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Until the discovery of the first Hot Jupiter, astronomers who studied the solar system thought they had a pretty good understanding of how we all got here.
During a billion years, slow globes of dust formed rocky planets in the internal solar system. Beyond the asteroid belt, large and powerful gaseous giants evolved from ice bodies the size of an asteroid into gigantic planets to form gigantic planets with thick gas atmospheres of several thousand kilometers collecting the abundant gas flowing around the initial solar system away from the sun.
Having never seen another planetary system to compare it with, the beautiful orderly growth and eventual separation of the different classes of planets into ordered, almost divinely mandated areas, had some appeal.
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This fits well with our implicit divisions between hierarchies and vassal-boss relationships stemming from the great disparity of powers that makes up the bulk of human history.. This began to change in the mid-90s after the discovery of exoplanets orbiting other suns, which directly questioned our assumptions and questioned almost everything we thought we knew about the formation of planets.
The abundance of hot jupiteurs and super-terrestrial gaseous astronomers
The discovery of Peg 51, the first ever-discovered exoplanet that orbits a star similar to ours, was not what we had ever seen. He has half of the mass and pretty much the same diameter like Jupiter but he only took 4 days to orbit its star, an orbital period that seemed impossible for something so massive.
The only way it made sense was if Peg 51 was less than 10 million miles from the surface of his star. Not only did subsequent observations confirm it, but other astronomers who were studying other star systems were discovering these so – called hot jupiters everywhere. Several of these star systems had even several bodies in very close orbit around their stars, many of them several or more land masses.
What they did not see in these solar systems was one that looked a lot like ours. The orderly and orderly divisions of our home system, with the small rocky worlds inside and the big gaseous giants on the outside – almost all the planets revolving around the sun in a well-formed ellipse with very few d & rsquo; Eccentricity – were actually a galactic phenomenon of nature.
In the years that followed, scientists began to examine the conditions of the solar system in which we live and the story that begins to emerge reverses the boring old story of a slow, steady and stable growth.
Understand the evolution of Hot Jupiter
The essential mystery of Hot Jupiters, to which astronomers were confronted while observing other systems, was trying to imagine what process could have brought an object of this size to settle in a high-speed orbit at one-tenth of the distance of his star.
Scientists have developed three major theories, but we only have to worry about one of them, the theory of migration.
Just as a black hole is surrounded by an accretion disk, the oldest stage of star formation also produces a similar disk of dust, gas and debris around the planet. ;star. Due to the way in which the gravity of the stars interacts with the gases of its accretion disk, the gases of the disk are slowly sucked into the star, creating a kind of stellar vortex with the stellar furnace at its core .
Since it is the outer regions of the accretion disk that are usually the most gas dense, this vortex effect on far more distant gases is even more powerful and could even reduce the radial velocity of the orbit of A gas giant effectively sweeping the gas giant. with its current and dragging it further into the star system in a spiral more and more tight towards the star.
Go home Jupiter, you're drunk
In ancient Greek and Roman mythologies, Jupiter – or Zeus, in his Greek manifestation – was a king of the classical pantheon, moody, violent and carefree. Whatever catastrophe Jupiter causes in the Universe, and there have been many, it is never Jupiter who suffered the consequences, but often innocent bystanders who were in the wrong place at the wrong time.
In the end, the planet Jupiter may not have been wiser in its youth than the mythological figure who named it. Just as astronomers sought to explain how a gas giant became a Hot Jupiter, others were trying to understand why our do not have become one and, so far, the evidence is beginning to reveal an early solar system that has been the scene of a remarkable series of events.
The most recent research tells us that Jupiter began life as an icy asteroid the size of the Earth. These data show that this icy body, which would form the core of the gas giant that we see today, began to four times as far from the Sun as Jupiter is today, placing his birthplace between the current orbits of Uranus and Neptune.
It is believed that 2-3 million years after his training in the Sun's accretion disk, Jupiter began a 700 million years A period that is what some scientists call the big turn, inspired by the kind of "tack" maneuver a boat makes as it moves to a buoy, bypasses and bypasses it and then moves away. in the direction in which he was heading. In the case of Jupiter, this maneuver of the giant gas giant in full expansion would profoundly affect the evolution of the solar system.
In other exoplanetary systems that we have studied, one of the predominant features is the predominance of systems with one to several planets the size of a Super Earth in close orbit around a star; Something is missing in our solar system.
In its reduced orbital migration, the gravitational influence of Jupiter would have resulted in innumerable asteroids and other protoplanetary materials cascading into the internal solar system. The gravity of Jupiters would also have deformed the orbits of the evolving worlds, from the size of a Super Earth, to more elliptical or superimposed worlds, while raining hell on an asteroid.
As violent as these collisions may have been, the most important effect of this cascade of asteroids and planetoids colliding with each other is what it caused to the gases of the internal solar system. The unexpected avalanche of rocky materials resulted in aerodynamic forces that captured the growing planetary bodies of the inner solar system in their currents and ultimately resulted in these planets in the very sun.
The simulations show that this great transfer of Jupiter would have completely destroyed one of the great bodies in evolution caught unawares before his inner pilgrimage to the Sun.
A punctual and moderate intervention
That should have been the case, but it clearly did not happen. Jupiter, rather than continuing his migration a few million kilometers from the Sun as it would have been hot Jupiter, has rather changed course: he has tackled.
As Jupiter arrived at the interior 1.5 AU of the sun, about the current position of Mars, her forward migration stopped and she started to retreat from the Sun. Jupiter was not the only gas giant on the move. Neptune and Uranus began their own version of this process, like the most important of all: Saturn.
Growing behind hundreds of millions of years behind Jupiter, Saturn had grown up enough that its gravity began to pull enough traction on Jupiter so that the orbit of Jupiter, instead of tightening itself, began to rise. Away from the Sun.
In a very short time, the orbits of Jupiter and Saturn were resonated, allowing the two gaseous giants to evacuate the remaining gases between them. Without these gases to drive their migrations, Jupiter and Saturn settled in their stable and current orbits.
What Jupiter left in the inner solar system, in cosmic terms, was almost nothing, but he was convinced that when Jupiter returned to its current orbit, there remained flotsam and jetsam in stable circular orbits. Over the next hundreds of millions of years, the debris left by Jupiter's destructive charge to the Sun would melt into the planets of the inner solar system we know today.
Jupiter occasionally eyeing one or two frozen asteroids on the inner planets – which, when the Earth was young, began to accumulate and eventually formed oceans of liquid water – but the role of Jupiter as that destroyer of worlds is largely finished. slowed by the moderate gravitational influence of Saturn.
Now, rather than our destroyer, Jupiter has become our protector. containing 2.5 times Due to the mass of all the other planets combined, Jupiter acts as a gravitational shield orbiting the inner solar system, redirecting most of its contents to almost all incoming asteroids and debris, away from the system. solar energy (there are, of course, important exceptions.
This respite has given the Earth the necessary time to develop increasingly complex life forms, protected from work delayed or destroyed by repeated and catastrophic impacts of asteroids. In return, Jupiter and Saturn We have on Earth a community of human beings who gratefully acknowledge the role of these planets, what no other gas giant in the universe can claim, to our knowledge.
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