The Sirens of Mars: Scientist gets up close and personal in search for life on Mars

Science: The Sirens of Mars

Sarah Stewart Johnson

Allen Lane, 288 pages, hardcover €25; e-book £9.99

The Sirens of Mars by Sarah Stewart Johnson

Refined: Sarah Stewart Johnson is a charming guide to the Red Planet

The Sirens of Mars by Sarah Stewart Johnson

Planet Mars.

Refined: Sarah Stewart Johnson is a charming guide to the Red Planet

Darragh McManus Twitter

July 18 2020 02:30 AM

Mars has long been a source of deep fascination for humans. Since ancient times, we have been studying the Red Planet, observing its movements, pondering its nature, speculating. Perhaps most importantly, we've searched it for signs of life.

As Sarah Stewart Johnson points out in this beautifully crafted melange of science and memoir, modern scientific developments created a profound malaise in humanity. Faced with proof that the universe is a cold, indifferent, mostly empty and inconceivably gargantuan place, despair can set in.

Where is the meaning in an individual life, doomed to end, in a cosmos itself doomed to dissipate into nothingness? As Kenneth Williams noted in his diary before killing himself: "Oh, what's the bloody point?" Or as Stewart Johnson more poetically puts it, "We were potentially alone in the enormity of the tenebrous night... This is the affliction of being human in a time of science: we spend our lives struggling to understand, when often we'll have done well just to apprehend." We are, she says balefully but accurately, "a finite tribe in a temporary world, marching towards our end."

One possible route to salvation, and central to Sirens of Mars, would be evidence of life on our neighbouring planet. For her, the search for extraterrestrial biology "is the search for infinity… a hope that life might not be ephemeral, even if we are".

We're fortunate in having a decent candidate so close. Obviously, that's relative - Mars is, on average 225m km away, though can be as close as 50m, depending on orbits. But it's reachable.

For half a century, scientists have been studying Mars from afar and up-close, by sending a variety of probes, rovers and gizmos. Some of these expeditions never, so to speak, got off the ground: landing on a hard surface after travelling very fast is tricky to pull off. But some landed successfully, and have travelled the surface of Mars, analysed samples, taken pictures and sent back a ton of useful data.

And yes, Mars is a decent candidate for life to exist, or at least, to have once done so. It's rocky, like Earth. Not too big and not too small. Not too near the Sun like broiled-alive Venus, or too distant like icy Neptune. It's in the famous Goldilocks zone, just about: biological life may not be likely on Mars, but it is possible.

Most excitingly, Mars has a lot of water - these days, mostly ice - and in the past a lot of liquid water. This is a prerequisite for life. The signs are promising, although a Nasa equivalent of Bertie Ahern might point out, a lot has been done but there's a lot more to do.

Sirens of Mars reaches into the early days of astronomical examination of Mars. We read about the 19th-century belief that it was crisscrossed by canals - proof of intelligent beings! Sadly, it was an optical illusion.

This book succeeds equally well as a primer on Mars, an insight into how cutting-edge science works day-to-day, a contemplation of the meaning of existence, and a vividly rendered autobiography of the author's journey as a scientist. Growing up in Kentucky, she was inspired to search the skies by her parents, especially her dad, and a sequence of supportive teachers and colleagues.

Stewart Johnson, who teaches astrobiology and planetary science at Georgetown University, is a lovely writer and a charming guide: she comes across as modest, refined and sharply intelligent.

Her description of what it means to fall in love is rapturous - and the perfect place to end a review of this singular book: "Despite the vast interiority of any life, there is a place where boundaries can dissolve, the continuity of the self can break, and we blur into the existence of another human being. I felt like those Arctic explorers who went into the wilderness only to find themselves suddenly, shockingly, no longer alone."