Finding water on Mars is far from a dry topic

The discovery of flowing water on Mars is important and exciting because it’s a step towards understanding, and possibly finding, new life, writes DANIEL PRICE.

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YOU may be bemused by the recent excitement from NASA. Is this really what US taxpayers’ money is used for? What difference does water on Mars make?

For me, it’s exciting not because of this particular new knowledge — we already have a lot of clues about Mars’ warm, wet past (and it’s now occasionally wet present) — but because it is part of a bigger story about the possibility of life elsewhere in the universe.

Science is like feeling your way around a dark room. You bump into all sorts of clues and slowly the surroundings start to make sense. With the occasional flicker of the clapped-out light bulb (a metaphor for science funding) you start to make out the randomly scattered jigsaw pieces and try to put them together.

In the case of Mars, the pieces of the puzzle have come together slowly, but we have a glimpse of how even seemingly inhospitable places like the dusty red planet can support the conditions necessary for life.

Flowing water is the latest in a series of clues about Mars’ ocean-covered past — including sedimentary rocks, evaporating ices and water-carved features — raising the tantalising possibility of something still surviving there in a warm, wet underground pocket.

Sure, it won’t be Little Green Men, but even evidence of ancient bacterial life on another planet would revolutionise our understanding of how life developed on Earth. As you know from the yoghurt ads, some of our best friends are bacteria.

All of this fits into our bigger picture of life elsewhere in the universe. When I left school in 1995, we did not know of any planets other than the eight (or nine, sorry Pluto) orbiting the Sun.

Since then we have detected more than 3000 planets around other stars. Working out the numbers from how many stars we’ve looked at implies that pretty much every other star in the sky probably has planets orbiting around them.

While many of them are nothing like those in our solar system, in the past few years we are discovering more and more planets in the “Goldilocks zone” that could potentially harbour life, suggesting those are also common in the universe. From watching those planets pass in front of their parent stars, we can even learn about their atmospheres, already finding hints of familiar chemicals such as H20 on strange, alien worlds.

In my own field of research, studying the birth of stars and planets, we are getting our first clues that the formation of planets is also commonplace (November last year brought our first picture of a solar system “caught in the act” of formation), again confirming that most stars in the Milky Way should have planets orbiting them. We’ve even taken pictures of some of the alien solar systems by carefully blocking the light from the central star, with many more such images to come.

Narrow streaks on Martian slopes such as these at Hale Crater are inferred to be formed by seasonal flow of water on contemporary Mars. Picture: NASA

But finding more planets around distant stars is not enough to tell us whether life can exist anywhere else. Mars is exciting because it shows that even places we might overlook at first could still harbour life. On Earth we find life in every nook and cranny, no matter how inhospitable it seems — the most surprising being whole ecosystems living on volcanic vents on the ocean floor. If life really did get going on Mars, there is every chance we will find it if we look hard enough (which probably means digging). Some, like physicist Paul Davies, have speculated that life started on Mars in ancient wet oceans and somehow hitchhiked to Earth on meteorites. Far-fetched, perhaps, but it’s a curious idea to think we might find long-lost cousins hidden under a Martian rock.

The other thing about Mars is that, unlike any of the planets around other stars, we can potentially go there and look for ourselves (just pack the shovel). Other places in our solar system are equally tantalising — Titan, for instance, with its lakes and rivers of methane, or Europa’s hidden ocean under the ice — but it’s unlikely that we’ll get there in our lifetimes. While the manned Mars mission has been on hold ever since space Lego went off the shelves — after all, it’s a three-year round trip with all the implied hazards and reality TV-style crew dynamics involved — any discovery that makes it worth the trip is a plus in my book. Remember that a trip to even our closest star would be a 10,000-year voyage.

Dark narrow streaks, called “recurring slope lineae”, emanate from the walls of Garni Crater on Mars. The streaks are hypothesised to be formed by flow of briny liquid water.

Perhaps most of all, the Mars discovery is a reminder of how little we really know. As humans we are curious creatures, exploring our surrounds and trying to understand and map out our place in the universe. Either the Earth is a lonely outcrop in a vast and empty universe or one of billions of life-bearing planets in a galaxy teeming with life. Is there life on other planets? I cannot think of a bigger question worth trying to answer.

I’ll be giving a public talk on this topic on Thursday, October 8, 6.30pm at the Monash University Clayton Campus. See http://moca.monash.edu/outreach/price3.html for details.

Dr Daniel Price is a senior lecturer and Australian Research Council Future Fellow in astrophysics at Monash University