He’s an origins man, really. Charley Lineweaver, an astrobiologist who works at the Australian National University in Canberra, studies the origins of life, of the earth, of language, and even of cancer. All to answer one simple question that reflects the identity crisis that has haunted mankind for ages: Where do we fit in?

In this case, ‘we’ means homo sapiens. It means the intelligent mammals with big brains that influence the planet we live on so strongly, that we might not be the dominant life form for much longer. We just might ‘think’ our way to our own extinction. But then again, would that be so bad? Lineweaver believes that the universe may be teeming with life that dies out way before it gets the chance to grow big brains, send out radio signals, and build big spaceships. If it would even be interested in those things.

Are we alone?

This weekend, Lineweaver will be speaking at the Fundamentals of Life conference, which brings hundreds of astrobiologists and synthetic chemists to Groningen. Each and every one of them studies the origins of life. On Friday night he will also give a public talk for Studium Generale about that other huge question: are we alone? Because if we are not, as many scientists believe, then where the hell is everybody? Where are the spaceships with technologically advanced aliens? Where are the radio signals that SETI has been hoping to pick up for decades now?

Lineweaver may not have the ultimate answer, but he does have some strong thoughts on the matter. The key problem, he thinks, is that people – including scientists – are mostly interested in themselves. ‘When we ask this question of whether we’re alone, what we really mean is: is there any functionally equivalent of us humans out there?’

‘Our closest relatives live here on earth. If we want to talk to another species, we can. But no one tries to talk to octopuses, or dolphins, or orcas. Even though the brain of an orca is bigger than ours and they use it to talk to each other and maintain a society.’

Instead, humans prefer to look to space, to try to find an alien species that also has big brains and technology. ‘And hopefully, they won’t try to kill us and have knowledge to share. We’re really looking for God!’

Intelligent kangaroos

That we somehow expect to find this advanced alien species is because many physicists believe that evolution favours intelligence. ‘They think there is some kind of intelligence niche that can only be inhabited by one species. And on earth, that species is homo sapiens.’

Not so, argues Lineweaver. ‘Relevant evidence comes from independent experiments. There have been independent experiments to prove this. They are called Madagascar, New Zealand and Australia. In one hundred million years of separate evolution, not a single intelligent kangaroo has evolved! Believing that is brain-worshiping, based on vanity.’

Lineweaver favours a more modest perspective, one that says that the chance we will even find vertebrate life anywhere might be slim, because even on earth 95 per cent of all life is non-vertebrate. For the first two billion years of life on earth, life was not even multicellular: we’re talking bacteria here.

Numbers

But what about the numbers? Astronomers tell us that the universe is so big that it’s highly unlikely life didn’t develop anywhere else. We now know that almost every sun has a planetary system, and hundreds of earth-like planets in a ‘habitable’ zone have already been found. The necessary molecules like water, carbon and amino acids are abundant in the universe as well.

Lineweaver smiles. ‘Yes! There is evidence that life may develop quite easily. On earth it developed very rapidly after the bombardments of meteorites on the surface ended and the earth cooled down. That means that the probability that it would develop was very high. So it follows that it probably has happened on other planets, too.’

Still, he is not starting up his spaceship quite yet, not even to find alien bacteria. Because there is another key factor that has been overlooked so far: not only do you need a planet at a distance from its sun that ensures that the temperature is just right for water to be liquid, you also need a carbonate silicon cycle.

‘Carbondioxyde dissolves in rain and is brought down to the surface as carbonic acid, bringing down the temperature’, he explains. ‘It erodes silicate rocks, weathering them, and forms calcium carbonate that flows into the sea. There, they get subducted and then volcanism brings them back into the atmosphere. The whole cycle is a negative feedback mechanism that stabilises the temperature of the Earth.’

No continents

It works as a non-biology dependent thermostat that keeps the planet from getting too cold and freezing over – like Mars – or from getting too hot and burning – like Venus. However – and here’s the catch – even though life may develop quite easily, even though many planets are in a habitable zone, they probably didn’t have continents to erode during the first billion years of their existence. ‘Earth could be unique.’

That would explain why we haven’t met any aliens. ‘The default might be for life to develop easily and go extinct again quickly, because the planet freezes over, or gets too hot. Life may not be able to control the global environment. It’s just a hypothesis, but one that is consistent with the data.’

Still, Lineweaver is not disappointed about the possibility that we very well might be a small, insignificant freak event in the universe. ‘I keep my expectations low. That way I’m pleasantly surprised, every time we find new evidence of how neat and cool the universe really is.’

Charley Lineweaver’s lecture ‘Are we alone in the universe?’ is at 8 pm on Friday 1 September in Groninger Forum, Hereplein 73. Tickets are available for free. Visit the Studium Generale Groningen website for more information.

Photo Zenit online

In 2012, NASA’s Curiosity landed on the surface of Mars. On board was SAM, a robot that takes soil and air samples and analyses them. Travelling to Mars is still a one-way trip, which means that the Mars lander itself studies the composition of the planet. Dutch astrobiologist Inge Loes ten Kate was one of the brilliant minds behind SAM. She is also one of the speakers at the Fundamentals of Life conference.

