Wild 2 Comet Analyzed

Mz6 writes "Back in January Slashdot reported about the Stardust probe and its capture of particles from the tail of Wild 2 (pronounced 'Vilt 2'). You might also remember about how it snapped 72 images of the comet and sent them back to JPL. Well, after a detailed analysis of the comet Wild 2 and building upon preliminary analysis in March, it has left astronomers at JPL astounded at an object that has no known peers in the solar system. The comet has towering protrusions and steep-walled craters that seem to defy gravity, more than a dozen jets of material shoot out from its insides, dust swirls around the comet in unexpectedly dense pockets, and boasts 2 large 'footprints', aptly named Left and Right."

Links

[Mz6]

Ok... Well when I submitted this story I forgot to include links to the Stardust Website [nasa.gov], Wild 2 Photos [nasa.gov], and some interesting Wild 2 Stereo Photos [nasa.gov] (2.0 MB). Best of all.. there's minimal reading, just pretty pictures. Enjoy :)

Re:Gravity defying craters?

[Mz6]

Here's a bit as to why... From the article:

Craters on Wild 2, presumably caused by run-ins with smaller objects, are strangely free of the powder, rocks and other debris commonly seen in impact craters on other bodies. Brownlee thinks this is because the comet is a bit like hard, frozen dirt that takes a hit but is brittle, so material flies out.

And because the comet is so small, the material does not fall back.

"There's almost no gravity at the surface," Brownlee said. "If you were standing on [the surface], you could jump into orbit."

Re:And the number 2?

[hopemafia]

Given that Vilt is the German pronounciation of Wild, I would guess 2 is pronouced zwei.

Jump into orbit?

[Rei]

The thing is, that doesn't seem right. You shouldn't be able to "jump into orbit" anywhere (barring atmospheric braking, a change of mass, additional thrust applied, etc, to change your velocity). Your path will either intersect the object you're jumping from, or break its escape velocity. Perhaps this is different for irregularly shaped bodies with irregular gravitational fields, but good luck trying to establish a stable orbit there through "jumping"....

Now, you *could* "run into orbit", assuming you can get the traction to do so, on a perfectly smooth low gravity atmosphere-less body - you run up to orbital velocity, then curl your body up, and you'll orbit at the altitude of your center of mass. But, if you were to have any significant "jumping" component, you'll likely make yourself intersect the body you're trying to orbit.

Also, you could jump up and throw a rock and enter orbit that way. However, in the case that you're dealing with a uniform graviational field around a perfect sphere, and the rock that you throw has the same mass as you, you'll hit it on the other side ;)

Re:And the number 2?

[The Grassy Knoll]

>I would guess 2 is pronouced zwei

or even "tsvai"?

Pedantically yours...

Re:crap science

[E-Rock]

You might try reading the rest of the article before you go all asshat. This is the comet's first trip thru the inner solar system.

"In 1974 it had a close encounter with Jupiter and was thrown onto a new orbit that brings it closer to the Sun. A comet loses material when it approaches the Sun, as solar radiation causes ice from its surface to "sublimate" into space, carring dust and larger particles with it. The process creates a cloud of material that reflects sunlight and creates the familiar head of a comet (scientists call it a coma) and sometimes a tail."

Re:crap science

[dylan_-]

If the planet has lost about 1 meter worth of material since 1974 then at that rate it would have lost about 937 miles worth of material at a constant rate since its "birth" "4.5 billion" years ago.

Firstly, it's not a planet, it's a comet.

Secondly, as the article says, "In 1974 it had a close encounter with Jupiter and was thrown onto a new orbit that brings it closer to the Sun. A comet loses material when it approaches the Sun"

Thirdly, if it had been a constant rate, it would have been 93210 miles, not 937.

Hope this helps...

Re:crap science

[0123456]

"If the planet has lost about 1 meter worth of material since 1974 then at that rate it would have lost about 937 miles worth of material at a constant rate since its "birth" "4.5 billion" years ago."

I guess it's too much to expect people here to have actually _read_ the article before they start claiming that the authors are idiots?

"Comet Wild 2 probably gathered itself together 4.5 billion years ago, just after the Sun was born, in a region beyond Neptune known as the Kuiper Belt. _In 1974 it had a close encounter with Jupiter and was thrown onto a new orbit that brings it closer to the Sun_."

Re:crap science

[nickstance]

yes, but if you read the article, you would have seen that "In 1974 it had a close encounter with Jupiter and was thrown onto a new orbit that brings it closer to the Sun. A comet loses material when it approaches the Sun, as solar radiation causes ice from its surface to "sublimate" into space" So in no way could you say that the loss is "uniform" before 1974, it would have lost damn little of it's mass

Re:What's it made of?

[Eclipce]

It is not a "dirty snowball". See James McCanney Science [jmccanneyscience.com]. You will need to read his two books "Planet X, Comets and Earth Changes" and "Atlantis to Tesla - The Kolbrin Connection" in that order.

Re:What's it made of?

[Anonymous Coward]

http://www.iscid.org/encyclopedia/Panspermia
http ://www.panspermia.org/
http://www.space.com/searc hforlife/aliens_all_0010 27-1.html
http://en.wikipedia.org/wiki/Panspermia

http://www.ucmp.berkeley.edu/archaea/archaea.htm l
http://www.bartleby.com/65/ar/Archaea.html
htt p://co.essortment.com/archaebacteriae_rmkr.htm

http://waynesword.palomar.edu/ploct97.htm

http://cas.bellarmine.edu/tietjen/Evolution/Time /e vidence_for_life_on_earth_more
_.htm
http://www. ncbi.nlm.nih.gov/entrez/query.fcgi?hold ing=npg&cmd=Retrieve&db=PubMed
&list_uids=1153661 7&dopt=Abstract
http://www.wkap.nl/prod/b/0-306-4 6689-9?a=1
http://jesse.usra.edu/articles/breiter man/breiterm an-paper.html
http://www.cosis.net/abstracts/COSP AR04/00315/COSP AR04-A-00315.pdf
http://smallcomets.physics.uiowa .edu/blackspot.htm l

errr... by not using a comma

[Saltation]

see subject...