The outer reaches of our galaxy may be more hospitable to life than we thought. Most of the elements required for the development of life as we know it decrease in abundance further from the centre of the Milky Way, but now astronomers have found organic molecules that could be the building blocks of life near the galaxy鈥檚 edge.
Lilia Koelemay at the University of Arizona and her colleagues used the ARO 12-Meter Radio Telescope on Kitt Peak in Arizona to search for complex molecules in 20 clouds of gas in the Milky Way鈥檚 spiral arms. They detected methanol 鈥� which is made of carbon, oxygen and hydrogen 鈥� in all 20 clouds, and cyclopropenylidene 鈥� made of carbon and hydrogen 鈥� in most of them.
These sorts of substances are the basic building blocks for many molecules that are crucial for life as we know it, including DNA, glucose and the carbohydrates that make up cell membranes. Koelemay presented this work at a virtual meeting of the American Astronomical Society on 8 June.
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鈥淭he abundances of these molecules do not drop off as you go out from the galactic centre, which is surprising because we know that the amounts of carbon, oxygen and nitrogen do drop off the farther out you go,鈥� she said.
This could change our ideas about where in our galaxy life could arise, which is also known as the galactic habitable zone and is generally thought to end about 29,000 light years from the galactic centre. But the discovery of organic molecules in these clouds, which were between 42,000 and more than 76,000 light years from the middle of the galaxy, may necessitate broadening that area, said Koelemay.
鈥淲e don鈥檛 know where life is in our galaxy. Could it be at the outer edges? It might,鈥� said team member Lucy Ziurys, also at the University of Arizona. 鈥淔inding these organic molecules was somewhat of a surprise, so there could be more surprises.鈥�
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