Two planets collided. Collision of the earth with a comet. New hypotheses about the origin of the moon
People are afraid of space. Most of these fears are caused by multiple films about the collision of the planet with an asteroid, which has global consequences and threatens the extinction of our civilization. Also, the constant forecasts of scientists about approaching asteroids and meteorites make the faint of heart dig underground bunkers. Today we will look at known cases of such collisions and the possibility of such collisions in the future.
New hypotheses about the origin of the moon
Scientists in Switzerland recently shocked the media with a claim that the moon was created by a collision between the Earth and a large rogue planet.
The collision of the planets, they say, happened over four billion years ago. An object the size of Mars crashed into the Earth, and "fluff and feathers" flew from the earth in different directions. Several fragments united, creating a new celestial body - the Earth's eternal satellite, the Moon.
Andreas Royfez - a scientist at the University of Switzerland - painted the situation like this: the collision of the planets occurred on high speed, and more than five hundred thousand pieces "fell off" into space from both. But only ten thousand of them became the Moon, and the rest flew away from the orbit from a large force of impact, so we do not see them.
Why is there such an assumption?
The fact is that scientists have long puzzled over recent studies of samples with great depths satellite showed that the rock is similar to the composition of the Earth. Hence the hypothesis appeared that only the collision of the Earth with the planet could create a new cosmic body due to the breakaway pieces.
Space "monster"
In 2004, scientists began to devote a lot of time to studying the complex name "Planet 2M1207". Previously, it was assumed that it is in close proximity to another - smaller 2M1207b. It was believed that the second, like the Moon, is simply a satellite of an older planet, but recent clear images have shown that this is one planet.
That is, there were originally two of them, but they managed to grow together and now live together. This "Sweet couple" was created by a very recent collision of planets, which took place literally the day before yesterday by cosmic standards, and by our - earthly - several tens of thousands of years have passed since that momentous day.
Their "union" can be seen, armed with a telescope, in the constellation Centavir. The appearance of such a "monster" was a whole event for astronomers, so they are still studying the details of the "accident on the space road."
Thus, the collision of the planets is a possible tragedy. It once happened on Earth, fortunately not yet populated. If this happens again, then not a single insect will remain here: the oceans will go beyond their borders, and maybe even evaporate completely due to highest temperature the surface of the earth caused by the impact.
Is 2017 the last year for our civilization?
The Americans are back on track. There was a dispute between these scientists: will our planet die in October 2017, or will the catastrophe pass us again?
Presumably on October 12 of this year, the asteroid TS4 will migrate in the immediate vicinity of the Earth. They say that its size exceeds the Statue of Liberty itself, so if he decides to "look into our light", then there will be a lot of this light. The consequences threaten several thousand people, which will exceed the scale of the tragedy in Chelyabinsk in 2013, when more than 1,200 people were injured as a result of the fall of a foreign body on the territory of the metropolis.
But this is half the trouble. Another scientist certifies that TS4 will pass by, but we will have to meet the giant Nibiru, or, as it was also called, planet X. The collision of two planets, that is, the Earth and Nibiru, should also take place in October, only the date of arrival of the space guest has not yet known.
The scientist only said that on October 5 she will completely close the Sun from earthlings, flying in the constellation Virgo. He also says that the consequences of the collision will be terrible, so it's time to dig bunkers, stock up on food and water. This is necessary in order to survive!
Earth is under the gun in 2029
In April 2029, the Earth will again become the target of an asteroid. This time, Apophis-99942 will approach us, its dimensions are supposedly between 400 and 600 meters in diameter. A little, but not a lot, for a catastrophe to happen.
His path will lie at a distance of 30 to 40 thousand kilometers from the Earth, so something will happen: in the best outcome, near-Earth space stations will be damaged, and in the worst case, a collision with the planet.
