If you’ve ever wondered why we are here, then you can thank Jupiter for part of the answer. A new study from Rice University suggests that if it weren’t for the gas giant, the Earth would have spiraled into the Sun during its formation.
One of the perks of being a pioneer of science is that you don’t have to sort out all the niggling details. How did the solar system form? A load of dust and gas converged, forming the Sun at the center and an accretion disk that became the planets. Thank you, and I’ll pick up my Nobel Prize on the way out.
The annoying bit for future generations is working out all the mechanics and crunching the numbers, only to find that it all raises new questions that need answers in a cycle that is basically aggravating.
One problem with the formation of the solar system is explaining why the Earth and the other planets of the inner solar system even exist. When a cloud of gas and dust collapsed into the solar system 4.57 billion years ago, the disc surrounding the protosun had a feature that should have meant the Earth was a non-starter.
It’s a phenomenon known as radial drift. That is, as the kilometer-wide planetesimals that would go to make up the planets formed, they should have been subjected to friction from the gas and dust around them that would make them spiral into the Sun, much as Earth-orbiting satellites eventually decay their trajectory, sending them into the atmosphere to burn up. The result of this should have been the early Earth, Mercury, Venus, and Mars likewise spiraling into a fiery doom.
Rice University
However, that did not happen. Equally strange is that entire classes of tiny objects called Non-Carbonaceous (NC) meteorites as distinct from Carbonaceous (CC) meteorites also exist when they shouldn’t. The big question for both is why?
According to observations made at the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile, a study of other solar systems shows that the Earth shouldn’t exist. It also shows a discrepancy, which is that our solar system has Jupiter, and that seems to have made all the difference.
From what has been seen in other systems, what should have happened in ours is that the dust and gas should have caused the protoplanets of the inner solar system to decay. As collisions with the dust and gas reduced them, more would spiral in from the outer solar system to keep feeding the decay until the protoplanets made their final fatal plunge.
However, what happened, according to the Rice scientists, is that Jupiter formed rapidly and as it bulked up it migrated inward before tacking in a manner analogous to a sailboat and moved out to its present orbit. As it did so, its gravitational pull formed a gap in the dust and gas ring, isolating the inner planets and allowing them to fall into stable orbits.
This also resulted in the segregation of the NC and CC meteorites that have distinctly different isotopic signatures, showing that they formed in separate regions of space.
“Jupiter didn’t just become the biggest planet – it set the architecture for the whole inner solar system,” said André Izidoro, assistant professor of Earth, environmental and planetary sciences at Rice. “Without it, we might not have Earth as we know it.”
The research was published in Science Advances.
Source: Rice University
