Sentences with phrase «need rocky cores»
One controversial theory posits that giant planets might not need rocky cores if they form directly from unstable whorls of gas in the nebula around a young star.
http://www.sciencemag.org/ Not exact matches
Some planets are so near their star that they are losing mass too rapidly to have been planets for very long.14 Besides, their rocky cores would have melted before the planet's evolution could begin.15 Others are too far from their star and the dust near the star needed to grow a planet.