Content about “

gravity

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Everyone knows what time is. We can practically feel it ticking away, marching on in the same direction with horrifying regularity. Time has enslaved the Western world and become our most precious commodity. Turn it over to the physicists however, and it begins to morph, twist and even crumble away. So what is time exactly?

This podcast featuring Paul Davies, a theoretical physicist and cosmologist at Arizona State University and Director of BEYOND: Centre for Fundamental Concepts in Science, explores this difficult question and accompanies our What is time article.

Would you like to get away from Earth? Here's how fast you would need to go.

Physicists believe that around 82% of all the matter in the Universe is invisible dark matter. But if it's invisible how do they know it's there?

A quick introduction to one of the greatest discoveries of the century.

A quick introduction to the monsters that lurk at the centre of each galaxy.

Why too many bodies present a problem.

Does light have weight? Newton thought so. His laws predicted that gravity would bend light, two centuries before Einstein's revolution.

Why (some) physicists want to modify Einstein's general theory of relativity.

Space is the stage on which physics happens. It's unaffected by what happens in it and it would still be there if everything in it disappeared. This is how we learn to think about space at school. But the idea is as novel as it is out-dated.

This is the first part of the lecture given by Astronomer Royal Martin Rees at Stephen Hawking's birthday symposium.