The European probe Rosetta discovered oxygen in abundance in the atmosphere of the comet Tchouri. A “total surprise” for scientists … who have already accumulated a large number of discoveries since the probe approached this heavenly body on which the robot landed Philae. Quick reminder scientific facts.
A space trip 11 years
AFP PHOTO ESA / CNES / Arianespace-S. CORVAJA
The Rosetta probe his robot lander Philae passenger take off March 2, 2004 from Kourou, French Guiana, aboard an Ariane 5. This is the beginning of a journey of 11 years at the complex trajectory, where both mechanical explorers will use several Earth and Mars to accelerate their speed -via the gravitationnelle- assistance in order to catch their flight to the comet and study, as detailed in this video:
Layout in orbit, the first steps
After ten years of waiting, in August 2014, Rosetta manages to maintain artificially around the comet through many maneuvers of approach. The time is the mapping of . orb to identify potential landing sites for Philae November 12 is the day of the plunge: the separation between the probe and the robot
(Credits. ESA / Rosetta / MPS for OSIRIS Team MPS / UPD / LAM / IAA / SSO / INTA / UPM / DASP / IDA)
Ask a device on a comet, it is a feat that n had never been done. And that was also not exactly go as planned: after its slow descent of seven hours in free fall observed since remote Rosetta (above) and filmed by an onboard camera (below), the robot could not dock as planned on Tchourioumov-Gerasimenko comet, more than 510 million kilometers from Earth.
(Credit: ESA / Rosetta / Philae / ROLIS / DLR)
He ended after at least two rebounds explained on the graph -dessous, wedged between cliffs in a place too little light for its solar batteries work as hoped. Just enough for 60 hours and have a first major discovery of four organic molecules, including methyl and acetone, precursors of molecules important for life, such as sugars and amino acids.
Philae was then immersed in a way of “sleep” long before the whole, led by the orbit of the comet, will eventually approach more sun and a fairly intense light to recharge the energy of the robot.
ESA / Rosetta / MPS – MPS / UPD / LAM / IAA / SSO / INTA / UPM / DASP / IDA
A little closer to the Sun
After seven months of hibernation, Philae woke up on June 13, shortly before the trio arrives at the nearest point of the Sun-or “perihelion.” – August 10, 186 million kilometers away from our star
As we approach the Sun, comets are ice vaporize and release when “degassing” an atmosphere rich in various molecules, jets of gas and matter (see below) that can be analyzed using Rosetta, also bristling of measuring instruments, as it continues rotate around the star. “The comet ejects 300 kilos of gas per second and up to a ton of dust per second,” noted Nicolas Altobelli, a planetary scientist at the European Space Agency (ESA).
(Credit: ESA / Rosetta / MPS for OSIRIS Team MPS / UPD / LAM / IAA / SSO / INTA / UPM / DASP / IDA)
Studying these objects considered vestiges of primitive matter can uncover the secrets of the universe, to understand the evolution of the solar system since birth. Ice and dust that compose them are rejected as comets approach the Sun: the tail of the comet.
ESA / Medialab ATG – ESA / Rosetta / NavCam – A. Bieler et al (2015)
This is how Rosetta has detected oxygen visible on the graph above, as well as carbon monoxide, carbon dioxide, sulfur, methyl noble gases but also molecules and acetone, when the comet was closest to the Sun
& gt; Read:. “This is the abundance of oxygen on Tchouri which is surprising”
The frosted mornings Tchouri
(Credit: ESA / Rosetta / VIRTIS / INAF-IAPS / OBS DE PARIS-LESIA / DLR; VIRTIS data projection is shape model by A. Zinzi ASDC)
Other discoveries of the Rosetta mission brought a better understanding of these amazing stars. The researchers particularly highlighted a “mechanism that reloads the surface of the comet in fresh ice “for each rotation on itself within 12 hours, the surface of the comet Tchouri is covered with a thin ice film. Then very quickly, due to the Sun, the ice turns into water vapor. Before the night falls that cools the surface, allowing the ice to form again, as shown in the animation above.
A principle that had never been observed over a significant period by a human instrument: Rosetta brings “the first observational proof” of the existence of this cycle of water ice.
An old “soft crash”
ESA / Rosetta / NAVCAM
Finally,” 67P / Churyumov-Gerasimenko, “his comet name complete, has a characteristic shape, sort of floating bath duck in Space, which also proves rich in lessons. The body and the duck’s head are two separate objects each having a structure in layers, like an onion, with The most important areas are modeled below.
These two original comets have merged at the end of a “soft crash” at the time of the early stages of solar system formation there has some 4.6 billion years. Unpublished findings, probably not the last, as the Rosetta and Philae mission will continue to continue to unravel the mysteries of comets.
ESA / Rosetta / MPS – MPS / UPD / LAM / IAA / SSO / INTA / UPM / DASP / IDA – Mr. Massironi et al ( 2015)
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