Forgotten discovery: how binary asteroids changed our understanding of the solar system

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Forgotten discovery: how binary asteroids changed our understanding of the solar system
Forgotten discovery: how binary asteroids changed our understanding of the solar system
Anonim

In 1989, Soviet astronomers concluded that asteroids have satellites. This was the fourth discovery of a new class of objects in the solar system in the history of astronomy. It changed our understanding of how the moon was formed, the satellites of other planets - and the system as a whole. However, history has a sense of humor: almost no one knows about this discovery of Soviet astronomers. Naked Science is the first media outlet to try to fill this gap, including for the first time publishing an electronic copy of the work itself on the discovery of binary asteroids.

Double asteroid Antiope

In our time, it is assumed that nothing can be hidden in today's information society - including important government secrets, often extracted from open sources. Moreover, many believe that it is impossible not to notice what they are not hiding.

Alas, practice shows that this is a delusion. In 2012, the author of these lines came across an interesting work by an American researcher, from which he learned that the water on the Moon was discovered by Soviet experts who analyzed samples of the satellite soil, delivered from there by Luna-24.

Then he wondered: why would he find out about this by reading in English and not in Russian? After all, in theory, the discovery is significant, and the domestic naupop should have told him about it? In order not to rack their brains for a long time, everything was attributed to insufficient energetic promotion of the discovery by its authors themselves. Unfortunately, the events that followed show that the situation is much more complicated than it seems.

Who discovered double asteroids and when?

In the late 1980s, the system of Soviet scientific institutions - especially in the provinces - began to experience growing difficulties in obtaining imported materials. For especially sensitive and high-quality photographic plates from Germany and the United States, one had to pay in currency, which the state was less and less willing to release for scientific purposes. As a result, as Lyudmila Karachkina, one of the observers of the Crimean Observatory of that time, recalls (her letter is at the disposal of NS),

“[Astronomical] observations [at the observatory] are gone. We also tried to shoot with some old stuff, but the results were sad."

Therefore, from shooting on photographic plates, a group of astronomers-observers led by Valentina Vladimirovna Prokofieva-Mikhailovskaya switched to television observations - including the asteroids of the main belt of the solar system, lying between the orbits of Mars and Jupiter. At first, Prokofieva's group planned to simply determine the periods of rotation of the asteroids.

Different parts of these bodies have different reflectivity, and when the light reflected by the asteroid is repeated over a certain period, this is interpreted as its rotation period. From April 26 to May 11, 1989, observations of the asteroid Sylvia were carried out at the Crimean Astrophysical Observatory, and it was they who became the basis for the future major discovery.

After the accumulation of the observational data themselves, a long period of their interpretation began. It was dealt with by V.V. Prokofiev-Mikhailovskaya and M.I. Demchik, then - yesterday's student. It turned out that not everything with rotation periods is so simple - the light curves changed in a more complex way than expected.It is as if another smaller asteroid revolved around asteroid 87 Sylvia, for example. The frequency analysis of the photometric data of asteroids was carried out using the algorithms of V.V. Prokofieva-Mikhailovskaya.

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The change in color as the asteroid rotates also carried information about the possible "duality" of the nature of the observed body - that is, the fact that in fact it consists of two bodies. After a long and painstaking work on understanding the situation, Prokofiev and Demchik published two short articles in the Comet Circular (then still published in Kiev) and the Astronomical Circular (still published in Moscow). They unequivocally stated: asteroid 87 Sylvia is double. The texts themselves are not easy to find without going to the library, so we have attached them in the form of illustrations.

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To appreciate the courage of both researchers, it is worth recalling: it was 1992. Then astronomers believed that asteroids were just a building material left over from the formation of the planets of the solar system. Therefore, they cannot have their companions. After all, the models of the appearance of satellites available at that time "allowed" them to form only from a protosatellite disk, which could reach significant sizes only in truly large giant planets. At that time, even how the Moon appeared on the Earth was not entirely clear - what can we say about asteroids.

