Astronomers detect sugar in interstellar space for the first time

By Katie Hunt, CNN

(CNN) — Astronomers have detected a natural sugar found in raspberries in clouds of interstellar dust and gas near the center of the Milky Way galaxy.

The sweet discovery shows for the first time that compounds that are key to life can form in the vast expanse between stars and fuels optimism that other molecules important for the origins of life might be found in space.

A team led by astronomers at Spain’s Center for Astrobiology detected the sugar, called erythrulose, which is made of four carbon atoms. Sugars play a pivotal role in living systems, helping to provide energy, build biological structures and form parts of genetic material such as RNA and DNA.

To make the observations, the team used two radio telescopes, one at the Yebes Observatory north of Madrid and the other at the Institute for Radio Astronomy in the Millimeter Range, known as IRAM, in the Sierra Nevada in southern Spain, to study a molecular cloud known as G+0.693−0.027 near the center of the galaxy.

Researchers identified the sugar by comparing its molecular signature in the radio wave data from the molecular cloud with the wavelength pattern for erythrulose measured in the laboratory. The team initially searched for simpler sugars with three carbon atoms but didn’t find any.

“This finding was unexpected, as the prevailing view in astrochemistry is that interstellar molecules grow in size through the sequential addition of carbon atoms,” Izaskun Jiménez-Serra, an astronomer at the Center for Astrobiology in Madrid and the Spanish National Research Council, said in a statement. Jiménez-Serra was the lead author of the research, which published Monday in the journal Nature Astronomy.

“Our discovery demonstrates that relatively complex sugars can already be synthesized in interstellar space, before stars and planets are born,” she added via email.

The study suggested that erythrulose can be made from simpler molecules on icy dust grains in space and may then become part of more complex chemical systems. Scientists have detected more than 340 molecules in the matter and gases that exist in the Milky Way’s interstellar space the but no sugars, the study noted.

“Sugar and sugar-related compounds have been found in asteroids, but the discovery of these compounds in interstellar space strengthens suggestions that our solar system may have been seeded with pre-existing organic compounds,” said Mark Sephton, a professor in the department of Earth science and engineering at Imperial College London, who was not involved in the study, in an email.

Scientists have long wondered how sugar molecules first formed on Earth; lab experiments have shown they do not form easily under the extreme conditions thought to exist in the earliest chapter of Earth’s history.

Previous detection of sugars such as ribose and glucose in primitive meteorites and in samples from the asteroid Bennu collected in 2020 suggested to scientists that some sugars may have originated in space.

Sephton said it’s possible that sugars would have been incorporated into asteroids as they formed and eventually delivered to Earth’s surface via meteorites.

Yoshihiro Furukawa, a professor at Tohoku University’s Department of Earth Sciences in Japan who was part of a team that found sugars in samples from Bennu, agreed that sugars could reach Earth and other planets via comets and asteroid dust, although the process of how life emerged remains unclear.

“This finding is very interesting, as we have been waiting for an actual detection like this,” he said.

The researchers estimated that between 0.5 million and 50 million metric tons of this sugar could have peppered Earth’s surface during what’s known as the Late Heavy Bombardment, a period about 4 billion years ago when asteroids pummeled the solar system’s inner planets. However, whether such a bombardment occurred is still a matter of scientific debate, according to NASA.

Found in tiny amounts in raspberries and some other fruits, erythrulose is also produced as an ingredient for cosmetics such as self-tanning and bronzing products because it reacts with the outer layer of the skin leading to a tanned appearance.

“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,” Carlos Briones, study coauthor and researcher in molecular evolution at the Spanish National Research Council and the Center for Astrobiology, said in a statement.

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