molecular level. The iconic capstone of this work was the sequencing of the human genome.

    But Steven A. Benner, a biological chemist at the University of Florida and member of the NASA Astrobiology Institute (NAI), is turning that trend toward reductionism on its head.

    “While all the biologists are rushing to become molecular biologists and chemists,” he says, “here we are chemists trying ...

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  1. Evidence of Recent Climate Change on Mars

    Based on a Brown University press release

    New images of the surface of Mars provide the first direct evidence that the climate of Mars has changed during the last 100,000 years, according to Brown University geologist John Mustard. This is much earlier than previous estimates, which calculated a climate change dating back hundreds of millions of years.

    The images were recorded by the Mars Orbiter Camera aboard NASA’s unmanned Mars Global Surveyor. They show a unique surface terrain of pits and hummocks that appears to have been soil once impregnated by water ice. The ice has since evaporated ...

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  1. Jupiter-Size Planet Found Orbiting Star in Big Dipper

    Based on a National Science Foundation press release

    A team of astronomers has found a Jupiter-size planet in a circular orbit around a faint nearby star, raising intriguing prospects of finding a solar system with characteristics similar to our own.

    The planet is the second found to orbit the star 47 Ursae Majoris (47 UMa) in the Big Dipper, also known as Ursa Major or the Big Bear. The new planet is at least three-fourths the mass of Jupiter and orbits the star at a distance that, in our solar system, would place it beyond Mars but within the orbit ...

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  1. Scientists Hunt for Light Flashes From Extraterrestrial Civilizations

    Adapted from a SETI Institute press release

    California astronomers are broadening the search for extraterrestrial intelligence (SETI) by looking for powerful light pulses coming from other star systems. Scientists from the University of California’s Lick Observatory, the SETI Institute, UC Santa Cruz, and UC Berkeley are coupling the Lick Observatory’s 40-inch Nickel Telescope with a new pulse-detection system capable of finding laser beacons sent by alien civilizations.

    “We are looking for very brief but powerful pulses of laser light from other planetary systems, rather than the steady whine of a radio transmitter,” says Frank Drake, Chairman of the Board ...

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