Jupiter (1995 June 25 / 1995 July 14)

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ROC
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Jupiter (1995 June 25 / 1995 July 14)

Post by ROC » Thu Jun 04, 2009 2:26 pm

APOD 6/25/95 stated that Jupiter is a gas giant with no solid surface, APOD 7/14/95 stated that Comet Shoemaker-Levy 9 impacted Jupiter causing several explosions and sending dust into the atmosphere. Which is it solid or gas?

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Re: Jupiter

Post by neufer » Thu Jun 04, 2009 2:39 pm

ROC wrote:APOD 6/25/95 stated that Jupiter is a gas giant with no solid surface, APOD 7/14/95 stated that Comet Shoemaker-Levy 9 impacted Jupiter causing several explosions and sending dust into the atmosphere. Which is it solid or gas?
Comet Shoemaker-Levy 9 was solid; Jupiter is gas.
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Re: Jupiter

Post by ROC » Thu Jun 04, 2009 2:42 pm

If Jupiter is gas, what did the comet collide with?

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Re: Jupiter

Post by bystander » Thu Jun 04, 2009 2:47 pm

Wiki: Comet Shoemaker-Levy 9
Wiki: Jupiter
ROC wrote:If Jupiter is gas, what did the comet collide with?
High density gas. If most meteorites burn up in the Earth's atmosphere and never reach the ground, think of how much harder it would be to penetrate Jupiter's atmosphere.
Wiki: Comet Shoemaker-Levy 9 wrote:The first impact occurred at 20:13 UTC on July 16, 1994, when fragment A of the nucleus slammed into Jupiter's southern hemisphere at a speed of about 60 km/s. Instruments on Galileo detected a fireball which reached a peak temperature of about 24,000 K, compared to the typical Jovian cloudtop temperature of about 130 K, before expanding and cooling rapidly to about 1500 K after 40 s. The plume from the fireball quickly reached a height of over 3,000 km. A few minutes after the impact fireball was detected, Galileo measured renewed heating, probably due to ejected material falling back onto the planet. Earth-based observers detected the fireball rising over the limb of the planet shortly after the initial impact

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Re: Jupiter (1995 June 25 / 1995 July 14)

Post by The Code » Thu Jun 04, 2009 3:12 pm

When does Gas become a solid?

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Re: Jupiter (1995 June 25 / 1995 July 14)

Post by bystander » Thu Jun 04, 2009 3:16 pm

mark swain wrote:When does Gas become a solid?
Depends on pressure and temperature and the type of gas.

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Re: Jupiter (1995 June 25 / 1995 July 14)

Post by neufer » Thu Jun 04, 2009 3:22 pm

bystander wrote:
mark swain wrote:When does Gas become a solid?
Depends on pressure and temperature and the type of gas.
http://en.wikipedia.org/wiki/Gas_giant wrote:
<<The four solar system gas giants share a number of features. All have atmospheres that are mostly hydrogen and helium and that blend into the liquid interior at pressures greater than the critical pressure. On Jupiter and Saturn there is no clear boundary between atmosphere and body, but on Uranus and Neptune some models show that the boundary could indeed be sharp. In this regard, our four gas giants exemplify the classic "matter phase-gradient" in the materials sciences. They have very hot interiors, ranging from about 7,000 kelvin (K) for Uranus and Neptune to over 20,000 K for Jupiter. This great heat means that beneath their atmospheres the planets are most likely entirely fluid (liquid or supercritical). Thus, when discussions refer to a "rocky core," one should not picture a ball of solid rock. Rather, what is meant is a region in which the concentration of heavier elements such as iron and nickel is greater than that in the rest of the planet.>>
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Re: Jupiter

Post by Chris Peterson » Thu Jun 04, 2009 3:38 pm

bystander wrote:
ROC wrote:If Jupiter is gas, what did the comet collide with?
High density gas. If most meteorites burn up in the Earth's atmosphere and never reach the ground, think of how much harder it would be to penetrate Jupiter's atmosphere.
Probably not high density at all. At the height where SL9 burned up, the atmosphere of Jupiter is pretty tenuous. The only high density gas was that which was being compressed directly in front of the fragments- that compression being the source of energy that burned up the fragments and produced the light we were able to see.
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Re: Jupiter (1995 June 25 / 1995 July 14)

Post by The Code » Thu Jun 04, 2009 4:21 pm

How deep did the probe get before it shut down?

I think it would of been a little harsher than a few flashing lights chris.
http://www.psi.edu/projects/siberia/siberia.html

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Re: Jupiter

Post by Case » Thu Jun 04, 2009 4:44 pm

Chris Peterson wrote:and produced the light we were able to see.
I mostly remember the dark impact spots that remained for some months. :wink:
I, for one, like Roman numerals.

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Re: Jupiter (1995 June 25 / 1995 July 14)

Post by Chris Peterson » Thu Jun 04, 2009 5:09 pm

mark swain wrote:How deep did the probe get before it shut down?
Are you talking about the atmospheric probe dropped by Galileo? It made it down about 150 km.
I think it would of been a little harsher than a few flashing lights chris.
Sorry, not sure what you're saying here. What would be harsher? What flashing lights?
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Re: Jupiter (1995 June 25 / 1995 July 14)

Post by The Code » Thu Jun 04, 2009 5:56 pm

Chris Peterson wrote:Probably not high density at all. At the height where SL9 burned up, the atmosphere of Jupiter is pretty tenuous. The only high density gas was that which was being compressed directly in front of the fragments- that compression being the source of energy that burned up the fragments and produced the light we were able to see.
What densities was the probe able to with stand? If it shut down at 150 KM Would that be the depth of SL9 impacted? If the gas giants have been cleaning the solar system for 4.5 Billion years,, What else is inside them?

You said lights we saw.. Made me think you meant they wasn't much of an event.

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Re: Jupiter (1995 June 25 / 1995 July 14)

Post by BMAONE23 » Thu Jun 04, 2009 7:11 pm

Don't forget, the Probe was teathered to a parachute and was traveling significantly slower than SL9 at the time of its impact with the Jovian atmosphere.

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Re: Jupiter (1995 June 25 / 1995 July 14)

Post by bystander » Thu Jun 04, 2009 7:24 pm

mark swain wrote:You said lights we saw.. Made me think you meant they wasn't much of an event.
To see much at all from earth based observatories, it must have been quite an event.

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Re: Jupiter (1995 June 25 / 1995 July 14)

Post by Chris Peterson » Thu Jun 04, 2009 7:36 pm

mark swain wrote:What densities was the probe able to with stand? If it shut down at 150 KM Would that be the depth of SL9 impacted?
The probe failed at a pressure of about 2.3 MPa (23 atmospheres). But it had lost all its cosmic entry velocity before the pressure even reached a half atmosphere. So its "impact", and heat shield ablation, was very high, before the atmosphere became very dense at all.

It is estimated that the largest fragments of SL9 had completely fragmented before the pressure even reached 1/4 atmosphere. So indeed, this happened while the atmosphere was still very thin.
If the gas giants have been cleaning the solar system for 4.5 Billion years,, What else is inside them?
No doubt, they've absorbed quite a bit of asteroidal and cometary material (as have the terrestrial planets). But in terms of their total mass, I'm sure it's a vanishingly small amount.
You said lights we saw.. Made me think you meant they wasn't much of an event.
Not at all! 6 million megatons equivalent is no small event. I only meant that the light we saw was from the heating of compressed atmospheric gases in front of the fragments, even though they themselves were still in a thin atmosphere.
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