Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Ales Ramsa on 28/02/2011 18:30:03

Title: How does gravity escape a black hole?
Post by: Ales Ramsa on 28/02/2011 18:30:03
Ales Ramsa  asked the Naked Scientists:
   
Hi Chris,

I love the Naked Scientist shows (http://www.thenakedscientists.com/HTML/podcasts/) and thank you so much for feeding my brain with so much exciting stuff :)

I have this question that is bothering me very much:

Can gravity bend gravity? And is there empirical proof that gravity escapes from within black hole even if light can't?
Assumption: we know that gravity warps space and so in turn bends light (beccause it only continues in a straight line in the warped space ...) 
Does it then sound logical that gravity is also bent by gravity because of the same reason?
Also, do we know for a fact if gravity escapes from inside black hole or is it possible that no gravity escapes from the inside of black hole and all the gravity around a black hole we can observe is only generated by matter that has not fallen into a black hole yet?
If gravity does escape from within a black hole, doesn't it then mean that it had to travel faster than light to do so (because light is traveling at speed of light and yet cannot escape)?

Thanks and looking forwad to all the future podcasts (http://www.thenakedscientists.com/HTML/podcasts/).

Kind Regards,
Ales Ramsa

What do you think?
Title: How does gravity escape a black hole?
Post by: Bill S on 28/02/2011 18:52:26
Hi, Ales, this is just the thoughts of a non-scientist.
If what we perceive as gravity is simply the warping of spacetime, not a force, and black holes form as a result of extreme warping of spacetime, what is there to escape?  The only way to lessen gravity in a BH is to take some of the mass out, or reduce its density, thus reducing the curvature of spacetime.

Perhaps you were thinking of gravity in terms of quantum theory, and were wondering about gravitons escaping.  If that's the case, you'll have to wait for an answer from someone with more expertise.  A theoretical particle mediating a force that is not a force, possibly escaping from infinitely curved spacetime, which may not be infinitely curved, is a bit beyond me.  [???]