As Comet Siding Spring passed close by Mars on Sunday (Oct. 19), NASA’s newest Mars spacecraft took a time-out from its commissioning to grab some ultraviolet pictures of its coma. What you see above is hydrogen, a whole lot of it, leaving the comet in this picture taken from 5.3 million miles (8.5 million kilometers).
The hydrogen is a product of the water ice on the comet that the Sun is slowly melting and breaking apart into hydrogen and oxygen molecules. Because hydrogen scatters ultraviolet light from the Sun, it shows up rather clearly in this picture taken by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft.
Check out more recent pictures of Siding Spring below.
Back in the 1960s and 1970s, Apollo astronauts set up a collection of lunar seismometers…
The dwarf planet Ceres has some permanently dark craters that hold ice. Astronomers thought the…
Cosmic rays are high-energy particles accelerated to extreme velocities approaching the speed of light. It…
NASA is in the business of launching things into orbit. But what goes up must…
A new theory suggests that Titan's majestic dune fields may have come from outer space.…
The BepiColombo mission, a joint effort between JAXA and the ESA, was only the second…