Global storms on Mars shoot dust towers up into the air
(CNN)Last year, a dust storm encircled Mars for months, ending NASA's Opportunity mission when sunlight couldn't reach the solar-powered rover.
But
other NASA spacecraft orbiting the Red Planet, like the Mars
Reconnaissance Orbiter, were able to track valuable information about
the storm that's helping scientists understand the phenomenon.
The
data sent back by the orbiters revealed dust towers within the 2018
storm. Dust towers occur when dust clouds react to the warmth of the sun
and rise vertically. The gigantic clouds can climb incredibly high due
to the thin atmosphere. They're also very dense.
The
towers are created when a large area of dust, which can be compared to
the width of Rhode Island, lifts up into the air. The dust grows into a
tower 50 miles high and spreads out to span the width of Nevada,
according to NASA. When the tower falls apart, the dust layer -- which
remains 35 miles up from Mars' surface -- could span the entire United
States in width.
The dust towers
don't require a global dust storm, which affects the whole planet, to
form, but there are many more of them during the global storms -- and
the churning towers could last for weeks.
"Normally the dust would fall down in a day or so," said Nicholas
Heavens, one of the study authors at Hampton University. "But during a
global storm, dust towers are renewed continuously for weeks."
It's
even possible that water vapor trapped in the dust could essentially
catch a ride on the towers and pass through Mars' thin atmosphere into
space. There, the water would be broken apart by solar radiation,
according to NASA. Researchers believe this is one possible explanation
for the disappearance of water that could once be found on Mars billions
of years ago.
Although Mars seems cold and inhospitable today, it was a different story three to four billion years ago. A 2019 study suggests
that the Red Planet was once warm enough to host rainstorms and flowing
water, which would have created an environment that could support
simple life.
The knowledge of
water on ancient Mars has been common for years, but its form was up for
debate. Scientists were unsure whether the water was trapped in ice or
it actually flowed over the surface. There was also uncertainty over the
duration of flowing water if temperatures were warm enough to allow it.
A warm surface with flowing water supports the idea that life could have formed independently on the planet's surface.
Water
vapor appears on Mars today as thin, wispy clouds. So if heated dust is
traveling upwards, it could carry gases and water vapor with it. Previous research has shown it's possible for global dust storms on Mars to send water up into the air.
Dust
storms are common on Mars, but planet-encircling storms are more rare.
This is why it's so difficult for scientists to understand them.
"Global
dust storms are really unusual," said David Kass, Mars Climate Sounder
scientist at NASA's Jet Propulsion Laboratory. "We really don't have
anything like this on the Earth, where the entire planet's weather
changes for several months."
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