The theory that extraterrestrial objects crashing into our planet could have brought chemicals crucial to the emergence of life has always been mooted, with an array of amino acids – the building blocks of proteins – already discovered on meteorites.
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The European Space Agency’s Rosetta spacecraft spotted them in samples from a gas and dust cloud of the 67P/Churyumov-Gerasimenko comet, scientists said on Friday.
While scientists had detected glycine on samples from a different comet in 2006, concerns about contamination resulted in much doubt over whether it was there to begin with.
“The beauty of it is that the material in the comet was formed before the Sun and planets formed, in the cold environment of the star forming region (known as the) molecular cloud”, said Kathrin Altwegg, a physicist at the University of Bern, Switzerland, who led the study.
“With all the organics, amino acid and phosphorus, we can say that the comet really contains everything to produce life – except energy”, said Kathrin Altwegg of the University of Bern and first author of the study. Astronomers have announced that the key ingredients of life have been discovered in the atmosphere of comet 67P – that great hunk of rock that Philae managed to land on back in 2014.
Rosetta’s comet has been found to contain ingredients that considered to have significance for the origin of life on Earth.
The research team also detected phosphorous, which is essential to all living organisms, for the first time in a comet as well as the presence of hydrogen cyanide and hydrogen sulfide.
It has been detected with the help of an instrument present on the probe, known as the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) mass spectrometer. Phosphorus (chemical element with symbol P), a key component of cell membranes, DNA and RNA, was also detected.
However, after analysing the latest Rosetta data, scientists say that comets had the potential to deliver the ingredients that are critical for the formation of life as we know it. ESA researchers note that they had “repeatedly” found the agent, as well as organic molecules and phosphorus, all of which are used by plants and animals to create proteins. They made a similar detection in March 2015, during a flyby, when Rosetta was 30-15 km from the nucleus of the comet, they said.
Rosetta first detected the protein in October 2014, when it was a mere 10 kilometres (6.2 miles) from the comet.
“We see a strong correlation of glycine to dust, suggesting that it is probably released from the grains’ icy mantles once they have warmed up in the coma, perhaps together with other volatiles”, the investigator said.
Glycine turns into gas only when it reaches temperatures just below 150°C, meaning that usually little is released from the comet’s surface or subsurface because of the low temperatures. Even though there are already many elements in it, the ingredients of life are still missing at this moment.
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More complex amino acids need liquid water to form, so they would have formed on Earth. Researchers speculate that while comets like 67P might have deposited glycine and phosphorous, other impacting celestial objects might have contributed the rest of the building blocks of life.
