Are blackholes

benzun_1999 · Oct 1, 2003

blackholes and light.....................

Dear Reader,
are blackholes capable of attracting light?
-benzun
the more dimensions we know, the more we know.

selfAdjoint · Oct 1, 2003

Yes. Light in the neighborhood of a black hole does odd things because of the gravitic attraction (= highly curved geodesics). I am sure some of our experts can give you links to anumations.

meteor · Oct 1, 2003

Hi,
In the framework of general relativity, mass is able to create a great distortion in spacetime, so spacetime around a BH will be very curved.
Photons have not mass, but they have energy, and in general relativity things with energy always follow the straightest way possible, that is called a geodesic. Near a black hole, the geodesic of a photon conducts to the black hole, so yes, photons will be attracted

Nereid · Oct 1, 2003

This site has some interesting animations, links to articles, etc:
http://www.phy.mtu.edu/bht/rjn_bht.html

Enjoy!

PS, I am not an expert.

Phobos · Oct 1, 2003

Welcome to Physics Forums, benzun_1999

russ_watters · Oct 1, 2003

meteor's explanation was good, but there is another implication here: since all mass warps space, all mass "attracts light"(not the wording I'd use, but it'll do). Black holes are not special in that regard.

For example, a photon passing by a star at a certain distance will have its path bent by the same amount as a photon passing by a black hole of the same mass at the same distance (measured from the center of each).

benzun_1999 · Oct 2, 2003

thanks....but....need more help

hi,
thank you phobos for inviting me. How does general relativity come hear. i am new to astronomy. i feel photons have relative mass.
-benzun
go easy on me

Mentat · Oct 2, 2003

Re: thanks....but....need more help

Originally posted by benzun_1999
hi,
How does general relativity come hear?

I'm not sure I understand the question. Are you asking why General Relativity has something to do with your previous question? If so, it's because General Relativity is the theory that showed that gravity is just a warping or curvature of spacetime. Thus it is not that the BH attracts light, but rather that the light must follow the straightest path possible (path of least resistance), and must thus curve its path right along with the curve in spacetime.

Of course, the velocity of the object plays a role, which is why most things do not "trap" photons (since they are travelling very fast), but blackholes are such a "steep" (for lack of a better word) curvature that even light cannot escape.

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Are blackholes

benzun_1999

selfAdjoint

meteor

Nereid

Phobos

russ_watters

Staff: Mentor

benzun_1999

Mentat