Meteorites containing water are probably not scarce, Zolensky says. But by the time researchers get their hands on the rocks, minerals that trap the water have dissolved away, and the water has evaporated. Worse, some researchers destroy the aqueous evidence by cutting meteorites open with rock saws and water. “I’m betting this isn’t such a rare find; it’s just that people have been mistreating their meteorites,” Zolensky says.
Of course, Zolensky’s team did get a bit lucky. Monahans 1998 was safe in their lab less than two days after it hit Earth, so they examined an unusually fresh sample. The scientists were intrigued to find vivid purple crystals of halite inside the meteorite, since halite is a salt mineral usually formed from liquid water. Even more curious were the hundreds of tiny bubbles suspended in the halite crystals. Zolensky’s team analyzed the bubbles by shining a laser beam through them and confirmed they were made of salty brine.
By dating the halite, Zolensky’s team found the water trapped inside it formed at least 4.5 billion years ago, back when most scientists believe our solar system was born. That means the briny relic may help researchers learn about the gaseous nebula that gave rise to our sun and planets.
But how did the meteorite get wet? One possibility is that a passing comet smashed into the rock, dropping off a load of liquid water. Or the rock might have chipped off an asteroid that holds pools of fluid. Zolensky’s team still needs to study whether the water comes from our own solar system. One thing is certain, however: the Monahans meteorite will fuel the debate on extraterrestrial life. “Water is a life-giver, so if you want to study where life came from in the solar system, you have to follow where water came from,” Zolensky says. A wet rock from space doesn’t mean little green men are coming soon to a planet near you, but it does raise hopes that we’re not alone in the universe.
