MADRID: An Erythrulose discovery in a Milky Way molecular cloud marks the first reported detection of a true sugar in interstellar space, according to a peer-reviewed study published on July 13.
Researchers identified the four-carbon ketose in G+0.693−0.027, a chemically rich cloud near the Galactic Centre. The cloud lies about 8.2 kiloparsecs, or nearly 27,000 light-years, from Earth.
The team analysed radio-frequency signatures captured by the Yebes 40-metre and IRAM 30-metre telescopes in Spain. They matched 17 spectral transitions with laboratory measurements of Erythrulose, the Nature Astronomy study said.
Lead author Izaskun Jiménez-Serra is an astrophysicist at Spain’s Center for Astrobiology, which operates under CSIC and INTA.
The researchers estimated that erythrulose was at least 8-17 times more abundant than the simpler three-carbon sugars glyceraldehyde and dihydroxyacetone. Neither three-carbon molecule was observed.
That result challenges the expectation that interstellar chemical families become less abundant as they gain carbon atoms.
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The team’s calculations and astrochemical models indicate that Erythrulose can form on icy dust grains from two-carbon compounds related to glycolaldehyde and ethylene glycol.
Researchers estimated that meteorites could have delivered between 500,000 and 50 million tonnes of erythrulose to early Earth.
However, the calculation depends on uncertain estimates of the delivery of organic material during the proposed Late Heavy Bombardment.
Read: Erythrulose Sugar First Detected Near Milky Way Centre
Erythrulose can also convert into threose under watery conditions. Threose forms part of TNA, a simpler genetic polymer proposed as a possible RNA predecessor.
The finding does not establish that interstellar sugar started life on Earth. Instead, it shows that molecular clouds can produce comparatively complex sugar molecules before stars and planets form.
