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Dropping stuff into the Sun


cubinator

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I was wondering if there is anything that, if dropped into the Sun, would survive for very long, say, long enough to get to the surface. What would happen if you dropped the same thing into different stars? If you changed the speed of the object? Discuss.

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"Survival" is a matter of perspective.

Anything big enough can exist long enough to reach the surface of the Sun. It's just a matter of adding more and more material until you have enough of it so it doesn't have enough time to burn off while approaching it.

Throwing it faster would also help.

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Just now, Shpaget said:

"Survival" is a matter of perspective.

Anything big enough can exist long enough to reach the surface of the Sun. It's just a matter of adding more and more material until you have enough of it so it doesn't have enough time to burn off while approaching it.

I see, as something like a planet would take a while to vaporize. I wonder what would happen to a neutron star if it were dropped in the Sun.

Just now, Shpaget said:

Throwing it faster would also help.

Would it really, though? Wouldn't there be more heat from compression?

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Solved problem.

6 minutes ago, cubinator said:

I see, as something like a planet would take a while to vaporize. I wonder what would happen to a neutron star if it were dropped in the Sun.

It would eat the Sun.

It would take a while.

It would look like this:

Spoiler

maxresdefault.jpg

And then it would look like this:

Spoiler

fig16.jpg

And then it would look like this:

Spoiler

96713main_DiskPreBurst.jpe

And then it would probably go supernova and leave behind a black hole.

15 minutes ago, cubinator said:

Would it really, though? Wouldn't there be more heat from compression?

"Compression" is not really the physics at play when you go sundiving.

22 minutes ago, Shpaget said:

Throwing it faster would also help.

Not really possible. Our biggest rockets, staged multiple times, couldn't come close to giving it a fraction of what it would get based solely on the sun's own gravity.

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10 hours ago, sevenperforce said:

Not really possible. Our biggest rockets, staged multiple times, couldn't come close to giving it a fraction of what it would get based solely on the sun's own gravity.

I don't consider our technical capabilities relevant. This is a thought experiment, a what if situation. Arbitrary propulsion technology is available, since we certainly don't have the capability to chuck anything sizable into the Sun.

I was thinking of a difference between just dropping something stationary (orbital speed = 0) in free fall towards the Sun from the height of Earth's orbit, vs giving it a decent push.

I don't know, maybe pushing would make things worse. Perhaps it would be better to brake once you start experiencing significant ablative damage to your heat shield.

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4 hours ago, Shpaget said:

I don't consider our technical capabilities relevant. This is a thought experiment, a what if situation. Arbitrary propulsion technology is available, since we certainly don't have the capability to chuck anything sizable into the Sun.

I was thinking of a difference between just dropping something stationary (orbital speed = 0) in free fall towards the Sun from the height of Earth's orbit, vs giving it a decent push.

I don't know, maybe pushing would make things worse. Perhaps it would be better to brake once you start experiencing significant ablative damage to your heat shield.

If your object were stationary relative to the sun at 1AU, it has Gravitational Potential Energy of approx 0.9GJ/kg, which would, if dropped, be all converted to kinetic energy, giving a final velocity (at zero distance, ie: at the centre-of-mass of the Sun) of around 42km/s. (Ahh! Ahh! 42! 42!)

Naturally, the speed would be somewhat less upon reaching the surface of the sun, some distance from the CoM, but you get the idea. 

Your "push" would have to be on the order of km/s to even be noticeable upon contact with the Sun.

There is no "normal" matter that would not be vaporised upon "contact" with the sun in a short space of time. Naturally "contact with the sun" is a hazy concept because being gaseous, its "edge" is ill-defined, and it gets pretty danged hot on approach as well.

Gravitationally bound object like neutron stars would survive, but in that case you are throwing an object with nearly the same amount of with a mass of the same order of magnitude as the sun, which is a bit like throwing a 20-ton boulder into a pond to see what kind of splash it makes - it will make an interesting splash, but you wont be left with the same pond afterwards.

Edited by p1t1o
fixed glaring error
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22 minutes ago, p1t1o said:

Gravitationally bound object like neutron stars would survive, but in that case you are throwing an object with nearly the same amount of mass as the sun*, which is a bit like throwing a 20-ton boulder into a pond to see what kind of splash it makes - it will make an interesting splash, but you wont be left with the same pond afterwards.

*greater than the mass of the Sun

If physics has taught me one thing, it's to be pedantic :P

Edited by Steel
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I do not understand everything of the question. The concept of a "surface" doesn't apply to a gas ball like the sun, the density rises when coming closer. The photosphere, that visual "surface" has a temperature of 4-5000K, so solid abjects from whatever real material are probably vaporized. If it sinks into the chromosphere the atoms would be turned into a plasma.

If you want to "drop" something from earths orbit you have to get rid of the orbital speed, +/-30km/s. Either according to Hohmann or by performing several swing-by maneuvers behind other orbital masses until the AP is low enough that the gases of sun's outer atmosphere will perform the rest. So the initial "small push" has to be at least strong enough to bring it behind another orbital mass (suggestion: Jupiter, he's good for a lot of things :-)) to initiate a series of swing-by(s) to drop the AP. Jupiter transfer can be made cheap, i think (a few km/s), that's the smallest initial push i could imagine.

I would guess that by the high orbital speed of an object, coming down all the way from Earth's or Jupiter's orbit, would be destroyed by friction in the gases surrounding the sun long before it comes close to the photosphere.

 

3 hours ago, Shpaget said:

 

I was thinking of a difference between just dropping something stationary (orbital speed = 0) in free fall towards the Sun from the height of Earth's orbit, vs giving it a decent push.

 

If you mean by "dropping" to decelerate the object from 30km/s to 0 relative to the sun and then wait you'll end up with a terminal speed "dive-in" speed of 30km/s (how comes :-)). If you give it "decent push" initially (to get behind another mass to initiate a swing-by series) you'll end up with 30km/s +/- decent push.

Is that correct ?

Edit: not considering any friction in interplanetary gases or near the sun

Edited by Green Baron
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28 minutes ago, Steel said:

*greater than the mass of the Sun

If physics has taught me one thing, it's to be pedantic :P

I shoulda said something more like "within the same order of magnitude" but hey-ho!

Well what I shoulda done is actually look it up.

But I was nearly right :wink:

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On 25/04/2017 at 3:22 AM, cubinator said:

I was wondering if there is anything that, if dropped into the Sun, would survive for very long, say, long enough to get to the surface. What would happen if you dropped the same thing into different stars? If you changed the speed of the object? Discuss.

I don't understand your question. Did you mean dropping normally where sun's gravity do the job, or being assisted any other means? Also "surface" is not a term that you should use when describing the sun since it's a gas ball of plasma powered by self-sustaining internal nuclear fusion with a very vague boundary between it's space, atmosphere and surface. Dropping it at another star? At what star magnitude? (Though I think the result is always the object being vaporized). Changing the speed of the object either makes it vaporized faster or dropped further (depend on what object)

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