All Space Considered, Jan 2015 Pt. 2 (Solar System)

Methane on Mars

There has been some debate as to whether there is methane on Mars.  Some Earth-based observations seemed to indicate quite clearly that there was methane on Mars, but there was still doubt due to possible alternative explanations.  Curiosity has more or less ended the debate, detecting methane in high enough concentrations to conclude that Mars itself is the source.  Methane gas is very transient, destroyed by UV rays constantly coming in from the sun.  For the levels to be so high, there had to be a source on Mars itself.  The significance of methane is that biological life is a strong contributor to Earth's methane levels.  Bacteria release it as a waste product from the guts of millions of animals everyday.  However, there are geological sources of methane as well, so we can't quite say "Life on Mars" yet and unfortunately Curiosity doesn't have the instrumentation to answer definitively.  However, it will likely be a major component of future missions to Mars.

The above map shows the methane concentration on Mars, with red being the highest levels and purple being the lowest.

Water Sampled By Rosetta

Rosetta is the satellite orbiting comet 67P, Churyumov-Gerasimenko.  It dropped Philae on the comet's surface back in November and is continuing to collect data about the comet.  From that data, it has been determined that the water on the comet is very different from the water on Earth.  It is widely speculated that Earth's water came from comets in the distant past.  However, if that were the case, the general character of the water should match what we find in comets.  Water can be differentiated by the concentration of heavy water (water that has a neutron in one or both of its hydrogen atoms).  Comet 67P's water has a much higher concentration of heavy water than the water on Earth.  This suggests that Earth's water came from asteroids rather than comets, but it is only one data point in a fairly big picture.

The above graphic shows just how high the levels measured by Rosetta are in comparison to Earth's water.  However, many other bodies have been analyzed and found to be a much better match.  As more data comes in, we should be able to generalize which class of bodies contributed the most.

Atmospheric Rivers

California got a lot of rain in December.  This was due to what is known as an "atmospheric river."  There is always a high concentration of airborne water around the tropics.  Occasionally, wind conditions are such that this moisture is swept north.  Once the airborne moisture hits land, the water cools, condenses and falls to the earth, a process known colloquially as "rain."  In case my words weren't clear, here's a picture showing why they call this thing a river.

The reason such terrestrial phenomena are so important to astronomy is that they help us understand what happens elsewhere.  By extrapolating what we know about how such systems operate on Earth, we can improve our understanding of observations of other planets, other moons and perhaps even dwarf planets.  That, in turn, helps us target places not only to search for life, but possibly to colonize ourselves as well.

CIA Tweets About UFOs

The fact that one of the most secretive agencies in the government Tweets is sort of news unto itself.  Not so surprising is that the Tweets tend to be about events in the 50s.  Okay, the 70s too.  In this recent tweet, the CIA admitted to flying secret reconnaissance missions at altitudes much higher than a standard airliner.  Specific flights correspond directly to UFO sightings by pilots and others during the period 1954-1974.  Now, if only they'd tell us what Roswell is all about.