It’s a question that’s puzzled scientists for years, but a new study could shed light on how life began on Earth.
Researchers from the University of Manchester have analysed meteorites dating back to the birth of the Solar System, 4.5 billion years ago.
Their analysis provides key clues to understanding the birth of life on Earth, as well as in other solar system.
The meteorites studied were ‘carbonaceous chondrites’ – space rocks that originated from asteroids that are as old as our Solar System.
In the study, the researchers analysed the isotopic makeup of oxygen in the organic materials found in these meteorites.
Isotopes are atoms of the same element that share the same number of protons, but have different numbers of neturons.
Isotopic analysis provides scientists with the isotopic signature or a compound, which acts as a fingerprint of processes involved in its formation.
By doing this, the team was able to pinpoint the origins of the organic materials within the meteorites, which are made up of the key elements needed for life – carbon, hydrogen, oxygen, nitrogen and sulphur.
The findings suggest that if organic materials can form by basic chemical processes operating in our Solar System, there is a possibility that they are widespread in other planetary systems.
Dr Tartese, who led the study, said: “Chondrites are a snapshot of the early solar system, providing key insights on how protoplanets and planets formed and were processes."
The team used samples of meteorites held in the Museum National d’Histoire Naturelle in Paris.
While previous studies have mostly focused on hydrogen and nitrogen in these meteorites, the researchers focused on oxygen instead.
Oxygen has a crucial advantage over other elements, as it is fairly abundant in these meteorites, comprising 10-20% of chondrite organics.
But most importantly it is made of three different stable isotopes, while hydrogen and nitrogen only have two stable isotope varieties.
This gives oxygen an extra level of information compared to hydrogen and nitrogen, providing critical clouds to further constrain the origin of chondritic organics.
Dr Tartese added: “The oxygen isotope pattern was similar to the relationship linking the composition of the sun, asteroids an terrestrial planets.
“Therefore, this likely implies that carbonaceous chondrite organics were formed through chemical reactions in the early Solar System, rather than having been inherited from the interstellar medium.”
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