The history of our planet is full of hard-to-explain events and cataclysms, including:
1) The riddle of the appearance of the Earth's satellite - the Moon;
2) The reason for the death of dinosaurs.
This hypothesis unites these two events into a single line of cause-and-effect relationships.
1. Iridium anomaly
The main hypothesis for the extinction of dinosaurs is the impact hypothesis of Louis and Walter Alvarez, suggesting the death of dinosaurs from the consequences of an asteroid fall on the Yucatan Peninsula in Mexico. The Chiksulub crater and the increased content of iridium in the layer at the Cretaceous-Paleogene boundary are given in support of this. The jump in the content of iridium in the soil is considered the moment of the fall of the asteroid and the beginning of a large-scale cataclysm.
Chemical analysis of the soil in the clay layer at the Cretaceous-Paleogene boundary showed that the average iridium content was 10-30 times higher. And in some places on the Earth, the excess has even greater values.
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According to the schedule drawn up by the Alvarez group, the moment of the beginning of the cataclysm is clearly traced. A sharp, abrupt increase in the accumulation of iridium in the layer is seen (Fig. 1).
Figure: 1. Graph compiled by Alvarez's group.
Let's pay attention to the amount of iridium entering the soil. It can be seen how until the end of the Cretaceous period, up to the border of 65 million years ago, the amount of iridium that got into the soil went at a uniform rate (Fig. 2).
Fig. 2. Rate of iridium entering the soil.
Then, at some point, there was a sharp jump in the amount of iridium in the soil, its intake instantly increased by 10 times (Fig. 3).
Fig. 3. Increased iridium intake.
This suggests that some event has occurred that has led to a sharp increase in the supply of iridium. The event had a planetary scale, since an increase in iridium in this period is found throughout the planet.
Further, a very interesting feature is visible - after a sharp increase in the amount of iridium, the period of its maximum intake continues, lasting 5 thousand years. Then, over 15 thousand years, there is a gradual decrease in the supply of iridium. And only 20 thousand years after the beginning of some event, the amount of iridium entering the soil returned to its normal value (Fig. 4).
Fig. 4. Smooth decrease in iridium supply over 15 thousand years.
The surplus iridium intake did not stop after a sharp increase, even if over a relatively short period of years or centuries. And he continued to do it for tens of thousands of years. The question arises - could the dust from the fall of the asteroid settle for so long? As many as 20 thousand years! And the sizes of the asteroid, 10 km in diameter, and the Earth, 12,742 km in diameter, are not comparable. The maximum that such an asteroid is capable of is regional atmospheric pollution, earthquakes and tsunamis. No single point source could have resulted in such a vast and even distribution of iridium across the planet. Moreover, it turned out that iridium may be of terrestrial origin. Studies of the ejection products from the Kilauea volcano, located in the Hawaiian Islands, have shown an unusually high concentration of iridium. Moreover, it was proved thatthat iridium did not come from the eruption of lava, but went out with volcanic ash and gases into the atmosphere, which ensured its extensive dispersion. It turned out that this volcano gives more iridium than meteorites.
The death of dinosaurs from increased volcanic activity is the second hypothesis, along with the impact one. Between 60 and 68 million years ago, a massive outpouring of magma from faults in the ground took place on the Indian subcontinent, as evidenced by the traps on the Deccan plateau in India. But the reason for the extensive volcanic activity on the planet remains unclear.
A single skeleton is interesting for identifying a species, but cannot reveal the reason for the extinction of the entire species. The discovery of "dinosaur graveyards", where the broken bones of both herbivorous and carnivorous dinosaurs are mixed up, suggests that an event occurred that brought together dinosaurs of different species in one place, from which they could not get out. Dinosaurs did not suffocate from ash or starve to death, but died from external physical impact, regardless of their type and size. The discovery of mass graves of dinosaurs on all continents speaks of global events that took place everywhere with the same intensity and swept across the planet many times. This was not a single asteroid impact or a regional eruption of a group of volcanoes. The event had an all-planetary, millennium-long, catastrophic scale.
All of the above suggests that the fall of the asteroid could not cause long-term geological processes. For such a massive death of entire species throughout the planet, an event is necessary that is not a point, local, but equally catastrophic for every part of the planet, for every corner. And it will last not years and centuries, but millennia. As a result, continents shifted, mountains collapsed, the seabed rose, and seas and oceans overflowed their shores, burying entire colonies of dinosaurs under them and throwing large marine predators onto land. Leaving a chance for survival only for small and nimble animals, capable of leaving a dangerous place in time. Not a single species weighing more than 25 kg survived the disaster.
