What Would it be Like to Fall into a Black Hole? |
In a way, a truthful answer to this question is a bit like a book sold a few years ago entitled, Everything Men Know About Women. It was a blank book.
Image courtesy of NASA's High Energy Astrophysics Science Archive Research Center.
No one has ever fallen into a black hole, and we have no firsthand knowledge whatsoever. The truth is, if anyone -- or any probe -- ever got close enough to a black hole to fall in, the person or machine likely would not last long enough to send back much useful information. And in the much more unlikely event that a person or probe survived the trip into the black hole, there appears to be absolutely no way to get any communications back out.
BACKGROUND: A black hole is the remnant of a massive star that has blown up, leaving its core to collapse under gravity. The momentum of the collapse is so great that nothing can stop it, and the gravitational pull so immense at its surface (the Event Horizon) that nothing, not even light itself, can escape. If light cannot escape, then the light cannot come to us and we cannot see it -- the object becomes a black hole. "Normal" black holes result from stars at least 3 times as massive as the Sun, and black holes in the cores of some galaxies can incorporate the masses of billions of stars.
But where we have no actual knowledge, we can speculate based on known physical laws. The exact timing of events of a person falling into a black hole depends a bit on the size of the hole, but the ultimate fate is death or at least total separation from the rest of the universe. Unless something odd and completely unexpected happens within the black hole, no living being can survive the fall into it. Immense gravitational force will assure that.
While we have reasonably convincing evidence that black holes do, indeed, exist, we know of none near the Earth or even the Solar System. Furthermore, there is no likelihood that the Sun or Earth will ever implode to become one. The best theoretical models require that an object have a mass several times greater than that of the Sun before there is any chance of it ending up as a black hole.
The outer apparent edge or surface of a black hole is known as the Event Horizon. For a small black hole, containing the mass of the Sun, any living thing likely would be dead long before it got to the Event Horizon, whereas for larger black holes, it is conceivable that a person falling into it could pass the Event Horizon before losing consciousness. The reason is that for the larger, more massive black holes, the Event Horizon occurs much farther from the black hole's center (the center of gravity).
Imagine a space-suited person who has ventured too close and is being pulled into the black hole feet first. Initially, because he or she is in freefall, there would be no abnormal feeling, just weightlessness. Soon, the person might begin to notice strange visual distortions due to the gravitational field of the black hole. The first bodily impression likely would be one of being pulled and stretched, perhaps a bit like the medieval torture known as the "rack." This happens because as our hapless spacefarer gets closer and closer, pretty soon the gravitational pull on his or her feet would be greater than on his or her head, because the feet would be slightly closer to the black hole than the head. This "differential gravitational pull" is similar to the effect of the Moon's and Sun's gravity that causes the tides on Earth. However, any body falling into a black hole will experience a much greater gravitational field, increasing rapidly as the center of the black hole nears.
As this feeling of being pulled from feet and head increases, the person likely would develop other pains, followed by light-headedness and soon unconsciousness. For all practical purposes this would be the end, because this unfortunate soul would never wake up.
But a loss of consciousness is just the prelude to the complete and utter destruction of the body. The increasing (differential) gravitational pull will rip seams in the spacesuit, exposing the body to vacuum, but more importantly, the body itself will begin to stretch and probably break, and continue the fall, becoming, as some have described, like a piece of spaghetti. Eventually even the molecules of the body will be pulled asunder, and the atoms broken and melded into the black hole itself.
It would not be a pretty sight, but then, no one would ever see it anyway. To an outside observer, far enough from the black hole to avoid being pulled in, the person falling into the black hole would do some rather odd things. First, instead of speeding up as it approached the black hole, the body would appear to slow down as a consequence of Einstein's Relativity. Also, the spacesuit would change color, appearing orangish, then reddish as the black hole's enormous gravitational field distorts the wavelengths of light. The person will continue to slow down as the Event Horizon approaches. Eventually the wavelengths of light will be shifted entirely out of the visible band into infrared and even lower, and the person, who by now already appears to be stopped still in space, will disappear!
Although there is some reason to believe that the material pulled into a black hole may someday reappear into the universe (due to quantum effects), the particular assemblage of atoms and molecules that was our unlucky astronaut is gone forever from the familiar world we know.
So, is there no hope that the astronaut could survive and emerge into some other universe? Frankly, that idea is far more suitable for science fiction than science.
The Laws of Physics as we know them break down in the singularity at the center of the black hole. We do not know know what happens there. However, the physics just outside the singularity seems pretty solid, and there appears to be no way a person could survive. Nor does there appear at this time any hope of developing a machine or process that would allow a person to pass through alive and intact. Yet, new discoveries may be made, and as Mr. Spock of "Star Trek" was fond of saying, "There are always . . . possibilities."
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