Remotely viewing oceans and clouds.
Northern Lights viewed from space.
The history of Cassini and its exploration of Saturn.
When tracking down criminals, the mantra has always been "follow the money". Likewise, in looking for life on planets in other solar systems it has been "follow the water". In the case of Mars, it might be more immediate to follow the methane.
The European Space Agency (ESA) has just released a series of spectacular images of the Mars canyon system and fractured landscape called Neli Fossae.
[caption id="attachment_4001" align="aligncenter" width="1024" caption="Neli Fossae on Mars ...