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## Can I find out what was fed black hole?

Jul

26

2013

Fiction |

Black holes have earned a terrible reputation. If you drop your keys in it, forget about them, they will not return. But whether the situation is so bad? Can a black hole “remember” that has eaten? Is the information – physical?

To answer the question, we need a little chew, that is a black hole. Although we have often talked about them and about any different .

Black holes and entropy

Энтропия

Black holes – or at least not rotating their views – incredibly simple objects. They have a point of no return, called the event horizon, the unfathomable singularity at the center, and in fact it is the whole structure. If you send your robot companion explore a black hole, and it even for a moment will fall behind the event horizon, it will not come back. Remember, we have considered the case : whether to transfer the information from there, over the horizon? – And came to very interesting conclusions. Nothing can leave a black hole – it’s something like the law.

But once we abuse analogies, “You – you are what you eat.” After reviewing your blood, vital organs, and, uh, leftovers, the doctor can say with confidence that moved down your esophagus.

Can you say the same thing about a black hole? Can we say that has fallen by studying the gravitational field?

According to the general theory of relativity, there are only three numbers, which are sufficient to completely describe the black hole: its mass, electric charge and angular momentum. In most cases it is only important to the first parameter.

To restore the robot will need more than three numbers. On the one hand, a black hole in the universal finite simplified. You put it in the object – and poof! – Irrespective of the object disappears. At first glance, it seems that here the second law of thermodynamics has given up the slack.

Not so long ago we talked about how that is entropy . The essence of the Second Law: Entropy – a measure of disorder in the universe – is increasing with the passage of time. But apparently, the black holes would spit on the second law. Looking at the whole thermodynamics of black holes, the most cold – absolute zero – which means that they do not have the entropy (and, incidentally, will live forever.)

Fortunately (at least for our hypothetical relationship with a robot, which we are thrown into a black hole at the beginning of the problem), black holes give the debate unfold. The fundamental randomness of the universe makes the event horizon in an incredibly interesting place. But to understand how, let’s delve into the world of information.

Entropy and Information

In 1948, Claude Shannon, a researcher at Bell Labs, founded the race of research known as information theory. Just as quantum mechanics has done everything physically possible modern computing, information theory has revolutionized cryptography and communications, and has helped to create such a thing as the Internet.

One of the major discoveries of information theory is that information and entropy are closely related. As gas entropy describes various ways by which atoms can replace each other, the information signal is described by various messages that can be transmitted.

Suppose I sent a message up to two characters. Basically, I could have sent the 26 x 26 = 676 different messages, but most of these combinations of letters would be absolutely meaningless. For scientists, experts, this means that although in theory you will need about 10 bits (1s and 0s, which are used for data storage) to distinguish all possible combinations of two letters, if you know what to pass the word, you will need only 7 bits. Savings.

Data transfer can be significantly reduced, noting that some letters are used less often than others. For example, in English E used more frequently than Z. If you play in the American “Balda”, the appearance of the letter Z on the battlefield significantly reduces the number of possible options. So, for example, in Morse Code E is:

.

while as Z:

-. .

Set Z takes much more time, but that’s OK, because you have to do it less often. The more advanced (or unlikely to be sent), the more information it carries, and the more bytes of data need to be stored on your computer.

There are very specific memory configurations that are more special than others. As in the case of “Balda”, we could accept that most combinations of 1 and 0 are just trash, but even in this case, pulling out of the bag tiles with letters (in the American game Scrabble, for example), we can accidentally make a call. The problem is that the randomly generated word will look the same as if it was a player intentionally.

If you find a drive with plenty of randomly placed ones and zeros, it is reasonable to assume that all these bits represent the actual data that is stored on the disk. In other words, we assume that all the complex patterns encoded in our brain, on the board, “Balde” or “Scrabble”, or the physics of the universe – it’s an accurate reflection of what actually happened in the past.

Information and Entropy – not one and the same, although mathematically they look very similar. In many ways they are opposites. System with a very high entropy contains very little information because we almost did not know about it. On the other hand, a system with high entropy can be seen as a device with the ability to store large amounts of information, unless you’re going to look at it up close.

Black holes evaporate

Черная дыра во всех цветах радуги

The black hole in all colors of the rainbow. Whole gallery .

All of which brings us to the black holes, and we can go back to the original question. If black holes do not contain information as they can remember, that has fallen to them?

In 1974, Stephen Hawking realized that black holes should radiate into space. Why? Because the vacuum of space is constantly flooded with the produced particles and anti-particles, and some are absorbed by the black hole, and some escape, causing the black hole is very poorly lit.

There are several major differences between the “classical” black holes (as they understood Einstein) and “quantum” black holes (supplemented by Hawking).

On the one hand, classic black hole live forever, so the information which is contained within, is not a problem (which is inside remains inside). In addition, the classical black holes (as we noted above) is enough to characterize the three numbers.

But as soon as you present things in the language of quantum mechanics , everything will become much more interesting. On the one hand, quantum black holes emit radiation (and eventually evaporate), which allows us to reluctantly say that they have some amount of heat. Heat – This is the bread and butter of thermodynamics, and with it there and the ability to encode information.

Black holes have a huge amount of entropy. To understand the scale of the problem on the surface of a supermassive black hole (in the center of our galaxy) as much entropy as there were in the entire observable universe at the beginning of time. All of these possible “microstates” carry the potential to store huge amounts of information. It should be noted, however, that while it is not clear exactly how to decode information on the surface of the black hole.

Moreover, if the black holes eventually (over quadrillion years) will evaporate, does not that mean that the radiation they send out into the universe, it is enough to restore our friend the robot?

It may well be, and this is no exaggeration. But to understand how quantum mechanics and black holes at a fundamental level, we need a theory of quantum gravity, which is not yet, unfortunately. That, in principle, does not prevent us to reason. By Stephen Hawking said:

“If you jump into a black hole, your mass energy will return to our universe, but in a distorted form, which contains the information about what you are, but in recognition of the state of the complex. It’s like a burn encyclopedia. The information does not disappear if left smoke and ash. But they are difficult to read. In practice, it would be too difficult to re-recreate a macroscopic object, like an encyclopedia, which has fallen into a black hole of information radiation, but the result is the preservation of information is important for microscopic processes involving virtual black holes. ”

That is, theoretically, a hundred thousand years may well be possible to decrypt this kind of information (and restore the people have fallen into a black hole). But will people of the future of patience for such a long and tedious process? It is not our business.

Also, maybe it will not people, and those who lack the patience zavsegda. What is missing is power.

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Tags: Information , Quantum Mechanics , Black Holes , Entropy .

Tags: Black Holes, entropy ., information, Quantum Mechanics

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