Our solar system contains three types of planets. Between the four terrestrial planets – Mercury, Venus, Terre and Mars – and the distant ice giants of Neptune and Uranus, seated two gas giants: Saturn and Jupiter.
These planets are mainly composed of hydrogen and gaseous helium. Researchers now appreciate that gas planets are more complex than the first thought. New results have implications on our understanding of the formation of these planets and will help to design future missions to visit them potentially.
How are gas giants formed?
The gas giants come from one of the two processes. The first method is called Core Acretion, explains Ravit Helled, professor of theoretical astrophysics at the University of Zurich. It starts with the birth of a new star, when the molecular clouds collapse under gravitational pressure. Gas protoplanetary disks, start -ups to turn around these new stars. Within these gas discs, heavier particles – Dust, rock or heavier elements than helium. These particles can group together, then suck the gas from the surrounding disc, forming a giant planet mainly composed of gas.
A second method that can form gas giants called disc instability – is a more recent theory that always causes some controversy among planetary theorists. According to this idea, when the massive protoplanetary discs are cooling, they become unstable and can produce tufts of rock and gas which evolve in gas giants. Above all, this proposed training process occurs much faster than basic accretion. Helled says that Saturn and Jupiter have probably formed by basic accretion, but that the instability of the disc can “explain very massive planets in large orbits or giant planets around small mass of mass”.
Land on a gas giant
Whatever they form, the structure of gas giants is in no way resembles that of terrestrial planets like earth. Jupiter and Saturn have no surface in the same way as the earth does. Instead, their atmosphere simply becomes thinner until there is no density to call the surrounding aerial part of the planet. “There is no place where you can say, okay, that’s where the planet stops,” explains Helled.
A spaceship trying to “land” on Jupiter’s “surface” should overcome certain important obstacles. Once you have entered the gas cloud which marks roughly the start of a giant like Jupiter, the temperature and pressure increase regularly as your head towards the heart of the planet, and the gas hydrogen and the helium transform in liquid form. Although the gas giants in our solar system are far from the sun, the heart of a gas giant is probably incredibly hot – Jupiter is estimated at around 43,000 degrees Fahrenheit. You will also have to pass through the thick clouds of ammonia found in the high atmosphere of Jupiter.
If you make your ship from difficult things – more than any known substance on earth – which could survive these conditions, this could go to the heart of a gas giant. What would find in the extraterrestrial Murk is not yet clear.
“For decades, it has been assumed that there was a defined nucleus,” said Helled. The recent probe missions, such as Juno and Cassini, have orbited Jupiter and Saturn, respectively. The information that these probes have sent back changed this view.
“We now think that they have what we call the fuzzy or diluted nuclei,” explains Helled. This means that there is no clear transition point between the upper layers of liquid gas and liquid hydrogen and helium and the nucleus of the planet.
In truth, Juno and Cassini’s data revolutionized our understanding of the structures of this planet. Helled explains that they probably have complex heat and composition gradients. Jupiter is famous with massive storms, such as the large red spot, which produces winds up to 425 MPH (640 km / h). Some of these changes can produce dramatic phenomena. Jupiter and Saturn probably have regions in which helium gas separates from hydrogen. Here, helium becomes a rain of droplets flowing towards the core of the planet.
These ideas can reveal more about the giants of our solar system, as well as similar planets outside our solar system.
“Now we realize that some of the simple hypotheses we have made to model these planets are wrong, and we have to modify the models,” explains Helled.
This story is part of popular sciences Ask us anything seriesWhere we answer your most bizarre and burning questions, from the ordinary to the wall. Do you have something you always wanted to know? Ask.
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