On Mars, the robot was looking for organic molecules, which are carbon-based. ‘All known life consists of these organic molecules’, Ten Kate explains. However, SAM did not find any. What it did find were organic chlorine compounds, which means there could be organic molecules on Mars.

Mars in a cabinet

These days, Ten Kate works at Utrecht University. In her laboratory, she recreates the Martian climate in a cabinet ‘the size of a large safe’. Here, she experiments with organic compounds that have been found on meteorites and asteroids. She studies whether these compounds could become substances that could ultimately create life under Martian circumstances.

Does she think there is life on Mars? ‘If I was convinced it was impossible I wouldn’t have started this research. But I’m not trying to prove that it does or ever did exist. I’m using Mars to see if it can teach us anything about the creation of life in general.’

Three and a half billion years ago, the first cells started crawling around on earth. ‘Around that same time, there were areas on Mars where the circumstances were the same as here on earth’, Ten Kate says. ‘So the big question is: was there life on Mars? And if there wasn’t: what did earth have that Mars didn’t?’

No fun

‘If there was life that has since adapted, it is probably underground in caves’, Ten Kate says. This is because Mars has undergone a transformation in the past 2.5 billion years. For one, the atmosphere disappeared. ‘This was caused by a number of things. For instance, Mars lost its magnetic field, which blocked much of the sun’s radiation. Not only is that radiation harmful to possible life, it also bounces molecules off the atmosphere.’

Moreover, Mars’ low gravity meant it had a hard time holding on to molecules, while fewer gases were released, and volcanoes stopped working. ‘Right now, living on Mars would be no fun at all.’

The loss of atmosphere led to an extreme difference in temperature during night and day: a difference of approximately one hundred degrees Celsius. It also means gases don’t hang around and almost all the water evaporates. We say almost, because there is a little bit of water left in Mars’ air. ‘At night, it freezes to become a bit of white frost, you can even see it’, she says. When it thaws in the morning, it is liquid for a short period of time. ‘It’s possible that might help any existing life.’

Ten Kate’s research into other planets will ultimately teach us more about ourselves. ‘For example, we now know that every planet had an atmosphere in its early years’, according to Ten Kate. Even if we never find life on Mars, or elsewhere, the study into extraterrestrial life still reveals the secrets of our own genesis.

Few things are as complicated as a living cell. They consist of a membrane, made of a fatty tissue. They contain proteins, saline, amino acids, DNA, and much, much more. Together, all those substances create a system that allows the cell to process nutrition, to grow, to divide, and to start all over again. All life is cell-based, but how exactly these cells work is still a mystery.

‘They are a black box’, Bert Poolman admits. The biochemist has close ties to the Origins Centre, which was recently awarded a 2.5 million euro grant to help them find out the origin of life. He will be speaking at the Fundamentals of Life conference. ‘There are too many elements influencing each other.’

So he decided on a different approach. Instead of taking a complex cell and figuring out how it works – the so-called top-down approach – he went the other way: to try and create a working cell from as few molecules as possible – the bottom-up approach. This allows him to keep an eye on every single step.

Should Poolman and his colleagues succeed, they will have found the holy grail of physical sciences. ‘We’d be crossing over from chemistry into biology. We’d be creating life.’

Unpredictable

But it is not that easy. Even a basic cell is immensely complicated. Poolman has been studying how cells get their energy for ten years: he is trying to figure out how a cell ‘eats’, and how to ensure that this reaction continues once it starts going. For chemists, this process is not self-evident. ‘A chemist will put reactive molecules together until they stop reacting. But when it comes to cells, equilibrium is equivalent to “death”.’

In addition, a cell is a different environment from a test tube. Molecule behaviour in a test tube can be predicted, but in a cell, they display ‘emergent behaviour’, which can’t be predicted. ‘A cell is filled to the brim’, Poolman explains. ‘We still don’t understand how everything in a cell relates to each other.’

At one point, he had created a cell that appeared to be working quite well. That is, until Poolman discovered that the cell was suffering from acidification, because ammonia was leaking out and the leftover acid protons remained. ‘This has never been discovered to happen in living cells.’ This meant he had to go looking for another solution. ‘It just becomes increasingly complex.’

Nevertheless, he recently reached an important milestone. He succeeded in building an energy system that continues on its own, using fewer than ten reactions. He also succeeded in blowing up the cells, which is the first step towards cell division.

A piece of the puzzle

But he will need to do more than that. ‘In terms of complexity, we are now at the limit of what we can comprehend’, he says. ‘So now we’re creating computer models to help us predict what will happen, which we can then test.’

In addition, he will have to start combining his work with that of his colleagues. Poolman’s group is merely studying one piece in a much bigger puzzle. His Groningen colleague Arnold Driessen, for example, is working on synthesising the fatty tissue that makes up the cell wall, and Cees Dekker, from Delft, is working on the molecules that will make the cell divide. They will both need Poolman’s energy system.

Poolman hopes the real living cell will be created in ten years’ time. ‘But this will provide PhD research material for hundreds of research assistants. I call it our “man on the moon” project. In 1961, the Americans announced that they wanted to put a man on the moon within the next ten years. That project suffered a lot of issues, but there was a clear, common ambitious goal. Just like there is with this project.’