“Rethinking Cosmology”

I wanted to pass along a recent talk from the Perimeter Institute (PI) by Paul Steinhardt, titled “Rethinking Cosmology“. It is a great lecture to a non-professional audience about how the current cosmological model (inflation + Big Bang + Quantum Theory + …) has failed from a theoretical place – and how it needs to be replaced (in part or whole) with a new theory.

For any of you who haven’t heard of the Perimeter Institute, here’s a description from its Wikipedia page:

Perimeter Institute for Theoretical Physics is an independent research centre in foundational, theoretical physics located in Waterloo, Ontario, Canada. It was founded in 1999…In addition to research, Perimeter also provides scientific training and educational outreach activities to the general public. This is done in part through Perimeter’s Educational Outreach team.

Besides being the home of some of the world’s best theoretical minds (Stephen Hawking is a regular visitor), PI is very close to my hometown and literally across the street from one of the places I used to work.

Here’s the link to the page from where the talk can be launched.

The first 40 minutes of Steinhardt’s talk focusses on how the current Inflationary/Big Bang model, while fitting many observations from the Universe, does not hold up theoretically. That is, the theory falls apart in several places when examined very closely.

Some quotes from his talk:

“The Big/Bang – Inflationary paradigm we know has failed. That may not be a sentence you have heard before, but is nevertheless true….It has taken a long time for us to begin to say it out loud.”

“How do we re-explain all this data in the context of a theory that really is predictive?”

“What are the assumptions I was making before, because at least one of them is going to need to be changed.”

Steinhardt then uses the last half of his talk to put forward his theory that replaces Inflation/Big Bang – “The Big Bounce“. As best I can understand it, The Big Bounce basically modifies the current model somewhat to say that the/an earlier Universe contracted to a place where the process was reversed (a “bounce”) and expansion happened again to create our current Universe. He believes that new model can overcome a lot of the difficulties with the current model.

The larger point here is that he puts it out there that the cosmological community recognizes (but are hesitant to admit) that their currently accepted theories, while good at explaining observations, are not the best theories to describe them. There are many other theories that would also explain the observations and have fewer inherent problems.

I can’t tell you how good it made me feel to hear someone in the field admit this growing “openness” to looking for new theories.

Filed under: In the News, The Model Tagged: big bang, big bounce, inflation, lecture, models, Paul Steinhardt, Perimeter Institute, quantum theory, Stephen Hawking