Oct. 6 (UPI) -- The moon was surrounded by an atmosphere some 3 to 4 billion years ago, according to a new study by a team of NASA scientists.
The moon was once a geologically dynamic place. The moon's baltic seas, or marries -- the large, flat, dark splotches seen on the lunar surface -- serve as evidence of the young moon's magmatic activities.
Lava once erupted from the moon's still-hot interior and flowed for miles. Analysis of lunar rocks suggest these magma plumes were rich in volatile gasses, including carbon monoxide, which includes the molecular ingredients needed to form water and sulfur.
When researchers modeled the moon's era of intense magmatic activity, they found the gasses would have accumulated at a rapid pace -- faster than they could dissipate into space, thus forming a transient atmosphere.
The analysis -- detailed this week in the journal Earth and Planetary Science Letters -- suggests the largest outflow of gas occurred when lava seas filled Serenitatis and Imbrium, two of the moon's largest basins, between 3.5 and 3.8 billion years ago.
"The total amount of H2O released during the emplacement of the mare basalts is nearly twice the volume of water in Lake Tahoe," Debra Needham, a research scientist at NASA's Marshall Space Flight Center, said in a news release. "Although much of this vapor would have been lost to space, a significant fraction may have made its way to the lunar poles. This means some of the lunar polar volatiles we see at the lunar poles may have originated inside the Moon."
During the period when the moon boasted an atmosphere, the moon enjoyed a more intimate orbit around Earth and would have appeared nearly three times as large.
"This work dramatically changes our view of the Moon from an airless rocky body to one that used to be surrounded by an atmosphere more prevalent than that surrounding Mars today," said David Kring, senior staff scientist at the Lunar and Planetary Institute.
Researchers believe some of the volatiles released during magmatic episodes could have become trapped in icy deposits near the lunar poles, remaining frozen in shadowed craters. These trapped volatiles could be mined for use by astronauts during lunar surface missions.