French scientists discovered cavities up to 47 meters deep in the bowels of comet 67P/Churyumov – Gerasimenko. The discovery is likely to help explain the mysterious jets of matter coming from this cosmic object that astronomers observed almost 10 years ago.

Experts know that comets in the Solar System are composed of ice, frozen gases, dust, metal and rocks. But scientists know almost nothing about the internal structure of such objects. Caves can help in this: they make it possible to study the geological structure of the subsoil from the inside and in much more detail than they can with the help of the same wells. But researchers still haven’t found caves in comets.

French astrophysicist Philippe Lamy (Philippe Lamy) and colleagues from the French National Center for Scientific Research were able to detect ice-filled cavities on comet 67P/Churyumov-Gerasimenko. For this, they used a three-dimensional reconstruction of the celestial body’s surface, created based on high-resolution images taken by the device. OSIRIS The flight of the Rosetta spacecraft took place on April 9-10, 2016.

Reconstruction showed three deep caverns in the core of 67P. Scientists created anaglyph 3D images to create the three-dimensional shape of these cavities and learn their approximate depth. It turned out to be between 20 and 47 meters. The aim is to publish the scientific study on this subject in a journal. MNRAStext viewable on preprint server arXiv.

“Visually, these caves look like bright spots 15 to 30 meters in size. We assume that there are many similar caves on the comet, but we do not have the data to prove this,” Lamy explained.

His team also came closer to answering the question of how the jets of gas and dust emitted from the comet that scientists observed in 2015 arise. These jets appeared each morning when sunlight warmed 67P’s cold surface.

With the help of the thermal model, experts discovered that a bright jet, recorded, for example, on July 18, 2015, was formed during brief illumination of one of the three cavities. So the mechanism by which these jets form is quite clear: When sunlight enters the cave, it melts the ice, and as a result, the material rises to the surface.

It is not yet clear what exactly the ice in these cavities consists of, but if it is water, it will be of particular interest to scientists. According to some data, Comet 67P/Churyumov-Gerasimenko formed around the same time as the Solar System, which is approximately 4.6 billion years old. This means that the ice in the comet’s interior has likely been stored there for billions of years. His research helped understand where water on Earth comes from. In any case, it is only a new space mission to this body that can finally clarify the question of the composition of comet ice.

In 2004, the European Space Agency launched a mission to study comet 67P/Churyumov—Gerasimenko (ESA) sent the Rosetta probe along with the Philae probe. After 10 years, the station entered the calculated orbit and a 100-kilogram module was lowered onto the surface of the comet. Unfortunately, Philly was only able to operate for about 60 hours (an unfortunate landing site caused the solar cells to die).

However, this time was enough for him to make the discovery of the device. He found molecules of organic matter in the gases ejected by the comet. Some contained carbon atoms, without which life as we know it would be impossible.

A year later, “Rosetta” made an important discovery. The station recorded not only the presence of water, carbon monoxide and carbon dioxide in the comet’s coma, but also an unexpectedly large number of oxygen molecules, which was a surprise for scientists. According to current models of the Solar System, when 67P formed about 4.6 billion years ago, oxygen should have been destroyed through a series of “hot chemical processes.” These processes were supposed to lead to a reaction between oxygen and hydrogen, leading to the formation of a binary hydrogen oxide or water compound. Rosetta studied the comet for two years, from 2014 to 2016.

In 2016, German scientists published a paper in which they said that about 70-80 percent of the total volume of Churyumov – Gerasimenko is occupied by the comet’s cavities, which are evenly distributed throughout the interior. At the time, researchers assumed microscopic caves had formed on the comet, but did not provide evidence.