Astrobiology: The search for life on Mars and beyond

This post was contributed by Guy Collender from Birkbeck’s External Relations Department.

There might be life on planets other than Earth, but it hasn’t been discovered yet and Birkbeck scientists are playing their part in the search.

This quest, the awe-inspiring enormity of the universe and the Earth’s 4.5 billion-year history were all discussed at a fascinating lecture as part of Science Week.

The talk on Tuesday 27 March was delivered by Dr Ian Crawford, of the Department of Earth and Planetary Sciences, at Birkbeck.

He mentioned how Birkbeck’s expertise is contributing towards the European Space Agency’s mission to land a spacecraft on Mars and drill below its surface. Dr Claire Cousins is involved through her work at the UCL/Birkbeck Centre for Planetary Sciences in the scientific development of the camera for the ExoMars rover.  

Dr Claire Cousins, of UCL/Birkbeck Centre for Planetary Sciences, carrying out experiments in the Arctic. Photo credit: Kjell Ove Storvik

Dr Claire Cousins, of UCL/Birkbeck Centre for Planetary Sciences, carrying out experiments in the Arctic. Photo credit: Kjell Ove Storvik

Crawford began by explaining his life-long interest in astrobiology – the science of trying to find life elsewhere in the universe based on the history of life on Earth. He said: “The Earth, as far as we know, is the only inhabited planet in the universe. What we know about life on Earth must inform our search.”

Life on Earth
A timeline was set out to show the history of the Earth and the slow evolutionary development of life upon our planet.

Following the birth of the Earth 4.5 billion years ago, its surface was bombarded by giant meteorites and its oceans were vapourised for the first few million years. This was followed by the emergence of a warm, wet and rocky planet – all necessary conditions for supporting life.

As a result, micro-organisms were born about 4 billion years ago. The transition from such origins of life to complex lifeforms took many millions of years, with multi-celled animals similar to “jellyfish” only appearing 600 million years ago.

Today there are thousands of planets across the universe that resemble the Earth as it was when it began to support life 4 billion years ago. This fact led Crawford to predict that microbial life might be common elsewhere in the universe, but multi-celled animals and intelligent life might be rare.

Searching for life on Mars
The history of Mars exploration followed, including details about the six spacecraft that have landed on the red planet. The dried-up river valleys on Mars indicate that rivers did exist in earlier times, leading Crawford to suggest that it was an “inhabitable” planet in the past.

He said: “There is no doubt that Mars was a warm, wet and rocky place, exactly the kind of place that life should have evolved upon.” Today’s Mars is inhospitable due to its the cold temperatures (-60 degrees), no ozone layer, and its red, dusty surface.

Despite finding nothing so far, the search for whether Mars supports life now, or ever did in the past, continues. The Mars Science Laboratory robot is due to land on the red planet this August, and the plan is for the ExoMars rover to follow suit in 2018.

Future space exploration
Crawford added that there will be no definitive answers about current or past life on Mars until field geologists step foot on the planet, and this remains years away. In response to a question, Crawford said that sending humans to Mars might, technologically, be possible by 2030 (more likely by 2060), but this would be unlikely because of economic and political considerations.

He also spoke about the need for better telescopes, and other potentially inhabitable parts of the solar system, including Europa – one of Jupiter’s moons – and Enceladus – one of Saturn’s moons.

Extraterrestrial intelligence
The question of aliens was also addressed, with Crawford saying that it is unlikely that extraterrestrial intelligence will be discovered, especially as nothing has been discovered since the search began 50 years ago. Whereas finding multi-celled animals elsewhere in the universe might be rare, finding lifeforms capable of sending technology might be even rarer. He said: “I think the galaxy looks like a quiet place.”

Despite finding nothing so far, Crawford stressed the importance of continuing to search for life in the universe.


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