2. The origin of the moon
The moon has been eye-catching for millennia and has been an object of study. But even with such close attention, the Moon continues to keep many secrets. First of all, this is the question of the origin of the moon. How could a satellite, which is so large compared to the planet, have formed at such a close distance from the Earth? Where does the Earth-Moon system have such an unusually high angular momentum?
Among the many hypotheses for the origin of the moon, the hypothesis of a collision of a proto-earth with a celestial body is considered to be the main one. As a result of the collision, the Moon was formed from the ejected substance. Another hypothesis is the hypothesis of the capture of the passing moon.
Each hypothesis has its own considerations, both "for" and "against".
The main drawback of the capture hypothesis is considered to be an almost circular orbit of the Moon, which is excluded when a body flying past is captured. In this case, the orbit of the Moon should be in the form of a highly elongated ellipsoid with a large eccentricity. The inability to solve the problem of rounding the Moon's orbit sweeps aside the, in my opinion, the most plausible hypothesis of the appearance of a satellite near the Earth.
The capture hypothesis needs to answer several key questions:
1. Birthplace of the Moon.
2. The reason for the de-orbit.
3. The capture mechanism.
4. Mechanism of rounding of an ellipsoidal orbit.
In search of the supposed place of the formation of the Moon and study of the composition of the planets, a clear pattern is revealed - the planet closest to the Sun has the largest core in relation to the mass of the planet (Fig. 5).
Fig. 5. The ratio of the masses of nuclei to the masses of the planets.
In a series of terrestrial planets, according to the ratio of the mass of the core to the mass of the planet, the Moon with its 2% becomes far beyond Mars. Showing us the region of the solar system among the gas giants, where to look for the place of the formation of the moon.
The next parameter - density, shows that the place of the Moon with a density of 3.3 g / cm³ is again behind Mars.
It makes no sense to put the Moon in a row of gas giant planets, these are objects of a completely different type and weight category. But with the satellites of some of these planets we can compare. Let's pay attention to the Galilean moons of Jupiter, most of all corresponding to the Moon in size and density. The density of the inner Galilean moons of Io and Europa is large enough to correspond to the density of the Moon. But the presence of atmospheres and volcanic activity in them, in contrast to the almost complete absence of an atmosphere and the absence of traces of volcanism on the Moon, shows that the Moon could not be at such a close distance from Jupiter. The two distant satellites Ganymede and Callisto have a density of only 1.9 and 1.8 g / cm³, respectively, which is significantly less than the lunar one. But the resemblance of the Moon to Callisto suggests that the Moon was formed somewhere nearby.
If you look at the orbital position of the Galilean satellites, then between Ganymede and Callisto, an empty orbit with a missing satellite is found (Fig. 6).
Figure: 6. Distances between satellites (thousand km).
The density of the Moon, calculated on the basis of mass and volume, is currently much higher than that of Ganymede and Callisto. Shown below is how the Moon, which previously had a lower density, gained additional mass, as a result of which its calculated density increased to its present value.
Having determined the possible place of the formation of the Moon, we will try to find out the reason for the departure of the Moon from this orbit.
The solar system is filled with asteroids and comets, the traces of the fall of which are observed on the surface of all bodies in the solar system. Even on Earth, there are many impact craters formed from asteroid impacts at different periods of Earth's history. We are more interested in the chains of similar craters located in a row that exist on the surface of some celestial bodies.
Until recently, the mechanism for the formation of such chains was unknown. After the fall of comet Shoemaker Levy 9 on Jupiter in 1994, the mystery of crater chains was revealed. It turned out that the planet can break apart an asteroid that approached the planet closer to the Roche limit.
Fig. 7. Comet Shoemaker-Levy-9.
Further, this chain of asteroids can be absorbed by the planet itself, as happened with the Shoemaker-Levy comet, or it can fall into one of the planet's satellites, leaving an impressive chain of craters on its surface. Confirmation that torn comets and asteroids fall into Jupiter's own moons is the Enki crater chain on the surface of Ganymede (Fig. 8).
Figure: 8. Enki crater chain on the surface of Ganymede.
Similar chains of craters are found on other moons of Jupiter.
Small asteroids do not pose a threat to satellites and do not cause them much harm, leaving only chains of craters as a reminder of their existence. But what happens if a metal asteroid 500 km in diameter approaches Jupiter? The tidal forces within the Roche limit will tear it into several rather large pieces, each of which is ready to destroy any natural satellite of Jupiter that stands in its path. If we add tremendous speed to these parts, which are 200-300 km in diameter (the Shoemaker-Levy-9 comet crashed into Jupiter at a speed of 64 km / s), then we get a line of deadly projectiles that can knock out any satellite of Jupiter from orbit.
