NASA LADEE Spacecraft Discovers Neon on Earth's Moon

First Posted: Aug 18, 2015 03:49 PM EDT

NASA's LADEE spacecraft has discovered something a bit unusual. It's found neon gas in the moon's atmosphere, something that has been confirmed for the very first time.

"The presence of neon in the exosphere of the moon has been a subject of speculation since the Apollo missions, but no credible detections were made," said Mehdi Benna, one of the researchers, in a news release. "We were very pleased to not only finally confirm its presence, but to show that it is relatively abundant."

There's not enough neon to make the moon visibly glow since the moon's atmosphere is extremely tenuous-about 100 trillion times less dense than Earth's atmosphere at sea level. A dense atmosphere like Earth's is relatively rare in our solar system because an object has to be sufficiently massive in order to have enough gravity to hold onto its atmosphere.

However, the moon's atmosphere is an exosphere, which means that it's so thin that its atoms rarely collide. Exospheres are the most common type of atmosphere in our solar system. Learning all we can about the moon's atmosphere is crucial since human exploration, including rocket exhaust, can impact it significantly.

Most of the moon's exosphere comes from the solar wind, which is a thin stream of electrically conducting gas blown from the surface of the sun into space at around a million miles per hour. Most of the solar wind is hydrogen and helium, but it contains many other elements in small amounts, including neon.

The researchers also found that argon is released from lunar rocks. Argon-40 results from the decay of naturally occurring radioactive potassium-40 found in the rocks of all the terrestrial planets as a leftover from their formation.

"We were also surprised to find that argon-40 creates a local bulge above an unusual part of the moon's surface, the region containing Mare Imbrium and Oceanus Procellarum," said Benna. "One could not help to notice that this region happens to be where potassium-40 is most abundant on the surface. So there may be a connection between the atmospheric argon, the surface potassium and deep interior sources."

The findings reveal a bit more about the lunar atmosphere, and possibly a bit more about how our moon formed in the first place.

To learn more about the LADEE mission, visit NASA's website.