The problem is that alien societies don’t exist for as long as signals need to travel in space, reports Science Alert.

New estimates provide an update of the famous Drake equation from 1961 – a method for calculating how many alien civilisations exist.

Named after US astronomer Frank Drake, it draws on variables such as the yearly birth rate of stars, the number of habitable planets and the odds of alien life developing.

Using these and other factors, the equation calculates the likelihood of receiving signals from beyond Earth.

A model of signal spread. (arXiv.org)

But the newly-crunched numbers don’t look promising for finding alien life.

“If the civilisation emitted from the other side of the galaxy, when the signal arrives here, the civilisation will already be gone,” researcher, Claudio Grimaldi from the Federal Polytechnical School of Lausanne in Switzerland, told Science Alert.

The scientists surmised an alien society would last 100,000 years – the time span it takes light to cross the galaxy. But the study found even a civilisation existing that long can only fill a small portion of the galaxy with signals.

For the past 80 years, signals have been sent out but they have only covered less than 0.001 percent of the Milky Way.

And further diminishing the chance of finding living aliens, one of their civilisations would need to be within 50 light years for us to have heard back from them at this time, the study found.

Despite the scientists’ efforts, the question remains whether lack of contact with alien life is because no one is out in space, or because Earth has next to no chance of hearing from them.

Source: 9 News