planetesimal

So collisions alone, he argues, can’t explain how planetesimals form.

Then, you produce protoplanets by colliding those planetesimals with each other.

It drifts around in a disk, then piles up to form 100 kilometer-scale “planetesimals,” the real building blocks of the planets.

These planetesimals can keep growing by self-collisions but not by any new dust originating in the outer solar system.

Jupiter’s growing core—a super-big planetesimal about ten times the mass of Earth—may have done exactly that.

The Planetesimal Theory suggests that these thickened knots are embryo planets and the central portion of the nebul an embryo sun.

Let us now inquire briefly into the bearing of this planetesimal hypothesis upon the early geological history of the earth.

On one point the new planetesimal theory differs from the other theories.

In deference to the opinion of a number of geologists we must glance once more at the alternative view of the planetesimal school.

But the planetesimal hypothesis has no room for this enormous percentage of carbon-dioxide in the primitive atmosphere.