NASA Finds Asteroid Vesta Once Had Flowing Liquid Water
Cold, arid asteroid Vesta was the last place anyone expected to find liquid water. And although the planet is not conducive to the presence of liquid water now, a new NASA study shows that it was host to flowing liquid water in the relatively recent past.
"Nobody expected to find evidence of water on Vesta. The surface is very cold and there is no atmosphere, so any water on the surface evaporates," study lead author Jennifer Scully (Scully!), a postgraduate researcher at UCLA, said in a NASA statement.
But when NASA investigated photos of the asteroid's surface taken by their Dawn spacecraft, they found curved gullies and fan-shaped deposits inside young craters. These gullies significantly resemble "debris flows" on Earth, which are the result of a flowing mixture of water, dirt, and rocks.
"They form kind of complex networks, similar to what we see in [Arizona's] Meteor Crater," Scully told Space.com.
The gullies' presence on Vesta, therefore, indicates that flowing water existed on the asteroid not too long ago. Scully and her research team believe that meteor strikes on Vesta caused subsurface ice to melt, which in turn caused the debris flows. NASA claims that laboratory experiments have confirmed that the sandy and rocky particles in the flow may have slowed the evaporation process for long enough that the gullies could have been formed from debris flows.
This study could have an enormous impact, not only on astrobiology, but on planetary science in general. According to UCLA's Christopher Russell, principal investigator for the Dawn mission, "These results, and many others from the Dawn mission, show that Vesta is home to many processes that were previously thought to be exclusive to planets."