|What creates these picturesque dark streaks on Mars?
No one knows for sure.
A leading hypothesis is that streaks like these are caused by
sand sliding down the banks of troughs and craters.
dark sand appears to have flowed hundreds of meters down the slopes of
The sand appears to
like a liquid around boulders, and, for some reason,
lightens significantly over time.
This sand flow process is one of several which can rapidly change the surface of Mars, with other processes including
dust storms, and the freezing and
melting of areas of ice.
The above image
was taken by the
HiRise camera on board the
Mars Reconnaissance Orbiter which has been orbiting Mars since 2006.
is a 700 kilometer long
trough in the
LPL (U. Arizona),