Comet 67P-G is exhibiting a certain cycle mostly associated with a planet orbiting a star, as scientists observed ice building and reducing.
According to Discovery News, the scientists who noticed the cycle on the comet published a study on their findings in the journal Nature. Such a cycle is associated with planets because different parts of their surfaces are exposed to their host star as they orbit, causing one side to heat up while the other cools.
The researchers were able to observe this cycle on Comet 67P-G thanks to the European Space Agency's Rosetta satellite and Philae lander, the first spacecraft to ever attach itself to a comet.
"We saw the tell-tale signature of water ice in the spectra of the study region but only when certain portions were cast in shadow," study lead author Maria Cristina De Sanctis, INAF-IAPS in Rome, said in a press release. "Conversely, when the Sun was shining on these regions, the ice was gone. This indicates a cyclical behavior of water ice during each comet rotation."
Rosetta first spotted water vapor ejections on Comet 67P-G when it was approaching the sun and its ice was warming up, melting, and breaking through like a geyser. The comet's closest approach to the sun has been ongoing for about two months now.
"We think that this cycle is able to replenish the surface layers of ice from the interior of the comet, sustaining the activity for many diurnal cycles," De Sanctis told Space.com. "Small outbursts have been observed on other comets at the morning terminator (dawn), and this is possibly due to a cyclical phenomenon such as the one we see. Thus, this cycle could be common on comets."
