Why Can’t Light Escape a Black Hole?

-- Cardin | May 24, 2021

Question:

Is the reason light cannot escape a black hole more due to the relative stop in time within the EH rather than the gravity slowing down the speed of light? The light could still be travelling at c but since v is a function of t, the relative t elapsed to an observer is always zero.

-- Cardin

Answer:

Within the event horizon of a black hole space is curved to the point where all paths that light might take to exit the event horizon point back inside the event horizon. This is the reason why light cannot escape a black hole. Another way to look at it is that the escape velocity from the event horizon of a black hole is faster than the speed of light. Since nothing can travel faster than the speed of light, nothing escapes the event horizon of a black hole.

-- Jeff Mangum

Facebook

Twitter

The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.
	Founded in 1956, the NRAO provides state-of-the-art radio telescope facilities for use by the international scientific community. NRAO telescopes are open to all astronomers regardless of institutional or national affiliation. Observing time on NRAO telescopes is available on a competitive basis to qualified scientists after evaluation of research proposals on the basis of scientific merit, the capability of the instruments to do the work, and the availability of the telescope during the requested time. NRAO also provides both formal and informal programs in education and public outreach for teachers, students, the general public, and the media.
	The National Science Foundation (NSF) is an independent federal agency created by Congress in 1950 "to promote the progress of science; to advance the national health, prosperity, and welfare; to secure the national defense..."
	AUI collaborates with the scientific community and research sponsors to plan, build, and operate cutting-edge facilities. We cultivate excellence, deliver value, enhance education, and engage the public.