Friends, we honestly admit that we did not have time to write anything interesting, so we will use someone else's work :) On the Web, we came across an excellent article that describes one of the key mysteries of theoretical physics in an accessible language. We decided to bring this material in full, because it is the original author's style that makes it especially fascinating. We hope it will appeal to those who are interested in the mysteries of our universe.

So what happens if you fall into a black hole?

Surely you believe that if you fall into a black hole, then instant death awaits you. But in reality, as physicists believe, your fate will be much stranger. This could happen to anyone in the future. Maybe you're trying to find a new habitable planet for human race or just fell asleep on a long journey. What happens if you fall into a black hole? You might expect to be crushed or torn apart. But it's not like that.

The moment you enter the black hole, reality will be split in two. In one, you will be immediately destroyed, and in the other, you will plunge into a black hole completely unscathed.

A black hole is a place where the laws of physics known to us do not apply. Einstein taught us that gravity bends space itself, deforms it. So given a sufficiently dense object, space-time can become so curved that it wraps itself in on itself, punching a hole in the very fabric of reality.

A massive star that has run out of fuel could provide the extreme density needed to create this warped patch of space. Sagging under its own weight and collapsing, massive object pulls space-time with it. The gravitational field becomes so powerful that even light cannot escape it, which dooms the region in which this star is located to a grim fate: a black hole.

outer border A black hole is its event horizon, the point at which the force of gravity resists the attempts of light to escape it. Get too close and there will be no return.

The event horizon glows with energy. Quantum effects at this boundary create streams of hot particles flowing back into the Universe. This is the so-called Hawking radiation, named after the physicist Stephen Hawking, who predicted its existence. After enough time, the black hole will evaporate its mass completely and disappear.

As you dive into the black hole, you will find that space becomes more and more curved until the very center becomes infinitely curved. This is the singularity. Space and time no longer have any meaning, and the laws of physics we know that require space and time no longer apply.

What happens at the singularity? No one knows. Another universe? Oblivion? Matthew McConaughey floating on the other side of the bookshelves? Mystery.

What happens if you accidentally fall into one of these cosmic aberrations? First, ask your space partner - let's call her Anna - who watches in horror as you swim towards the black hole while she remains at a safe distance. She observes strange things.

As you accelerate towards the event horizon, Anna sees you stretch and distort as if she is looking at you through a giant magnifying glass. Also, the closer you get to the horizon, the more your movements slow down.

You can't shout since there's no air in space, but you can try signaling Anna a Morse message with your iPhone's light (there's even an app for that). However, your words will reach it slower and slower as the light waves are stretched to lower and lower and redder frequencies: “Okay, good, good…”.

When you reach the horizon, Anna will see that you are frozen, as if someone has pressed the pause button. You will be imprinted there, immobilized and stretched across the entire surface of the horizon, as the rising heat begins to consume you.

According to Anna, you are slowly being erased by the stretching of space, the stoppage of time, and the heat of Hawking's radiation. Before you plunge into the darkness of a black hole, you will turn into ashes.

But before we start planning the funeral, let's forget about Anna and see this macabre scene from your point of view. And you know what's going on here? Nothing.

You swim straight into nature's most sinister manifestation and don't get bumped or bruised - and certainly not stretched, slowed down, or fried on radiation. Because you're in free fall and don't experience gravity: Einstein called it "the happiest thought."

After all, the event horizon is not a brick wall floating in space. It's a perspective artifact. An observer who stays outside the black hole cannot see through it, but that's not your problem. There is no horizon for you.

If the black hole were smaller, you'd be in trouble. The force of gravity would be much stronger at your feet than at your head and stretch you like spaghetti. But luckily for you, it's a big black hole, millions of times more massive than the sun, so the forces that could spaghettify you are weak enough to be ignored.

What's more, you could live the rest of your life in a large enough black hole and then die in a singularity.

How normal this life will be is a big question, given that you were sucked against your will into a gap in the space-time continuum and there is no turning back.

But if you think about it, we all know this feeling, from the experience of communicating not with space, but with time. Time only goes forward, never backward, and sucks us in against our will, leaving no chance for retreat.

This is not just an analogy. Black holes warp space and time to such an extreme state that inside the black hole's event horizon, space and time actually reverse roles. In fact, it is time that sucks you into the singularity. You can't turn around and walk out of a black hole just like you can't turn around and walk back into the past.

At this point, you ask yourself: what is wrong with Anna? If you're chilling inside a black hole, surrounded by empty space, why does your partner see you burn up in radiation at the event horizon? Hallucinations?

