Yes, really, there is such a thing, and it is important to science fiction. Here’s why.

Whenever we discuss the possibility of life on other planets, or even the likelihood of finding other, albeit empty, Earth-like planets in other solar systems, we are very short of actual data. Telescopes are now doing a wonderful job of discovering Jupiter-like planets orbiting other stars, but small, rocky planets like ours are much harder to see.

This is where the archaeology comes in. The evolution of stars is a well-studied part of cosmology. We know that one day our own sun will probably end up as a white dwarf. For us that’s far in the future, but many white dwarf stars already exist in our galaxy. If they were once surrounded by a collection of rocky planets like Earth then some evidence of the existence of those planets should still be visible.

That is the theory behind a study by a team of astronomers headed by Dr Jay Farihi of Leicester University. Their fascinating conclusion is that at least 3%, and possibly as many as 20%, of all white dwarf stars studied once had rocky planets circling them. Obviously those planets may have been more like Mars than Earth, but it is still a very promising sign.