The surface of the comet where it “died” is like the froth of a cappuccino

Lander Philae continues to amaze even after her “death”. Thanks to the discovery of the location of its accident and the location of its reflection, scientists were able to accurately determine the composition of the comet’s surface and reveal billion-year-old ice, the portal informed the matter. Sciencealert.

Despite the fact that Lander Philae hasn’t sent any signals to Earth since July 2015, scientists are still interested in its fate. Lander has been on Comet 67P / Churyumov-Gerasimenko since 2014, where he arrived using the Rosetta spacecraft.

Among other things, Rosetta contributed to the observation unusual phenomenon in the form of ultraviolet aurora on this comet.

However, Lander did not land as expected. On November 12, 2014, during the landing maneuver, the docked harpoons did not strike and the Lander Philae bounced off the original landing site called Agilkia at a speed of 38 cm / and climbed to a height of approximately one kilometer.

He then fell back to the surface from which he bounced off, eventually hitting the site of his non-destructive incident, which was not discovered until 22 months in the Abydos area, just weeks before the mission ended. pages.

Pre curiosityif Philae bounced off the surface at a speed of 44 cm / s, it would likely escape the comet’s gravity. The greatest and, for scientists, the last mystery was the second place of reflection, which could not be discovered for many years.

But even after 6 long years, why are they interested in the lander and the place of its reflection? Sensors on Philae indicated that the lander’s impact revealed ice that had been hidden beneath the comet’s surface for 4.5 billion years. Scientists managed to solve this mystery only in a study published in the journal Nature, where its authors describe, among other things, the composition and porosity of comet 67P / Churyumov-Gerasimenko.

In search of this “lost” site, the researchers first focused on data obtained using the OSIRIS instrument (optical, spectroscopic and infrared remote sensing system), which brought the Rosetta probe with it. Using this data, they looked for bright spots on the comet’s surface to indicate the presence of ice. However, due to the fluctuations in brightness on the surface, the process of discovering this place is like looking for a needle in a haystack.

The breakthrough came after reading data from a ROMAP (Rosetta Magnetometer and Plasma) device designed to monitor changes in the comet’s magnetic field. Using this data, the scientists were able to reconstruct the entire course of the accident.

It turned out that Philae had spent nearly two minutes on the spot of the second bounce, coming in at least four times with her surface. The “stop” itself is located 30 meters from the last “resting place” Philae. During the impact, ROMAP created a 25-centimeter depression in an ice boulder, the porosity of which was calculated to be 75%, which also corresponds to the porosity of the entire surface of the comet, the website informed. Universe.

“The shape of the boulders Philae hit reminded me of a skull when viewed from above, so I decided to nickname this region ‘the top of the skull’ and continue on that for other observed traits,” said scientist O ‘ Rourke.

However, data obtained with the OSIRIS instrument also played a role, the analysis of which confirmed that there was indeed ice at the 3.5m site within months of impact.². However, this was not visible in the images taken upon landing because the whole area was in shadow.

These new discoveries have also provided an interesting insight into the surface of this comet. According to the study authors, the surface of the ice is as soft as “cappuccino foam or bath foam”.

“This is a fantastic result of several tools that not only fill in the gaps in Philae’s story, but also inform us about the nature of the comet,” said one of the authors, Matt Taylor.