Astronomers have discovered a naturally occurring sugar found in raspberries in clouds of interstellar dust and gas near the center of the Milky Way galaxy.
The exciting discovery shows for the first time that compounds key to life can form in the vast space between stars, and raises optimism that other molecules important to the origins of life may be found in space.
A team led by astronomers at the Spanish Center for Astrobiology discovered a sugar called erythrulose, which is made up of four carbon atoms. Sugars play a key 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 of Millimeter Wave Radio Astronomy, known as IRAM, in the Sierra Nevada of southern Spain to study a molecular cloud known as G+0.693-0.027, near the center of the galaxy.
The researchers identified the sugar by comparing its molecular signature in the molecular cloud radio wave data to the wavelength signature of erythrulose measured in the laboratory. The team initially looked for simpler sugars with three carbon atoms, but did not find any.
“This discovery was unexpected because the prevailing view in astrochemistry is that interstellar molecules increase in size through the successive addition of carbon atoms,” Izascun Jiménez-Serra, an astronomer at the Center for Astrobiology in Madrid and the National Research Council of Spain, said in a statement. Jimenez-Serra was the lead author of the study, which was published Monday in the journal Nature Astronomy.
“Our discovery shows that relatively complex sugars can be synthesized in interstellar space before the birth of stars and planets,” she added by email.
The study found that erythrulose can form from simpler molecules on icy dust particles in space and can then become part of more complex chemical systems. Scientists have discovered more than 340 molecules in the matter and gases that exist in the interstellar space of the Milky Way, but did not find sugars, the study notes.
“Sugar and related compounds have been discovered on asteroids, but the discovery of these compounds in interstellar space strengthens speculation that our solar system may have been seeded with pre-existing organic compounds,” Mark Sefton, a professor in the department of earth sciences and engineering at Imperial College London, who was not involved in the study, said in an email.
Scientists have long wondered how sugar molecules first formed on Earth; Laboratory experiments have shown that they do not form easily under the extreme conditions thought to have existed in the earliest chapter of Earth’s history.
Previous detections of sugars such as ribose and glucose in primitive meteorites and asteroid Bennu samples collected in 2020 led scientists to speculate that some sugars may have originated from space.
Sefton said it was possible that sugars were incorporated into asteroids during their formation and eventually brought to the Earth’s surface via meteorites.
Yoshihiro Furukawa, a professor in the Department of Earth Sciences at Tohoku University in Japan who was part of the team that discovered the sugars in the Bennu samples, agreed that sugars could reach Earth and other planets through comets and asteroid dust, although the process by which life originated remains unclear.
“This discovery is very interesting because we have been waiting for such a real discovery,” he said.
Researchers estimate between 0.5 and 50 million metric tons Some of this sugar may have reached the Earth’s surface during the so-called Late Heavy Bombardment, a period about 4 billion years ago when asteroids struck the inner planets of the solar system. However, according to NASA, whether such a bombing occurred is still a matter of scientific debate.
Erythrulose, found in small amounts in raspberries and some other fruits, is also used as an ingredient in cosmetics such as self-tanning and tanning products because it reacts with the outer layer of skin, resulting in a tanned appearance.
“The discovery of erythrulose is very exciting because it opens up the possibility of finding other sugars in space, such as ribose, which is part of RNA, and other important molecules for the origin of life,” Carlos Briones, study co-author and molecular evolution researcher at Spain’s National Research Council and Center for Astrobiology, said in a statement.
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