"It's possible they contributed to the building blocks of life," the geologist says.

Meteors come from various locations in the universe, says Marvin. "They come from other planets, [from] rubble from asteroids, and a few from comets," she says.

A few lunar rocks have been found on Earth as well. Although the moon is physically close to the earth and is approximately the same age, its rocks do not resemble terrestrial rocks, says Marvin.

Since there is no water on the moon's surface and the atmosphere is nonexistent, Marvin says, lunar rocks change very little over time.

"We can look at a rock that formed four billion years ago and it looks like it formed yesterday," she said.

Terrestrial rocks, on the other hand, are highly susceptible to change from the elements, says Siever. "Most things are obliterated by erosion and weathering," he says.

A lot of information about the past can be gained by examining meteorites, Marvin says. Since cosmic rays continually bombard meteors in space, researchers can determine the age of meteors by using radioactive isotope dating techniques. This dating method allows scientists to infer what conditions prevailed when the sun and earth were formed, Marvin says.

Though extensive research is being done on meteorites, practical application of this information is still far away, say the geologist. Mining for minerals on other planets or asteroids is unlikely due to economic reasons.

"If you want to use a mineral, there has to be enough of it to mine profitably," Marvin said. "There are cheaper ways of getting minerals right now."