In fact, Anna is in perfect health. From her point of view, you really burned out on the horizon. This is not an illusion. She could even collect your ashes and send them home.

In fact, the laws of nature require that you stay outside the black hole, as seen from Anna's point of view. It's because the quantum physics requires that information is not lost, not lost. Every bit of information that speaks of your existence must remain outside the horizon so that Anna's laws of physics are not violated.

On the other hand, the laws of physics also require that you sail across the horizon without hitting hot particles or anything out of the ordinary. Otherwise, you will violate the "happiest thought" of Einstein and his general theory relativity.

So, the laws of physics require that you be both outside the black hole as a pile of ash and inside the black hole, alive and well. And there is also a third law of physics which says that information cannot be cloned. You must be in two places, but there can only be one copy of you.

Somehow, the laws of physics lead us to a conclusion that seems rather nonsensical. Physicists call this puzzle the black hole information paradox. Fortunately, in the 1990s they found a way to solve it.

Leonard Susskind concluded that there is no paradox, since no one sees your copy. Anna sees only one copy of you. You see only one copy of yourself. You and Anna will never be able to compare them (and your observations too). And there is no third observer who can simultaneously observe a black hole from inside and outside. So no laws of physics are violated.

But you probably would like to know whose story is true. Are you dead or alive? If black holes have taught us anything, then there is simply no answer to this question. The reality depends on who you ask. There is Anna's reality and your reality. That's all.

At least that's what they thought for a long time. In the summer of 2012, physicists Ahmed Almeiri, Donald Marolph, Joe Polchinski, and James Sully, collectively known as AMPS, conceived a thought experiment that threatened to upend everything we had gathered about black holes.

They suggested that Susskind's decision was based on the fact that any discrepancy between you and Anna is mediated by the event horizon. It doesn't matter if Anna saw an unfortunate version of you torn apart by Hawking radiation, because the horizon prevents her from seeing another version of you floating in a black hole.

But what if she had a way to find out what was on the other side of the horizon without crossing it?

Ordinary relativity will say no, no, but quantum mechanics blurs the rules a bit. Anna could see beyond the horizon using a little trick that Einstein called "creepy action at a distance."

This happens when two sets of particles separated in space are mysteriously "entangled". They are part of a single invisible whole, so the information that describes them is mysteriously linked between them.

The idea of ​​AMPS is based on this phenomenon. Let's say Anna scoops up some information from the horizon - let's call her A.

If her story is correct, and you've already gone to a better world, then A, scooped up in the Hawking radiation outside the black hole, must be entangled with another bit of information B, which is also part of the hot cloud of radiation.

On the other hand, if your story is correct and you are alive and well on the other side of the event horizon, then A must be entangled with another piece of information C, which is somewhere inside the black hole. But here's the point: each bit of information can only be confused once. It follows that A can be entangled with either B or C, but not both at the same time.

So Anna takes her particle A and puts it in a manual entanglement decoding machine, which gives her the answer: B or C.

If the answer is C, your story wins, but the laws quantum mechanics are violated. If A is entangled with C, which is deep inside the black hole, then that piece of information is lost to Anna forever. This violates the quantum law of the impossibility of information loss.

That leaves B. If Anna's decoding machine detects that A is entangled with B, Anna wins and general relativity loses. If A is entangled with B, Anna's story will be the only true story, which means that you are in fact burned to the ground. Instead of sailing straight across the horizon as relativity would suggest, you will encounter a blazing wall of fire.

So we're back to where we started: what happens when you fall into a black hole? Do you slide through it and live a normal life thanks to a reality that is strangely dependent on the observer? Or do you approach the horizon of a black hole only to encounter a deadly wall of fire?

Nobody knows the answer, which is why this question has become one of the most controversial in the field of fundamental physics.

For more than a hundred years, physicists have been trying to reconcile general relativity with quantum mechanics believing that one of them will eventually have to give in. Solving the paradox of the aforementioned wall of fire should point to the winner, as well as lead us to an even deeper theory of the universe.

One of the clues may lie in Anna's decoding machine. Figuring out which of the other bits of information is entangled with A is an extremely difficult task. So physicists Daniel Harlow of Princeton University in New Jersey and Patrick Hayden of Stanford University in California set out to figure out how long it would take to decode.

In 2013, they calculated that even with the fastest computer available, it would take Anna an incredibly long time to decipher the entanglement. By the time she finds the answer, the black hole will have long since evaporated, vanished from the universe, and taken with it the riddle of the deadly wall of fire.

