comets

Abundant tiny particles of diamond dust exist in sediments dating to 12,900 years ago at six North American sites, adding strong evidence for Earth's impact with a rare swarm of carbon-and-water-rich comets or carbonaceous chondrites, scientists report.

The discoveries are consistent with theory of Clovis-age disruption by a cosmic event, according to researchers.

(University of Illinois at Urbana-Champaign) According to new research, old ideas about water behavior are all wet.Ubiquitous on Earth, water also has been found in comets, on Mars and in molecular clouds in interstellar space.

Now, scientists say this common fluid is not as well understood as we thought.

Last October, astronomers all over the world were astounded when the normally very faint Comet Holmes erupted in the largest outburst for more than a century.

Comets are bodies orbiting the Sun composed of frozen gases and microscopic solid particles in a small solid nucleus.

When they come close to the Sun, they heat up and some of the icy material turns to gas, producing characteristic tails.

But during this outburst, Comet Holmes released a large amount of its material all at once.