Ice on the surface of comet 67P/Churyumov-Gerasimenko, better known as the object that the ESA’s Rosetta orbiter has been tracking since August 2014, formed at approximately the same time as the solar system itself, according to a new Astrophysical Journal Letters study.
Using data gathered by the spacecraft’s Rosina mass spectrometer, a team of researchers led by experts at the French National Centre for Scientific Research (CNRS) and Marseille University measured the amount of nitrogen, carbon monoxide and argon in the ice of Comet 67P.
They then compared the results of that analysis with data from laboratories studying amorphous ice, as well as models describing the composition of ice capable of trapping gas molecules. They found that it has argon and nitrogen levels that corresponded to those of gas hydrate models, and one one-hundredth as much argon as can be trapped in amorphous ice, the Daily Mail said.
This discovery confirms that the ice in Comet 67P has a crystalline structure, which as Popular Science explained means that its water molecules are arranged in a neat, orderly pattern. If the ice was found to have been amorphous, with disordered water molecules, it may have indicated that the comet originally formed in interstellar space, outside of the solar system.
Findings indicate the comet formed in the protosolar nebula
However, since the comet’s surface ice is crystalline, it means that the water was allowed to cool relatively slowly – in the cooling nebular of the early solar system, for instance. Comet 67P’s ice most likely formed between -378.4 degrees and -369.4 degrees Fahrenheit, the authors said.
Based on their observations, the scientists believe that the ice on Rosetta’s comet likely formed at approximately the same time as the solar system, roughly 4.6 billion years ago, the Daily Mail and Popular Science explained. Specifically, the crystalline structure indicates that it formed in the protosolar nebula, a cloud of gas and dust that preceded the solar system’s formation.
The observations indicate that the protosolar nebula would have been hot and dense enough to turn ice from the interstellar medium into gas, the researchers explained. The findings mean that scientists can now determine the age of comets, and the research could provide new insight into the formation of the solar system – particularly the gas giants and their moons (which scientists believe formed as the result of the agglomeration of crystalline ice).
Rosetta, which launched in 2004 and spend 10 years traveling to Comet 67P, will continue to monitor and collect data through September, at which time it will slowly descent and eventually crash-land onto the surface of the object. It will continue to gather information and collect new images right up until the moment of impact.
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Image credit: ESA
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