If so, then the sheer complexity of this problem may prevent Anna from finding out whose story is true. Both stories will remain equally true, the laws of physics intact, reality dependent on the observer, and no one in danger of being swallowed up by the wall of fire.

It also gives physicists new food for thought: the tantalizing links between complex calculations (like the ones Anna can't do) and spacetime. Perhaps there is more hidden here somewhere.

These are black holes. They are not only annoying obstacles for space travelers. They are also theoretical laboratories that bring the laws of physics to white heat, and bring the subtle nuances of our universe to such a level that they can no longer be ignored.

If the true nature of reality is lurking somewhere, the best place to look for it is in a black hole. True, it is better to look from the inside. Let's send Anna, now it's her turn.

P.S. If you have interesting materials, references, tips, life hacks on absolutely any topic, then send them to This e-mail address is being protected from spambots, you need JavaScript enabled to view it

MOSCOW, November 10 - RIA Novosti, Olga Kolentsova. The trajectory of a falling person, the length of the flight and the place of landing depend on many conditions. Forensic experts by the nature of the injury can determine the circumstances of the fall. Information about how the human body behaves in flight can help not only solve a crime, but also reduce the severity of injuries.

Falls can be "active" or "passive". In the first case, a person is accelerated by some extraneous force (for example, he was pushed) or by himself (having made a jump or pushed off the window sill). "Passive fall" occurs without additional acceleration - for example, when falling off the roof.

In both cases, during the flight, the body can change position, as well as deviate from the perpendicular connecting the point from which the fall began and the landing site. This occurs due to the mutual movement of body parts having different masses and volumes, as well as due to the rotation of the torso around the center of gravity or the point of impact with obstacles. This factor depends on the physique - height, weight, individual features, as well as on the starting position, fall height, trajectory, the presence of an accelerating force and the point of its application.

The initial push does not always increase the departure distance. The closer to the center of gravity (it is located in the navel area) the accelerating force is applied, the farther the body flies away from the perpendicular. Conversely, an impact much above or below the center of gravity is usually accompanied by a downward motion in a straight line, and the body lands at or even in front of the point of impact perpendicular to the plane of impact (if the starting point was a protruding part of the building).

If the body falls from a vertical position without additional acceleration, then it flies along a parabola, and the place of impact with the surface is always further than the fall perpendicular. The amount of deviation in such cases depends on the height.

© RIA Novosti illustration. Alina Polyanina

The researchers found that when falling, the dummy rotates around the center of gravity in the frontal plane. The number of turns depends on the height. Falling from seven or eight meters (third floor), he turns 180 ° and hits the ground with his head; flying from a height of ten to eleven meters (fourth floor) results in a 270° turn, after which the person lands on their back.

© RIA Novosti illustration. Alina Polyanina

The impact force during landing depends on the mass of the body and the speed of its movement. Moreover, the mass itself does not affect the speed in any way. The different speed of falling bodies with different masses is associated with air resistance, which, of course, will be greater for a feather than for a weight. If the human body is at rest before the flight, then the speed of its movement will depend on the height and acceleration of free fall. The latter value depends on the level at which the object is initially located, but it is so insignificant that this change is usually neglected. In practice, the speed of a body's flight is determined by its height.

© RIA Novosti illustration. Alina Polyanina

© RIA Novosti illustration. Alina Polyanina

The severity of the injuries received is directly related to the speed of the fall, and not to the height. In flight, a person instinctively tries to cling to branches or balconies in order to slow himself down. Of course, this can lead to additional injuries, but it will mitigate the damage on the last hit to the ground.

Greater speed is obtained when falling from a fast moving object. When we fall off a bike or jump out of a car, our body gets the speed of that vehicle and tends to move forward. This is how inertia works - the property of a body to remain at rest or uniform rectilinear motion in the absence of external influences (air resistance or friction forces). Due to inertia, we are flying forward when the vehicle stops abruptly.

In the case of a forced jump, you can choose the direction in which to jump. Physics says that it is more correct to jump backwards in order to reduce the speed acquired from a moving object. But in any case, there is a threat to fall, as top part the torso will still move when the legs have already stopped, touching the ground. Therefore, it is safer to fall in the direction of the train than backwards - in this case, the person puts his feet forward (or runs a few steps), preventing a fall. When jumping back, this saving movement will not be, and the likelihood of injury becomes higher. In addition, jumping forward, a person puts his hands in front of him and weakens the force of the blow. However, if you want to throw luggage from the train, it is better to do it against the movement of the train.

