Most planetary systems are made up of a few rocky super-planets orbiting extremely close to their stars, making our system — multiple, distant bodies — an oddball outlier. And according to new research, Jupiter could be to blame (thank?).
Normally, planetary systems are typified by big giants close to the star — closer than Mercury is to the sun. The absence of any close super-planets in our system has been puzzling scientists, and now a team of researchers led by Konstantin Batygin and Gregory Laughlin has a theory why.
In a paper published in Proceedings of the National Academy of Sciences today, the pair have shown a set of calculations that agree with the 'Grand Tack' theory, which proposes that Jupiter got pulled towards the sun after its formation, disturbing the asteroid belt and interstellar dust, using its powerful gravitational field to disturb the formation of planets close to the sun.
By upsetting the orbits of the baby planets, Jupiter would have caused a chain-reaction of collisions and destruction — the same kind of thing that's going on with space debris and satellites around Earth today. Most of the debris spiralled into the sun, leaving some material to form an inner ring of small planets, also known as Mercury, Venus, Earth and Mars.
Once it had done the dirty deed, Jupiter caught up with Saturn, and the two of them pulled each other back to their respective modern-day orbits.
"The results imply that our terrestrial planets formed after Jupiter's early migration wiped the slate clean and set the stage for formation of gas-poor objects," Batygin said. "The fact that all of these characteristics of the solar system turn out to stem from the same process is exciting — it is as if the scattered pieces of the puzzle are finally falling together into a coherent picture." [PNAS]