"comets (being composed of ice, methane and rocks)"
per NASA:
Deep Space 1 Finds Hot, Dry Surface On Comet Borelly
Apr 5 2002 @ 11:40 by NASA/JPL
Comets are sometimes described as "dirty snowballs," but a close flyby of one by NASA's Deep Space 1 spacecraft last fall detected no frozen water on its surface.
Comet Borrelly has plenty of ice beneath its tar-black surface, but any exposed to sunlight has vaporized away, say scientists analyzing data from Deep Space 1, managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif.
[no evidence of this produced]
"The spectrum suggests that the surface is hot and dry. It is surprising that we saw no traces of water ice," said Dr. Laurence Soderblom of the U.S. Geological Survey's Flagstaff, Ariz., station, lead author of a report on the Borrelly flyby results appearing in the online edition of the journal Science.
"We know the ice is there," he said. "It's just well-hidden. Either the surface has been dried out by solar heating and maturation or perhaps the very dark soot-like material that covers Borrelly's surface masks any trace of surface ice."
[not exactly based on scientific evidence, that statement]
The Deep Space 1 science team released pictures and other initial findings days after the spacecraft flew within 2,171 kilometers (1,349 miles) of the comet's solid nucleus on September 22, 2001. This week's report provides additional details about the nucleus and the surrounding coma of gases and dust coming off of the comet as measured by one of Deep Space 1's scientific instruments.
"Comet Borrelly is in the inner solar system right now, and it's hot, between 26 and 71 degrees Celsius (80 and 161 degrees Fahrenheit), so any water ice on the surface would change quickly to a gas, " said Dr. Bonnie Buratti, JPL planetary scientist and co-author of the paper. "As the components evaporate, they leave behind a crust, like the crust left behind by dirty snow."
[so let's see: it's hot and we can't see the ice, but by golly it's gotta be an ice ball--we just know that]
Borrelly is unusually dark for an object in the inner solar system. The comet's surface is about as dark as a blot of photocopy toner, possibly the darkest surface in the solar system. It is more like objects in the outer solar system such as the dark side of Saturn's moon Iapetus and the rings of Uranus.
[hmmmmm, it's hot--in space-we can't see the ice, and its pretty damn dark, unlike most snow/iceballs]
"It seems to be covered in this dark material, which has been loosely connected with biological material." Buratti said. "This suggests that comets might be a transport mechanism for bringing the building blocks of life to Earth." Comets may have played an important role in supplying organic materials that are required for life to originate.
[an interesting speculation]
Soderblom points out that Borrelly's old, mottled terrain with dark and very dark spots -- different shades of black -- are apparently inactive. Ground based observations estimated that 90 percent of Borrelly's surface might be inactive, and the observations taken by Deep Space 1 show that this is indeed true.
"It's remarkable how much information Deep Space 1 was able to gather at the comet, particularly given that this was a bonus assignment for the probe," said Dr. Marc Rayman, project manager of the mission. Deep Space 1 completed its original goal to test 12 new space technologies and then earned extra credit by achieving additional goals, such as the risky Borrelly flyby. "It's quite exciting now as scientists working with this rich scientific harvest turn data into knowledge."
hypography.com
02.03.06
Deep Impact Team Reports First Evidence of Cometary Ice
Comet Tempel 1, which created a flamboyant Fourth of July fireworks display in space last year, is covered with a small amount of water ice. [how much? stay tuned] 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.
[we knew it, we just had no evidence. Hmmmmmm, doesn't sound like science]
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.”
[a very interesting speculation]
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.
[a spectacular explosion that produced no evidence of an interior made of ice]
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 [speculation] 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 [more speculation] send this surface ice, as well as interior ice [which didn't show up when we hit it with a projectile that produced a spectacular explosion], 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 Press Release
nasa.gov
300,000/1.2 bil= 0.025% of which only 6% was ice
There is no scientific proof comets are made of any substantial proportion of ice, but they do appear to have the potential to be transport mechanisms that brought water, organic and other matter to Earth. They are hot and extremely dark. They do not melt when they pass near the sun, even in areas with a temperature of 1,000,000 degrees. |
