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   Sir Tony Leggett
and Sir Roger Penrose

(5th June, 7.30-9.30 pm, Hebb theatre, 2045 East Mall, UBC)


(1) Tony Leggett (Urbana, USA)

  Why can't time run backwards?

We can all tell when a movie of some everyday event, such as a kettle boiling or a glass shattering, is running backwards. Similarly, we can remember the past and affect the future, not vice-versa. So there is a very clear "arrow" (direction) of time built into our interpretation of our everyday experience. Yet the fundamental microscopic laws of physics, classical and quantum-mechanical, look exactly the same if the direction of time is reversed. So what is the origin of the "arrow" of time? This is one of the deepest questions in science; I will review some relevant considerations, but do not pretend to give a complete answer.

Additional resources for this talk : slides andvideo.


(2) Roger Penrose (Oxford, UK)

  Seeing through the Big Bang into Another World?

One of the great questions of our time is - how did the universe begin? A recent theory, conformal cyclic cosmology (CCC), proposes that what we presently regard as the entire history of our universe is merely one phase (an "aeon") of an infinite succession of similar aeons. The ultimate expansion of each aeon, appears - infinitely scaled down - as the big bang of the next one. Collisions between supermassive black holes in the aeon prior to ours would leave an observable imprint on our cosmic microwave background, apparently already detected by WMAP and Planck space satellites.

I will give an introductory presentation of the questions and issues here, and also discuss recent claims that BICEP2 south-pole telescope observations provide the "smoking gun" for an 'inflationary' beginning to our universe's expansion, arguing that CCC provides an alternative explanation with intriguing consequences.

Additional resources for this talk : slides and video.

Questions and Answers : video