The Importance of Jupiter

·A planet out of reach

We will not try at all to explain the functioning of the largest planet in the Solar System, neither its intricate chemical structure-physics, as even astronomers haven't been able to dig deep into the secrets hidden by its dizzying fluxes of stormy clouds fueled by the intense heat that goes up from the core to the surface and the 47,000 km/h to which the colossus revolves around its axis; its climatic conditions are dictated by temperatures and pressures such as to upset the physics conceived here on planet Earth and to influence the intrinsic behavior of the individual hydrogen atoms that for 80% make up its mammoth mass. Of Its strength was witnessed the Galileo spacecraft that in 2003, after 8 years of close studies, was precipitated towards its bowels disintegrating after reaching the speed of 50 km/s. The energy it emits is even greater than that it receives from the Sun (because of the Kelvin-Helmholtz mechanism) and its magnetosphere is the largest non-solar structure of our planetary system, bypassing the orbit of Saturn. Let us instead, with reasonable humility, see why we owe our lives to this distant gas giant.

1. The southern hemisphere and the Great Red Spot in a photo taken by the Juno spacecraft in 2016. (NASA credits)

·Jupiter and the Heart life

According to the nebular hypothesis, 4.5 billion years ago, during the formation of the Solar System large quantities of dust and gas that formed part of the accretion disc of the proto-Sun were pushed by the latter’s radioactive winds outwards, at a distance of sufficiently low temperatures to allow hydrogen, ammonia, water and methane to rapidly agglomerate, inducing the formation of the premature proto-planets Saturn and Jupiter, which reached a good percentage of the current composition. Solid substances remained in the inner orbits.

Orbiting 524 million km from the Sun, Jupiter narrowed its parabola attracted by its star, and again expanded its position progressively moving away to its present location thanks to the attraction of Saturn: it was during this "gravitational elastic" that it dragged with it many of those rocks and ice debris that had a narrower orbital trajectory than the Sun, some of them of modest size, others with considerable masses, so much so that some of these materials had already compacted (according to some theories formulated by computer simulations) to generate three of the four major moons of Jupiter. From the solid materials rejected by the gas giant that continued to maintain a distance close to our Sun, the rocky planets including the Earth are generated, and there remains a fossilized trace represented by the asteroid belt.

Millions of years later, many of the archaic solid remnants of the formation of the Solar System (mostly made of ice) that served as the outermost ring away from the Sun, were disturbed by the swirling orbit of the gaseous planets guided by Jupiter and by its great gravitational attraction, and were thrown in the direction of the inner Solar System giving rise to what is known as the Late Heavy Bombardment.

For approximately 300 million years (4.1 to 3.8 billion years ago) fragments and boulders of rock and ice impacted the surfaces of Mars, Venus, Mercury, the Earth, the Moon. The assumptions surrounding this scenario are not unanimously shared by the scientific community, but there is one (the most plausible) that seals the theory that the Late Heavy Bombardment provided the Earth with enough water-rich material to cover its surface with the first primordial oceans.

In addition, during this phase, it is assumed that four large collisions would have generated impact erosion, transforming those parts of the surface affected by the impacts in molten lava; this latter process allowed the outward release of radioactive metals such as uranium and potassium, which were latent under the earth’s crust before the bombardment and which acted as a thermal regulator, making sure that the outer earth’s crust cooled rapidly and that water did not evaporate: we are not here to tell ourselves what the link between water and life is.

2. X-ray polar auroras captured by Hubble in 2007

·Our survival

With a mass of 1.89819x10^27 kg, an average rotation speed of 13.056 km/s and a very intense magnetic field of which we have previously mentioned, has always been able to influence the motions of all the celestial bodies constituting the Solar System and, more than once, decide its fate.

Acting as a "great magnet" has for billions of years served as the protector of the inner rocky planets, stabilizing the orbital trajectory of the asteroid belt and deviating or often even absorbing the icy comets that from the distant Kuiper Belt launched in free fall towards the heart of the Solar System.

Shoemaker-Levy 9 was the first comet ever observed to orbit a planet instead of the Sun. Studies of its orbit revealed, in 1993, that it was captured by the gas giant and forced to an increasingly tight motion for at least 25 years, undergoing disintegration in various minor fragments, which were eventually overcome by gravity and rushed to the planet causing frightening impacts visible for months even from Earth, in the form of brown spots.

This (the most obvious) is however only one of many cases;in fact there are numerous periodic comets captured from the orbit of Jupiter, just as it is thought to behave equally effectively towards asteroids.It is estimated that the collisions to which it is subject are from 2000 to 8000 times more frequent than on Earth and that without its existence the impact extinctions like the one that in the Cretaceous ended the existence of the Dinosaurs would be much more frequent.

By virtue of these illuminating considerations has become very important during the recent research of exoplanets that could host life, the presence in these "alien Solar Systems" of jovian planets, which could play the same protective role that for us has represented, represents and certainly will continue to represent for millions of years salvation, prosperity, fatherly security.

3. the light games of the south pole, taken from the Juno probe (NASA credits)

• source from NASA, Focus, Web.