The building blocks of all life are being collected in an icy hell under radiation?
Tiny fragments of an ancient asteroid returned to Earth have changed scientists' understanding of where and under what conditions the first organic molecules might have formed. New research shows that amino acids can form not only in warm water, as was previously thought, but also in icy environments exposed to radiation early in the history of the Solar System.
The samples in question are from the asteroid Bennu , returned to Earth by NASA's OSIRIS-REx mission in 2023. These particles are considered to be virtually unchanged material, approximately 4.6 billion years old. A team from Pennsylvania State University studied the microscopic grains of rock and the organic compounds they contain. The analysis showed that the traditional requirement for warm liquid water for amino acid synthesis is not supported.
Glycine, a simple amino acid found in proteins in living organisms, was discovered in the samples. To reconstruct the history of its formation, scientists measured the isotopic composition of the molecules. This approach allows us to understand the environment and processes that produced a substance using isotopic ratios, as different conditions leave a distinct chemical signature.
The results disagreed with the classical model known as Strecker synthesis. This scheme describes the formation of glycine in the presence of liquid water and moderate heating. Isotopic data pointed to a different scenario. According to the authors' calculations, the protein precursor molecules formed within frozen ice exposed to irradiation in the outer regions of the young planetary system. There, low temperatures and radioactive exposure combined to trigger chemical reactions without water.
The quality of the measurements was crucial here. The lab used specially modified instruments capable of "seeing" the isotopic composition of even trace amounts of organic matter. These samples have concentrations so low that conventional methods yield too crude a result. According to the study's authors, without such sensitive equipment, it would have been impossible to understand exactly how glycine formed in these particles.
The data from the samples were then compared with data from the Murchison meteorite, which fell in Australia in 1969 and remains a key reference point in the study of extraterrestrial amino acids. Its composition points to a more "mild" scenario of chemical reactions, at moderate temperatures and involving liquid water. Samples from Bennu, by contrast, reveal a different story involving cold and intense radiation.
This difference means that early on, several distinct chemical zones existed , each governed by different rules. In some places, organic matter arose in aquatic environments, while in others, it arose within frozen masses under the influence of radiation. This means that the basic molecules for future biology could have emerged in parallel through different means, and then arrived on young planets via meteorites.
Tiny fragments of an ancient asteroid returned to Earth have changed scientists' understanding of where and under what conditions the first organic molecules might have formed. New research shows that amino acids can form not only in warm water, as was previously thought, but also in icy environments exposed to radiation early in the history of the Solar System.
The samples in question are from the asteroid Bennu , returned to Earth by NASA's OSIRIS-REx mission in 2023. These particles are considered to be virtually unchanged material, approximately 4.6 billion years old. A team from Pennsylvania State University studied the microscopic grains of rock and the organic compounds they contain. The analysis showed that the traditional requirement for warm liquid water for amino acid synthesis is not supported.
Glycine, a simple amino acid found in proteins in living organisms, was discovered in the samples. To reconstruct the history of its formation, scientists measured the isotopic composition of the molecules. This approach allows us to understand the environment and processes that produced a substance using isotopic ratios, as different conditions leave a distinct chemical signature.
The results disagreed with the classical model known as Strecker synthesis. This scheme describes the formation of glycine in the presence of liquid water and moderate heating. Isotopic data pointed to a different scenario. According to the authors' calculations, the protein precursor molecules formed within frozen ice exposed to irradiation in the outer regions of the young planetary system. There, low temperatures and radioactive exposure combined to trigger chemical reactions without water.
The quality of the measurements was crucial here. The lab used specially modified instruments capable of "seeing" the isotopic composition of even trace amounts of organic matter. These samples have concentrations so low that conventional methods yield too crude a result. According to the study's authors, without such sensitive equipment, it would have been impossible to understand exactly how glycine formed in these particles.
The data from the samples were then compared with data from the Murchison meteorite, which fell in Australia in 1969 and remains a key reference point in the study of extraterrestrial amino acids. Its composition points to a more "mild" scenario of chemical reactions, at moderate temperatures and involving liquid water. Samples from Bennu, by contrast, reveal a different story involving cold and intense radiation.
This difference means that early on, several distinct chemical zones existed , each governed by different rules. In some places, organic matter arose in aquatic environments, while in others, it arose within frozen masses under the influence of radiation. This means that the basic molecules for future biology could have emerged in parallel through different means, and then arrived on young planets via meteorites.
