Scientists Discover Sugar Near Milky Way's Centre, Raising Hope In Search For Life

A simple sugar found naturally in raspberries and used in fake tan lotions has been discovered in a massive cloud of dust and gas near the centre of the Milky Way. Scientists say the finding suggests that compounds important for life can form in the cold regions between the stars, reported NASA.

The sugar, called erythrulose, appears to form through chemical reactions on tiny interstellar dust grains. Scientists believe these grains can later fall onto nearby worlds or become part of comets that eventually collide with planets.

Dr Izaskun Jimenez-Serra from Spain's Centre for Astrobiology said this is the very first sugar to be detected in interstellar space and that it is important because it shows such sugars are more common than previously thought. She added that the discovery opens the possibility for life to develop on other worlds in a similar way to how it did on Earth.

Scientists have long tried to understand how simple sugars became abundant on Earth because laboratory studies suggest they would not have formed easily on the young planet. 

Earlier discoveries of sugars in ancient meteorites and on the Bennu asteroid hinted that some sugars may have come from space, but this is the first time such a compound has been directly detected in the interstellar medium.

Jimenez-Serra and her team used two Spanish radio telescopes to study a dust cloud called G+0.693-0.027 near the centre of the Milky Way. After failing to find simple sugars with three carbon atoms, the researchers were not expecting to find others. However, they detected the signature of erythrulose, which has four carbon atoms. Jimenez-Serra said that, to her surprise, she saw the signals.

Writing in Nature Astronomy, the researchers explained that erythrulose can form when two organic compounds, glycolaldehyde and ethylene glycol, combine on microscopic dust grains. They said these reactions take place even though temperatures in the region remain around -250 degrees Celsius.

The researchers said that, besides providing energy for life, simple sugars such as erythrulose can react to form ribonucleotides, which are the building blocks of what was probably the first genetic material, RNA. As life evolved, DNA became a more stable store of genetic information, while RNA took on the role of carrying information between genes and proteins.

The scientists estimated that millions of tonnes of erythrulose could have fallen onto Earth when asteroids and comets heavily bombarded the planet during the Late Heavy Bombardment. Jimenez-Serra said that this rain of organic material appeared to have been a key step and that it could have contributed to prebiotic soups where the first biomolecules were synthesised.

Erythrulose is found in small amounts in red raspberries and is also used in fake tan lotions. The sugar reacts with amino acids in dead skin cells to produce brown polymers called melanoidins through the Maillard reaction, the same process that gives steak its dark crust.