Not all scientists working with observations and experiments have the courage to publish a result that contradicts the prevailing theories. Let us recall the example above: in 1979, in the USSR, water was found in the lunar soil, but only brief articles about it were published in "Geochemistry", but nothing of this was included in the final collections based on the results of the study of the lunar soil.

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The reason is simple: most scientists are very sensitive to their reputation. To make a loud statement about the discovery, which then does not come true - a blow to your reputation, and a big one. Therefore, the history of science is full of cases when a person discovered something, but did not dare to "substitute himself" by publishing his work. For example, Karl Gauss pondered non-Euclidean geometry for a long time, but never dared to publish on this topic.

To simply decide on the statement "asteroids can be double", it took a lot of courage - asteroids already had precedents of harsh criticism for the very idea of ​​a satellite. On December 11, 1978, American astronomers observed an "eclipse" of a distant star when the asteroid Melpomene passed between it and the Earth. But this "coverage" was not one-time, but intermittent: as if Melpomene had a satellite, and not one.

As the Soviet researcher Symonenko wrote in a popular 1985 paper: "These results seemed so unusual that they aroused mistrust." When you really want to find fault with something, you can always find something, and critics wrote off the observations as light cloudiness that was during the night of observation.

Symonenko considered astronomers' doubts about observing asteroid satellites justified: within the framework of the ideas of that time, it seemed that the stable existence of satellites in asteroids was extremely unlikely - in a short time such a satellite "should" (according to theoretical views) either leave the parent body or fall on it.

Nevertheless, Prokofieva and Demchik, after careful rechecking, decided to publish their observations in scientific literature, thereby obtaining the status of the first scientists to unequivocally declare such a discovery. As Lyudmila Karachkina correctly notes: “The discovery of double asteroids in our television group was an accident that is based on a dozen iron laws” - and this is indeed the case. The discovery would not have been natural - Prokofiev and Demchik would not have put their scientific reputation on the unambiguous statement “Asteroid 87 Sylvia is a double one”.

But in the West, they did not know about it in the nineties, they do not know today, and they are unlikely to know about it tomorrow.Normally, no one read Soviet scientific publications there, even if their content was presented in English.

The overwhelming majority of scientists - then in the West, and today in our country - follow a rather limited number of scientific journals on the topic, and also the servers of preprints (in 1992, of course, there were none). They, like other citizens, learn about everything else from science pop - well, or they don't.

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The specificity of the 1990s was that in post-Soviet societies there was a sharp drop in the activity of science pop. The population was largely not up to the periodicals, its circulation fell, the activity of people working in the industry - too. A different time required other heroes, from a world a little far from science, at least astronomy. Therefore, almost no one found out about the discovery, not only in the Western, but also in the post-Soviet scientific world.

Meanwhile, the discovery was extremely significant. Until 1992, four classes of objects were known in the solar system: a star (one), planets (eight "real" and many "dwarf"), planetary satellites (discovered by Galileo Galilei in 1609) and asteroids (discovered in the 19th century). If we count the trans-Neptunian objects as a fundamentally new type of bodies, then to these two discoverers one can also add Clyde Tombaugh, who discovered Pluto in 1930. Please note that we are talking about highly distinguished astronomers, with the last of them making his discovery 90 years ago.

And two more were added to this list in 1992, who discovered the fifth, a new type of objects in the solar system - asteroid satellites. The discovery, which, as we will show below, seriously changed the ideas of astronomers about the development of our system as a whole.

Why did astronomers consider asteroid satellites impossible?

If we want to know how a house is built, we must understand what it was built from. For the solar system, the planets' bricks were planetesimals - that is, simply put, asteroids. Therefore, for a long time it was believed that those that remained were simply "unclaimed bricks" of our system. Of course, the properties of "bricks" and "houses" are different, that's why no one expected to see satellites near asteroids.

The main difference lies in the mechanism of education. It is believed that initially all matter in the protoplanetary disk around the young Sun was represented by dust grains and gas. The dust grains accidentally collided with each other, while their average speed dropped - after all, the kinetic energy of the dust grains was extinguished against each other.

