Surprising Amount of Sugar Found in Space - A Clue to How Life Began

Researchers have discovered the sugar molecule erythrulose in a gas cloud near the center of the Milky Way, 27,000 light-years away. This marks the first time a true sugar has been found outside our solar system, supporting the theory that life's building blocks formed long before Earth itself existed.

Published in Nature Astronomy, the discovery was made by scientists at Spain's Center for Astrobiology using two radio telescopes. The molecule was detected in the cloud G+0.693, already known for hosting a rich variety of complex molecules.

While related molecules like glycolaldehyde - often called the "simplest sugar" - have been found across the universe before, glycolaldehyde is not chemically a true sugar. Erythrulose is.

What makes the find remarkable is the abundance. Erythrulose appears to be 8 to 17 times more plentiful than smaller sugar molecules. Normally, larger molecules are rarer, but here the opposite is true. Researchers believe erythrulose forms efficiently on the surface of tiny dust grains coated with ice, where two smaller building blocks - glycolaldehyde and ethylene glycol - link together.

Erythrulose is now the largest non-ring-shaped molecule ever found in interstellar space. It is also the first molecule in space with four oxygen atoms and only the second with chirality - the property of having left- and right-handed mirror-image forms. Life on Earth consistently uses only one mirror version of many molecules, and how this bias arose remains a major mystery. Finding a chiral sugar in deep space strengthens the idea that this preference was partly set before Earth even existed.

Sugars are essential to life, serving as energy sources and as building blocks for RNA and DNA. Previous discoveries of sugars like ribose in meteorites and on asteroid Bennu suggested that some of Earth's sugar supply came from space. Now it appears these molecules can form in space itself, before planets or asteroids ever existed.