Promoting the role of Physics in research, education, industry and the community

Log in


From Black-Hole Singularities to Cyclic Cosmology

  • 2 Feb 2022
  • 8:00 PM
  • Online (AEDT)

The AIP Tasmanian Branch and the Australasian Society for General Relativity and Gravitation invite you to attend a public lecture by Roger Penrose (2020 Nobel Prize in Physics).


The title of the lecture From Black-Hole Singularities to Cyclic Cosmology (more information in the attached flyer).


To due COVID the lecture will be delivered via Zoom only: 


This is a public lecture - all ages welcome.

The “singularity theorems” of the 1960s, demonstrated that large enough celestial bodies, or collections of such bodies, would collapse gravitationally to what are referred to as “singularities”, where the equations and assumptions of Einstein’s classical theory of general relativity cannot be mathematically continued. These singularities are normally expected to lie deep within what are now referred to as black holes, and would, themselves, not be observable from the outside. Nevertheless, their presence is regarded as fundamentally problematic for classical physics and it is argued that a quantum theory of gravity would be needed to resolve this issue. Similar arguments (initiated by Stephen Hawking) apply also the “Big-Bang” picture of the origin of the universe, showing, again, the inevitability of a “singular” structure of such an initial state. However, a puzzling yet fundamental distinction between these two types of singularity is found, deeply connected with the 2nd law of thermodynamics, according which the “randomness” in the universe increases with time. It is hard to see how any ordinary procedures of “quantization” of the gravitational field can resolve this problem. Nevertheless, a deeper understanding of the special nature of the Big Bang can be illuminated by examining it from the perspective of conformal geometry, according to which the Big-Bang singularity becomes non-singular, this being quite different from the situation arising from the singularities in black holes. In conformal geometry, big and small become equivalent, which can only hold for a singularity of the type we seem to find at the Big Bang. This situation is also relevant in relating the extremely hot and dense Big Bang to the extremely cold and rarefied remote future of a previous “cosmic aeon”, leading to the picture of conformal cyclic cosmology (CCC) according to which our Big Bang is viewed as the conformally continued remote future of a previous cosmic aeon. It turns out that there are now certain strong observational signals, providing some remarkable support for this highly nonintuitive but mathematically consistent CCC picture.

Powered by Wild Apricot Membership Software