Tiny Pebbles Built the Gas Giant Behemoths

astroengine writes: Scientists have long puzzled over how gas planets like Jupiter and Saturn got to be so big. Current theories suggest the cores of these behemoths are comprised of mini-planets, some 62- to 620 miles in diameter, which collided and gradually merged together over time. But computer simulations show this process is more likely to produce hundreds of Earth-sized worlds. Instead, a new study suggests "slow pebble accretion" is a more likely process.

Comments

Re:Magnetism

[Rei]

Even stony asteroids contain grains of metallic iron. Iron asteroids are, of course, predominantly iron-nickel alloy. And some of its oxides are even better candidates - most notably, magnetite. I was very surprised when I found that random pieces of basalt from my land were showing an easily measurable magnetic field, until it occurred to me that some percentage of the grains that make it up will naturally be magnetite.