By Jude Holmes
On 18th February, NASA celebrated a big win. After a seven-month voyage across the solar system, the Perseverance rover (lovingly nicknamed Percy) landed safely in the Jezero Crater. Percy’s nearest neighbour is the Curiosity Rover (a geologist, famous for singing happy birthday to itself), a mere 2,300 miles away. Armed with a drill to take samples for a future pick-up and holding onto the Ingenuity helicopter – watch out for the first attempt at flight in early April -, Percy’s job is to search for habitable conditions and life on Mars. But what does that mean? Today we tackle the potential of life, Jim, but not as we know it.
The famous line from Arthur C. Clarke, “Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.”, might steer you towards blissful ignorance and away from the rest of this article. However, for the brave among you, buckle up because here comes some theory.
While You’re Here…
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The Goldilocks Effect
You may recall from your school days that Earth is one of eight (with apologies to Pluto) planets in the solar system, and astronomers have measured lots of stars and concluded that our sun is a bit on the small side. Surely something must be out there, right? The thing is that most planets aren’t suitable for the diverse, vibrant life that we see on Earth.
Our planet’s lonely-hearts ad for space might read a bit like this: carbon based, enjoys water, oxygen and ambient temperatures within a fairly small range, best placed under an ozone shelter from ionising sun rays.
There’s a narrow window of orbit around a star that contains those kinds of life-holding atmospheres, and we call that range of suitability the Goldilocks effect – not too hot and not too cold. Scientists are currently searching for and marking these for future research – it might even dictate where we send future rovers. Earth is the gold star for this, but when looking elsewhere in the solar system, Mars is our next best bet.
Ground Control to Major Tom
There are three main theories about where we are now. The first is that we are the most advanced species in the universe. Therefore, no one is looking for us. Rather, we are the ones looking for others.
Second is that there are other similarly developed species, but they are too far away, either by billions of years or by technology, or both. We haven’t even put a human at the edge of the solar system yet, so there’s a long way left to search.
The third option is that there exists a more advanced species than our own, they might even know about us, and they’re just keeping their distance. That might be because we aren’t worth their time, we don’t have valuable resources, or they’ve simply seen the state of us.
Life on Mars
On Earth, we’ve got a huge range of what constitutes life. From tiny bacteria to whales, trees, sea snakes, ants, monkeys, seaweed, rabbits, donkeys, ladybirds, roses, kingfishers, frogs and everything in-between and unknown are all examples of ‘life’ and yet look nothing alike.
When we’re looking for life on Mars, we aren’t really searching for holidaying clangers or little green men. Rather, we’re searching for tiny bacteria – and we’d be very excited to find some. Especially following this research from NASA which suggests that complex life is much less likely than previously thought.
“It’s life Jim, but not as we know it“
There’s another part to this that feels a little like a modern Frankenstein story. We’re carbon-based, which is handy as carbon has four potential bonds with a given atom to form molecules. This allows carbon to make the complex chains which form our basic building blocks called amino acids which make us – nature’s version of a Lego set if you will.
All of our assumptions about finding life are based on this idea of carbon-based life forms. However, carbon isn’t the only element with this property. Some of the candidates are unlikely, as the lower down the periodic table you go, the heavier elements get and their relative rareness is linked to that. It also changes their reactivity and interaction with other elements which might mess up life systems. However, silicon is being touted as a likely option and researchers are currently trying to determine if this is possible.
Closer to Home
Occasionally, it seems that evidence just turns up on our doorstep. Meteorites land on the Earth’s surface all the time, giving us an insight into the kinds of organic material that may have helped form life. While the debunked conspiracy theories of Area 51 (and even 52) and Roswell continue to dominate, unexplained evidence such as the Wow! Signal recorded in the 70s continues to intrigue scientists.
There’s an ethical discussion behind this search too; if we do find life, are we ready for it? In the wise words of Spock, “you may find that having is not so pleasing a thing as wanting. This is not logical, but it is often true”. Space might just be the most high-stakes blind date of all time. So if we want to “make contact”, let’s hope they like us too.
Jude Holmes is a staff writer at The International. Find her here on LinkedIn.