A reader asks whether the stars are still there

A reader wrote to me this week with a question she said had been sitting in her since she was a child. Is it true, she asked, that the stars we look at have mostly died already, and that what reaches us is only their light, still travelling, a sort of postcard from something that is no longer there. She had read it somewhere, the way we all have, and it had lodged in her as half sad and half beautiful, which is exactly the kind of idea that stays.

I love this one. I have loved it since I was small myself. So it costs me something to tell you, as gently as I can, that for almost everything you can see with your own two eyes on an ordinary night, it simply is not true.

Nearly every star you can pick out without a telescope is a neighbour. The great majority sit within a few hundred light years of us, and even the far ones run to a couple of thousand at most. That means the light landing in your eye tonight left them somewhere between a handful of years and a long human age ago. And stars of the sort you can actually see live for millions, often billions, of years. Set those two numbers beside each other and the arithmetic turns quietly reassuring: the star whose light you are catching now is, in almost every case, still out there, still burning, getting on with the same business it was busy with when that light set off.

There are exceptions, and they are worth knowing, because they are grander than the myth. On a dark night you can find a faint smudge over towards Andromeda. That is not a star but a whole galaxy, and its light has been crossing the dark for around two and a half million years. Look at it and you are genuinely seeing deep into the past, at something that set out before there was anyone here to look back. But that is a galaxy of hundreds of billions of stars, not one guttering ember, and it is still there too.

The light is old. The star is present tense.

What I would offer the reader, and you, instead of the graveyard, is this. The sky you stand under is not a museum of the dead. It is a room full of the living, seen at a slight delay. And here is the part I find genuinely strange and lovely, out on the back step with a mug going cold in my hands: no two stars in your sky are showing you the same moment. One is a decade old, one is four centuries, one is a thousand years. You are looking at a single picture stitched together out of many different nows, and your eye assembles it into one calm evening without complaint.

So the next clear night, go out and pick a star, any one, low or high. Hold in your mind that it is out there at this very moment, doing what it was doing when its light left, and will most likely still be doing it long after you and I have stopped wondering about it. That is not a postcard from the dead. It is a hand held up across an enormous distance by something that is, right now, alive.