What's That in the Moon's Exosphere?

The moon is a large space rock that orbits our Earth every single day, and despite being so close, we’re still so far away from understanding every aspect of the moon’s existence and environment.
 
In fact, we know very little even about the moon’s exosphere. It wasn’t until recently that we discovered the existence of Neon gas in the moon’s limited and thin exosphere.


 
Despite numerous claims in the past that there was Neon gas in the moon’s exosphere, it hasn’t been proven with cold, hard evidence until recently. The LADEE spacecraft came crashing down on the moon’s surface due to a lack of fuel supply in 2014.
 
Although the spacecraft went down onto the moon’s surface, the information LADEE collected is still alive and well, and as it turns out, the information is proving to be very valuable to helping scientists learn more about the moon.
 
LADEE’s Neutral Mass Spectrometer (NMS) is responsible for detecting the gas in the moon’s exosphere, and as it turns out, there is a very abundant supply of Neon gas in the moon’s exosphere considering how thin the moon’s exosphere actually is.
 
"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 of NASA's Goddard Space Flight Center in Greenbelt, Maryland and the University of Maryland, Baltimore County. "We were very pleased to not only finally confirm its presence, but to show that it is relatively abundant."
 
Because the moon’s exosphere is so thin, the Neon gas can’t glow like we’d expect it to. Had the moon’s exosphere been just a bit thicker, the Neon gas would have been more noticeable. In fact, NASA says that the moon’s exosphere is 100 trillion times less dense than the atmosphere here on Earth at sea level.
 
The new findings will have scientists re-thinking the way they model distant exospheres and atmospheres alike.
 
"The data collected by the NMS addresses the long-standing questions related to the sources and sinks of exospheric helium and argon that have remained unanswered for four decades," said Benna. "These discoveries highlight the limitations of current exospheric models, and the need for more sophisticated ones in the future."
 
In addition to Neon, the moon’s exosphere also includes traces of Helium and Argon, and interestingly, the levels between the three were never the same – they fluctuated often.

Source: NASA