Nothing, not even light, escapes a black hole. Once someone has crossed the event horizon, they can never come back. However, before their painful death – what would they see from inside a black hole?
A black hole is a phenomenon that is formed when a massive star dies and then collapses in on itself. This process creates an area in space with a large density and gravity. The event horizon is the boundary at which you are destined to enter the central singularity. This is because a black hole bends spacetime infinitely and therefore there is no way to escape, no matter how fast you were travelling. While, according to Einstein’s theory of general relativity, all masses curve the fabric of spacetime, black holes curve it significantly at one point, known as the singularity.
The further away you are from a black hole, the less curved spacetime is and the harder it is to distinguish gravity from the black hole from any other large mass. Visually, however, the black hole would look like a dark sphere (or black hole) where magnetic fields and matter swirl around it. The complete darkness of the event horizon would be juxtaposed with the distorted light from the matter of space surrounding it.
It is known that, when travelling through space, the distance between you and a star is proportional to how large the star appears. For example, if you travelled halfway to a star, that star’s angular size would appear twice as big. This is not the case when approaching black holes. Due to the way that space is curved, upon approach of a black hole, it will begin to look much larger than expected. You will begin to see “lines of light” around the black hole, due to spacetime curving more radically the closer to the singularity it gets.
By the time you are a few Schwarzschild radii away from the event horizon, the black hole itself would almost completely take up your entire view. Once you cross the innermost stable circular orbit at 150% of the radius of the event horizon, you would only be able to see darkness. Looking behind you and away from the black hole, the starlight will start to compress into a small dot. In addition to this, due to gravitational blueshifting, the color will change to blue, then red, white and blue again just before you enter the event horizon. This is because the cosmic radio and microwave backgrounds are moved to the visible part of the spectrum.
Once you have entered the event horizon, no light from the universe can meet you and you are left, unsurprisingly, in complete darkness. Assuming that the event horizon is one light-hour in diameter, it would only take you 20 seconds to reach the singularity at an increasing acceleration and with no chance to escape. If you were to shine a torch at this point, the light beam would fall towards the singularity, no matter which direction you tried to shine it.
Of course, in reality, spaghettification will happen to you way before you could even travel to the event horizon, as the gravitational pull will be much stronger on the areas of you body that are closer to the black hole, causing you to elongate and rip apart. Perhaps, for now, it is best that the inside of a black hole remains a mystery.
Siegel, E. (2018, January 19). What Would you See as you Fell into a Black Hole? Retrieved from Forbes.com: https://www.forbes.com/sites/startswithabang/2018/01/19/what-would-you-see-as-you-fell-into-a-black-hole/#46b7d5878583
Woo, M. (2015, May 4). What Would you See in a Black Hole? Retrieved from bbc.com: http://www.bbc.com/future/story/20150501-what-youd-see-in-a-black-hole