The Search for Life on Mars
"Yet across the gulf of space, minds that are to our minds as ours are to those of the beasts that perish, intellects vast and cool and unsympathetic, regarded this earth with envious eyes, and slowly and surely drew their plans against us."
These iconic words open War of the Worlds, written around 125 years ago by H.G. Wells, who was born just down the road in Bromley. This tale became famously associated with Orson Welles' 1938 radio broadcast, which caused widespread panic in the US.
Today, no one seriously entertains the idea of complex life on Mars, and even the prospect of simple life seems unlikely. The intriguing question addressed in Professor Andrew Coates’ excellent talk was whether life once existed there. Mars, after all, was - albeit for a 'brief' time - a more hospitable planet.
Celestial Highlights for December
Before Andrew's talk, Mike Meynell provided a fantastic tour of the upcoming month's night sky. Jupiter reaches opposition early in December, presenting opportunities to observe Io transits accompanied by Io’s shadow. After opposition, the shadow will precede Io's transit. Mercury and Venus will also be at their most visible - Mercury reaching maximum western elongation, visible before sunrise in the eastern sky, and Venus achieving eastern elongation, visible after sunset in the western sky. Seasonal highlights include the NGC 2264 Christmas Tree Cluster, the Geminids meteor shower (challenged this year by the full moon), and the ever-photogenic Orion Nebula (M42).
Are We Alone?
The search for life on Mars is part of the ultimate question: are we alone in the universe? Discovering life - or evidence of extinct life - elsewhere in the solar system would revolutionise our understanding of the origins of life. It could help us determine whether life arises easily on different worlds, follows common evolutionary pathways, or might even be seeded from a shared source, such as amino acids originating from beyond our solar system.
Andrew discussed three key 'local' candidates for life: Europa, Enceladus, and Mars. Europa and Enceladus, moons of Jupiter and Saturn respectively, host subsurface oceans in contact with rocky cores, making them strong contenders for harbouring primitive life. Missions like the Europa Clipper and JUICE are critical to this exploration.
Not Always the 'Red Planet'
Mars, half the diameter of Earth, loses heat roughly four times as quickly. Around 3.8 billion years ago, it boasted Earth-like oceans, polar caps, active volcanoes, a magnetic field, and a substantial atmosphere. However, as Mars' molten core solidified, its magnetic field was lost, allowing the solar wind to strip away its atmosphere. Oceans evaporated, leaving the rocky, arid landscape we see today.
The crucial question is whether the relatively brief period - around 200 million years - between the end of asteroid bombardment and the freezing of the core was long enough for life to emerge.
Rosalind Franklin Rover
Professor Andrew Coates also discussed the upcoming Rosalind Franklin mission, in which his team has played a major role, designing the Pancam instrument - the 'science eyes' of the rover.
Andrew provided a fascinating behind-the-scenes look at how missions like this come together, from instrument design and testing to the complexities of relying on third-party launchers. The mission was delayed from 2022 due to the fallout from Russia's invasion of Ukraine, but is now scheduled to launch in 2028, with a landing in 2030. The chosen landing site is Oxia Planum, thought to have once been a beach.
Half of the rover’s eight instruments will help select drilling sites through surface rock analysis, while the other half will collect and analyse samples. Unlike previous missions such as Perseverance, which stores samples for future retrieval, the Rosalind Franklin rover will drill to a depth of 2 metres, avoiding surface radiation effects, and analyse the samples on-site. While fewer samples will be collected, the data will become available much sooner than that from Perseverance, whose samples must be returned to Earth for study.
Thank you, Andrew, for a fascinating talk - roll on 2030!
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