Due to this, the dust particles after collisions more and more often did not scatter in different directions, but stuck together, forming larger and larger bodies. When their diameter exceeded a kilometer, the gravity of such bodies became sufficient so that they began to attract each other, and not just randomly collide with only those bodies that were right in their path.

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Kilometer and more bodies are called planetesimals - and those of them that have reached 100 kilometers in diameter are the "embryos" of protoplanets. When they collided with each other, planets were formed. Some of them were gigantic and rich in light elements - Jupiter, Saturn, Uranus and Neptune. Only their core consisted of dense rocks, the outer shell included a lot of gas and ice. Other planets - those closer to the Sun - were formed from protoplanets, in which there were few light and highly volatile substances.

In such a system of representations, satellites can be formed by only three methods. First, from protoplanetary clouds, from which giant planets later arose. Secondly, in the form of collision debris in orbits around small, solid planets. They had insufficient gravity to form large satellites in their protoplanetary cloud - but at the same time, in the case of the Earth, there is clearly a Moon. Thirdly, some of the satellites can be captured from outer space by asteroids (Phobos and Deimos near Mars) or dwarf planets (Triton near Neptune).

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Often "captured" can be distinguished by the "wrong" orbit.If a planet and a satellite were formed from one protoplanetary cloud, then they should rotate in the same direction - to where this very cloud once rotated. Triton, on the other hand, rotates "against the grain", in the direction opposite to the direction of rotation of Neptune.

In other words, the opinion that satellites arise as a result of the formation of planets or the capture of nearby asteroids by gravity of these planets has long dominated in astronomy.

Of course, there was little room for asteroid satellites in such a scheme. Obviously, they did not go through the same processes as the planets during their formation. They could not have a noticeable protosatellite disk like the giant planets.

When colliding with other asteroids, satellites, logically, could not form either: the gravity of a typical asteroid is tens, hundreds and thousands of times weaker than Earth's. Even the largest body in the asteroid belt, Ceres, loses any body knocked out of its surface if its speed exceeds 0.51 kilometers per second. The average speed of collisions in the asteroid belt is about 5 kilometers per second. That is, the debris knocked out by the fall of another body on the asteroid should fly into space, and not form satellites in the orbit of the asteroid.

And why do these satellites still exist and how is this related to the Moon and the solar system as a whole?

To understand how satellites could appear in asteroids, Prokofieva-Mikhailovskaya and her co-authors published an article in 1995 ("Satellites of asteroids", Uspekhi fizicheskikh nauk) with an attempt to assess how satellites of asteroids could have arisen.

At the very beginning of the history of the solar system, a very low-mass protosatellite disk was supposed to revolve around many asteroids, and in the same direction as the asteroid itself. By itself, it could not become the source of the present satellites of small bodies: such a disk is much less in mass than that of a typical satellite of an asteroid.

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As other small bodies (other asteroids and meteoroids) fell on the asteroid, debris was formed. Some of them were "knocked out" in the same direction as the asteroid itself and its satellite disk rotated. The debris that flew out of the asteroid against the direction of its rotation lost their energy from the collision with the protosatellite disk - that is, their speed decreased, and they fell on the asteroid.

Those debris that flew in the direction of rotation of the protosatellite disk found themselves in a situation where they could no longer quickly lose their speed and fall back onto the asteroid. After all, subsequent waves of debris collided with the "embryo" of the asteroid's satellite, and gave it an additional impulse (and mass). As a result, the satellite of the asteroid grew and gradually moved away from the asteroid itself.

In such a situation, two main scenarios for the further development of events with their satellites can operate on asteroids. If they begin to constantly actively increase their mass due to the flow of dust and stones from the surface of the parent asteroid, then the distance between the satellite and the asteroid itself will begin to decrease over time.

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Ultimately, the satellite will smoothly "land" on the asteroid, forming the characteristic figure of a "snowman" - two spheres, one of which (the former parent asteroid) is slightly larger than the other (the former satellite of the asteroid). A variant of this development of events: the satellite can crash into its asteroid, piercing canyons on its surface, as on Vesta, in the asteroid belt (pictured).