Fall damage depends on both the laws of physics and the structure of the human body. Since the tissues of the body are elastic, have different elasticity and resistance, and some parts of the body can move, this significantly reduces the impact force. But, of course, it can be weakened by elastic flexion of the limbs and simultaneous landing on several points.

Incredible Facts

It is probably impossible to find a person among us who would not read (or listen to!) the following lines of the unforgettable Russian Soviet children's writer Agnia Barto in childhood: "A bull is walking, swaying, sighing on the go: - Oh, the board is ending, now I will fall!". It is difficult to say whether the quintessence of childhood nightmares, cruelty, or just normal childhood curiosity was a completely logical question: So what, after all, will happen to the bull when it falls? What awaits him in that obscurity that the "heartless" Agniya Lvovna painted for us? However, the years go by, and we understand that the bull-calf, in fact, was not in danger of anything! Well, I would have hit my forehead on the ground, I would have got up, and I would have gone for a walk on my own. Next time he will be more careful and think a hundred times before climbing where he shouldn't!

However, Americans, who are clearly not familiar with the work of the famous children's writer, continue to ask quite childish questions, already at a very respectable age! Judge for yourself: quite recently, on the pages of a well-known English-language Internet resource dedicated to various aspects related to travel and mysterious stories, slipped information about the study of American scientists, who were tasked with finding out what would happen to a person if he fell into ... a volcano? The question sounds, at the very least, strange, but one thing cannot but be "reassuring" in this whole story - far-sighted scientists knew that a person who got too close to the edge of the vent and fell down would undoubtedly die. But how exactly will he die?

As it turns out, the question concerned mainly active volcano. It is not known what research methods the Americans used in the study this issue(whether they threw a couple of volunteers into the blazing abyss, or did without victims), but the question caused a much greater resonance than any sane person could at first glance seem to think! As a result, having made remarkable efforts, scientists were able to answer the question, without leaving a drop of hope to the most complete optimists: a person who falls into the mouth of a volcano will die!

However, his death will not be as colorful as, say, the death of Gollum, one of the heroes of the novels of the English writer Tolkien, whose works were filmed in the film trilogy "The Lord of the Rings". If anyone does not remember, the end of Gollum was terrible - he fell into the lava, which immediately swallowed him. However, Gollum is not alone - a similar end awaited all Hollywood (and not only) characters falling into lava or the crater of a volcano.

In fact, lava is a substance of extremely high density (of course, because it consists of molten solid rocks), which means that any creature, which falls from a height into the lava, will not be absorbed by it, but rather simply stick to the surface of the fiery stream. However, this does not mean at all that the unfortunate inattentive wretch who got into such trouble will have at least some chance of salvation!

His fate is quite predictable - a person will immediately be engulfed in flames, and he will burn to the ground literally within minutes. Well, one cannot help but be filled with gratitude to the researchers, since now it becomes clear that one should stay away from the mouth of the volcano. However, a quite reasonable question arises: if a person who has fallen into lava fails to "drown" in it due to his small weight and high density of the fiery flow, then what will happen to a living object of greater mass? Say, with a cow? Or with an elephant! There is still something to think about for American scientists, there is something to experiment with ...

What to do if you fell from the scaffolding from the height of a 10-story building? Or if your parachute didn't open? The chances of survival will be very small, but survival is still possible. The main thing is not to get confused, as there are ways to influence the speed of your fall and reduce the force of impact when landing.

Steps

What to do if you fall from a height of several floors

Grab onto something as you fall. If you manage to grab large object, for example, for a board or a bar, you will greatly increase your chances of survival. This object will take some of the impact during the landing and, accordingly, will partially remove the load from your bones.

Try to divide your fall into segments. If you fall from a building or a cliff, you can slow your fall by grabbing onto ledges, trees, or other objects. This will slow down your fall and break it up into several separate stages, giving you a better chance of surviving.

Relax your body. If you clench your knees and elbows and tighten your muscles, then hitting the ground will cause much more damage to your life. important bodies. Don't strain your body. Try to relax your body so that it can more easily bear the impact on the ground.

• One way to help you (relatively) calm down is to focus on the steps that will increase your chances of being saved.
• Feel your body, move your limbs so that they do not shrink.

