In the whole universe, there is only one place where our modern technology cannot survive, and obviously, it is a Black Hole. But just for a minute, suppose that scientists have made a powerful and strong action camera that can survive any threat in the universe and dropped it into a black hole. What will it record for us?
Let us find it out.
The action camera falling into a black hole may transmit a signal to us up to the intersection of the event horizon. As you approach a black hole, the time for the camera will slow down, which will lead to a shift of its signal to the region of long waves (gravitational redshift), and the shift will noticeably increase every second.
The redshift is a consequence of the time dilation for the action camera in the frame of reference of an observer located far from the black hole. That is, the camera in its frame of reference of 60 frames per second will still shoot and send us its records, but 1 second for the camera can turn into hours, years and ultimately billions of years for us.
That means that huge intervals of time will pass for an observer on the earth between the arrival of frames, and the picture will change very slowly.
Therefore, soon after starting the camera, the usual technique will not be able to catch this signal and restore the video from it, but if necessary, you can create devices that can capture the long-wave signal and turn it into a video.
Another, more significant problem will be the noise of the signal and the huge temperature, because a huge amount of substance usually falls into a black hole, which, when dropped, heats up to hundreds of millions of degrees and emits electromagnetic waves.
Nevertheless, let’s say that we were able to protect the camera from high temperature and filter the signal, so what will we see?
The view that the camera records depends on how massive the black hole will be. In black holes of stellar mass, the gravitational field is very heterogeneous, huge tidal forces appear in it that will tear the camera apart long before it approaches the black hole. All that we will see in this situation is a hot accretion disk and darkness in the middle of horizon events. To see something more interesting, you need to send the camera into a supermassive black hole, where the tidal forces are much weaker.
Near a black hole, space-time is strongly curved, and the closer to the singularity, the greater the curvature of space-time. When the camera begins to “sink” into the gravitational well of the black hole, the field of view of the camera will begin to narrow, in fact, the light on one side (right or left) of the camera will cease to reach it, and eventually all the light of the universe will degenerate into a small blue dot (due to gravitational blue shift). Before passing the event horizon, total darkness will come, however, we will not have time to see this, because for us, by that time, billions of years will pass.