was once a wet world, with abundant bodies of water on its surface. But
this changed dramatically billions of years ago, leaving behind the
desolate landscape known today. So what happened to the water?
Scientists have a new hypothesis.
said this week that somewhere between about 30% and 99% of it may now
be trapped within minerals in the Martian crust, running counter to the
long-held notion that it simply was lost into space by escaping through
the upper atmosphere.
find the majority of Mars' water was lost to the crust. The water was
lost by 3 billion years ago, meaning Mars has been the dry planet it is
today for the past 3 billion years," said California Institute of
Technology PhD candidate Eva Scheller, lead author of the NASA-funded
study published on Tuesday in the journal Science.
in its history, Mars may have possessed liquid water on its surface
approximately equivalent in volume to half of the Atlantic Ocean, enough
to have covered the entire planet with water perhaps up to nearly a
mile (1.5 km) deep.
is made up of one oxygen and two hydrogen atoms. The amount of a
hydrogen isotope, or variant, called deuterium present on Mars provided
some clues about the water loss. Unlike most hydrogen atoms that have
just a single proton within the atomic nucleus, deuterium - or "heavy"
hydrogen - boasts a proton and a neutron.
hydrogen can escape through the atmosphere into space more readily than
deuterium. Water loss through the atmosphere, according to scientists,
would leave behind a very large ratio of deuterium compared to ordinary
hydrogen. The researchers used a model that simulated the hydrogen
isotope composition and water volume of Mars.
are three key processes within this model: water input from volcanism,
water loss to space and water loss to the crust. Through this model and
matching it to our hydrogen isotope data set, we can calculate how much
water was lost to space and to the crust," Scheller said.
researchers suggested that a lot of the water did not actually leave
the planet, but rather ended up trapped in various minerals that contain
water as part of their mineral structure - clays and sulfates in
trapped water, while apparently plentiful when taken as a whole, may
not provide a practical resource for future astronaut missions to Mars."The
amount of water within a rock or mineral is very small. You would have
to heat a lot of rock to release water in an appreciable amount,"
Scheller said. Collected from Daily Star..