Deep Impact

I looked up the composition of common metorites and they are mostly iron if I got the right info not carbon. How does this apply to the comet? I thought they were different than metorites?

In pondering the structure of comets it makes sense to me that comets are made the same as meteors-that is with iron cores. It could be the meteors are comets striped of their atmosphere of ice and gases and the comet is a new arrival in the solar system. This would be a logical result if as I have been saying gravity is not a force centered at a mass center as is assumed by everyone else here and elsewhere. In this perspective the comet enters the solar system from interstellar space which is impossible according to everyone who places the center of gravity at a mass center.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Jim</i>
<br />I looked up the composition of common metorites and they are mostly iron if I got the right info not carbon. How does this apply to the comet? I thought they were different than metorites?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Most meteorite discoveries are of iron meteorites because they are so different from terrestrial rocks and easy to spot. But iron meteorites are rare compared with chondritic meteorites, which make up &gt;80% of all meteorite falls. And when we go to special places such as Antarctica, where every rock is necessarily a meteorite, we do indeed find almost all chondritic and carbonaceous meteorites and very few irons.

Comets in mainstream models (the "dirty snowball") are indeed very different. But in the exploded planet hypothesis, they are the same as asteroids, but have not yet had all their volatiles boiled away. And most meteor showers such as the Perseids and Leonids are associated with comets. Dust particles in Earth's atmosphere, collected by high-altitude balloon flights, contain more carbonaceous material right after a shower of meteors from a comet than at other times. -|Tom|-

Thanks for the info about the carbon based rocks that makeup some meteors found on Earth. Is this is a kind of rock not found in the geological record? It is assumed that carbon rocks in the crust of Earth formed by biological activity and since rocks from space are carbon based I guess that assumption is false. Carbon rocks can form without a biosphere-or do you think they were formed by a biosphere somewhere? I hope the Deep Impact probe will resolve this.

I was watching a NASA/JPL news conference Monday afternoon where they were showing some of the first images from the impact. The quality of these images is great. My hat is off to the scientists, engineers and technicians responsible for the hardware and software comprising this mission.

Several images were described as showing "jets" comming from the nucleus. The speaker seemed quite confident about this, but I don't understand why. Even though Temple 1 rotates slowly (40 something hours I believe) I would still expect to see some evidence of curvature in a matter jet due to that rotation. Instead the images showed absolutely straight lines radiating out from the comet.

Rather than matter jets, my first guess as to an explanation would be light reflected from the comet onto a surrounding cloud of particles. But I suppose 40 something hours might be such a slow rotation rate that jet curvature would be imperceptable. It would depend on the speed of ejection of the jet particles.

For the impact itself this speed would be quite high and curvature of the impact jet ought to be too small to be seen, at least in a "close up". But for traditional comet jets I would expect some portion of the particles to be moving as slowly as a few meters per second. And I would expect to be able to see some curvature in such a jet.

Has anyone seen images from this comet (or any other comet) that shows curved jets?

Regards.
LB

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Larry Burford</i>
<br />Has anyone seen images from this comet (or any other comet) that shows curved jets?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">This is an excellent point, Larry. No curvature is seen even for comets that rotate much faster than Temple 1. That implies very high ejection speeds if the objects really are jets. But earlier data trying to measure such speeds indicated that the particle speeds must be very moderate. -|Tom|-