* Astronomy

What is the smallest possible space in the universe?

Science's ongoing quest to find the smallest possible objects remains tantalisingly incomplete, as physicist Prof Andy Parker explains.
Physics has a problem with small things. Or, to be more precise, with infinitely small things.
We imagine that we can move any distance we like, no matter how small.
The basic building blocks seem to be points, certainly smaller than 0.0000000000000000001 metres across.
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Horizon: How Small is the Universe? is on BBC Two at 21:00 BST on Monday 3 September.

See also Planck length