The Last Tree

In around 5 billion years' time, the Sun will exhaust its core hydrogen supply. The core will begin to contract, until it begins to burn helium instead. This new pulse of heat will force the star's outer layers to bloat up, into a vast red giant.

It isn't currently clear quite how big the Sun will get. It will definitely expand as far as the current orbit of Venus and probably as far as the Earth's. Some models send it much of the way to Mars.

Whether or not the Earth is physically-swallowed by the expanding Sun, the results will still be terminal. Here we see the carbonised remains of the last tree, probably having died millions of years before, silhouetted against the bloated Sun. Its shadow falls over a charred landscape of ash and lava.