# Sun Density profile and meteors

The wikipedia article on our Sun describes well the different layers of the sun.

What is the fate of a common meteor that strikes the sun ? (for discussion purposes assume a meteor made of iron and striking normally (perpendicular) to the surface). I would assume that the outer layers offer minimal resistance and the meteor travels quite a distance before it stops / disintegrates into a spray…

Also, whats the speed needed for a meteor to enter the core of the sun ? (assume the meteor is made of ceramic with an extremely high fusion point.)

Any takers ?

I expect the typical meteor simply melts long before it hits.

As for penetrating to the core,we’re talking about penetrating hundreds of kilometers of extremely hot, progressively dense gas. You’d probably have to do something ridiculous like throw an object at 0.9999999999999999999999951c* light speed so that the subatomic particles that used to be the object punch their way though to the core.

*Number pulled from this xkcd what-if article because it’s the speed of the fastest real particle I’ve heard of and a neat article; so don’t take it too seriously.

It’s going to slowly break apart and burn up, same as for meteors hitting earth’s atmosphere.

Thanks for replying - but its not like earth’s atmosphere - right ? to begin with there isn’t any oxygen to burn up…

And more than likely, the meteor has the heaviest elements in it compared to the sun - so will the elements sink to the core ?

Is there a simulation or calculations showing such an encounter ?

Fair enough, so how many layers does a typical meteor penetrate ?

It’s not burning up in the sense of combustion; it’s being boiled away due to the heat of the Sun and if it actually gets close, friction with the solar atmosphere.

Possibly, but it would take a very long time; the Sun is enormous.

Not very far at all, if it even reaches the Sun. Most meteors don’t even reach the surface of the Earth, and Earth is tiny and cold compared to the Sun.

The sun’s photosphere is about 5800 K. No known material remains solid at that temperature when exposed to vacuum.

I think it might be possible for a solid object to reach the photosphere if it’s very massive and moving fast (so it doesn’t all boil away before it gets there). My WAG is that it would have to be the size of a large asteroid. And there’s no way it would get all the way through the convection zone. The pressure at the bottom of the photosphere is already something like 100 millibar, so there is a fair amount of conductive heating in addition to radiation.

NASA is currently building the Solar Probe Plus which really represents how close we can get a probe to the Sun. It only gets to about 8.5 solar radii. (Though I think it’s limited more by orbit than thermal design - remember, if you want to drop something onto the sun, you need to kill all its orbital speed. IIRC it takes more energy to reach the surface of the sun than to escape from the solar system.)

Great that we agree it differs from what happens when a meteor hits the earth’s atmosphere. So the predominant mode of heating up of the meteor is radiation from the sun - right ? The friction would be very little since it is the lighter elements - right ? Or maybe the density is very high in the atmosphere of the sun due to the gravity ?

The outer portion of the Sun’s atmosphere is very diffuse, but about at the point where you get to the visible surface, the density goes up rapidly. Overall, the density of the Sun is somewhat more than that of water.

As a rough rule of thumb, an object passing through a fluid will be stopped when it’s swept through an amount of fluid equal to its own mass. A metallic asteroid (the densest kind) is still somewhere less than 8 times the density of water. So even that will only get you a few times the asteroid’s size into the surface.

Thats a great rule of thumb and it makes sense from conservation of energy perspective. But I think in this case though, it will settle at the terminal velocity, not stop. What is the terminal velocity in sun’s atmosphere ?

It’ll depend on the size of the asteroid, which will be rapidly changing as the outer layers boil away and vaporize. (Specifically, the terminal velocity of an object is usually proportional to its radius.)