Extraterrestrial life

 

I think a lot about time and eternity and recently got into conversation with a pupil at Giggleswick School provoked by thoughts I shared on Remembrance Sunday. I was asked what my thoughts were about the apparent absence of extraterrestrial intelligent and sophisticated life and where would I think the barriers preventing the emergence of a highly developed alien species would be located between the existence of dead matter and the rise of an interstellar civilisation? This got me thinking some more, hence this blog. Picture from Herstmonceux Observatory.

Thinking about intelligent alien life, how probable do we suppose it is? Might we simply be incapable of detecting it or interpreting signs of it? Might extraterrestrials prefer to colonise dark matter or even exist in a physical dimension we can’t access? We know Einstein´s theory of general relativity implicates at least four dimensions and the string theory even suggests eleven dimensions so the barrier to accessing extraterrestrials might be our confines for now in a very parochial ‘stay at home’ space and time.

Nick Bostrom´s Vulnerable World Hypothesis suggests one of the barriers preventing the emergence of highly developed alien species beyond human beings is that the same sort of technologies are likely to be discovered by all forms of intelligent life and they result in their extinction! That’s cynicism par excellence! Like the myth of Icarus coming near this sun and his aspiring wings getting melted off! Picture Jacob Gouwy Peter’s Fall of Icarus 17th century. 

‘Exterminate! Exterminate…’ I’m old enough to remember my younger brother hiding behind the settee in 1963 when the Daleks appeared on the science fiction ‘Doctor Who’ BBC series exploring the universe in a time-travelling space ship called the TARDIS appears as a blue British police box common in those days. With various companions, the Doctor combats the Daleks and other foes saving civilisations over a cosmic sphere. Science fiction becomes fact so often but over 60 years we have yet to find extraterrestrials.

Screen shot of the screensaver for SETI@home, a project in which volunteers donate idle computer power to analyze radio signals for signs of extraterrestrial intelligence. The search for extraterrestrial intelligence (SETI) is a collective term for scientific searches for intelligent extraterrestrial life, for example, monitoring electromagnetic radiation for signs of transmissions from civilizations on other planets. This investigation began shortly after the advent of radio in the early 1900s, and efforts went up a gear from the 1980s.

In June 2021 the BBC reported on a US government report on UFOs (unidentified flying objects) after numerous reports from the US military of vehicles seen moving erratically in the sky. It saw the US military and US political leadership go from extra-terrestrial-sceptic to ET-curious. Although no earth-shattering revelations emerged, the existence of a government report on a much-ridiculed issue shows how UFOs have beamed out of the realm of purely science fiction pop culture and into the world of US national security. 

I enjoyed reading April 2022’s Astronomy Now which profiles the ‘earths’ of the star Proxima Centauri, exoplanets detected in the nearest neighbour to our solar system. The discovery of exoplanets gets us thinking more optimistically about extraterrestrial beings. The four planets discovered look to be orbiting in Proxima’s habitable zone so liquid water, prerequisite for life on Earth, might exist on their surfaces even if there are many other factors serving planetary habitability. 

Part of artist Michael Carroll’s imagined surfaces of Proxima b, one of four planets now known to orbit the closest star to the sun, Proxima Centauri, copied from April 2022’s Astronomy Now. It is calculated that this planet may rotate in a habitable zone around its coolish red dwarf star. How earth-like might Proxima b be? Water-rich or rocky? We have a mass estimate of the order of that of Earth, calculated from wobbles in its mother star. How large Proxima b is links to its density, one of many unknowns, even if the discovery of a potentially habitable planet so near to Earth is exciting.

There’s movement on Mars as these pictures show. They are on display at the London Planetarium and were taken by the Hubble Telescope which has played an important role in our exploration of the planets in our Solar System. The contrast shows a global dust storm blanketing Mars in 2001. Images like this reveal weather conditions that future rovers may have to endure. There’s movement on Mars but is there life? Has there been life? 

This artist's impression of seas on Mars in the Science Museum is from 1884. Astronomers thought then that patches they had seen on the surface of Mars through telescopes were huge swathes of vegetation. But in 1965 the Mariner 4 spacecraft returned the first detailed pictures of the Red Planet and showed that the surface actually appeared barren and covered with craters. Missions since then have focused on the search for microbial life, on and beneath the planet's surface.

In June 2021’s Scientific American John Gertz suggests if some UFO sightings are genuine sightings of aliens they must be of robotic probes rather than vessels crewed by biological beings. If nothing else, such beings would be crushed by the g-forces of their purported, very large, accelerations. To succeed, extraterrestrial beings would have to probe millions of promising nearby stars continuously and keep a dedicated receiver for each target star so as not to miss a return message if and when it arrives. 

Our best hope of meeting extraterrestrial life is well away from our own solar system. The individual features in this glorious picture may well contain planets with non-human beings. They would have to be planets not stars as life can’t live in or close to such fiery matter only in cooler lands circulating at a distance from stars. The picture of star cluster Westerlund 2 at London Planetarium was taken 2015 by the Hubble Telescope using both visible and infrared light.

‘Bigger is still better’ was the picture caption at London Planetarium contrasting the sizes of the new James Webb Space Telescope and the Hubble Space Telescope. The second picture details its sunshade. James Webb was launched on Christmas Day and reached its orbit, beyond the Moon, in late January 2022. Its large mirror will allow us to see further into the distant cosmos than ever before. A step nearer to discovering extraterrestrial beings?