Back in March of 2004 the European Space Agency launched the Rosetta space probe to intercept and study the comet 67P/Churyumov–Gerasimenko which it did 10½ years later. The international team of researchers have now announced what they say is the most surprising discovery of the project -- the presence of oxygen in the atmosphere of the comet, a finding that they said could change our understanding of how the solar system formed.
In fact they said the DFMS mass spectrometer aboard the Rosetta spacecraft detected “a lot” of molecular oxygen in the cloud of gas, or coma, surrounding the nucleus of comet and that it is the fourth most abundant compound in the gaseous coma of 67P after water, carbon monoxide and carbon dioxide.
"It is the most surprising discovery we have made so far in 67P because oxygen was not among the molecules suspected in a cometary comas,” declared Kathrin Altwegg, of Switzerland's University of Bern and project leader for the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) who was a a co-author of the paper describing the discovery. “The first time we saw it I think we all went a little bit into denial because it was not expected to be found in a comet."
Altwegg noted that, “Molecular oxygen is very reactive. There was a lot of hydrogen around when the solar system was formed. Everybody and all models showed that molecular oxygen would react with the hydrogen and would no longer be present as molecular oxygen.” IOW, since oxygen easily bonds with other kinds of atoms and it was thought that all the oxygen that was around at the dawn of the solar system would have long ago combined with the abundant hydrogen present at the time to form H20 -- water.
"All the models say it shouldn't be there and it shouldn't survive for such a long time," agreed Andre Bieler, a physicist at the University of Michigan who studies cometary science and is the lead author of the paper which puts it this way: "Current Solar System formation models do not predict conditions that would allow this to occur."
Bieler added that they detected oxygen almost immediately but to make sure that they weren't mistaken or the equipment wasn't defective they continued studying the comet for several months before reaching their conclusion.
Bieler said that the team checked oxygen levels at different distances from the comet and found that the closer to the comet the spacecraft flew, the more oxygen it detected meaning that it was present "in the whole body" of the comet which led us to the idea that it was primordial so the O2 must have been present at the formation of the comet."
The researchers think that the oxygen was likely built onto the icy grains of the comet. "We came up with the idea that it could happen through radiolysis, a common effect that is known in the solar system on other icy bodies and in the rings of Saturn," explained Bieler. Radiolysis occurs when energetic particles emitted by the sun break up the bonds of water ice. Experiments have demonstrated that hydrogen can diffuse out of this process, leaving the oxygen with no other molecules with which to react.
The findings lead to two obvious questions. What conditions were necessary for molecular oxygen to get trapped in the icy crystals of a comet like 67P and how did that oxygen remain in its pure state for so long?
Further Reading:
In fact they said the DFMS mass spectrometer aboard the Rosetta spacecraft detected “a lot” of molecular oxygen in the cloud of gas, or coma, surrounding the nucleus of comet and that it is the fourth most abundant compound in the gaseous coma of 67P after water, carbon monoxide and carbon dioxide.
"It is the most surprising discovery we have made so far in 67P because oxygen was not among the molecules suspected in a cometary comas,” declared Kathrin Altwegg, of Switzerland's University of Bern and project leader for the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) who was a a co-author of the paper describing the discovery. “The first time we saw it I think we all went a little bit into denial because it was not expected to be found in a comet."
Altwegg noted that, “Molecular oxygen is very reactive. There was a lot of hydrogen around when the solar system was formed. Everybody and all models showed that molecular oxygen would react with the hydrogen and would no longer be present as molecular oxygen.” IOW, since oxygen easily bonds with other kinds of atoms and it was thought that all the oxygen that was around at the dawn of the solar system would have long ago combined with the abundant hydrogen present at the time to form H20 -- water.
"All the models say it shouldn't be there and it shouldn't survive for such a long time," agreed Andre Bieler, a physicist at the University of Michigan who studies cometary science and is the lead author of the paper which puts it this way: "Current Solar System formation models do not predict conditions that would allow this to occur."
Bieler added that they detected oxygen almost immediately but to make sure that they weren't mistaken or the equipment wasn't defective they continued studying the comet for several months before reaching their conclusion.
Bieler said that the team checked oxygen levels at different distances from the comet and found that the closer to the comet the spacecraft flew, the more oxygen it detected meaning that it was present "in the whole body" of the comet which led us to the idea that it was primordial so the O2 must have been present at the formation of the comet."
The researchers think that the oxygen was likely built onto the icy grains of the comet. "We came up with the idea that it could happen through radiolysis, a common effect that is known in the solar system on other icy bodies and in the rings of Saturn," explained Bieler. Radiolysis occurs when energetic particles emitted by the sun break up the bonds of water ice. Experiments have demonstrated that hydrogen can diffuse out of this process, leaving the oxygen with no other molecules with which to react.
The findings lead to two obvious questions. What conditions were necessary for molecular oxygen to get trapped in the icy crystals of a comet like 67P and how did that oxygen remain in its pure state for so long?
Further Reading:
Abundant molecular oxygen in the coma of comet 67P/Churyumov–Gerasimenko Abstract
Rosetta sniffs oxygen around comet 67P
Oxygen found on comet in Rosetta mission: 'Most surprising discovery ... so far'
Oxygen discovered on Rosetta comet, stunning scientists
Oxygen Discovery Could Complicate Search for Alien Life
Possibly limited time access to the full paper available here as well as here
Rosetta sniffs oxygen around comet 67P
Oxygen found on comet in Rosetta mission: 'Most surprising discovery ... so far'
Oxygen discovered on Rosetta comet, stunning scientists
Oxygen Discovery Could Complicate Search for Alien Life
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