Even if intelligent aliens exist they may never achieve space travel like us, research says

Even if intelligent alien species exist, the physical constraints posed by some planets may prevent them from traveling to space, a new study says.

The research article in the Journal of the British Interplanetary Society assessed the possibility of alien civilisations living in other worlds, and the factors that may govern their ability to explore space.

It looked at the influence exerted by a planet’s escape velocity in allowing a species to launch into space and explore its Solar System.

For instance, the Earth has an escape velocity of 11.2 km/s (kilometres per second) which is over 40,000 kph – and is the speed a rocket should attain to escape from our planet’s gravitational pull.

Most super-Earth planets identified in recent studies as potential candidates for hosting alien life have much higher masses and gravity.

These planets may have up to 10 Earth masses, meaning any intelligent alien civilisation living on them may have to deal with much higher escape velocities.

“It could therefore be the case that an intelligent species on these planets would never be able to travel into space due to sheer physical impossibility,” Elio Quiroga, the study’s author and a professor at the Universidad del Atlántico Medio in Spain, said.

In the research, Dr Quiroga calculates the likely escape velocity for some known planets outside the solar system, and introduces a measure called the Exoplanet Escape Factor (Fex).

The research argues that space travel would be unlikely on a planet with a Fex value of 2.2.

“Values of Fex greater than 2.2 would make space travel unlikely for the exoplanet’s inhabitants,” the study noted.

“They would not be able to leave the planet using any conceivable amount of fuel, nor would a viable rocket structure withstand the pressures involved in the process, at least with the materials we know,” Dr Quiroga writes.

Not only leaving super-Earths, but re-entry of spacecraft would also pose significant challenges.

Some other type of planets where life has been speculated to likely exist are what Dr Quiroga calls “fishbowl worlds” where species may exist in oceans.

In such an ocean world, he says, unaided communication across vast distances may happen much more easily similar to how whales share information on Earth.

An intelligent species living in such a world may not be challenged to create communication devices, the study argues.

“Telecommunications technology might never emerge on such a world, even though it could be home to a fully developed civilization,” Dr Quiroga writes.