NASA's 'Deep Impact' Team Reports First Evidence of Cometary IceFebruary 03, 2006Comet Tempel 1, which created a flamboyant Fourth of July fireworks display in space last year, is covered with a small amount of water ice. These results, reported by members of NASA's Deep Impact team in an advanced online edition of Science, offer the first definitive evidence of surface ice on any comet. "We have known for a long time that water ice exists in comets, but this is the first evidence of water ice on comets," said Jessica Sunshine, Deep Impact co-investigator and lead author of the Science article. A chief scientist with Science Applications International Corporation who holds three Brown University degrees, Sunshine said the discovery offers important insight into the composition of comets - small, Sun-orbiting space travelers that are believed to be leftovers from the formation of the solar system.
"Understanding a comet's water cycle and supply is critical to understanding these bodies as a system and as a possible source that delivered water to Earth," she said. "Add the large organic component in comets and you have two of the key ingredients for life." The findings help satisfy one of the major goals of the Deep Impact mission: Find out what is on the inside - and outside - of a comet. To that end, NASA's Jet Propulsion Laboratory teamed with the University of Maryland to slam a space probe into Tempel 1, then analyze materials from the comet's surface and interior. On July 4, 2005, mission members hit their mark when the copper-tipped probe collided with Tempel 1 and created a spectacular extraterrestrial explosion 83 million miles from Earth. Since then, the Deep Impact team has reported a few key findings. These include an abundance of organic matter in Tempel 1's interior as well as its likely origins - the region of the solar system now occupied by Uranus and Neptune. According to the new research in Science, the comet's surface features three pockets of thin ice. The area the ice covers is small. The surface area of Tempel 1 is roughly 45 square miles or 1.2 billion square feet. The ice, however, covers roughly 300,000 square feet. And only 6 percent of that area consists of pure water ice. The rest is dust. "It's like a seven-acre skating rink of snowy dirt," said Peter Schultz, professor of geological sciences at Brown, Deep Impact co-investigator and co-author on the Science paper. Sunshine, Schultz and the rest of the team arrived at their findings by analyzing data captured by an infrared spectrometer, an optical instrument that uses light to determine the composition of matter. Based on this spectral data, it appears that the surface ice used to be inside Tempel 1 but became exposed over time. The team reports that jets - occasional blasts of dust and vapor - may send this surface ice, as well as interior ice, to the coma, or tail, of Tempel 1. "So we know we're looking at a geologically active body whose surface is changing over time," Schultz said. "Now we can begin to understand how and why these jets erupt." Brown University | |||||||||||||||||||||
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Related Deep Impact News Articles Deep Impact extended mission heads for comet Hartley 2 NASA has given a University of Maryland-led team of scientists the green light to fly the Deep Impact spacecraft to Comet Hartley 2 on a two-part extended mission known as EPOXI. The spacecraft will fly by Earth on New Year's Eve at the beginning of a more than two-and-a-half-year journey to Hartley 2. APL Astronomer Spies Conditions 'Just Right' for Building an Earth An Earth-like planet is likely forming 424 light-years away in a star system called HD 113766, say astronomers using NASA's Spitzer Space Telescope. Computational actinide chemistry: Are we there yet? Ever since the Manhattan project in World War II, actinide chemistry has been essential for nuclear science and technology. Comet probes reveal evidence of origin of life, scientists claim Recent probes inside comets show it is overwhelmingly likely that life began in space, according to a new paper by Cardiff University scientists. UAF geologist studies Chicxulub impact crater About 65 million years ago, a massive disruption led to worldwide extinction of dinosaurs. The impact of a giant asteroid created massive tsunamis and spewed forth a global cloud of carbon gases that altered Earth's atmosphere and blocked the light for weeks, possibly years. In recent years, that impact event has been linked to a 112-mile-wide crater, dubbed Chicxulub, on the coast of Mexico's Yucatan Peninsula. Evidence for more dust than ice in comets Observations of Comet 9P/Tempel 1 made by ESA's Rosetta spacecraft after the Deep Impact collision suggest that comets are 'icy dirtballs', rather than 'dirty snowballs' as previously believed. NASA's Deep Impact Craft Observes Major Comet 'Outburst' NASA's Deep Impact spacecraft observed a massive, short-lived outburst of ice or other particles from comet Tempel 1 that temporarily expanded the size and reflectivity of the cloud of dust and gas (coma) that surrounds the comet nucleus. A Promise Of Half A Million Years: EU Research Provides New Insight Into Climate Change Within the EUR3,6 million EU research project PROMESS1 (PROfiles across MEditerranean Sedimentary Systems), with a EU EUR2,7 million contribution, European scientists have collected 500 000 year-old sediment cores from the bottom of the Mediterranean Sea. These samples will allow researchers to reconstruct climate variations since pre-historic times, thus providing keys for understanding what is happening to Earth's climate now. Ocean drilling is crucial in understanding changes in climate, as the sediments hold archives of past developments. PROMESS1 involves partners from France, Germany, Italy, Spain, the Netherlands and the United Kingdom. "The findings of the PROMESS1 project plac Nature press release for 1 August issue [1] LIFELINES: EARLY EGGS MAKE MICE (pp497-498) Normally it takes an adult female mouse to produce a fully functioning mouse egg. Now researchers have removed immature egg cells from fetal mice and completely matured them in vitro, with a success rate of over 90%. The techniques, described in this week's Nature, will give researchers a window on egg development, and may help us understand infertility and birth defects. If the methods can be used in humans - which is still some way off - they could save the fertility of women undergoing chemotherapy or radiotherapy, by removing an ovary before treatment. And being able to rescue and develop the huge numbers of immature egg cells that normally Nature press release for 21 June issue [411924] CHEMISTRY: BEADY WHEN WET (pp924-927; N&V) French physicists Pascale Aussillous and David Quéré of the Colle'ge de France in Paris show this week how to move a liquid across a surface without wetting it. By coating water droplets with a fine powder, the researchers turn them into tiny beads that roll over glass without sticking or leaving any trace. These ‘liquid marbles’ behave less like liquids and more like soft solids — as if made from very squishy rubber. The researchers think their non-stick droplets could find a variety of technological uses. They experience so little friction that very small forces induce motion. This might be useful in the em More Deep Impact News Articles |
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