NASA’s MAVEN Discovers How Mars Lost Its Atmosphere
“The good news for us, mind you, is that the magnetic field here on Earth shows no sign of ceasing anytime soon. The dynamo in the core may do things like flip and reverse, swapping north-and-south magnetic poles, but we should continue to stay protected from the solar wind far into the foreseeable future: for billions of years (at least) to be sure. We could, conceivably, one day suffer the same fate as Mars, but our mass, our rotation and our active, dynamic core should keep the Earth’s magnetic field in business for at least as long as the Sun shines!”
If you had taken a trip to our Solar System four billion years ago, you would have found two worlds with liquid water oceans, temperate atmospheres and all the conditions we believe are needed for life. Earth would have been one of them, but Mars would have met all those criteria, too. It was long suspected that something happened to Mars around a billion years into the Solar System’s history that caused it to lose its atmosphere, something that should still be going on today. Thanks to NASA’s Maven mission, we’ve measured this atmospheric stripping by the Sun for the first time, and we’ve reached a few incredible conclusions, including that in about two billion years, Mars will be completely airless, and that if we were to terraform Mars today, it would hang onto this new atmosphere for millions of years.