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Fraser
2005-Jun-21, 06:38 PM
SUMMARY: New images taken by NASA's Deep Impact spacecraft show the actual nucleus of its target, Comet Tempel 1. The nucleus is the heart of the comet, and largely composed of ice and rock. Surrounding that is a halo of gas and dust that largely obscures the view. Tempel 1 isn't a sphere, but an oblong potato-shaped object, 14 km (9 miles) long by 4.8 km (3 miles) wide. By continuing to watch the nucleus as it approaches, Deep Impact will provide scientists with a better idea of the comet's rotation and orientation, so they can fine tune the final collision on July 4.

View full article (http://www.universetoday.com/am/publish/first_view_tempel1_nucleus.html)

What do you think about this story? Post your comments below.

antoniseb
2005-Jun-21, 07:28 PM
Over the next two weeks, this story (Deep Impact, not the first image) is going to get a lot of press, and it deserves it. The results should be interesting.

gofree
2005-Jun-21, 09:32 PM
[QUOTE]"Next wee need to determine using additional nucleus detectors, how the comet is rotating in space, so we can figure out what part we will hit on July 4th."

A'Hearn and his fellow mission scientists expect the impact to create a crater several hundred feet in size; ejecting ice, dust and gas from the crater and revealing pristine material beneath. The impact will have no significant affect on the orbit of Tempel 1, which poses no threat to earth.



[SIZE=1]_______________
"If anyone thinks he has acquired knowledge of somthing, he does not yet know [it] just as he ought to know [it]" 1Corinthians 8:2 :unsure:

katinas21
2005-Jun-21, 09:57 PM
What is probability when ball will bonk with comet and ball changes comet trajektory? If ball change comet trajektory comet can will bonk with Earth? What is yours opinion? Write your opinion please... And what is this comet magnitude? If you know please write? :huh:

antoniseb
2005-Jun-21, 10:13 PM
Originally posted by katinas21@Jun 21 2005, 09:57 PM
What is probability when ball will bonk with comet and ball changes comet trajektory? If ball change comet trajektory comet can will bonk with Earth?
The probability that this will make the comet hit the Earth is zero.

Joff
2005-Jun-21, 10:51 PM
Originally posted by katinas21@Jun 21 2005, 09:57 PM
What is probability when ball will bonk with comet and ball changes comet trajektory? If ball change comet trajektory comet can will bonk with Earth?
For the quick answer (as per antoniseb) read the Deep Impact FAQ (http://deepimpact.jpl.nasa.gov/faq3.html#q1) on this.

Tempel 1 is roughly at perihelion at time of impact with an orbital velocity in the region of 100 000km/hour. The Deep Impactor is closer to aphelion with an orbital velocity of about 65 000km/hour. The two orbits are in the same direction but the comet, being faster, "runs over" the impactor, with a relative speed of over 35 000km/hour. All this happens very near the orbit of Mars (although not near the planet itself). See this orbital chart (http://deepimpact.umd.edu/amateur/where_is.shtml).

Mass of Tempel 1 is at least 10 000 million tonnes. Mass of the impactor is 0.37 tonne. The change in orbital momentum of the comet is about 13 k tonne-km/hour which compares to the total orbital momentum of 1 million million k tonne-km/hour. Thus the maximum proportional change is one eighty-thousand-millionth of the total orbital momentum, which would be an orbital velocity change of 1cm/hour.

This miniscule effect, completely swamped by other effects (especially Jupiter's gravity at the other end of the comet's orbit), would in effect contribute to a tiny degree to reduce the aphelion of the comet - that is, to circularise its orbit ever-so-slightly. It would still be way outside Mars' orbit for 9/10 of the time though.

Scientists would be overjoyed if they detected any change at all in the comet's orbit, because this might allow a more accurate calculation of the comet's mass. Realistically, it's not going to happen though.

buzzlightbeer
2005-Jun-27, 04:50 PM
is there any site or info for some1 who knows nothing about star maps etc. on how to watch this? would binoculars work? etc etc
thanks!

gofree
2005-Jul-03, 05:29 AM
Originally posted by buzzlightbeer@Jun 27 2005, 04:50 PM
"...the bright point in the center of the coma."
Was that event an image of primordial light, is that what it looked like.


___________
"If anyone thinks he has acquired
knowledge of somthing, he does
not yet know [it] just as he ought
to know [it]." 1Corinthians 8:2