The violent past of our solar system

When we examine the planets and moons of our solar system today, it would be very easy to believe that everything has always been that way. But in recent years, scientists have learned with surprise that the solar system is very different from the solar system. Below, we will list some shocking discoveries that show how a series of violent events have transformed our solar into what we see today.

1. When Theia crashed on Earth

The question of how the moon formed has long been an argument among astronomers, but the evidence in recent years suggests a dramatic response: it was formed by a direct collision with the Earth by another planet .

According to the giant impact hypothesis, about 100 million years after the formation of the Earth (4.5 billion years ago) were affected by a planet the size of Mars.

Known as Theia, this little planet was completely erased by the collision. The Earth has scarcely resisted better, with a huge mass of materials thrown off by the impact – materials that would one day reform and cool down like the Moon.

The theory may seem far-fetched, but now it has general approval, with evidence of this amazing encounter with each study.

2. The period of late bombardment

We know that the formation of the early solar system was to be a violent place, filled with rocks and debris flying everywhere. The most spectacular proof is given by the innumerable craters observed on all the planets, the moon and even the asteroid of the solar system.

All the more so each of these bodies shows that they must all be formed and sufficiently cooled before the onset of impacts.

This period, known as the "late bombardment period", would have occurred about 4 billion years ago. It would in fact have been caused by the remaining debris from the solar system formation thrown away like pinball machines.

As evidenced by various craters, it was a particularly violent time. At first, we did not know what could have caused this sudden bombardment, but now we have a clue …

3. The Nice model with five planets

For a very long time, no computer model of the formation of our solar system has resulted in the layout of the planets we see now. It was amazing because the global process of planetary formation is something we can observe around other stars.

An astonishing solution, proposed in 2005 by a group of astronomers in Nice, France, is that the planets we see now have not formed in these positions, but have drifted in time. If this is true, the Nice model would certainly explain why the late bombardment period occurred.

But that goes further: the most recent version, Nice-V, claims that the solar system had a giant ice planet, which was driven out of our solar system by the movements of other giant planets.

If all this seems exaggerated, the problem is that the calculation works well. It remains, to this day, the only computer model of the solar system that really predicts the positions of the planets as we see them now.

Curiously, even the nice models have nothing to say about the supposed Planet Nine, which means that the Nice models are wrong – or that Planet Nine, if it exists, may have been captured by another star system .

4. Wandering Jupiter

The evidence supporting the Nice model continues to accumulate. This week, a forthcoming Astronomy & Astrophysics study has modeled how Jupiter has evolved in the early solar system. Their conclusions are striking.

According to the Lund University study, Jupiter initially formed in an orbit four times farther from the sun than today. In less than a million years, Jupiter has migrated to its current orbit.

Apart from all that has been covered so far, striking evidence in this regard comes from Trojan asteroids, which share the orbit of Jupiter. There are two distinct groups, and the computer models show that they must have been picked up while Jupiter was wandering in its current position.

We will learn more about this because NASA will soon launch a space probe named Lucy to analyze these Trojan asteroids.

5. When a planet collides with Uranus

A strange feature of Uranus is that the planet runs efficiently on its side compared to other planets in the solar system. This proved impossible to explain by normal means. The only viable alternative is a collision theory.

Originally, it had been suggested that a comet might have collided with the gas giant, but more recent models suggest that it would have taken something much bigger to knock Uranus off if completely on his side, something twice as big as the Earth.

A computer modeling done by astronomers from Durham University published a study last July suggesting that a proto-planet, composed mostly of rock and ice, would have struck Uranus about 4 billion years ago. . According to the Nice model, this may have happened while the giant planets were still moving in the solar system.

This theory of collision, however, adds an interesting new twist: the fallout of the collision effectively stifled the Uranus core, thus preventing the heat from reaching the outside atmosphere, thus explaining the reason why Uranus has an otherwise inexplicably cold surface temperature.

6. When Neptune captured Triton

It is not only the planets that have moved in the solar system. Research now suggests that Triton, the largest moon around the planet Neptune, did not initially form there.

The key evidence in favor of this theory is that Triton orbits Neptune in a retrograde move. Indeed, it recedes compared to the other moons of Neptune.

Computer modeling has since shown that Neptune could actually have captured Triton, especially when the gas giant was migrating through the solar system to its current position, along with the other giant planets.

7. Mercury colliding?

It may seem that planetary collisions are a rare and extraordinary event, yet we have another possible scenario in the form of Mercury.

In simple terms, mercury is so unusually dense that it looks more like a planetary core than a planet. But if so, where is the rest of Mercury?

Even though Mercury is very close to the sun, heat and solar winds are not enough to eliminate the outer layers of Mercury. Computer modeling suggests that a giant impact on another small planet could have created what we see now.

However, this theory is not clear. The biggest problem being, if something hit Mercury, where was the rest?

8. Phaeton – the planet that never existed?

A popular theory in the 18th century saw a pattern in the sequence of planets. Later known as the Titius-Bode Law, she successfully predicted the position of Uranus, although she failed to predict Neptune's position.

However, part of the sequence fell on the asteroid belt. Some of the early astronomers thought that meant that there was a planet out there, only to be somehow destroyed – perhaps by the gravity of Jupiter.

The idea has fallen into disuse and current science believes that the asteroid belt is only the rest of the solar system formation.

There are two curious reasons, however, for which we could still have more discussion on this subject.

The first is that the asteroid belt consists of two main groups of distinct asteroids, of very different composition. The second is that one of the most massive asteroids in the region, 16 Psyche, gives any suggestion of being a small planetary kernel.

Is it possible that the asteroid belt was formed by the collision of two small planets? We will soon know that NASA will soon launch a probe to explore the asteroid belt, and in particular 16 Psyche.

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