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The second possible scenario for the evolution of a satellite is tidal acceleration. In it, the central body slows down its rotation around its own axis, transferring part of this energy to its satellite due to tidal acceleration. Each of us sees such a scenario since childhood, although he does not realize it: the Moon slows down the rotation of the Earth and due to this, it is itself more and more (albeit extremely smoothly) moving away from our planet.

The authors of the 1995 paper note that the mechanisms of formation of satellites in asteroids and planets are very similar.It was on this theoretical basis that an article appeared in 2007 in Izvestia of the Crimean Astrophysical Observatory explaining the formation of the Moon by the same mechanism.

It is interesting that the analysis of the mechanism of formation of satellites in asteroids and solid planets made it possible to better understand how satellites of giant planets with "wrong" rotation "against the grain" - like Triton in Neptune, were formed. Contrary to the previously painted pictures, the same Triton was not completely captured by the gravity of Neptune. It was formed already in orbit around the giant planet.

This happened due to the interaction of the asteroids captured by Neptune with the same rarefied protosatellite disk. Asteroids, which skirted the planet in a forward or reverse direction, collided with particles and gas from the "forward" (the direction of rotation coincides with the direction of rotation of the planet) protosatellite disk. If the captured asteroid itself had a reverse orbit, then its velocity and the velocity of the particles of the protosatellite disk in the collision were added. In this case, the deceleration of the asteroid was carried out much more efficiently than if it was direct, In addition, the influence of the Sun's gravity makes the reverse orbits of the satellites of the giant planets more stable than the direct ones. And the farther the satellite is from its planet, the more stable the reverse orbit will be. As noted by physicist Nikolai Gorkavy, the author of a model of multi-impact formation of satellites due to the collision of asteroid debris with a protosatellite disk, this is especially clearly seen on the example of the satellites of Saturn and Neptune.

For example, Saturn's return satellite Phoebus is noticeably more massive than Jupiter's reverse satellites: the capture of the mass of asteroids in reverse orbits from distant planets was clearly more effective. Among the satellites of Neptune, in general, almost all mass falls on Triton, a body larger than Pluto and at the same time rotating in a reverse orbit around Neptune.

A pattern emerges: the farther the planet is from the Sun, the longer it has been bombarded by asteroids, the larger and more massive it has as a result of its reverse satellites. Jupiter's reverse satellites are less massive than Saturn's reverse satellites, and these, in turn, are less massive than Neptune's reverse satellites.

What practical implications does the discovery of asteroid duality have?

From the above, it is clear that the discovery of binary asteroids changed the idea of ​​how satellites are formed in the solar system and, most likely, in other systems too. Thanks to this, we began to better understand how the moon came into being. Moreover, from such a model it follows that the Moon is not at all an anhydrous body, as it was imagined until recently.

Because it turns out that Selena arose not from the molten debris of Theia and our planet, but from the "cold", not molten debris of the Earth. Then, under its surface, a noticeable amount of water can be hidden. And not only under it: according to the latest data, there are at least one hundred billion tons of water ice in the polar regions of the Moon. In theory, the relative "water content" of Selena is already a good practical return. Knowing about it, you can plan to search for water ice in lava caves.

But there is another important point. As you know, asteroids are a major (or even the largest) extinction threat to life on Earth. According to modern concepts, it was they who caused at least the extinction of dinosaurs and, possibly, an even larger Permian extinction.

It is estimated that 10% of all asteroids in the solar system can have satellites - that is, the vast majority of satellites, in principle, are precisely satellites of asteroids. It is technically quite possible to combat an asteroid falling to Earth. For this, one missile with a sufficiently powerful thermonuclear warhead is enough. However, if such an asteroid has a satellite - and even not discovered in time - then after the destruction of the main body, it will continue its flight to our planet.

