Caves have been spotted on comet 67P/Churyumov-Gerasimenko. (Image Credit: Philippe Lamy, Guillaume Faury, David Romeuf, Olivier Groussin, MNRAS/News9).
The Rosetta spacecraft, launched on board an Ariane 5 rocket from the spaceport of the European Space Agency in Kourou, French Guiana, in March 2004. After a ten year long journey, the spacecraft reached its destination and target of study, the comet designated as 67P/Churyumov–Gerasimenko (67P), an icy body original from the Kuiper belt in the fringes of the Solar System. The spacecraft spent two years in orbit investigating the comet using various on board instruments, before crashing into 67P. The Optical, Spectrocopic and Infrared Remote Imaging System (OSIRIS) system on board captured several images of the comet.
Researchers have now used observations by the OSIRIS instrument conducted between 9 and 10 April, 2016, to assemble high resolution anaglyphic images of the surface. These images use the motion of the spacecraft to simulate stereoscopic views, which in turn allows for depth perception, just like the binocular vision of human eyes. The researchers were then able to identify cavities or caves on the nucleus of the comet, that were associated with well known jets. These cavities were measured to be between 15 and 30 metres across, with depths estimated to range between 20 and 50 metres. The cavities are transient features, that can persist for up to two years.
If confirmed, this may be the first time that caves have been spotted on any cometary body. Preexisting cavities on the surfaces of comets is good news for future missions to explore comets, that have an easier access to the pristine material in the depths of comets. Robotic probes can potentially access this pristine material in the remote interior of icy bodies. These comets are just like time capsules, preserving the material from the infancy of the Solar System, and can provide scientists with valuable information on the environmental conditions just after the Sun was born. The paper is titled ‘Detection and characterisation of icy cavities on the nucleus of comet 67P/Churyumov-Gerasimenko’.