The orbit of the impending body passes between us and the Moon, and this, as Sergey Smirnov, a senior researcher, says, is very bad. The thing is that the situation will resemble a chip floating between two moving ships. And in which direction this chip will be thrown back by waves is not clear.
Breaking an asteroid in space is also not possible, since its exact size and composition of the rock is not known, so it is impossible to find a suitable "weapon".
In any case, do not panic ahead of time, because scientists have predicted the end of the world many times due to the collision of our planet with another, but not a single prediction has come true yet.
In the latest issue of Nature, an article by Jacques Lascar, one of the leading experts on the solar system's planetary dynamics, appeared with the impressive title: Existence of collisional trajectories of Mercury, Mars and Venus with the Earth (" The existence of collisional trajectories of Mercury, Mars and Venus with the Earth").
All this means that there is no chance to calculate even on super-powerful computers the true fate of the inner planets of the solar system for the entire period allotted to us by the Sun (ie 5 billion years). So the only thing we can do is collect statistics: i.e. take many different slightly different initial conditions, run simulations of them, and then see what percentage of the simulation sessions produce which type of behavior.
So, among the inner planets produces chaos. But such chaos is safe enough for the planets themselves, since the eccentricities of their orbits remain small. Each planet revolves around the Sun in its own narrow ring, and there is no danger of orbits crossing.
However, it has long been known that Mercury can break this whole idyll on a longer scale, on the order of billions of years. It has a specific resonance with Jupiter, as a result of which, if Mercury successfully gets "in phase" at some of its revolutions, its eccentricity can swing to large values: 0.9 or even more. An ellipse with such an eccentricity is already crawling out of the orbit of Venus, and since all this happens in almost the same plane, it becomes possible collision Mercury with Venus (or another outcome - the fall of Mercury on the Sun).
An illustration of how a highly eccentric orbit can lead to collisions. Picture from the news Planetary science: The Solar System's extended shelf life from the same Nature.
- By the way, retreat. The effects of relativity appear to be of great importance in calculating the percentage of trajectories that develop a large eccentricity. If these effects are neglected, then about half of all Mercury's trajectories over the next 5 billion years have time to visit the e>0.9 state. If the effects are taken into account, then there are only about 1% of such tractors. Relativistic effects seem to somehow knock down the resonance with Jupiter and prevent the eccentricity from swinging.
It is precisely all this that Lascar's group has now overcome. They ran a fair simulation of planetary dynamics with variable time steps: usually the step was 0.025 years, but if the distance between any pair of planets became dangerously small, then the time step was further reduced to maintain numerical accuracy. Well, all the planets plus Pluto, as well as the Moon were taken into account, and the effects of general relativity were taken into account. 2501 simulations were launched, which differed only in one parameter - the initial value of the semi-major axis of Mercury's orbit - by the value k * 0.38 mm, where k = [-1200,1200]. A solution with a given value of k was designated S k .
Now the results.
- Of all 2501 trajectories, 20 have developed a large eccentricity of Mercury, e>0.9, over 5 billion years.
- Of these, 14 have not yet been counted by the time this article was written (and will be counted for several more months), since they fell into a dangerous area and their time step has greatly decreased.
- Of the remaining six: Solution S −947 successfully reached 5 Gyr by avoiding a collision, although it survived a close approach (6500 km) between Venus and Mercury.
- In the solutions S −915 , S −210 and S 33 Mercury fell on the Sun 4 billion years later.
- Decision S −812 pushed Mercury into Venus.
- And finally, the most interesting solution is S −468, in which the Earth and Mars approached at the time of 3.3443 billion years by less than 800 km (ie 1/8 of the Earth's radius).
