Question: Hey, what theory do you have that the world will end one day and when? from St Joseph's College pupils Ellen and Lois

Elliot Jokl answered on 15 Jun 2016:

Hello, and thanks for the question!

This mainly depends on what you mean by the end of the world!

If you mean the end of human beings, we might be uncomfortably close! There are over 7 billion people on our planet. A lot of us use up a lot of resources that will run out eventually. Oil is one of the obvious ones, which we need to make petrol and plastics and other things we rely on.

Slightly less obvious, but just as important are minerals that we use for fertilisers to grow food for 7 billion people. Fertilisers usually contain nitrogen, potassium and phosophorus as these are important to help plants grow. There are quite a lot of these minerals around now, but they will get more and more expensive to make as the minerals get harder and harder to find in large enough quantities. We might start struggling with this in as little as a few hundred years.

Clean water might also be hard to get enough of – there is obviously a lot of water in the oceans, but this is very salty and so is not very good for drinking or growing crops.

This is why we need to start being very careful about the environment and how we use our natural resources!

If the population keeps growing, and demand keeps going up and up, we might find we use up all these important things and humanity can’t survive well without them!

As for the end of the Earth, I think the sun is due to explode in a few billion years or so and burn it up. Which is a rather dramatic finish!