Could the sugar in our bodies have first come from space?

A: It is possible, though we don’t yet know for sure.

In fact, astronomers recently found a complex sugar in deep space for the first time. Using powerful radio telescopes, a team affiliated with institutes in Spain and five other countries spotted a complex sugar called erythrulose in a giant interstellar molecular cloud near the centre of the Milky Way galaxy. Their findings were published in Nature Astronomy on July 13.

While scientists have previously found molecules that can give rise to sugars in space, erythrulose is itself a sugar. Sugars are essential building blocks of life: they provide metabolic energy and form the structural backbone of RNA and DNA. Scientists have found sugar molecules on meteorites and asteroids but this is the first time such a molecule has been found in the vastness between stars. And it proves  the complex chemical ingredients necessary for life can form in the extreme conditions of space, and don’t need planets.

The researchers used advanced computer models to show that the erythrulose likely formed on the icy surfaces of dust grains. When simpler molecules, such as glycolaldehyde and ethylene glycol, collide on these frozen particles, they can react to form larger, more complex sugars. Eventually, these molecules can be incorporated into comets and asteroids, which may have seeded the early earth with the necessary ingredients for biological life.

Erythrulose is also a chiral molecule, meaning it has separate right-handed and left-handed versions. Because life on the earth only uses one specific handedness for its molecules, finding chiral sugars in space could help scientists understand why our biology evolved the way it did.

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