Scientists believe that, when the Solar System was still young, Jupiter swept through it like a wrecking ball

Mar 24, 2015 09:26 GMT  ·  By
Young Jupiter probably killed an entire generation of primitive planets
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   Young Jupiter probably killed an entire generation of primitive planets

Our Solar System is a calm, peaceful place these days. Sure, we get the occasional asteroid visit and there are some spacecraft flying around, but other than that, the planets are all orbiting the Sun in an orderly fashion and there's not all that much commotion going on.

Eons ago, however, chaos and killings were happening. Or so scientists with the University of California - Santa Cruz and fellow researchers concluded after having taken the time to study the anatomy of several other planetary systems similar to our own.

In a new paper published in the journal Proceedings of the National Academy of Sciences, they argue that, when the Solar System was still young, Jupiter probably went on a killing spree and ended up crushing an entire generation of planets that would have been Earth's older siblings.

More precisely, the University of California - Santa Cruz scientists and their colleagues have reasons to believe that, before finally settling into its orbit, Jupiter played the wrecking ball and swept through the Solar System, destroying each and every celestial body unfortunate enough to cross paths with it.

Our Solar System is a rather odd place

The majority of the foreign planetary systems astronomers have until now identified and studied have rocky planets complete with a dense atmosphere orbiting close to their parent star. These planets originate from a dense disk of gas and dust surrounding all young stars.

When it comes to our Solar System, however, it's not some rocky giant but oddly-small Mercury that is the closest planet to the Sun. Since all planetary systems form in the same manner, i.e. from debris orbiting a star, the fact that Mercury is the closest planet to the Sun does not really make sense.

“The standard issue planetary system in our galaxy seems to be a set of super-Earths with alarmingly short orbital periods,” said University of California - Santa Cruz researcher Gregory Laughlin. “Our Solar System is looking increasingly like an oddball,” the specialist added.

Rewriting the history of the Solar System

To explain the Solar System's odd anatomy, scientist Gregory Laughlin and colleagues argue that, shortly after having formed, Jupiter embarked on an adventure that brought it closer to the Sun. Simply put, it migrated towards the inner regions of the Solar System.

Some time after, Saturn came into being and its gravitational pull caused Jupiter to shift direction and move further away from the Sun, all the way to its current orbit. The thing is that, by the time Saturn came into play, Jupiter had already wreaked all sorts of havoc in the Solar System's inner regions.

Thus, it is believed that, while moving closer to the Sun, Jupiter disturbed the orbits of a primitive generation of planets and triggered a series of collisions that ended with the destruction of all the celestial bodies orbiting our parent star in the early days of the Solar System.

This scenario, first proposed by another team of scientists in 2011 and known as the Grand Tack, also explains why Mercury, Venus, Earth, and Mars are rather small and don't have very dense atmospheres. In a nutshell: chances are they formed from the debris left behind by the planets destroyed by Jupiter.

“There is a lot of evidence that supports the idea of Jupiter's inward and then outward migration. Jupiter's ‘Grand Tack’ may well have been a ‘Grand Attack’ on the original inner solar system,” researcher Gregory Laughlin commented on his and his colleagues' work.

It's odd that small Mercury is the closest planet to the Sun
It's odd that small Mercury is the closest planet to the Sun

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Young Jupiter probably killed an entire generation of primitive planets
It's odd that small Mercury is the closest planet to the Sun
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