Faraway star clusters offer best chance of extra terrestrial life
GLOBULAR clusters – dense balls of ancient stars at the outermost edge of the galaxy – may be the best places to look for alien civilisations, an expert has claimed.
For many reasons, the distant regions might be favourable locations for intelligent life, astrophysicist Dr Rosanne Di Stefano believes.
One is their age. Globular clusters, situated in the halo that extends beyond the Catherine wheel arms of the Milky Way, contain stars estimated to be at least 10 billion years old – ample time for life to evolve to an advanced level.
Another is that their stars are so close together. It takes just a month or so for light waves to travel between neighbouring stars in one of the clusters. In comparison, the nearest star to the Earth is 4.2 light years away.
“It would be easier for a civilisation to explore and set up outposts on other worlds,” says Dr Di Stefano, of the Harvard-Smithsonian Centre for Astrophysics in Cambridge, USA.
The sun is only 4.6 billion years old, so if globular cluster civilisations exist they could be billions of years more advanced than us.
So far only one exoplanet, nicknamed Methuselah, has been discovered in a globular cluster known as M4 in the constellation Scorpius.
It orbits a binary system consisting of a pulsar – a compact rotating star emitting pulses of radiation – and a “white dwarf” star at the end of its life. At 12.7 billion years, Methuselah is the oldest exoplanet on record.
Writing in the BBC’s Sky At Night magazine, Dr Di Stefano said: “It would be strange if there were not many others.
But, she did admit: “Of course, this is all conjecture.”