Among the chains of craters known to us, we observe a series of dozens of small craters, as evidence of the disintegration of a stone body into dozens of smaller ones. But if it was not a stone asteroid that was torn apart, but a metal one only into a few very large parts, then it makes no sense to look for a long chain of craters. We will only see a few huge craters lined up in a row.
In search of an answer to the question of why the Moon left orbit, let's take a look at the surface of the Moon. Even with the naked eye, traces of those old events are visible from Earth.
On an expanded map of the moon, we clearly see four craters that make up a single chain. Ascending - Goddard Crater (1), Sea of Crises (2), Sea of Clarity (3) and Sea of Rains (4) (Fig. 9).
Fig. 9. Goddard Crater (1), Sea of Crises (2), Sea of Clarity (3) and Sea of Rains (4).
The uniformity of the surface inside the craters shows that the energy of the fallen bodies was the same and so high that the bodies that had penetrated into the thickness of the Moon melted the internal structure, the spills of which we see around these craters. The presence of magnetic and gravitational anomalies in the area of craters indicates the metallic composition of the asteroids (Fig. 10).
Fig. 10. Location of gravity anomalies.
Metal bodies caught in the initially light Moon, which had the density of Ganymede and Callisto, increased its mass. Thus, the estimated density of the Moon increased, which became higher than the density of satellites, next to which the Moon was formed.
A chain of deadly missiles from the torn giant asteroid lined up in a row tens of thousands of kilometers long and rushed across the moon. Small asteroids flew ahead, and the largest bodies closed the chain. The energy of each of the metallic asteroids was terrifying, they flew at a speed of about 70 km / sec.
The first bell rang for the Moon when it was hit by the head, the smallest asteroid that created the Goddard crater. It stuck into the body of the Moon, squeezing a stream of molten rock onto the surface that formed the Edge Sea. The second, slightly larger asteroid with an epicenter in the Sea of Crises (2), formed the Sea of Serpents, Sea of Waves, Sea of Foam and Sea of Smith.
Fig. 11. Goddard Crater (1), Sea of Crises (2).
The third asteroid, which pierced several tens of kilometers deep into the body of the Moon, was so powerful that it changed the Moon's orbit. The epicenter of the blow fell in the Sea of Clarity (3). Liquid rock flooded the lunar surface and created structures such as the Sea of Tranquility, the Bay of Severity, the Sea of Nectar and the Sea of Abundance.
But the moon was waiting for a truly monstrous blow, the largest asteroid from the chain, whose diameter was close to 400 km, hit it. The impact was so strong that the Moon could no longer stay in orbit. We see the trail from the gigantic asteroid stuck in the Moon as the Sea of Rains, and the poured lava spilled out and formed the Ocean of Storms and a dozen seas.
Fig. 12. A chain of craters that knocked the moon out of orbit.
Metal asteroids hit the light, porous moon like a sponge. The structure of the Moon extinguished the huge speeds of asteroids without fractures and catastrophic consequences. All the energy was spent on heating the inner structure of the Moon, which spilled out on the surface in the form of the ocean and seas.
Knocked out of orbit, the moon rushed along a curve into the inner regions of the solar system.
Taking into account the increase in the force of gravity when moving deeper into the solar system, the initial orbital velocity of the Moon increased by 8-10 km / s and by the time it reached the Earth's orbit it was equal to the Earth's orbital speed of 30 km / s, which took 2.5-3 years (Fig. 13).
Fig. 13. Departure of the moon from orbit.
Approaching the Earth tangentially, the Moon was captured by the Earth's gravity and it entered an elongated elliptical orbit lying in the ecliptic plane with an inclination of only 5 °. This is why the Moon's orbit does not lie in the plane of the Earth's equator.
From this moment, which happened 65 million years ago, the unenviable fate of dinosaurs begins.
3. The death of dinosaurs
The moon miraculously escaped a collision with the Earth, flying at a minimum distance from our planet. From the Earth, it was possible to observe how the Moon, appearing out of nowhere, rapidly closes the floor of the sky, sweeps over the surface and just as quickly leaves away. But the Moon could no longer escape from the gravity of the earth, continuing to revolve around the Earth in a highly elongated elliptical orbit.
