Jim Al-Khalili: Is There Anybody Out There?

Edinburgh International Book Festival

On 24 August 2017

Review by David Chadderton

In his book Aliens: Science Asks: Is There Anyone Out There?, Jim Al-Khalili has assembled writing from leading experts in several different fields to apply their specialist subjects to the question of whether life may exist elsewhere in the Universe.

Questioned on stage by Bob McDevitt, he traced the current serious search for extra-terrestrial life to Enrico Fermi's question, while working on the Manhattan Project at Los Alamos in the 1950s, in a conversation about UFO sightings, "where is everybody?"—this became known as the Fermi Paradox.

Frank Drake, one of the founders of SETI, the Search for Extra-Terrestrial Intelligence, created the Drake Equation to calculate the likelihood of there being alien life, which was then refined by Sara Seager, one of the contributors to the book.

Al-Khalili said the discovery of life on an exoplanet (a planet not part of our solar system) would be the greatest discovery since Copernicus and Galileo showed that the sun didn't revolve around the earth.

NASA's new James Webb telescope is to be the successor to the Hubble, which can learn about the chemical elements that are contained on planets using spectroscopy. It is assumed that life elsewhere will probably be carbon-based as carbon is the most useful element for building complex molecules.

In our own solar system, Saturn and Jupiter and their moons are being examined as they have magnetic fields and therefore have the energy to melt ice into liquid water, which may give opportunities for life to exist below the surface even of a frozen planet. He mentioned Enceladus, Cassini and Europa.

It is still thought by many that there may have been life on Mars in the past, even if there isn't now. Any life that is found, past or present, is most likely to be single-cellular forms like bacteria rather than multi-cellular, let alone sentient. However he said he finds it hard to believe that life doesn't exist somewhere else in the Universe.

Aliens by Jim Al-Khalili is out now in paperback.