Written for Skoda’s “The Mind Behind” series for BBC Culture
It’s a long way from Brisbane to Los Angeles, 11,559 kilometres to be exact. To Australian astrobiologist Dr Abigail Allwood it’s a relatively short distance to consider in her line of work.
After all, she’s grown accustomed to planning her work around the distance to Mars. Our large red neighbour fluctuates in distance from Earth at about 50 million km at its closest orbit, to about 400 million km when it’s on the other side of the sun, slightly further than a 12-hour flight, in other words.
Now stationed at NASA’s Jet Propulsion Laboratory in Pasadena, California, Dr Allwood is one of seven scientists tasked with finding evidence of life on Mars via the next Mars Rover, due to be launched in 2020. As a world-leading astrobiolologist, she’ll be looking at rock samples with an instrument known as PIXL (Planetary Instrument for X-Ray Lithochemistry) that measures the chemicals in rocks at high spatial resolution.
While her career trajectory has carried her to the peak of science and space exploration, Dr Allwood’s launching pad to becoming an astrobiologist was an unexpected one. As a young girl in Brisbane, she took great delight in peering at the night sky through a telescope and enjoyed reading science fiction novels, but a path to a career in space seemed as far-fetched as the planets themselves.
She had found conclusive evidence of some of the earliest known life on Earth, dated at about 3.43 billion years old."
Primitive Ponds
“Growing up, I had absolutely no idea what sort of careers even existed for becoming involved in space exploration. Stupidly, I decided to study physics initially, thinking I’d become an astrophysicist but I had no idea how much maths would be involved so I dropped out of that fairly quickly.”
It was in one of Dr Allwood’s early electives in geology, however, that she rediscovered a passion for the natural world and ultimately settled on a new quest in understanding the origins of life on Earth. She revelled in the opportunity to spend time outdoors doing fieldwork and exploring new locations, an element of geological study she still loves.
The ability to grasp a very deep sense of time was the aspect Dr Allwood found most fascinating, as she pondered events millions, and even billions, of years ago through the physical evidence she found herself regularly inspecting.
Her big career breakthrough came while studying rock formations in the Pilbara region of Western Australia as part of her PhD with the then newly created Australian Centre for Astrobiology. In an area hundreds of kilometres inland, Dr Allwood was surprised to find the remnants of an ancient shoreline.
“One of the slopes of a ridge that I was walking up had eroded and exposed what had once been a beach. There was a beautifully planed off surface that had actually preserved the ripple marks of waves that had moved the sand around.”
It was, however, the fossil stromatolites (formed by ancient communities of microbes) Dr Allwood found on the nearby ancient reef that made her the toast of the scientific community in 2006. Through the correct identification of seven different stromatolite fossils, she had found conclusive evidence of some of the earliest known life on Earth, dated at about 3.43 billion years old.
It’s widely understood this period was when Mars and Earth might have shared similar characteristics for supporting life. Mars is now completely unhospitable, and has been for most of its history, but Dr Allwood says there was an early period of a few hundred million years where conditions were not unlike the early Earth.
“We know there were at least decent-sized lakes, if not an ocean at that time, which is the sort of environment we know for sure that life could have existed in. The question is, were those habitable conditions on Mars around long enough for life to have gained a foothold?”
What I still find absolutely amazing is that this will be the fifth Rover to land on Mars, so I’m working with an organisation that’s become accustomed to regularly landing spacecraft there."
Miracle mission
Sending a Rover to Mars is an incredible undertaking on its own, so finding the ideal location to study the right rock formations presents its own unique challenges. Dr Allwood has seen enough from her colleagues at NASA, however, to have full confidence in their ability to get her PIXL instrument to where it needs to be.
“What I still find absolutely amazing is that this will be the fifth Rover to land on Mars, so I’m working with an organisation that’s become accustomed to regularly landing spacecraft there. It’s still incredibly challenging, but there’s a level of sophistication now where we can move beyond just landing and taking a picture, we can actually start doing some more challenging science while we’re there.”
The next giant leap in exploration of the red planet will be to return physical samples extracted from Mars’ surface back to Earth. Like any space exploration project, however, the exact timing of that mission will be determined by the political/financial levers that dictate funding, but Dr Allwood is pragmatic about their chances.
“From what I’ve seen over the years, Mars has never been a political football, so it’s unlikely to become one now. While it would be nice to be achieve everything tomorrow, you do need to be realistic in terms of budgeting the miracles out over a timeline.”
Dr Allwood is no stranger to putting things into perspective, especially considering the increments of time she measures for her day job. When asked how she’s able to mentally frame such gargantuan time periods, she offers a simple analogy.
“The way I explain it to my daughter, if you look at the length of your arm as the length of time that Earth’s been in existence, starting at your shoulder, it’s not until you get down to about your hand or your wrist that even microbial organisms appear. Then, it’s not until you get down to a scrap of your fingernails that represent the entire existence of humans on Earth.”
While the majority of us are content to merely imagine the possibilities of finding life on other planets, Dr Allwood would rather not dabble in the imaginary. Her answer to one of the biggest questions in human history reveals her determination: is there life on Mars?
“We definitely know there’s a possibility that life could have existed on Mars. But we don't know that it did. And that, to me, is motivation enough to go and find out.”