Three billion years ago, Earth was a very different place.
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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 ...
September 28, 2001 • Posted by: Shige Abe • Report issue
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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 ...
September 26, 2001 • Posted by: Shige Abe • Report issue
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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 ...
September 24, 2001 • Posted by: Shige Abe • Report issue
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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 ...
September 14, 2001 • Posted by: Shige Abe • Report issue
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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 ...
September 10, 2001 • Posted by: Shige Abe • Report issue
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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 ...
September 07, 2001 • Posted by: Shige Abe • Report issue
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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 ...
September 04, 2001 • Posted by: Shige Abe • Report issue
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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 ...
August 31, 2001 • Posted by: Shige Abe • Report issue
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Guerrero Negro
Guerrero Negro, a small town of 10,000 located halfway down Mexico’s Baja peninsula, is a popular destination for ecotourists. They come to gaze at the gray whales, or to marvel at the diverse population of shorebirds.
But in June, Dr. David Des Marais and his colleagues headed to the area to investigate an ecosystem not likely to be mentioned in any travel guide. Des Marais is a senior research scientist at the NASA Ames Research Center in Mountain View, CA, and a member of the NASA Astrobiology Institute. His research team made the trek south to study microbial ...
August 24, 2001 • Posted by: Shige Abe • Report issue
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Having a Ball on Mars
Based on a Science @ NASA story by JPL
Researchers at the Jet Propulsion Laboratory (JPL) have hit upon an idea for exploring the Red Planet that seems to be equal parts fun and serious science: it’s a lightweight, two-story tall beach ball called “the tumbleweed rover.” Equipped with scientific instruments and propelled by nothing more than the thin Martian breeze, the tumbleweed could potentially explore vast tracts of planetary terrain.
The wind blowing across the face of the Red Planet would be the only engine needed to move such a ball from place to place, says Jack Jones of ...
August 22, 2001 • Posted by: Shige Abe • Report issue
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Advances in Our Understanding of Life
Excerpts from the testimony of Jack D. Farmer, Director and Principal Investigator of the NASA funded Astrobiology Program at Arizona State University, for the “Life in the Universe” hearings before the House Subcommiteee on Space and Aeronautics
Over the past two decades, advances in a number of scientific disciplines have helped us better understand the nature and evolution of life on Earth. These scientific developments also have helped lay the foundation for astrobiology, opening up new possibilities for the existence of life in the Solar System and beyond.
A New Look at LifeCarl Woese of the University of Illinois ...
August 20, 2001 • Posted by: Shige Abe • Report issue
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Water on Mars: Not So Ancient, After All
Based on a University of Arizona press release
Scientists have known for decades that Mars, at least in its ancient past, has had a considerable amount of water.
But when Mars Global Surveyor began mapping the Red Planet in sharp detail early in 1999, it disclosed startling evidence that water has shaped Martian landforms within the past 10 million years.
The discovery challenges the prevailing view that Mars’ surface has remained extremely cold and dry – much as it is today – for the past 3.9 billion years.
It confirms the idea that internal heat periodically triggers short-term warmer ...
August 15, 2001 • Posted by: Shige Abe • Report issue
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Gravity Hurts (So Good)
Based on a Sceince@NASA press release by Karen Miller.
Gravity hurts: you can feel it hoisting a loaded backpack or pushing a bike up a hill. But lack of gravity hurts, too: when astronauts return from long-term stints in space, they sometimes need to be carried away in stretchers.
Gravity is not just a force, it’s also a signal — a signal that tells the body how to act. For one thing, it tells muscles and bones how strong they must be. In zero-G, muscles atrophy quickly, because the body perceives it does not need them. The muscles used ...
August 12, 2001 • Posted by: Shige Abe • Report issue
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Life on Ice
From Arctic sea ice to Antarctic lakes and dry valleys, scientists study microbes that tolerate freezing temperatures on Earth to learn where to look for life on other worlds. Among the possibilities are fossils in ancient Martian lakebeds and bacteria wrapped in mucus and ice on Jupiter’s moon Europa.
“It’s terribly important that we learn more about cold-adapted microbes because all the environments we even contemplate for supporting life elsewhere [in our solar system] are cold,” says microbiologist Jody W. Deming, an oceanography professor at the University of Washington in Seattle.
“We need to know how all ...
August 10, 2001 • Posted by: Shige Abe • Report issue
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Extrasolar Planets With Earth-Like Orbits
Most of the planets discovered outside our solar system don’t have orbits like Earth’s. Either the planets are closer to their stars, with orbital periods of only a few days, or they have highly elliptical orbits – some of which better resemble the paths of comets. Recently, however, a team of astronomers from the Geneva Observatory in Switzerland announced they had discovered a planet with an orbital path very similar to Earth’s.
Dubbed HD 28185 b, this planet has a nearly circular orbit and is about the same distance away from its star as the Earth is from ...
August 08, 2001 • Posted by: Shige Abe • Report issue