Life could flourish on distant exoplanets eerily similar to Earth

2 Aug 2018

Image: Sing5pan/Shutterstock

The latest search for exoplanets in the universe has seen us come across a group of planets that appear to be very similar to Earth.

The seemingly endless search for life elsewhere in the universe is starting to look like it might finally have an end in the near future if recent discoveries on Mars are anything to go by.

Farther out into the cosmos, a recent discovery by a team from the University of Cambridge and the Medical Research Council Laboratory of Molecular Biology (MRC LMB) has identified a series of planets that could look very similar to our own.

While we can’t observe their actual physical appearance as we can with other planets in the solar system, we are able to tell that their chemical composition is very similar to Earth.

Entering the abiogenesis zone

In a paper published to Science Advances, the team said the chance of life developing on a rocky planet similar to Earth is intrinsically linked with the type and strength of light given off by its host star.

When a star gives off a sufficient level of ultraviolet (UV) light, it can kick-start a series of chemical reactions that produce the fundamental building blocks of life.

Using this concept, the team has now identified a range of planets that fit this criteria, and that lie within the ‘Goldilocks’ range where liquid water can exist on their surfaces.

The researchers have categorised these planets – such as ‘Earth’s cousin’, Kepler-452b – as falling into the abiogenesis zone.

“This work allows us to narrow down the best places to search for life,” said Dr Paul Rimmer, a joint affiliation at Cambridge’ s Cavendish Laboratory and the MRC LMB, and the paper’s first author.

“It brings us just a little bit closer to addressing the question of whether we are alone in the universe.”

Dabbling in ‘dark chemistry’

This latest research follows on from previous work conducted in 2015, which proposed that the deadly poison cyanide was one of the key ingredients in the primordial soup that led to life on Earth flourishing.

This hypothesis suggested that carbon from meteorites reacted with nitrogen in the atmosphere when hitting Earth, creating hydrogen cyanide.

As UV light was used to create the chemical reactions necessary to test it in the lab, Rimmer went about seeing whether this reaction would happen when the lights were switched off.

As it turned out, the ‘dark chemistry’ experiment run with hydrogen cyanide and hydrogen sulphite resulted in an inert compound, incapable of spawning life.

“There’s an important distinction between what is necessary and what is sufficient,” Rimmer said.

“The building blocks are necessary, but they may not be sufficient; it’s possible you could mix them for billions of years and nothing happens. But you want to at least look at the places where the necessary things exist.”

Colm Gorey was a senior journalist with Silicon Republic