Jupiter swallowed a super-Earth?

[n2doc]

11 August 2010 by David Shiga

JUPITER might have secured its position as the solar system's mightiest planet by killing an up-and-coming rival, new simulations suggest. The work could explain why the planet has a relatively small heart, and paints a grisly picture of the early solar system, where massive, rocky "super-Earths" were snuffed out before they could grow into gas giants.

Jupiter and Saturn are thought to have begun life as rocky worlds with the mass of at least a few Earths. Their gravity then pulled in gas from their birth nebula, giving them dense atmospheres.

In this picture, all gas giants should have cores of roughly the same size. Yet spacecraft-based gravity measurements suggest Jupiter's core weighs just two to 10 Earth masses, while Saturn's comes in at 15 to 30.

New simulations by Shu Lin Li of Peking University in China, and colleagues, may explain why. They calculated what would happen when a super-Earth of 10 times the mass of our planet slammed into a gas giant. The rocky body flattened like a pancake when it hit the gas giant's atmosphere, then barrelled into the giant's core about half an hour later. The energy of the collision could have vaporised much of the core.

more

http://www.newscientist.com/article/mg20727733.600-jupiter-swallowed-a-superearth.html

[tridim]

1. I thought the gas giants formed close to the sun and moved outwards..

due to orbital resonance of the two?

Has that theory been scrapped now? It's hard to keep up these days.

[leahcim]

3. I don't see how the two theories conflict.

Gas giants can form close to the sun and move outwards while being hit by other planets just fine.

[Esra Star]

4. have you seen the "Nebular Hypothesis"

formulated in the 18th century?

http://en.wikipedia.org/wiki/Nebular_hypothesis

[Confusious]

6. Gas giants are always suppose to form farther out, some wander in.

When a young star ignites, it pushes the lighter gases farther out of the solar system. The inner planets get the heavier elements and gasses, the gas giants get the lighter gasses.

[Zadoc]

7. Other way around...

The theory is that they form farther out, and migrate to the star, which is why we see some many "hot Juputer" exoplanets.

[damntexdem]

2. Oh, the indigestion!

"I can't believe I ate the whole thing."

;-)

[Orrex]

5. Like father, like son