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Frozen sugar at centre of Milky Way

RHIANNON EDWARD

ASTRONOMERS have found a cloud of frozen sugar near the centre of our galaxy, the Milky Way, it was revealed yesterday.

The discovery heightens the possibility of early building blocks of life originating in interstellar space.

Molecules of a simple sugar, glycolaldehyde, were detected in a cloud of gas and dust called Sagittarius B2 about 26,000 light years away.

Observations indicated large quantities of the sugar frozen to a temperature only a few degrees above absolute zero, the point at which all molecular movement stops.

Glycolaldehyde consists of two carbon atoms, two oxygen atoms and four hydrogen atoms.

This type of molecule is known as a two-carbon sugar. Significantly, it can react with a three-carbon sugar to produce the five-carbon sugar ribose - the molecule which forms the backbone of DNA.

The discovery adds to the growing evidence that the foundations of life can be traced to chemical reactions within interstellar clouds.

The clouds, which are often many light years across, provide the raw material from which new stars and planets are formed.

Radio astronomer Dr Jan Hollis, from the American space agency NASA’s Goddard Space Flight Centre in Green- belt, Maryland, said: "Many of the interstellar molecules discovered to date are the same kinds detected in laboratory experiments specifically designed to synthesise prebiotic molecules.

"This fact suggests a universal prebiotic chemistry."

Gravitational attraction causes lumps to form in interstellar clouds which eventually condense into stars and planets.

The process generates so much heat that any prebiotic molecules within the planetary lumps would probably be destroyed.

But the new findings show that life’s building blocks could exist in the frozen wastes beyond the planet-building zone of an embryonic solar system, where comets form.

A collision with a comet or a brush with a comet’s tail could then "seed" a young planet with the material needed to kick-start life.

The Green Bank Telescope which was used in the study is the world’s largest fully-steerable radio telescope. Its dish covers more than two acres of signal-collecting area.

Dr Philip Jewell, another member of the Green Bank team, said: "The large diameter and great precision of the telescope made this discovery possible, and also holds the promise of discovering additional new complex interstellar molecules."