ScienceAlert... We finally have an understanding of how Mars transformed from a once habitable, Earth-like planet into the dry world we see today. NASA researchers have just announced that Mars' once rich atmosphere was stripped away by solar winds in the early days of the Solar System, causing the planet to dry out.
Solar winds blast out from the Sun at around a million miles per hour (about 1.6 million km/h), and fortunately Earth is protected from these by our magnetic field. But although Mars used to have a magnetic field, it lost it as its planet cooled down billions of years ago, and that allowed the ions in its atmosphere to effectively be blown away.
Scientists were able to figure this out using the MAVEN (Mars, Atmosphere and Volatile Evolution) spacecraft, which has been orbiting Mars since 2014. Last year, the probe was lucky enough to be able to observe the direct impact of a solar storm on Mars' atmosphere, and showed that the solar particles were energising the gases in the upper atmosphere, causing them to blast into space – and likely out of our Solar System.
You can see that happening below:
The measurements have also provided some insight into the gases that were lost from the Martian atmosphere, which include hydrogen, oxygen, and carbon dioxide – all things needed to create a habitable world.
And as far as we can tell, Mars really was oh-so habitable back in the day. NASA researchers believe that around 4.3 billion years ago, Mars had incredibly deep oceans that held more water than the Arctic Ocean here on Earth.
From this new research, it appears that Mars' oceans evaporated due to the planet's thinning atmosphere, and then slowly leaked out into space. The results have been published in four papers in Science (here, here, here, and here).
Why is Mars' atmosphere important?
Why do we need to know what happened to Mars' atmosphere? Because once we understand that, we'll be able to work out what happened to water on the Red Planet, and it could also hold clues as to the habitability of Mars in the future. Not to mention the findings might prove crucial to NASA's mission to Mars (which it's currently recruiting for, just FYI).
NASA dropped a big clue on Twitter that the findings may have something to do with the solar wind.
‘Gone with the Solar Wind’: Watch live at 2pm ET for a new #MarsAnnouncement. Qs? #askNASA https://t.co/KX5g7zfYQe https://t.co/81ChANXqH7 — NASA (@NASA) November 5, 2015
We're hoping this means we might also find out something about the mysterious, super-powerful aurora spotted earlier this year on Mars.
Either way, we're excited. So settle in with some popcorn (or if, like us, it's 6am where you are, maybe a strong coffee) and watch as we finally find out the story of Mars' atmosphere. Ask your questions on Twitter via #askNASA.
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