Dust storms on Mars can fling water to higher altitudes in the atmosphere than scientists thought, and this rapid process helped strip the Red Planet of its limited water supply — draining its precious oceans — for billions of years, according to a recent study published in the journal Science.
Mars' dust storms may have helped strip oceans of water away
The new research shows how summer dust storms can lift water to the top of Mars' atmosphere, where the molecular structure of water is broken down — enabling hydrogen to escape into space, reports phys.org.
Scientists think Mars used to have one or two oceans in its ancient life. But sadly the water once abundant on the Red Planet's surface and possibly supporting a habitable atmosphere was lost throughout billions of years — a mysterious disappearance scientists want to piece together.
Using NASA's Mars Atmosphere and Volatile EvolutioN spacecraft (MAVEN), scientists have discovered how powerful summer dust storms can lift water above the Red Planet's hygropause — a cold layer in the Martian atmosphere that acts as a boundary to lower altitudes.
Dust storms produce hydrogen atoms at '10 times' typical rate
"Dust storms inject a sudden splash of water into the upper atmosphere," lead study author and University of Arizona grad student Shane Stone told Space.com via email.
Stone and his colleagues relied on data MAVEN collected during its deep plunges into the atmosphere — which went ton for more than two Martian years (mildly shorter than ours). They discovered how the abundance of water peaked during summer in the southern hemisphere, when the Red Planet is nearest to the sun, and worldwide dust storms happen with greater frequency.
"During a global dust storm, the new process we describe produces [hydrogen] atoms at a rate that is 10 times that of the classical process," explained Stone, to Space.com.
New process is like 'sudden splash' of water into upper atmosphere
Here on Earth, the hygropause helps to hold water in the lower atmosphere, and when water rises high enough to reach cold areas, it condenses from a gas to a liquid — forming clouds. After it's condensed, it doesn't go any higher.
Earlier studies have shown how water might be transported above the Red Planet's hygropause, but the new research lays out a seasonal trend with a curious link to dust storms and the amount of water present in Mars' upper atmosphere.
Previous modeling of this process supposed the planet's water was lost via a "slow bleed" from the middle atmosphere into the hygropause, and then onward into the cold reaches of space.
"The classical process is like a slow and steady trickle of hydrogen into the upper atmosphere which varies from Martian year to Martian year, while the process we describe is like a sudden splash of water into the upper atmosphere," said Stone, to Space.com.
Water in Mars' upper atmosphere lasts roughly four hours
Dust storms generally block heat and light, keeping them from pushing their way to the planet surface, so they instead warm the hygropause. This weakens it and lets more water escape the atmosphere. Additionally, Mars' southern summer temperatures are warmer, which adds to atmospheric heat — which further decreases the hygropause's ability to hold water down.
Once water molecules enter the upper atmosphere, they react with charged particles (ions), and split to form hydrogen and oxygen atoms. Hydrogen is the lightest atom, which means some of them accelerate to escape velocity and zoom their way into space.
"Once water reaches the upper atmosphere, it has a lifetime of about four hours," Stone told Space.com.
Possible puzzle for terraforming, colonizing Mars
Earlier today, Elon Musk tweeted about how humans will live in Mars, or rather — in what, given the uninhabitable atmosphere. "Life in glass domes at first. Eventually, terraformed to support life, like Earth," read his tweet.
However, the process of terraforming Mars will have to take into account the effect major dust storms have on water, lest a human population set up glass domes and fill reservoirs of water outside only to watch it all be whisked away into the Red Planet's upper atmosphere — where the precious molecules could be ripped mercilessly into pieces and flung into outer space.