Here, in general, it is interesting that before that it was about the collisions of Mercury with Venus, but then it suddenly turned out that everyone can collide with everyone. As it turns out, this is the reason. Mercury with a large eccentricity sometimes interacts so successfully with distant giant planets that they transfer to it a significant part of the angular momentum. At the same time, its eccentricity decreases, but the orbit rises higher, i.e. closer to the orbits of other planets. If after that Mercury quickly collides with Venus, then there are practically no consequences for the Earth and Mars. And if it successfully avoids a collision, then the destabilization of the entire inner solar system begins, and the eccentricities of Mars, Earth and Venus also increase greatly. As a result, a collision of any pair becomes possible.
An example of a collisional trajectory between Earth and Mars. Shown eccentricity Mercury, Earth and Mars . The horizontal scale is time from 0 to 3.5 billion years. It can be seen that at first the eccentricity of Mercury grows, then Mercury causes an increase in the eccentricities of other planets, and at some point they collide. Image from the original article.
And finally, about the probabilities. Gazeta.ru wrote without further ado that "the Earth can collide with Venus or Mars with a probability of 1%" (well, not only Gazeta.ru, of course). This is not true. 1% is the probability that Mercury will develop a very large eccentricity. But most of these events will be disastrous for Mercury, but not for the Earth. What is the likelihood that this will begin the destabilization of the entire inner solar system is still unknown. Indeed, now there is only one single trajectory from the initial set of 2501, in which destabilization, potentially dangerous for the Earth, actually occurs.
Therefore, the authors do not yet undertake to give direct estimates for the probability that the Earth will collide with someone. But for sure in a couple of years, when more statistics are collected, they will give these estimates.
And of course, it’s completely wrong to write, as, for example, Compulenta wrote:
And the probability of a collision between the Earth and Venus is 1:2500 and can occur no earlier than in 3.5 million years.
(by the way, there is a typo - we are talking about 3.5 billion years). I repeat once again: completely unknown- and will never be known! -- how the dynamics of the inner solar system will actually develop on a scale of billions of years. There is no guarantee that an impact will or will not occur in the next 3.5 billion years. Unknown! One can only evaluate the "typicality" or "atypicality" of certain trajectories.
What about headers like " Earth is predicted to collide with Mars or Venus (PHOTO)" or " Mars attacks in three billion years"I'm completely silent :)
Collisions of the Earth with a comet - that's what people began to fear, ceasing to see the harbingers of wars in comets. Many scientists are actively working on this problem.
So what is the problem of space threat? In the solar system there is a huge number of small bodies - asteroids and comets, witnesses of the era when the formation of planets took place. From time to time they move into orbits that intersect with the orbits of the Earth and other planets. In this case, there is a possibility of their collision with the planets. Evidence of the existence of such a probability is the giant astroblem craters that dot the surfaces of Mars, Mercury, the Moon, as well as the unusual situation with the mass and inclination of the axis to the plane of the orbit of Uranus. The successive formation of planets from the Sun one after another followed with a subsequent increase in their masses - Neptune, Uranus, Saturn, Jupiter, but why now the mass of Uranus turned out to be less than that of Neptune? Naturally, when the planets form their satellites, their masses decrease in different ways. In this case, the reason is not only this. Let us pay attention to the fact that Uranus rotates around its axis “lying” on the plane of the orbit. Now the angle between the axis of rotation and the plane of the orbit is 8°. Why is Uranus tilted so much compared to other planets? Apparently, the reason for this was a collision with another body. In order to bring down such a massive and unsolid planet, this body needed to have a large mass and high speed. Perhaps it was a large comet, which received a large inertia from the Sun at perihelion. On the this moment Uranus has a mass 14.6 times greater than the Earth, the radius of the planet is 25400 km, it makes one revolution around its axis in 10 hours. 50 min. and the speed of movement of the points of the equator is 4.1 km/sec. Acceleration free fall on the surface 9.0 m/s2, (less than on Earth), the second escape velocity is 21.4 km/s. Under such conditions, Uranus has a ring of a certain width. There was a similar ring during a collision with another body. After the collision of Uranus, the axis suddenly falls and the force holding the ring disappears, and countless pieces of various sizes are scattered into interplanetary space. Partially they fall on Uranus. Thus, Uranus loses some of its mass. The change in the direction of the axis of Uranus may have contributed to a change in the inclination of the plane of the orbits of its satellites. In the future, when Uranus begins to rotate around its axis at a lower speed, the mass that is concentrated in the ring will return to it again, i.e. Uranus will pull it towards itself and its mass will increase.
