In the first look at results from the LCROSS mission, which sent a probe crashing into the Cabeus crater near the moon’s south pole, NASA’s main investigator said their instruments clearly detected water, despite the underwhelming plume.
Within the field of view of their instruments, the team measured approximately 220 pounds or about 26 gallons of water. Next, the team will try to understand how the compounds they saw in the plume relate to what’s actually embedded in the lunar regolith at the bottom of the permanently shadowed crater.
“We need to take all the information — the amount of ejecta, the size of the crater — and reconstruct the entire event and understand how it all fits back into the ground,” Colaprete said at a NASA Ames press conference.
For about a decade, lunar scientists have known the moon contained a lot of hydrogen, thanks to the Lunar Prospector mission, but it wasn’t entirely clear what form that hydrogen was stored in. Now, the LCROSS observations provide a handy explanation for the hydrogen: It’s bound with oxygen to form water.
Other analyses have also provided evidence that water exists on the moon, including most recently, the Indian satellite Chandrayaan . But the latest LCROSS observations are different.
“[Chandrayaan] could not see into the shadowed craters. Their observation is entirely unique and complimentary. We looked inside the shadowed craters. The amounts and flavors could be distinctly different,” Colaprete said. “They saw water bound and adsorbed in grains. We saw, potentially, real crystalline water ice.”
Combined with the various confirmations of water ice on Mars, it’s becoming clear that water — at least in ice form — is present throughout our solar system.
Astronomers are gaining a new appreciation for celestial bodies that once seemed rather staid.
“[LCROSS] is painting a really surprising new picture of the moon. This is not your father’s moon,” said Greg Delory of the University of California, Berkeley. “Rather than a dead and unchanging world, it could be a dynamic and interesting one.”
Delory, who is not on the LCROSS team, also called the discovery “exciting and extraordinary,” saying lunar science could now move on to other fascinating questions.
“What’s equally important is what we do next,” Delory said. “Where did the water come from? How long has it been there? What kind of processes are involved in putting it there and removing it and destroying it?”
There are all kinds of sources for the water, Delory said. It could come from comets, the solar wind, the moon itself or even the Earth.
“Now that we know that water is there we can begin in earnest to go to the next set of questions,” he said.
And answering them could tell us a lot about the solar system and its planetary bodies’ relationship to water, which is necessary to all forms of life we know.
Colaprete may have another surprise in waiting, hinting that they glimpsed other interesting compounds in the plume that arose from Cabeus crater.
“This goes beyond the water, there’s a lot of stuff that came out of there,” Colaprete said, before saying he didn’t want to say “too much beyond” that.
Delory was equally excited but circumspect saying, “I’m sure the LCROSS team is going to reveal new and exciting discoveries as they continue to analyze their data.”
So, while the first LCROSS surprise — the wimpy plume — was disappointing, perhaps the next one the mission delivers will be happy.