(ORDO NEWS) — A sample recovered from an asteroid far from Earth confirmed that RNA nucleotide bases can be found in space rocks.
An analysis of the dust brought home from the Ryugu asteroid showed the presence of uracil one of the four nitrogenous bases that make up RNA in addition to niacin, a form of vitamin B3 that plays an important role in metabolism.
This adds to the growing body of evidence that the building blocks for life are formed in space, and may have been at least partially delivered to Earth by asteroid bombardment early in our planet’s history.
“Scientists have previously found nitrogenous bases and vitamins in some carbon-rich meteorites, but there has always been a question of contamination due to exposure to the Earth’s environment,” says astrochemist Yasuhiro Oba of Hokkaido University in Japan.
“Because the Hayabusa 2 spacecraft collected two samples directly from the Ryugu asteroid and brought them back to Earth in sealed capsules, contamination can be ruled out. out.”
How life rged, and how common this appearance in the Milky Way galaxy might be, are two questions that humanity would like to know the answers to.
One way to interrogate them is to find the building blocks of life in space and explore potential mechanisms for getting them from there to here.
As we discover more and more, there are many building blocks for life. They have been seen in planet-forming dust and in the star-forming dust clouds that enshroud the heart of our galaxy.
And they were found in many meteorites that entered the Earth’s atmosphere and fell to the ground.
Taken together, the evidence suggests that the building blocks of life may indeed have been alien… but certainty remained elusive until scientists were able to establish the infiltration of Earth material into space rocks after their arrival here.
To figure out what was in the pristine samples that Hayabusa2 brought back from Ryugu, Oba and his colleagues used a new technique they had developed for small-scale… large-scale detection and identification of nitrogenous bases in tiny amounts.
The team took two samples from different locations on the asteroid and immersed them in hot water and subjected them to high performance liquid chromatography combined with electrospray ionization high-resolution mass spectrometry.
This method, applied to the Murchison meteorite that fell to Earth in 1969, made it possible to obtain all five canonical nitrogenous bases.
The range of biomolecules found in Ryugu was smaller, but still significant, the researchers said.
“We found uracil in the samples at low levels, ranging from 6 to 32 parts per billion (ppb), while vitamin B3 was higher, ranging from 49 to 99 parts per billion,” Ohba says.
“Other biological molecules were found in the sample, including a range of amino acids, amines, and carboxylic acids, which are present in proteins and metabolism, respectively.”
The identified compounds, which combine about 20 amino acids previously found in Ryugu samples, differ from compounds found in other carbon-rich meteorites that have fallen to Earth.
Earth, but generally similar. This suggests that biomolecules may be quite common in carbonaceous meteorites and may have been brought to Earth during bombardments.
As for how they got to the asteroids, scientists believe that compounds containing nitrogen may have been formed. from simpler molecules including formaldehyde, ammonia and hydrogen cyanide.
They were not found in the Ryugu samples, but were likely present if the asteroid or its parent body was a comet covered in ice rich in these molecules early in its history.
However, Ryugu is only the beginning. NASA has collected a sample from another asteroid, Bennu, and is shipping it home to Earth for analysis. Early research indicates that it also contains organic materials consistent with the building blocks of life.
“The discovery of uracil in Ryugu samples lends strength to current theories regarding the source of nitrogenous bases in the early Earth,” says Oba.
NASA’s OSIRIS-REx mission will return samples from the asteroid Bennu this year, and a comparative study of the composition of these asteroids will provide additional data that can be used further. theories.”
It seems that the stellar matter that we are made of has bypassed the asteroids.
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