speed of light vs black hole

[starchild185]

Im new to this site and my education on space stuff lacks much theory but here goes...If light cannot escape a blackhole would that not prove that the blackhole's gravity is pulling much faster then the speed of light and thus counter the theories that its impossible to reach the speed of light? Im probably looking at it the wrong way but I was just pondering this and would like to know <img src="/images/icons/wink.gif" />

 

[the_id]

A black hole is black because its escape velocity is greater than the speed of light. That is why even light cannot escape.

 

[larper]

You can look at it a couple of ways:<br /><br />1) Photons are affected by gravity just like anything else. As a photon approaches a mass, any mass, it bends toward the object. The resultant orbit is hyperbolic. However, with a black hole, if a photon gets close enough to get inside the event horizon, its orbit is no longer hyperbolic. It is now truly in orbit of the black hole. The photon has been captured by the black hole. <br /><br />2) Imagine some of the mass within the even horizon of the black hole. An event occurs which release a photon. The photon takes off in a radial direction, heading for the event horizon. As it moves out, it is getting redshifted to the extreme. Its wavelength becomes infinite. By the time it gets to the event horizon, it is no longer a photon.<br /> <div class="Discussion_UserSignature"> <p><strong><font color="#ff0000">Vote </font><font color="#3366ff">Libertarian</font></strong></p> </div>

 

[Maddad]

Starchild185<br />Welcome to SDC! Good first question, by the way.<br /><br />Space itself is not subject to the speed of light (c) limitation. This allows the universe to inflate faster than c, and it also allows space within the event horizon to shrink faster than c. Objects can be carried along with expanding or contracting space and therefore change their position at a rate that exceeds c. They just cannot travel through space this fast.

 

[a_lost_packet_]

Starchild<br /><br />Welcome to SDC!<br /><br />The escape velocity analogy is correct. Here is a simple explanation:<br /><br />Imagine you are at the bottom of a hill. You have enough energy to walk up the hill because it isn't very steep. However, picture yourself at the bottom of a much steeper hill. Try as you might, you just don't have the energy to climb to the top.<br /><br />The mass of a black hole, concentrated in such a small space, exerts tremendous gravity within that space. It's just to "steep" for light to climb out and escape. As far as physics is concerned, the speed limit in our space-time seems to be limited to the speed of light. Nothing is capable, as far as we are aware, of traveling faster than the speed of light in our 4 dimensional space. This would include objects, light or any other "information conveying" particle. However, as maddad pointed out, the Universe is expanding. So, if two objects are travelling very fast and the distance between them expands (due to the natural expansion of the Universe) then it may seem as if they are traveling "faster than light."<br /><br />The interesting thing is; Scientists are trying to figure out how to go "around" the hill instead of walking up it. One day, we may find out how to transmit information or move an object "faster" than the speed of light without having to entirely traverse our normal, 4D spacetime.<br /><br /><br /> <div class="Discussion_UserSignature"> <font size="1">I put on my robe and wizard hat...</font> </div>