That is, each individual satellite of an asteroid dangerous to us is another dangerous asteroid.To deflect a double body from collision will be twice as difficult, and a triple body will be three times more difficult. By the way, the asteroid Sylvia, whose satellite was discovered at the Crimean Observatory, as a result of further observations was recognized not even as double, but triple - that is, it has two asteroid satellites at once, not one.

It is interesting that if we find out in advance whether the dangerous asteroid has a satellite. and what are its parameters, then you can try to deflect both bodies with the help of just one terrestrial apparatus. The fact is that an asteroid rarely crashes into our planet at once. Normally, it first flies close to it in an elliptical orbit, and then over and over again approaches to a smaller distance until it collides.

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If the interceptor apparatus, years before a possible collision, hits the surface of the asteroid's satellite and thereby changes the parameters of its orbit, then the satellite's gravity can change the trajectory of its host asteroid so much that there will be no collision - as in the video below.

Conclusion: astronomers should, if possible, identify in advance the satellites of all potentially dangerous asteroids for the Earth. And the sooner the better.

On the danger of non-proliferation of knowledge

So, the discovery of double asteroids began a new era in astronomy. Thanks to him, it became clear that satellites have common, universal mechanisms of formation for different bodies. It was possible to understand how the Moon was formed, why there is water on it, and that it can be more difficult to defend against an asteroid threat than we thought. Finally, it became clear how such cosmic bodies as "snowmen" in the Kuiper belt (pictured above) or such strange phenomena as impact canyons and snowman craters on the asteroids of the Main Belt appeared. All these are undoubted advantages.

But there are also disadvantages in the outlined situation. It should be understood that in the West they not only believe that double asteroids were discovered by Galileo, but they are also not aware of the theory of the universal mechanism for the formation of satellites that arose on the basis of the discovery of these double asteroids. It is still believed there that the moon came from the impact of Theia, and that the small "snowman" planets arose due to some fantastic coincidence.

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This is not unusual. At the beginning of the text, we have already given an example of how Soviet data on lunar water were ignored outside the USSR. Earlier NS wrote about a similar situation in archeology and anthropology: the scientific results of Latin American archaeologists for decades were ignored by American archeology, which could not but delay the development of our ideas about the settlement of the New World.

The negative side of this phenomenon is a huge waste of scientists' time, forced over and over again to rediscover what has already been discovered before them. And okay if we are just talking about the pioneering of the satellite of the asteroid Sylvia, which happened in the United States already in the 21st century. Worse when it comes to wasting time in painstaking theoretical work.

Following the work of physicist Nikolai Gorkavy in 2007 on the formation of binary asteroids and the Moon, similar works were published in 2014 and 2015 - the last one in the West. However, it was authored by Israeli researchers, therefore, in the American scientific literature on the issue of the multiimpact theory of the formation of the Moon, no one has disputed yet - with a high degree of probability, all these publications there have remained unnoticed by most researchers.

From this, today in the United States they are still looking for opportunities to somehow patch up inconsistencies in the mega-impact theory of the formation of the Moon, announcing how light elements could survive on it if its material was melted. It is even difficult to calculate how many man-hours of researchers were spent trying to keep afloat a hypothesis that was outdated in the 1990s, after the discovery of double asteroids. It is even more difficult to say when this situation will finally end and the results of many years ago will finally become available to theorists around the world.

Alas, in this story, a noticeable part of the blame is not on the actual Western astronomers, who do not closely follow the scientific publications in Russia. As we have already noted, modern specialization in science is such that scientists often learn about the existence of new works on their topic from scientific pop.

It must be admitted that the Russian-speaking scientific pop did absolutely nothing in order to acquaint the citizens of their own country with the fact of the discovery of double asteroids by Soviet astronomers. And there is very little to acquaint anyone with the theoretical implications that this discovery has for understanding the entire history of the solar system.

When Clyde Tombaugh, who discovered Pluto, died in the United States, it was widely reported even in the press, far from scientific pop. When V.V. died in Russia in 2020. Prokofieva-Mikhailovskaya - have we seen a lot of reports about this in the press? We cannot seriously ask the Western scientific world for not knowing something about our science. Indeed, in this, in fact, it is our own fault.

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