The Nobel prize for physics has been awarded to three scientists for experiments that led to the detection of X-rays from outer space and sub-atomic particles from the Sun – the invisible elements of sunshine.

Professor Raymond Davis, 87, of the University of Pennsylvania in Philadelphia, shares half of the £700,000 prize money with Professor Masatoshi Koshiba, 76, of Tokyo University. The other half is awarded to Professor Riccardo Giacconi, 71, of Associated Universities in Washington DC. Professor Davis and Professor Koshiba worked independently to build sensitive instruments for detecting cosmic neutrinos, the unreactive particles emitted by the Sun and other stars during the process of nuclear fusion.

So unreactive are neutrinos that many millions of them pass straight through our bodies every second. Many more stream straight through the Earth without being stopped.

The Royal Swedish Academy of Sciences, which awards the physics prize, says: "This year's Nobel laureates in physics have used these very smallest components of the universe to increase our understanding of the very largest: the Sun, stars, galaxies and supernovae."

Professor Giacconi is honoured for his efforts to construct space telescopes.