ESA’s Rosetta mission to orbit and land a stationary rover on Comet 67P/Churyumov-Gerasimenko has been a mixed bag of success and failure. Although Rosetta’s Philae lander successfully planted itself on Comet 67P back in November, an unfortunate misfiring of one of its hooks settled it into an area with little to no sunlight, effectively preventing the mighty lander from harnessing energy from the sun for power. Recently, Philae has been absorbing bits of light thanks to Comet 67P’s orbital approach to the sun, giving ESA/NASA scientists hope that Philae will again fully awake. Despite Philae’s setback, the Rosetta spacecraft continues to orbit Comet 67P, and this week has released stunning images of several sinkholes on the comet’s surface.
Why the discovery of sinkholes on Comet 67P is a big deal
Similar to how sinkholes and pits form on Earth, scientists studying comet 67P’s sinkholes are assuming the same forces are also giving them shape. More importantly, 67P’s sinkholes are giving scientists a chance to peer deep into the comet’s belly, which may include material that existed during the very formation of our solar system.
They are almost as deep as they are wide. The largest one is about 200m wide and 200m deep [and]it’s amazing because it gives us the possibility to look inside the comet for the first time. JEAN-BAPTISTE VINCENT, from the Max Planck Institute for Solar System Research in Göttingen, Germany
Scientists studying these sinkholes suggest they are the result of sublimation. Basically, as comet 67P approaches the sun, water trapped under the surface of the comet warms until it turns directly into vapor. This forms holes under the surface that get bigger and bigger until the surface collapses. “Comets are extremely cold: they have a lot of ice in their interior. And these comets are also in the vacuum of space, so the water goes directly from ice to vapor: It’s a process called sublimation,” explains Rosetta researcher Dennis Bodewits.
So far, eighteen pits have been identified across the comet’s northern hemisphere. Adding to the magnitude of these discoveries is the fact the depths of these pits might include icy material and building blocks that date back 4.5 billion years.
With more insight into the nature of what’s causing these sinkholes (it may very well not be water) and material they contain, scientists will learn more about the history of our solar system and how it formed. Clearly, the Rosetta mission has been a roaring success.