1. Bend your knees. Perhaps the most important (or easiest) thing to do to survive a fall is to bend your knees. Studies have shown that by bending your knees, you can reduce the impact force by 36 times. But do not bend them too much, do it just enough so that they do not strain.

   Land feet first. No matter how high you fall, always try to land feet first. This way, the impact force will converge on a very small area, allowing your legs to take the brunt of the damage. If you are in the wrong position try to straighten yourself out before you hit.

   • Fortunately, accepting such a position is an instinctive action.
   • Slide your feet tightly together so that they touch the ground at the same time.
   • Land on the toes of your feet. Point your toes slightly down so that you land on the balls of your feet. This will allow the lower body to absorb the impact more effectively.

2. Try to fall on your side. After landing on your feet, you will fall on your side, either on your back or on the front of your body. Try not to fall on your back. According to statistics, falling on your side gives the best results. If you fail, then fall forward and stop the fall with your hands.

   Protect your head when rebounding. When falling from a great height, you are more likely to bounce after hitting the surface. In many cases, survivors of a fall (often to their feet) have been fatally injured by re-strike to the ground after the rebound. At the time of the rebound, you will most likely be unconscious. Cover your head with your hands, elbows forward in front of your face, and interlace your fingers behind your head or neck. This will cover most of your head.

3. Get medical attention as soon as possible. After a fall, your body's adrenaline rush can be so high that you don't even feel pain. So even if at first glance you are not injured, you may still have fractures or internal injuries that require immediate treatment. Regardless of how you feel, you need to get to the hospital as soon as possible.

   What to do if you fall from an airplane

   1. Slow your fall by arching. You will only have time for this if you fall from an airplane. Increase the area of ​​your body by spreading your limbs as if you were skydiving.

      • Position your body with your chest toward the ground.
      • Bend your body forward as if you were trying to reach your head with your toes.
      • Stretch your arms to the sides and bend them at the elbows at a right angle so that they are parallel to your head, palms down. Spread your legs shoulder width apart.
      • Bend your knees slightly. Do not strain your knees, relax your leg muscles.

   2. Find the best place to land. In the case of falls from very great heights, the type of surface has the most big influence on your chances of survival. Look for steep slopes that gradually flatten out so that you can gradually slow down after a fall. Watch the surface below you as you fall.

      • Hard, hard surfaces are the worst choice for landing. Very uneven surfaces, which will provide less space for the distribution of impact force, are also undesirable.
      • The best choices are surfaces that will break on impact, such as snow, soft ground (plowed field or swamp), and trees or dense vegetation (although in this case there is a high risk of being pierced by a branch).
      • Falling into water is not dangerous only when falling from a height of no more than 45 meters. In the case of a greater height, the effect will be comparable to a fall on concrete, since in this case the water will not have time to compress. If you fall into the water, you can also drown, as you will most likely lose consciousness from hitting the surface. The chances of survival will increase markedly if the water is in a bubbling state.

   3. Point yourself towards the landing site. If you are falling from an airplane, then you will have approximately 1-3 minutes before landing. You have to overcome a considerable distance, being in an upright position (about three kilometers).

      • By adopting an arcuate position, as described above, you can change the direction of the fall to a more horizontal one. To do this, move your arms slightly back to your shoulders (so that they are not too far forward) and stretch your legs.
      • You can move backwards by spreading your arms and bending your knees as if you want to touch your head with the heels of your feet.
      • The right turn can be performed by slightly bending your body to the right (lowering the right shoulder) while in an arcuate position, and the left turn can be performed by lowering the left shoulder accordingly.

   4. Use correct landing technique. Remember to relax your body, keep your knees slightly bent, and try to land feet first. Try to fall forward rather than backward, and cover your head with your hands in case of a rebound.

      • If you are in an arc position, assume an upright position before landing (to get a better idea of ​​the available time, remember that when falling from a height of 300 meters, you will have 6-10 seconds before landing).
   • If you start to spin, try to straighten out into an arched position. At least that way you'll be at least a little calmer.
   • If the place you fell into is sand or clay, then there is a chance you could get stuck there. Do not panic! Start moving as if you are climbing stairs, helping yourself with your hands. You should have enough oxygen for about a minute, this should be enough for you to reach the surface,
   • Stay calm, if you panic you won't be able to think clearly!
   • If you're above a city, you won't have much choice in terms of possible landing sites, but glass or tin roofs, sheds, and cars will be better than streets and concrete roofs.
   • Good shape and youth increase the chances of survival. You can't get any younger, but if you need an incentive to take care of yourself, here it is.