Why Leave Earth?

I’m often called mad, delusional and insane when I say ‘We need to leave the planet’. People say, the Earth is perfect, the climate is good, there’s water. Yes there are a few natural disasters every now then, but they’re not a major problem. And they’re pretty accurate. The Earth is a darn good home, for now.

Here I want to set out why we should leave the planet, our home, planet Earth and set sail for Mars before moving on far beyond the Solar System.

We all almost weren’t here, almost gone, vanished, extinct. 75,000 years ago almost all the of the human species died out (it’s estimated that only 10,000, or even less, survived). Why? What happened? Quite simply it was a volcanic eruption, not just any eruption but a VEI 8 eruption (the largest on the scale), a super-eruption. We even know which volcano was responsible. It was Toba in Indonesia.

The Lake Toba Caldera – The remains of the volcano

We all, here in Europe, now know that volcanoes don’t just affect the immediate area. We just need to look back to Iceland and that almost unpronounceable volcano ‘Eyjafjallajökull‘. That grounded air traffic for nearly week and affected a vast swathe of Europe.

What’s the problem with these eruptions though? The problem is is that they are Plinian eruptions. That’s an explosive eruption that causes that big pillar of smoke to bellow out high into the sky. In these plumes are lots of gases, as well as ash particles and so on. The nasty gas in here though is sulphur dioxide.

Let’s scale this up. A massive super-eruption happens. Millions and millions of tonnes of sulphur dioxide are thrown high up into the atmosphere, so high in fact that it all gets into the stratosphere. What happens? Well sulphur dioxide is very good at absorbing radiation from the Sun, so good in fact that a lot of it doesn’t reach the surface, and it cools. Not only that, so much stuff would be thrown into the atmosphere that it could blot out the Sun. A normal nice summers day (like this Indian summer in the UK at the moment) would be dark, equivalent to a night with a full moon. Photosynthesis stops.

You can start to see how bad things would get now. Not only that, a lot of the sulphur would mix to form acid rain, killing off yet more vegetation and poisoning animals. Animals and plants start to die, quickly. The world is plunged into a volcanic winter for years or even decades. I for one don’t think we, with all our technology and infrastructure, would cope very well given such a disaster. I think a number of us would survive, but civilization?

What if the volcanic eruption was even worse? Perhaps it was a massive continental flood basalt. 1000’s of times worse than the worst VEI 8 eruption, and lasting for millions of years. These massive lava flows are credited with starting off the dinosaurs demise. They weren’t doing too well 65 million years ago, well on the way to extinction and then just to top it off, BANG, an asteroid. A volcanic nuclear winter. Pretty bad huh.

The thing is all this will happen again. There will be more super-eruptions, there will be an asteroid and there’s nothing we can do about them.

So why leave Earth? Well, for the most practicable reason imaginable…staying alive. By spreading ourselves throughout the Universe we safeguard our species. If there was a catastrophe somewhere, no bother, the species wouldn’t become extinct.

And so we’ll just be fulfilling our basic instincts. Survival.  And we can start now, and we have indeed started now. We are looking for other habitable planets with the Kepler space telescope and many others. We’re sending missions to Mars, learning about the atmosphere, the history, the possible existence of life. One day I imagine we will terraform Mars, and that will be the beginning of the human expansion to space.


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