“We saw a very interesting pattern. We had the most water in the morning, the least water at noon, and we slowly regained it … again in the evening.” — Jessica Sunshine
Researchers from the university’s astronomy department have made the unexpected discovery of water on the moon while conducting a completely unrelated space mission.
In conjunction with departments and institutions across the county, the Deep Impact team originally sent a spacecraft to study comets. But after another craft detected light wavelengths coming from the moon’s surface, researchers had something new to study.
“I was somewhat flabbergasted,” Deep Impact team member Tony Farnham said. “It was kind of an amazing thing because we had always assumed that the moon was pretty much completely dry. So when the data was coming in we were thinking, can this really be? Are we doing something wrong with the data or is this really happening?”
The Deep Impact spacecraft, a two-part shuttle launched in Jan. 2005, was originally designed to carry out an impact mission on the comet Tempel 1. After surviving that mission, was given an extended mission to characterize extra solar planets.
Searching for water on the surface of the moon was not part of the plan until a device on India’s Chandrayaan-1 spacecraft, the Moon Mineralogy Mapper (M3), detected the beginning of the light spectrum for water on the moon. Because its equipment was not sufficient enough to definitively determine whether or not there was in fact water on the moon, senior research scientist Jessica Sunshine, a team member of both the M3 mission and the Deep Impact mission, suggested that they use Deep Impact’s more advanced technology to further examine M3’s discovery.
Because Deep Impact was already planning on flying by the moon to calibrate its instruments, the researchers simply increased the length of the mission to allow for two passes by the moon, on June 2 and 9 of this year.
“We couldn’t do it all at once, so we observed the moon twice, separating time by one week, which is a quarter of a lunar day,” Sunshine said. “We saw a very interesting pattern. We had the most water in the morning, the least water at noon, and we slowly regained it again, at the same values we had in the morning, again in the evening.”
The similar process on Earth involves the formation of dew, but it generally reforms over night when the sun is completely absent, leaving researchers to hypothesize about how the water re-formed when there was still some sunlight present on the moon. They’ve attributed this cycle of loss and recovery to the moon’s lack of atmosphere and have theorized that wind from the sun carries hydrogen to the moon, where it bonds with oxygen-rich minerals in the moon’s surface to form water.
While this is an important discovery for lunar science, the solar wind source theory can also be applied to other places in the solar system without an atmosphere, making the discovery relevant to many aspects of astronomy.
“It’s also a process that will be taking place on Mercury and potentially on some other asteroids in the inner solar system,” Farnham said. “This opens up the question that there may be water where we didn’t expect it before, and that leads to a lot of different implications on observations and research that people have already studied.”
Though the process of water creation is relevant to science, the location where water was discovered on the moon is especially significant. For years, scientists have been looking for water in cold crevices and craters on the moon where sunlight couldn’t penetrate, but finding water in the surface of the soil is a unexpected discovery.
“It was exciting because of the astro-biological implications that it could have in terms of life because astrobiologists usually say follow the water, in terms of looking for life in our solar system or even in our planet,” said Julia DeMarines, a summer intern with the Deep Impact program.
It’s important to note, however, that the actual quantity of water in the moon’s soil is quite small, less than the amount of water in any desert on Earth.
“If you filled a two-liter bottle with lunar soil, you could probably get two eye-droppers full of water molecules,” Sunshine said.
Until scientists create an efficient way of harnessing the molecules, it would take an entire baseball field to get a quart of water. So far, no new missions have been planned to collect or study moon water, and the Deep Impact spacecraft is now on course to reach the comet Hartley 2 in Nov. 2010, where its mission will end when it runs out of fuel.
“It’s not something that will immediately change space missions, but it’s going to open up new venues for research,” Farnham said.
Regardless of the quantity of water, however, the repercussions of these findings will have far-reaching consequences on many aspects of science.
“Maryland should be darn proud of this discovery,” said Sunshine.
jborowski@umdbk.com
