It's possible that Comet 67P/Churyumov-Gerasimenko's nucleus contains organic material that formed way before our solar system did.
Media by the European Space Agency (ESA)
In 1969, Soviet astronomer Svetlana Ivanovna Gerasimenko exposed a photograph for the Comet 32p/Comas Solà. Using the same photographic plates, Klim Ivanovich Churyumov, another Soviet astronomer, discovered an unknown comet. This turned out to be Comet 67P/Churyumov-Gerasimenko, named after the two astronomers, a Jupiter-family comet that came from the Kuiper belt.
On March 2, 2004, the European Space Agency (ESA) launched the Rosetta mission, whose main task was to study Comet 67P/Churyumov-Gerasimenko. Spacecraft Rosetta finally arrived at the comet 10 years later on August 6, 2014. The mission ended on September 30, 2016, but Rosetta and its lander module Philae were able to gain significant data on the comet. Philae became the first spacecraft to ever be able to land on a comet's nucleus.
Learn more about Rosetta and Philae's mission from this touching video by ESA.
An illustration of Rosetta ending its mission by landing on Comet 67P [Image by ESA/ATG medialab]
The Rosetta mission's data revealed that as much as 40% of the mass of the comet's nucleus was made of organic materials. These organic materials include carbon, oxygen, hydrogen, and nitrogen. These elements in particular served as the building blocks of life on Earth. By itself, this piece of information isn't that remarkable. However, the researchers say that these organic molecules on Comet 67P were formed in interstellar space. Interstellar space is the space beyond the reach of the sun's magnetic field and flow of material. The researchers also assert that the molecules were formed before the solar system ever was.
Scientists have known for 70 years that organic materials exist in interstellar space. According to the researchers, the organic molecules of Comet 67P were formed in diffuse interstellar bands (DIBs), an area of interstellar space with observable absorption lines. DIBs absorb only a select set of light wavelengths. The Milky Way is full of DIBs, but, as the researchers point out, they're not as prevalent in primitive nebulae.
DIBs don't absorb as much light in primitive nebulae because of one thing. The organic molecules that form DIBs clump together in the heart of these nebulae. As a consequence, the clumped material absorb less light.
A close-up of Comet 67P [Image by ESA]
These kinds of nebulae eventually turn into solar systems like ours, with a central star, planets, and comets as well. According to Rosetta's findings, comet nuclei form as particles clump together and form a larger body. These larger bodies eventually clump together as well and form even larger bodies. Eventually, the comet nuclei grow up to a few kilometers wide.
This means, therefore, that the organic molecules in primitive nebulae don't get destroyed. Instead, they clump together and form the nuclei of comets. It turns out that these molecules have been hanging on in the solar system for 4.6 billion years.
These findings also impact the search for extraterrestrial life. Scientists believe that these organic molecules were responsible for the formation of life on Earth. If these very old organic molecules still exist in comets, is it possible that they've planted life on other planets in the Milky Way as well?
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