One argument against the comet theory is that a comet would have left a large hole in the Earth's surface.

VOA: special.2009.01.20

The researchers say the report offers evidence that one or more comets were responsible for a sudden cooling period on Earth's surface.

VOA: special.2009.01.20

When this happens, one plate moves past the other, suddenly causing the Earth's surface to split.

VOA: special.2010.01.12

Most maps of the world show lines that are not on the Earth's surface.

VOA: special.2010.07.14

This forces apart pieces of the Earth's surface in a violent earthquake.

VOA: special.2011.01.04

As many as twenty tectonic plates cover the Earth's surface.

VOA: special.2009.07.07

Hubble orbits about six hundred kilometers above the Earth's surface.

VOA: special.2009.09.30

Then,seventy-million years ago, the Earth's surface, or crust,pushed upward.

VOA: special.2010.01.04

Scientists have long believed that Earth's satellite lacks the ability to hold water near its surface because it has no atmosphere.

VOA: special.2009.09.30