All the planets, except for Mercury, Venus and Jupiter, even Saturn, whose mass is 95 times the Earth, have axes inclined to the plane of the orbit. This suggests that they, like Uranus, collided with either asteroids or comets. If there is a collision of planets with their satellites, i.e. the planets attract them to themselves, then in this case they fall in the region of the equators and therefore the axes of the planets do not deviate. Mercury and Venus were saved from many collisions with asteroids or comets by the proximity of the Sun, which attracted these asteroids and comets to itself. And Jupiter, having a huge mass, swallowed all the bodies hitting it and its axis did not deviate.
Works of historians, modern astronomical observations, geological data, information about the evolution of the Earth's biosphere, results space research planets testify to the facts of the existence of catastrophic collisions of our planet with large cosmic bodies (asteroids, comets) in the past. Our planet has repeatedly collided with large cosmic bodies in its history. These collisions led to the formation of craters, some of which still exist today, and in the strongest even to climate change. One of the main versions about the death of dinosaurs is that the Earth and a large cosmic body collided, causing a strong climate change, reminiscent of a “nuclear” winter (the fall caused a strong dusting of the atmosphere with small particles that prevented the passage of light until earth's surface, thereby leading it to a noticeable cooling).
One can imagine what such a disaster would look like. When approaching the Earth, the body would begin to increase in size. At first, an almost imperceptible star in a short time would change its brightness by several magnitudes, becoming one of the most bright stars in the sky. At the climax, it would be almost equal in size to the Moon in its size in the sky. Upon entering the atmosphere, a body with 1-2 space speed would cause a sharp compression and heating of nearby air masses. If the body had a porous structure, then it would be possible to split it into smaller parts, and the combustion of the main mass in the Earth's atmosphere, if not, then only the outer layers of the body would be heated, a slight slowdown in speed, and after the collision, the formation of a single large crater. In the second version of events, the consequences for life on the planet would be apocalyptic. Of course, much depends on the size of the body. The existence of intelligent life can be put to rest by a collision even with a small body, having about several hundred meters in diameter, a collision with bodies bigger size can practically destroy life altogether. The flight of a body in the atmosphere would be accompanied by a sound similar to the sound from jet engine magnified several times. A bright tail formed by superheated gases would remain behind the body, which would present an indescribable sight. With the first option, thousands of fireballs would be visible in the sky, and the spectacle itself would look like meteor Rain, only noticeably superior to him in strength. The consequences would not be as catastrophic as in the first option, but large fireballs, having reached the earth's crust, could cause some damage on a small scale. If a large body hit the earth's crust, a powerful shock wave would form, which, merging with the wave formed during the flight, would level a huge surface area with the ground. If it hit the ocean, a powerful tsunami wave would rise, which would wash away everything from territories located a few hundred kilometers from coastline. Strong earthquakes and volcanic eruptions would occur at the junction of tectonic plates, which would lead to new tsunamis and dust emissions. For many years, an ice age would have been established on the planet, and life would have been thrown back to its initial forms. If the dinosaurs died out after all due to the collision of a cosmic body with the Earth, then it most likely had a small size and an integral structure. This confirms the incomplete destruction of life, an insignificant cooling of the climate, and the presence of a single crater, presumably in the Gulf of Mexico. It is possible that such events occurred more than once. In support of this, some scientists cite as an example some formations on the surface of the Earth.
