A NASA spacecraft, the Mars Reconnaissance Orbiter (MRO) orbiting Mars has send pictures showing dark lines appearing to flow down steep ravines indicating the presence of liquid water at a particular time on the red planet.

The orbiter’s High Resolution Imaging Science Experiment (HiRISE) captured the images of the planet.

"The best explanation for these observations so far is the flow of briny water," said the University of Arizona's Alfred McEwen in a statement released by NASA. McEwen is the main investigator for HiRISE.

The MRO has entered the Martian orbit in March 2006 after it was launched on August 12, 2005. The orbiter’s mission was to come to end by the end of 2010, however, the orbiter continues to work and provide essential data.

The images sent by HiRISE shows dark, finger-like lines between 0.5 and 5 meters wide appearing in summer months and flowing down on Martian slopes. These lines are commonly spotted as in some areas the instrument spotted as many as 1,000 individual flows.