I wondered if people might like to see what it looks like: this picture has an asbestos fibre taken from a biopsy slide – it’s the elongated dark feature in the bottom right quadrant of the image.

The physical length of the fibre is about one hundredth of a centimetre: the original biopsy slide was enormous (about 20Gb) compared with this little bit.

My lab. does lots of work on pictures of this kind, trying to count things like asbestos fibres automatically. Computationally, the “needle in a haystack” simile comes nowhere near the scale of the task.

There are lots of pictures like this one publically available: but Leeds is an international centre for the advanced study of them.

Roger