Why life on Mars could be a bad omen for humankind

Why life on Mars could be a bad omen for humankind

An illustration of NASA’s Perseverance rover operating on the surface of Mars.CREDIT:NASA/JPL-CALTECH

By Liam Mannix

What if finding life on Mars is a bad thing?

A small robot touched down on the red planet this week, the latest to hunt for life there. Perseverance is now sitting in the bowels of the Jezero Crater, which NASA thinks was once a river delta.

Just about everyone is hoping Perseverance will find life. Everyone except Oxford University philosopher Nick Bostrom. “I would find it interesting, certainly – but a bad omen for the future of the human race,” he wrote in the MIT Technology Review.

“I hope that our Mars probes discover nothing. It would be good news if we find Mars to be sterile. Dead rocks and lifeless sands would lift my spirit.”

To understand why Bostrom is concerned – and why you might be too – we need to dive into the science of alien life.

Mars today is hostile to life as we know it. The planet’s average temperature is minus 62 degrees. The atmosphere is too thin to block harmful ultraviolet radiation. There is no oxygen to breathe.

But Mars billions of years ago was different. The planet had running water, which has left streams and lakes carved into the dry surface. The planet’s atmosphere once was thicker, possibly keeping it warm and protected. It probably had surface springs filled with hot water – one of the potential starting points for life.

“It has what appears to be the ingredients for life, early in its history. It has volcanic heat. It has rocks with silicon and carbon. And it had surface flowing water. And those are the ingredients we think are really important for getting life started on Earth,” says Professor Martin Van Kranendonk, director of the Australian Centre for Astrobiology. “As far as we know, it is certainly the best candidate at the moment.”

Van Kranendonk would dearly love to find life there. “It would be unbelievably exciting, and would really help firm our place in the universe,” he says.

But let’s zoom out for a moment, so we can see where Bostrom’s fears are coming from.

There are somewhere between 100 and 400 billion stars in our galaxy, the Milky Way. And by scientists’ best estimate, there are hundreds of billions of galaxies in the universe.

We now know that nearly every star has at least one planet. It seems mathematically impossible for complex life not to exist elsewhere, right?

Modern humans evolved just 200,000 years ago, barely a blink in the eye of the 13.8 billion-year-old universe, yet we’re already working on interplanetary colonisation.

One of the drawings for spaceship concepts in the original Alien movie, by film designer and artist Ron Cobb. The movie imagines a future in which humans have mastered deep-space exploration.
One of the drawings for spaceship concepts in the original Alien movie, by film designer and artist Ron Cobb. The movie imagines a future in which humans have mastered deep-space exploration.

It would seem aliens have had plenty of time to colonise the galaxy.

There should be aliens. As far as we can tell, there aren’t. This is called the Fermi Paradox, after the Nobel-prize winning physicist Enrico Fermi, who stated it more simply: where is everyone?

Maybe it’s that space travel takes a lot of time. The distances are vast and spaceships can travel no faster than the speed of light.

“The universe is a big place. You talk about looking for a needle in a haystack,” says Van Kranendonk.

But a ship travelling at light speed would take only 200 million years to cross the entire galaxy. Even travelling at 10 per cent of the speed of light we could make it to a nearby star in just 88 years.

Maybe, argues Van Kranendonk, the universe has only now filled up with enough heavy elements (such as iron, arsenic and gold) to support life. Or maybe colonising the galaxy is much harder and more expensive than we expect?

NASA has unveiled new footage of the Perseverance rover landing on Mars.

“We’re pretty happy if we can get a person to Mars. It takes billions of dollars to send a single rocket. Think about the resources needed to colonise planets,” says Van Kranendonk.

But consider how much progress humanity is likely to make in the next 1000 years. A civilisation that is only 10,000 years older than ours could be magnitudes more advanced.

So, where is everybody?

Astronomers have lots of theories. But here, I want to focus on just one: the great filter. This is the answer to the Fermi Paradox that gives Bostrom the shivers.

If we accept alien life should exist, and it has had plenty of time to colonise our galaxy, the question becomes: what is stopping it?

Is there some great limit – a great filter – imposed on life that stops it colonising the galaxy?

Perhaps there is something exceptionally difficult about going from basic life to complex, intelligent life? Perhaps life gets stuck somewhere along the way?

“There are millions and trillions of reactions required to get some of even the fundamental components of life. We have not been able to do even the simple things in the lab. To get even the most primitive life, it is an unbelievably complex series of reactions,” says Van Kranendonk.

If that’s the case, good. We won’t find life on Mars, because life is exceptionally, exceptionally rare, and we somehow lucked out. Intelligent life is probably exceptionally rare.

But what if we do find life on Mars? That suggests the great filter is in front of usIt means life is common across the universe – but something is keeping it from building interplanetary civilisations.

What if countless alien civilisations have got to where we are before and then been wiped out by something? An asteroid, perhaps, or a species-exterminating nuclear war, or runaway global heating?

If we find life on Mars, you’ve got to wonder: what is that great cataclysm that stopped other alien races from colonising the stars – and can we survive it?

This article originally appeared in The Age

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