Approaching the Earth, the Moon ironed continents and seas with its gravity, raising waves of the earth's crust. The moon's gravity has triggered volcanic activity across the planet. Molten magma poured through the more recently green forests and plains. The ash of volcanoes covered the entire Earth, destroying vegetation and throwing out the iridium found by the Alvarez group. Some plots of land rose up, others sank to the seabed. The strongest earthquakes occurred with the regularity of modern ebbs and flows. The chemical composition of sea water has changed dramatically, killing a large number of marine animals. The gravity of the moon led to continental drift and continental displacement, changing the face of the planet.
Seas and oceans overflowed their shores, creating mudflows and burying entire colonies of dinosaurs. Small nimble animals could escape only in time by moving to a hill. In search of rescue, dinosaurs huddled in groups, regardless of species and size. But the merciless Moon caught the migrating herds of dinosaurs by surprise, covering them with mudflows of mud and stones, burying them alive. The dinosaurs were washed away in streams in a heap, they folded in unnatural positions, were covered with liquid mud and preserved. The integrity of many skeletons suggests that dinosaurs did not remain in the open after death and did not fall prey to scavengers.
4. Rounding the Moon's orbit
All satellites in synchronous orbit are in tidal capture of the planet's gravity. Any satellite, regardless of size, has an internal inhomogeneity, due to which the planet's gravity keeps the satellite facing the planet with a specific side, preventing the satellite from turning around its axis. All attempts of the satellite to rotate around the axis are stopped by the planet's gravity and only lead to the swaying of the satellite, libration. The planet's gravity returns the satellite to its original position. If the planet's gravity did not turn the satellite with a specific side towards itself, then any deviation of the satellite's orbit from an ideally round shape would lead to an axial rotation of the satellite relative to the planet. But in nature there are no perfectly round orbits. The orbit of the modern Moon, as we know, is elliptical. Hence,if the Earth did not turn the Moon at the right moment with a certain side to itself, then we would see the Moon from all sides, it would smoothly rotate around its axis. The Earth's gravity constantly corrects the position of the Moon, which leads to the deceleration of the axial rotation of the Moon. Such inhibition leads to a redistribution of forces. The moment of inertia of the Moon (axial rotation) passes into the moment of inertia of the Moon-Earth system, causing a displacement of the Moon's orbit in the form of a precession.causing a displacement of the Moon's orbit in the form of a precession.causing a displacement of the Moon's orbit in the form of a precession.
The same thing happens with Mercury. Mercury synchronizes its axial rotation with the orbital only at perihelion. Leaving perihelion, Mercury moves away from the Sun at a distance where the tidal forces of capture cease to act and Mercury gains freedom of rotation around the axis. On the next approach to perihelion, Mercury turns to the Sun with the other side, but not exactly along the axis of the tidal capture. He does not have time to complete a revolution by only a few degrees, and solar gravity corrects the position of Mercury by twisting it. The addition of energy to the axial rotation of Mercury leads to the transition of excess energy from the moment of inertia of Mercury to the moment of inertia of the Sun-Mercury system. As a result, the orbit of Mercury shifts and we observe the well-known precession.
When the Moon was in orbit with the satellite of Jupiter, its axial rotation was synchronous with the orbital and was equal to approximately 12 Earth days (average between Ganymede and Callisto). The moon was constantly facing Jupiter with one side. After the capture of the Moon by the Earth, its moment of inertia was preserved, but the axial rotation did not equal the orbital revolution around the Earth. The moon moved in a highly elongated ellipsoidal orbit, turning to Earth with one or the other side. The entire orbit of the Moon, both at perigee and apogee, was inside the sphere of tidal capture. The gravity of the Earth began to slow down the axial rotation of the Moon, transferring the moment of inertia of the Moon to the moment of inertia of the Moon-Earth system. The Perigee began to move away, the apogee was approaching.
Having plowed the Earth up and down with its gravity, the Moon began to move away from the Earth. With the receding of the moon, geological activity gradually decreased, volcanoes reduced emissions into the atmosphere, and stabilization gradually began. Only after 20 thousand years, indicated in the schedule of Alvarez, the Moon moved away at a distance sufficient to stop volcanic activity. Further, the Moon moved away already without such catastrophic consequences.
According to available data, the Moon's receding continues to this day. The process of measuring the distance to the Moon is very complicated. With the advent of instruments that allow you to measure the distance to the moon both at perigee and at apogee, the perigee distance and apogee approach will be detected. Which will indicate the continuation of the rounding of the Moon's orbit.
Vasily Minkovsky