By Dr David Whitehouse BBC News Online science editor

These are the most detailed pictures ever taken of the surface of the Sun. They have been described as a breakthrough in observational solar physics.

They were obtained by the new Swedish 1-metre solar telescope on the Canary Island of La Palma. The images show new solar features and hitherto unknown details in sunspots.

Catching the Sun's rays

A striking feature in the images of sunspots is the existence of dark cores within bright filaments. This is an unexpected discovery and astronomers are uncertain what it signifies.

Published in the journal Nature, the new observations realise a long-stated goal for solar observers to see the solar surface at a resolution better than 100 kilometres.

It is believed that fundamental processes in the Sun's atmosphere take place on such scales.