The most ancient craters are unlikely to have been preserved due to the movement of earth rocks, but the cosmic origin of some formations has been scientifically proven. These are: Wolf Creek (location - Australia, diameter - 840 meters, shaft height - 30 meters), Chubb (location - Canada, diameter approximately equal to 3.5 kilometers, depth - 500 meters), "Devil's Canyon" - Arizona meteorite crater (location - USA, diameter - 1200 meters, height above the earth's surface - 45 meters, depth - 180 meters), as for comets, the collision of the Earth with the comet's nucleus was not registered (currently there is a debate that a small comet could be the Tunguska meteorite of 1908, but the fall of this body gave rise to so many hypotheses that this cannot be considered the main version and assert that the collision with the comet did happen). Two years after the fall of the Tunguska meteorite, in May 1910, the Earth passed through the tail of Halley's comet. At the same time, no major changes occurred on Earth, although the most incredible assumptions were made, there was no shortage of prophecies and predictions. Newspapers were full of headlines like: "Will the Earth perish this year?" Experts gloomily predicted that in the shining gas plume there are poisonous cyanide gases, meteorite bombardments and other exotic phenomena in the atmosphere are expected. Some of the enterprising people began to sell on the sly pills, supposedly having an "anti-comet" effect. The fears were empty. No harmful auroras, no violent meteor showers, or any other unusual phenomena were noted. Even in air samples taken from the upper atmosphere, not the slightest change was found.
A vivid demonstration of the reality and grandiosity of the scale of cosmic impacts on the planets was a series of explosions in the atmosphere of Jupiter, caused by the fall of fragments of comet Shoemaker-Levy 9 on it in July 1994. The nucleus of the comet in July 1992, as a result of its approach to Jupiter, was divided into fragments, which subsequently collided with the giant planet. Due to the fact that the collisions took place on the night side of Jupiter, earthly researchers could only observe flashes reflected by the planet's satellites. The analysis showed that the diameter of the fragments is from one to several kilometers. 20 comet fragments fell on Jupiter.
Scientists believe that the dinosaurs were born and killed by the collision of the Earth with a large cosmic body. The collision of the Earth with a comet or asteroid, which occurred about 200 million years ago, was accompanied by a rapid increase in the dinosaur population of the Jurassic period. The impact of a celestial body on the Earth resulted in the extinction of many species, the lack of competition with which opened the way for dinosaurs to adapt and increase in numbers. These are the latest findings of scientists conducted in 70 districts North America. Specialists examined the footprints of dinosaurs and other fossil animals, and also analyzed the footprints chemical elements in rocks.
At the same time, iridium was discovered - an element that is rare on Earth, but quite common for asteroids and comets. Its presence is strong evidence that some celestial body crashed into the Earth, experts point out. "The detection of iridium makes it possible to determine the time of impact on the Earth by a comet or an asteroid," says Professor Dennis Kent of the American Rutgers University. “If we correlate the results of this discovery with the data we have about the plant and animal life of that time, we can find out what happened then.”
However, the same process then hit, after 135 million years, the lizards themselves. Many scientists believe that a powerful impact on the Earth of a certain space object in the Yucatan Peninsula in Mexico 65 million years ago led to such a transformation of the planet's climate, in which the continued existence of dinosaurs was impossible. Simultaneously, favorable conditions arose for the development of mammals. Asteroids and comets, whose orbits cross the Earth's orbit and pose a threat to it, are called dangerous space objects (HEOs). The probability of a collision primarily depends on the number of HEOs of one size or another or another type. 60 years have passed since the discovery of the first asteroid whose orbit intersects the Earth's orbit. At present, the number of discovered asteroids ranging in size from 10 m to 20 km, which can be attributed to the NEO, is about three hundred and increases by several tens per year. According to astronomers, the total number of OEOs with a diameter of more than 1 km, which can lead to a global catastrophe, is from 1200 to 2200. to the Sun at the Earth's distance from the Sun, has a one in 400,000,000 chance of colliding with the Earth. Since about five comets pass on average at this distance from the Sun per year, the nucleus of a comet can collide with the Earth on average once in 80,000,000 years. Collisions in the solar system. From the observed number and orbital parameters of comets, E. Epic calculated the probability of collision with comet nuclei of various sizes (see table). On average, 1 time in 1.5 billion years, the Earth has a chance to collide with a core with a diameter of 17 km, and this can completely destroy life in an area equal to the area of North America. For 4.5 billion years of the history of the Earth, this could happen more than once.
