'Sweet spots' for life identified - and our solar system isn't one

Posted by Emma Woollacott

Astrobiologists say they've discovered where in outer space complex organic molecules - the building blocks of life - are most likely to form.

And, they say, there are solar systems out there that have been a good deal likelier than our own to develop life.

The New York Center for Astrobiology at Rensselaer Polytechnic Institute team searched for methanol, a key ingredient in the synthesis of organic molecules.

"Methanol formation is the major chemical pathway to complex organic molecules in interstellar space," says the center's director, Douglas Whittet. Follow the methanol, he says, and it should be possible to follow the chemistry that leads to life.

In the right conditions, carbon monoxide on the surface of interstellar dust can react at low temperatures with hydrogen to create methanol - which forms an important stepping stone to the formation of the much more complex organic molecules that are required to create life.

Scientists have known that methanol is out there, but so far there has been little information on where it's most readily produced.

What the team's found is that methanol is most abundant around a very small number of newly formed stars. it's also, for the first time, been discovered in low concentrations in the cold clouds that give birth to new stars.

The scientists conclude that there's a 'sweet spot' in the physical conditions surrounding some stars. Its existence depends on how fast certain molecules reach the dust grains surrounding new stars.

"If the carbon monoxide molecules build up too quickly on the surfaces of the dust grains, they don't get the opportunity to react and form more complex molecules. Instead, the molecules get buried in the ices and add up to a lot of dead weight," Whittet says.

"If the buildup is too slow, the opportunities for reaction are also much lower."

This means that under the right conditions, the dust surrounding certain stars could hold greater potential for life than most of its siblings. The presence of high concentrations of methanol could essentially jumpstart the process to create life on the planets formed around certain stars.

The scientists found was that methanol concentrations at the birth of our solar system were actually close to the average in interstellar space.

"This means that our solar system wasn't particularly lucky and didn't have the large amounts of methanol that we see around some other stars in the galaxy," says Whittet. "But it was obviously enough for us to be here."