Science-Videos

“Where did it all come from?” This eternal question has served as the driving force for human innovation and evolution.

In this talk, Erik Verlinde will offer a philosophical, an observational, and a theoretical argument for his theory of gravity, known as entropic, or emergent, gravity. Firstly, the particle physics paradigm is encapsulated in the the reductionist idea that, by reducing all physical phenomena to the smallest building blocks, we can obtain greater understanding. However, meaning often comes from the bigger picture. Emergence, defined as the observation of phenomena at a macroscopic scale which are derived from a microscopic scale, where they have no a priori meaning, is the foundation of this new theory.

Secondly, the truth value of theories often depends on their scale. Newtonian gravity works well for planets, but not for black holes. Einsteinian gravity works well for black holes, but not for galaxies, where dark matter and energy must be postulated to account for the speeds of orbiting cosmic objects. Emergent gravity should be able to account for all three. The third, theoretical argument, guides us through what it would be like to fall into a black hole, and uses this example to explain how emergent gravity works.

Erik Verlinde is a theoretical physicist and string theorist at the Institute for Theoretical Physics of the University of Amsterdam. He held the position of Senior Staff Member at CERN, before becoming a physics professor at his Alma Mater in 1996. He has held two subsequent Professor of Physics: at Princeton and, currently, at the University of Amsterdam.

SETI Talks archive: http://seti.org/talks 

Cosmological observations show that the universe is very uniform on the maximally large scale accessible to our telescopes, and the same laws of physics operate in all of its parts that we can see now. The best theoretical explanation of the uniformity of our world was provided by inflationary theory, which was proposed 30 years ago.

Rather paradoxically, inflationary theory also predicts that on a very large scale, much greater than what we can see now, the world may look totally different. Instead of being a single spherically symmetric balloon, our universe may look as a "multiverse", a collection of many different exponentially large balloons ("universes") with different laws of physics operating in each of them.

In the beginning, this picture looked more like a piece of science fiction rather than a scientific theory. However, recent developments in inflationary cosmology, particle physics, and string theory provided strong evidence supporting the new cosmological paradigm. It changes the standard views on the origin and the global structure of the universe and on our own place in the world.

Join astrophysicist Matt O’Dowd on a journey through the deepest, darkest, coolest corners of the universe. Math, physics, and astronomy can’t get much bigger than this.

On the acclaimed PBS Digital Studios series Space Time, Matt explores the outer reaches of space, the craziness of astrophysics, the possibilities of sci-fi, and anything else you can think of beyond Planet Earth. Visit the series home on YouTube for new weekly episodes and challenges that prompt your classroom to think differently about physics and push the rules of space and time to the limit.

This is part update, part remake of our earlier film on Sir Roger Penrose’s Conformal Cyclic Cosmology(CCC). 

Conformal Cyclic cosmology is a scheme whereby the universe is seen to be cyclic even though it never re-collapses and bounces back out. Instead it undergoes whats called a conformal rescaling.

What’s that ? Watch the film, all will be explained. CCC promises to solve many deep mysteries in cosmology such as why was the entropy of the big bang so low? What happened before the big bang? where does the dark matter in our universe come from? We address both the theory of CCC and the possibility of experimental verification. We also address criticisms of the theory.