NASA has documented a solar storm blasting away Mars' atmosphere. The event provides an important clue as to how water disappeared from the planet.
NASA said on Thursday its Mars-orbiting MAVEN spacecraft caught such a storm on March 8.
MAVEN lead researcher Bruce Jakosky says the loss of atmosphere on Mars was mainly caused by solar winds.
"Up until about 3.7 billion years ago, water seemed to be very abundant and active. So the stripping of the solar wind, the stripping by the solar wind, of the atmosphere, would have occurred in that same timeframe. That's when the extreme ultraviolet photons from the sun, when the solar wind were most intense."
The researcher adds the loss of atmosphere on Mars likely began hundreds of millions of years ago.
Unlike Earth, Mars does not have a geo-magnetic field to protect its atmosphere.
MAVEN, or the Mars Atmosphere and Volatile Evolution Mission, has studied Mars since arriving there in September last year.