Although the probability of a collision with NEO, leading to global consequences, is small, but, firstly, such a collision can occur next year in the same way as in a million years, and secondly, the consequences will be comparable only with a global nuclear conflict. In particular, therefore, despite the low probability of a collision, the number of victims from the disaster is so high that, per year, it is comparable to the number of victims of air crashes, murders, etc. What can humanity oppose extraterrestrial danger? The OKO can be affected in two main ways:
- -change its trajectory and ensure a guaranteed passage past the Earth;
- -destroy (crush) the OKO, which will ensure the passage of some of its fragments past the Earth and the combustion of the rest in the atmosphere, without causing damage to the Earth.
Since the destruction of the NEO does not eliminate the threat of its fall to the Earth, but only reduces the level of impact, it seems more preferable to change the trajectory of the NEO. This requires intercepting an asteroid or a comet for a very long distance from the earth. What can affect the OKO? It could be:
- - kinetic impact of a massive body on the surface of the OKO, a change in the reflective light capacity (for comets), which will lead to a change in the trajectory under the influence of solar radiation;
- - irradiation with laser energy sources;
- -placement of engines on OKO;
- -exposure to powerful nuclear explosions and other methods. An important circumstance is the capabilities of rocket and space technology. The achieved level of rocket and nuclear technologies makes it possible to formulate the appearance of a rocket and space complex, consisting of a space interceptor with a nuclear charge for delivery to given point OKO, the upper stage of the space interceptor, which ensures the launch of the interceptor to a given flight path to the OKO of the launch vehicle.
At present, nuclear explosive devices have the highest concentration of energy compared to other sources, which allows them to be considered as the most
a promising means of influencing dangerous space objects. Unfortunately, on a cosmic scale, nuclear weapons are weak even for such small bodies as asteroids and comets. The generally accepted opinion about its capabilities is greatly exaggerated. By using nuclear weapons you cannot split the Earth, evaporate the oceans (the energy of the explosion of the entire earth's nuclear arsenal can heat the oceans by one billionth of a degree). With all the nuclear weapons of the planet, it is possible to crush an asteroid with a diameter of only nine kilometers with an explosion in its center, if this were technically feasible.
However, we are still not powerless. The task of preventing the most real threat of collision with a small celestial body one hundred meters in diameter is solvable at the current level of earth technology. Existing projects are constantly being improved and new projects are emerging to protect the Earth from space threats.
For example, according to the research of a scientist from the United States, a giant air cushion may one day save the world from a cosmic collision with a comet: Hermann Burchard from State University Oklahoma is proposing to send a space craft equipped with a massive air bag that can be inflated to a size several miles wide and used as soft resistance to an invading solar system away from the ground collision course.
"It's a safe, simple, and realistic idea," says Burchard. However, he acknowledges that there are still numerous details that need to be worked out. For example, the material for an air cushion, which must be light enough to move in outer space and at the same time strong enough to reflect a comet from its course to Earth.
After a careful study of the material on comets, I found out that, despite their careful study, comets are still fraught with many mysteries - what are the many theories about their origin and an endless string of new discoveries! .. Some of these beautiful "tailed stars" , shining from time to time in the evening sky, can pose a real danger to our planet. But progress in this area does not stand still. Existing and new projects for the study of comets and the protection of the Earth from space threats are constantly being improved. So, most likely, in the coming decades, humanity will find a way to "fend for itself" on a cosmic scale.
