Monday, July 04, 2005

BULL'S EYE Surely, Temple Probe a Success


Since ancient times, the appearance of comets caused fear and desolation. These flying stars frightened humans and were called "catastrophes" and they portended the death of kings and the fall of empires. They can certainly be dangerous. After all, they might have wiped out many life forms in the past after striking the earth!

This 4th of July, we witnessed yet another successful unmanned scientific mission for NASA. The probe sent to Temple 1 nailed its target and produced a huge cloud of dust. Now we can learn more about these amazing objects.

And learn we must! This is literally life and death. We need to know a great deal about comets for good reasons.

Back in 1994, we witnessed an amazing event. A comet fell into Jupiter's deep gravitational pool and was tugged apart as it passed through each LaGrange point until it was a necklace of burning debrie. Jupiter is only one step below a small star so the comet blazed brightly as the parts burned as it fell. There was intense speculation at the JPL over the density of the comentary fragments and if it would even disturb Jupiter's surface or just disappear silently without a trace.
The impact was pretty amazing. Here is a NASA artist, David Seal's rendition of what it looked like as the comet fragments flew into the south pole of Jupiter, as seen from below:
The fireballs as the fragments entered Jupiter's interesting chemical stew of an atmosphere set off tremendous fireballs.
Scientists were awestruck and immediately wondered what was the material compostion of comets which would cause such a massive effect. Prior to this, they called comets "dirty iceballs" and had wildly divergent estimations of the density of these comets but after this huge event, the density of comets was raised much higher.

Previous probes got some interesting shots of a comet which looks an awful lot like objects in the asteroid belt. Like the Borrelly probe in 2001:
Don Yeomans, a Jet Propulsion Laboratory scientist who studies asteroids and comets, said the new images were better than those taken of Halley.

Yeomans described comet Borrelly as an icy dirtball. The new observations support other recent studies indicating that comets may not contain as much water as was once thought -- an assumption that had earned them the name "dirty snowballs."
Scientists have to assume many things until better equiment allows them to certify information. Very often, the information is astonishing and amazing and sometimes, revolutionary. After all, the concept of "revolutionary" as meaning great change comes directly from the change in ideology brough about by the great astronomical work, "De Revolutionibus Orbium Coelestium" by Copernicus.

Curiousity as to what comets were rose as the photos of the space probe gave scientists a clear shot:
From some regions, which appear like smooth plateaus and are lighter, jets of gas and dust can be seen shooting out. Three small jets combine to form what is seen in a more distant image as one large jet shooting outward about 37 miles (60 kilometers).

The jets are not the same as the tails that make comets famous. Tails point away from the Sun, driven outward by the solar wind. The newly spotted jets, however, point nearly toward the Sun and are thought to be created when sunlight burns water and other chemicals from the comet's surface.

The jets are the result of ice sublimating, or turning directly to a gas and evaporating off the comet. The gas carries dust with it, and the dust reflects sunlight and makes the jets visible, the researchers explained.
Last night's successful strike will give us a great deal of information for this is an object from the Kuiper belt which surrounds our solar system at the outermost reaches of the sun's LaGrange gravity points. This is the stuff which makes up all those mysterious "dark matter" clouds that obscure much of our view of our own galaxy.
Probe hitting the comet, raising a huge cloud of dust.

From the NYT:
A space probe hit its comet target late Sunday in a NASA-directed, Hollywood-style mission that scientists hope will reveal clues to how the solar system formed. It marked the first time a spacecraft touched the surface of a comet, igniting a dazzling Independence Day weekend fireworks display in space.

NASA scientists talked on Sunday about the space probe that was on course to intercept a comet early on Monday.
The successful strike 83 million miles away from Earth occurred just before 11 p.m. PDT, according to mission control at NASA's Jet Propulsion Laboratory in Pasadena, which is managing the $333 million mission.

Scientists at mission control erupted in applause and gave each other hugs as news of the impact spread.
The joy of the scientists is always fun to watch. Far from the stereotypes of cold blooded people, nearly all scientists I have known are quite open about their joy at discovery and they really do love new information and new challenges.
The mothership had a front-row seat to the comet strike 5,000 miles away. NASA's fleet of space telescopes, including the Hubble Space Telescope, Chandra X-ray Observatory and Spitzer Space Telescope, and dozens of ground observatories also viewed the impact.
I can't wait for the other images and the data! This is very fascinating. And I am betting, every comet is unique and has different properties and composition. The material floating around in space after 12 billion years of combining/breaking apart is diverse and diffuse.

Every asteroid and every planet and every comet and every star...each is individual, unique and variable as every living thing on earth is different and variable.

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