Two plucky NASA spacecraft found that Mars is wobbling in its rotation just like Earth, potentially telling us more about the search for life on the Red Planet.
The so-called “Chandler wobble” came to light after an incredible 18 years of observations were collected by Mars Odyssey and the Mars Reconnaissance Orbiter, which both orbit the Red Planet. The spacecraft also suggest the wobble is due to properties within the planet itself, and not factors such as how much the polar ice caps melt and reform each year, although more data collection would be ideal to confirm.
Watching how much Mars wiggles from a perfect rotation has huge implications for how the planet was made. The wobble provides a window into the interior of the Red Planet, specifically in the mantle — that bulky zone just beneath the crust of the planet. Modeling shows that the wobble should have slowed down by now, but it’s possible that changes in the atmosphere of Mars are continuing to drive the motion.
Mars, for example, is slowly bleeding its atmosphere out into space; that’s why it lost so much water on the surface billions of years ago. That water could have sustained life, and NASA’s Perseverance rover is en route for a landing next month to see if it can (eventually) cache any rock samples with ancient microbial fossils.
But there’s more to learn about that wobble, for sure. We still aren’t clear if the wobble is an echo back to the era when Mars had a lot of water on its surface, in the form of large lakes and potentially (some researchers say) as oceans. With only two planets known to have a “Chandler” wobble, it’s a bit of a stretch yet to point out that both the known planets had or have a lot of water on their surface. But it may be something to consider in the ongoing search for life around the universe.
Beyond the inherent value of the science findings, we also have – yet again – a wonderful demonstration for why it’s so important to keep science missions running for a long time, as long as the instruments are sound. Just like how the Landsat satellite series on Earth shows us the long-term changes associated with global warming, these two NASA spacecraft show us long-term changes on the surface of Mars, along with its motions.
It’s slow work, it may sound tedious to the outsider, but consider that humanity has only sent a few dozen spacecraft to Mars since the 1960s and landed a mere fraction of those on the surface. You want to search for life on another world? You need to be systematic, patient and comprehensive. You need multiple types of observations spaced over long periods of time. You need evidence of water flow from orbit and evidence of water-formed rocks at the surface, along with organics and ideally, fossils.
We won’t build up this kind of picture overnight, but after years of creeping along in our research we are getting closer. That’s why scientists are so eager to see what Perseverance holds in store for the search for life.
A study based on the research was recently published in Geophysical Journal Letters.