Scientists have detected sugar molecules in interstellar space for the first time, identifying erythrulose in vast clouds of gas and dust near the center of the Milky Way. This discovery raises the possibility that essential ingredients for life were forged in the cosmos and delivered to early Earth.
The finding, published in the journal Nature Astronomy, is significant because sugars are fundamental molecules for life, providing energy and forming key components of DNA and RNA. While sugars have previously been found in meteorite and asteroid samples, this marks the first direct detection of a sugar in the interstellar medium.
Researchers used two ultra-sensitive radio telescopes to identify erythrulose by matching 12 distinct radio signals from a molecular cloud with the unique spectral fingerprint of the sugar. They estimate that up to 50 million tons of this sugar could have reached Earth approximately four billion years ago, a period when the planet was frequently impacted by space rocks.
"The detection of erythrulose is very exciting because it opens up the possibility of discovering in space other sugars such as ribose, which is part of RNA, and other important molecules for the origin of life," said Carlos Briones, a co-author of the study.
While erythrulose is not directly found in DNA or RNA, its presence indicates that complex sugars can form naturally in space. This strengthens the hypothesis that other biologically important sugars, such as ribose, may also exist in interstellar clouds. Scientists believe erythrulose can form from simpler molecules within icy dust grains in space.
Previous research, including a NASA announcement last year, identified sugars like ribose and glucose on the asteroid Bennu. These extraterrestrial findings, along with the detection of amino acids and other organic molecules, suggest that the building blocks of life are widespread throughout the solar system. Researchers emphasize that these discoveries are not evidence of alien life but provide crucial clues to understanding the origins of life on Earth.
The detection of interstellar erythrulose suggests that the interstellar medium could be a viable source of sugar feedstock for the prebiotic synthesis of the first nucleic acids, not only on primitive Earth but also elsewhere in the universe, according to the study's authors.