Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: moccacake on 09/12/2006 17:43:48

Title: How close can a satellite orbit the sun
Post by: moccacake on 09/12/2006 17:43:48

How close can a space probe get to the sun before it gets sucked in by the gravity?

Title: Re: How close can a satellite orbit the sun
Post by: ukmicky on 09/12/2006 18:37:17

I suppose it would depend on how much angular momentum you gave it.

Title: Re: How close can a satellite orbit the sun
Post by: Soul Surfer on 09/12/2006 23:39:35

Nothing ever just gets "sucked in" by gravity.  Assuming that it initially is in an orbit around the sun it can continue to change its orbit and get closer to the sun until the density of the sun's atmosphere slows it down so much that it will fall into the sun  like satellites and meteors burning out in the earth's atmosphere.  That means gettin opretty close to the surface of the sun as we sre it but by then it will have melted anyway.

Title: Re: How close can a satellite orbit the sun
Post by: lyner on 16/12/2006 14:48:53

Yes - People have this same problem with black holes. You could be in orbit   around a black hole  for ever as long as you weren't near enough for relativity to be a consideration.
lyner

Title: Re: How close can a satellite orbit the sun
Post by: daveshorts on 17/12/2006 12:20:03

This is true under newtonian mechanics, however unforutunately for simplicity, it doesn't quite work when you enter the realm of general relativity. If spacetime is very curved, like very close to a black hole, then orbits cease to be stable.
http://www.fourmilab.ch/gravitation/orbits/

Title: Re: How close can a satellite orbit the sun
Post by: syhprum on 17/12/2006 12:42:08

I think the minimum orbital time for a body around the Sun is about 95 minutes but in practice nothing could survive that close.
Planets have been observed orbiting somewhat smaller stars in two days