When you look around you, almost everywhere on earth, you see life. The earth seems extremely supportive of life: we see it in the air, in the water, in the land and even deep underground.
But was it inevitable? We know that there have been mass extinction events in the past, some of which have taken down most of life on Earth. However, since life began and spread on earth, there has been no event completely eradicated life. Natural! Otherwise we would not be here to reflect on it.
Yet it is interesting. This means that, despite some temporary events that are seriously unsuitable, the Earth’s climate has remained relatively stable for 3-4 billion years.
This is also strange. We know that stars like the sun get warmer as they age, and that the sun was about 30% fainter a long time ago. This means whether the ancient earth should have been solidly frozen, or, assuming it was a clamp, the earth would now have to be warm. None is true, which is a mystery.
This is called the Faint Young Sun Paradox, and has prompted many scientists to assume that the Earth has some kind of thermostat, a set of conditions that tend to balance a system that breaks down so that it does not get too hot or too hot. do not get hot. cold. This would be a negative feedback system, and if there is a condition to heat the earth, for example, things will change to cool it down again.
But we know that there are also positive feedback conditions. If you release too much carbon dioxide into the air, the oceans will heat up, releasing more CO2, and you get a feedback loop that ends badly. As we see now. And if there is too little CO2 in the air the earth would be solidly frozen.
So maybe we are just happy and our environment happens to have remained stable for all the centuries that life has existed.
So is it accidental or by mechanism? Or both?
To find out, a scientist performed a clever experiment. He created a simulation of 100,000 planets (!!) where each received a set of random feedbacks from the climate, some negative and others positive, and followed their temperature for 3 billion years – no other variables (for example water content or breathing)) was simulated. For simplicity, he just wanted to see if a planet could maintain a habitable temperature for a long period of time, as the earth did.
To be clear, the simulation feedback was not based on rights such as CO2 in the air; instead he randomly assigned the planets mathematical feedback, strict numerical situations to see what would happen. He also randomly made larger changes to mimic external temperature coercion, similar to things like asteroid impact or supervolcano eruptions.
Each planet sim was then run 100 times, with the variations in it to see what happens to the temperature.
The point here was not to create a complete climate simulation, but to see how big a role chance plays in the habitability of a planet. He tested two hypotheses. Hypothesis 1 is that feedback has no effect, so random fluctuations rule the day; it is just a chance that a planet will remain in a habitable temperature range for billions of years. The second hypothesis is that feedback, whether negative or positive, guarantees either success or failure, by chance no matter.
In other words, he was hoping to see if the feedback from the climate was the reason why the earth had been inhabited for so long, or that we were just happy. A planet is considered habitable if the temperature remained relatively stable during the 3 billion year simulation.
What he found is interesting. Of the 100,000 planets, 9% were successful at least once (and 1400 were successful on the very first run out of 100 runs). Some planets were twice successful, some three times … and in fact, when he looked at 100,000 planets, he had every number between 1 and 100 successful runs.
But only 1 planet had 100 successful runs out of 100. It is a robust planet indicating that nothing could stop it from being a nice place to live (and least of all in temperature).
In general, he considers the conclusion and the random chance to play a role in a planet’s ability to stay within a viable temperature range. Although the success rate varies from model to model, the change of factors over the 100 runs still supported the idea that mechanism and chance play a role.
It seems that fortune benefits the prepared planet.
Can we therefore extrapolate it to earth by saying that it is both the feedback and a random chance that our righteous world retains, justify? If we rewind the tape and the circumstances change a bit, would we still have a livable world to live from?
I would not go that far. This seems to support the idea, but as the author himself said in the newspaper: ‘The simplifications and uncertainties in the model design mean that it has to be unrealistic in some respects. Care is therefore needed in extrapolating model results to reality. ”
In other words, it is a very simple test, and much more complicated needs to be done. After all, the earth has come close to the tipping point a few times, so it’s not hard to imagine a huge asteroid impact or any other factor that makes us dirty. But still, this simulation is an interesting first step!
This makes a prediction: most exoplanets similar to Earth will be uninhabitable, as has happened in most of its test runs. Planets like Earth were the exception. If we find that to be true, it is not so. proof the hypothesis, but support It. And if we really find it is habitable, well, that would be interesting, right?
And that serves as a warning. We do not really know know how robust the Earth is, how well it can hit a hit and keep going to keep going. It has been hit in the past, stunned and shaken things up, but not without some long-term environmental impact. And our own species, our civilization, is currently balancing on a razor. It will not take such a huge hit to cause our innumerable disasters, even if the earth’s ecosystem somehow manages to survive.
I have a lot of problems with people, but I prefer that we do not go extinct. Uncontrolled fiddling with the feedback that is already in place strikes me as a pretty awful idea. The earth may be robust, but we are not.
We need to be more careful. There are reasons why these things are called warning stories.