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One hundred years ago, a solar eclipse proved Einstein’s theory of general relativity was onto something. Known as the Eddington expedition, in 1919 two teams of astronomers set forth to witness a total solar eclipse from either side of the Atlantic. The photographs, once developed, showed that the background stars, made visible by the moon shading the sun, appeard to be a tiny bit closer towards the sun’s disc than they normally appeared in the night sky. The triumphal announcement was the first new evidence, predicted by Einstein, that large masses in the universe are accompanied by a bending of spacetime, and made Einstein the most famous scientist of the twentieth century. At a special event held by London’s Royal Astronomical Society, where Eddington worked at the time, astronomers and archivists explain more to Science in Action, as does this year’s recipient of the Eddington Medal, Bernard F. Shutz, who is hoping gravitational waves will point us in the direction of the next big breakthrough in cosmology.

Murray Gell-Mann
A week ago we learned of the death of physicist Murray Gell-Mann. His Nobel prize was awarded exactly 50 years after the Eddington expedition in 1969, for work elucidating the particles now known as quarks. Oxford emeritus prof Frank Close gives his evaluation of Gell-Mann’s influence on particle physics.

Apples were big long before humans
Robert Spengler, of the Max Planck Institute in Jena, spends his time thinking about the evolutionary origins of certain crops we eat every day. His recent work suggests that apples, rather than being bred to be large by human beings, may well have evolved long before that to be big. Human beings’ influence on the domesticated crops we now eat came much later.

How are we evolving?
Medical intervention has disrupted natural selection in humans as many more children survive into adulthood than did a few centuries ago. And as our DNA continues to evolve, in order to adapt to our environment, how might human beings of the future be different from us? Anand Jagatia explores how some humans, over just a few thousand years, have adapted genetically to live at high altitudes of the Tibetan Himalayas or in the cold climates of Inuit Greenland.

(Photo: Image of the 1919 Solar eclipse taken by Arthur Eddington (1882-1944). Credit: Science Photo Library/RAS)

Producer: Alex Mansfield
Presenters: Roland Pease and Anand Jagatia