There'd be a collectibles market - you could break a Mars rock into tiny pieces and mount each one inside a glass case.

Its level and pace are most appropriate to interested newcomers who want a quick overview on topics ranging from Mars rocks to shooting stars.

The one draped on the Mars rock that inspired headlines like "Life on Mars"?

Students from Idaho to India have sent local rocks to scientists who will compare them with Mars rocks and post the results on the Internet.

By chance, a researcher using an electron microscope in 1993 realized that he was looking at a Mars rock.

The Mars rock continues to generate debate, but it has already done beneficial work.

The talking Mars rock belongs in that play.

He said he told them, "Let me be more generous" and gave them seven grams of Mars rock.

Also, an appreciation of planets: Thanks to the Mars rock, they're the hottest field in astronomy.

But the discovery of life in a Mars rock, now owned by the Smithsonian, pushed the price to $2,500 at a show in Denver last week.