argon tagged posts

DFMS mass spectra in the m/z ranges of 36 and 38. The spectra demonstrate the clear identification of the two isotopes 36Ar and 38Ar and of the interfering molecules. The exact m/z locations are given in the text. The spacecraft background spectra were obtained before the cometary signal became apparent (2 August 2014, heliocentric distance of 3.6 AU, almost 800 km from the nucleus).

This measurement adds to the debate about the role of comets in delivering various “ingredients,” such as water, to Earth. Comets are considered to be representative of icy planetesimals that may have contributed a significant fraction of the volatiles to planets in the very early solar system...

Artist’s concept of NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft in orbit above the moon. Credit: NASA Ames / Dana Berry

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 till now. There’s not enough neon to make the moon visibly glow because 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 to have enough gravity to hold onto it.

The behavior of a dense atmosphere is driven by collisions between its atoms and molecules...