Star clusters might host intelligent civilizations, study says

In addition, so many stars are clumped together that it would be easy to hop from one planet to another, keeping an advanced society going, she said.

Globular clusters like 47 Tucanae (above) could be excellent places to search for advanced alien civilisations. But DiStefano doesn’t think we should give up on the idea of life in the clusters.

Di Stefano presented the new research on January 6 at the 227th meeting of the American Astronomical Society in Kissimmee, Florida.

There are more than 150 globular clusters in our Milky Way.

By analyzing the distances between stars in various globular clusters, DiStefano and Ray identified a “sweet spot” where conditions would be stable enough for a planet to form and survive for billions of years.

“Now we can use the information that we’ve gleaned from other planet discoveries – and there are over 2,000 planets known today – to ask, is it likely that they’d be in globular clusters”.

Di Stefano and her colleague Alak Ray of the Tata Institute of Fundamental Research in Mumbai have several theoretical arguments to make.

While planets the size of Jupiter are found around stars that contain heavy elements, earth-sized planets do not have any such conditions for their configuration in space. Some in the past have argued that the clusters don’t contain large amounts of heavy elements necessary for planet formation.

If an alien civilisation has been around for millions of years longer than we have, it is probably technologically light-years ahead of us.

They say globular star clusters on the outskirts of the Milky Way might be the first place we find intelligent life. The study states that the ancient, clusters lying at the fringe of Milky Way are the best source for existence of extraterrestrial intelligence (Seti). Lots of closely packed stars could also mean lots of planetary systems not very far from one another.

These bright pockets of starlight might not host many planets at all, let alone any that are habitable. They stressed that there is no evidence of existing space bodies in clusters that could be referred to as planets.

[That means that the] predominant stars in globular clusters are faint, long-lived red dwarfs.

Once planets form, they can survive for long periods of time, even longer than the current age of the universe.

Staying wet, however, isn’t the only challenge for a life-bearing planet in a crowded cluster. They formed about 10 billion years ago on average. The clusters are ancient, so if any planets formed near the beginning of the stars’ lifetimes, life would have billions of years to evolve. Scientifically and technologically, they would be literally light-years ahead of us.

The researchers noted that this will not help expedite the search for alien civilizations, but does lay out a new area for research. The nearest star to our solar system is four light-years, or 24 trillion miles, away. This would make interstellar communication and exploration significantly easier. Interstellar means from star-to-star.

The reason DiStefano wants us looking at globular clusters is that the culture of spaceflight for an intelligent species that evolved there would be radically different from our own. “Sending a broadcast between the stars wouldn’t take any longer than a letter from the U.S.to Europe in the 18th century”, said Di Stefano. So, interstellar travel would take a lot less time.

The findings reveal that it may be possible that space-faring civilizations could be found in globular clusters. So far, only one exoplanet has been located.

So far, from the globular clusters themselves … only silence.

Astronomers might even spot free-floating planets through gravitational lensing, in which the planet’s gravity magnifies light from a background star.