Roger Penrose: Infinite Cycles of the Universe Punctuated by Big Bang Singularities

Cosmic Expansion and the Cosmological Constant

• The universe underwent exponential expansion, a discovery made in the early 21st century via observations of exploding supernovae.
• This expansion is driven by the cosmological constant, a term Einstein originally introduced to maintain a static universe before retracting it following the Big Bang theory's acceptance; the speaker notes this was not an error, but a correct insight.
• The current trajectory suggests a future where the universe becomes increasingly "boring" as it expands exponentially.

The Future of Matter and Black Holes

• Astrophysical activity will initially shift toward black holes swallowing clusters of galaxies, including a merger between the Milky Way and Andromeda.
• Over an "unbelievable length of time," these black holes will eventually evaporate via Hawking radiation, leaving a universe dominated by photons.
• In this remote future, the absence of massive particles means no "clocks" or "rulers" exist, as mass is required for the precise measurement of time and space (derived from $E=mc^2$ and $E=h\nu$).
• While mass provides a scale for spacetime, massless photons retain only the "conformal structure" (shape) without a defined scale or time duration.

Conformal Cyclic Cosmology (CCC) Mechanism

• The speaker proposes that the remote, cold, photon-dominated future of one "aeon" is conformally scalable to become the hot, dense Big Bang of the next aeon.
• Although the physical states appear opposite (extreme density vs. extreme rarefaction), the mathematical "squashing" of scale renders them structurally equivalent at the boundary of infinity.
• The speaker interprets "infinity" not merely as a mathematical boundary (as in Euclidean geometry) but as a physical transition zone, analogous to the geometric boundary in M.C. Escher's Circle Limits (hyperbolic geometry), where the previous universe's end becomes the next universe's beginning.

Information Transfer and The Fermi Paradox

• Signals from the previous aeon may survive the transition, specifically gravitational waves generated by black hole collisions spiraling into one another.
• This mechanism implies that information can theoretically propagate from one cosmological cycle to the next.
• The speaker suggests the Fermi Paradox (the silence regarding extraterrestrial life) might stem from looking in the wrong places:
  • Current searches (e.g., SETI) look for civilizations within our current timeline.
  • Potential signals could originate from civilizations in previous aeons that survived their own epochs and successfully propagated signals through the Big Bang singularity.
• The speaker acknowledges this is speculative and that we currently lack the methodology to detect or understand these cross-aeonic communications.