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| Composite image shows present-day Mars, dry and barren, with how it may have looked 3.5 billion years ago. Credit: Jon Wade |
The Martian surface today is a dry, frozen and inhospitable place but new evidence suggests that it was once a warm environment where water flowed freely, potentially supporting life. Scientists have been unable to answer the mystery of what happened to all this water. Now they say they have the answer.
Previous research has
suggested that most of it was either lost into the atmosphere because of high
winds after the planet's magnetic field collapsed or it became locked away as
ice below the surface. But a study published in the journal Nature suggests
that much of the water may have been absorbed by rocks.
Scientists at Oxford University
found that basalt rocks on Mars can hold around 25% more water than those on
Earth, allowing them to suck up the majority of H2O from the Martian surface.
This discovery is very important and will lead to more astonishing discoveries about
Mars.
"The Earth's current
system of plate tectonics prevents drastic changes in surface water levels,
with wet rocks efficiently dehydrating before they enter the Earth's relatively
dry mantle," said Jon Wade, lead author of the study.
"But neither early
Earth nor Mars had this system of recycling water. On Mars, water reacting with
the freshly erupted lavas that form its basaltic crust resulted in a
sponge-like effect," he continued.
"The planet's water
then reacted with the rocks to form a variety of water-bearing minerals. This
water-rock reaction changed the rock mineralogy and caused the planetary
surface to dry and become inhospitable to life."
Wade explained that the
reason this process occurred on Mars and not on Earth was down to the fact that
Mars is much smaller with a different temperature profile and contains more
iron in its mantle – the geological layer between the crust and the inner core.
These features made the surface of Mars "more prone to reaction with
surface water and able to form minerals that contain water," Wade said.
"Because of these
factors the planet's geological chemistry naturally drags water down into the
mantle, whereas on early Earth hydrated rocks tended to float until they
dehydrate."
Via IBTimes