From: mk_thisisit
Sir Roger Penrose is a mathematical physicist whose work has fundamentally shaped our understanding of the universe [00:11:12]. In 2024, he received the Stanisław Lem Prize in the science category for his significant contribution to the development of physics [01:10:00].
Identity and Approach to Science
Penrose identifies himself primarily as a “mathematical physicist” [00:12:00], leaning more towards physics than pure mathematics [08:17:00]. His work often lies at the intersection where mathematics meets physics, making it difficult to separate the two disciplines [08:55:00].
He views science and learning as intertwined with enjoyment [14:37:00], noting that mathematical physics, including his work on aperiodic figures like the Penrose cube and staircase, is largely done for fun and the desire to solve problems [14:55:00]. His techniques, including those that led to his Nobel Prize, were developed for pleasure, driven by curiosity about the structure of space-time and the boundaries of the future [15:24:00].
Nobel Prize-Winning Work
Penrose was awarded the Nobel Prize for demonstrating the falsity of the statement that singularities (points of infinite density) would not appear in complex systems [00:38:00], [07:09:00]. His contribution centered on proving the existence of singularities if a certain criterion of collapse (the “trapped surface”) is adopted [05:00:00].
Prior to his work, the Oppenheimer-Snyder model (1939) described a spherically symmetrical dust cloud collapsing into a singularity, but it was largely disbelieved due to its unrealistic assumptions (no pressure, perfect spherical symmetry) [05:17:00]. A paper by Lvshica and Kalatnikov further tried to prove that in complex, non-symmetrical systems, singularities would not form [06:40:00].
Penrose analyzed these works, identifying an error in the Lvshica and Kalatnikov paper (later corrected by Beliński) [07:15:00]. He independently demonstrated the necessity of singularities using completely different, novel methods [07:44:00]. Instead of solving equations, he analyzed the general characteristics of space-time and its causal structure [09:31:00]. He developed the concept of a “trapped surface,” a two-dimensional surface in space-time where light rays converge on both sides, which allowed him to prove the existence of singularities without specific assumptions about the collapsing object’s shape or internal dynamics [11:13:00], [12:32:00].
Collaboration with Stephen Hawking
Penrose often mentions his collaboration with Stephen Hawking [00:44:00], [12:44:00]. He states that while Hawking later used different terminology and developed certain techniques further, the key ideas for their joint work on singularities were his own [00:49:00], [04:36:00], [13:13:00], [13:53:00]. Hawking’s early work, particularly his doctoral thesis, contained errors that were often corrected by Brandon Carter or Hawking himself after Penrose (as a reviewer) pointed them out [13:22:00].
Penrose acknowledges Hawking’s enormous contribution to science with the discovery of “Hawking pairing” or Hawking radiation, which describes black holes not being completely cold but having a temperature and eventually evaporating over vast timescales (around 10^100 years for the largest black holes) [19:25:00].
Conformal Cyclic Cosmology (CCC)
Penrose has developed a cosmological model called Conformal Cyclic Cosmology (CCC), in which the universe did not begin with a Big Bang as a singular starting point [17:01:00]. Instead, he proposes a cyclical universe where the Big Bang of one “eon” is the distant future of the previous one [17:17:00]. This theory suggests that black hole collisions from the previous eon produce gravitational wave signals that create rings in the sky in our current eon [17:31:00]. He cites findings by Priscilia Lopez of galaxy circles and analyses by his Polish colleague Krzysztof Meer as potential confirmations [17:41:00].
Furthermore, he suggests that evaporating supermassive black holes from the previous eon, through “Hawking pairing,” would cause single-point explosions that create signals in the microwave background radiation, observed as spots in the sky with a high confidence level of 99.98% [18:06:00], [20:26:00]. He notes that conventional theory does not explain these spots [21:03:00]. His book, Cycles of Time, elaborates on the transition between eons [21:32:00]. While currently speculative, he believes there’s a good chance these ideas are true [22:04:00].
Twistor Theory and Other Concepts
Penrose’s heart is deeply connected to the part of twistor theory that relates to physics [00:21:00], [08:39:00], even though twistor theory extends further into pure mathematics [08:46:00]. He believes that future developments in twistor theory might help combine it with his cosmological model [22:01:00].
His early interest in the theory of relativity led to the development of “conformal infinity” [24:12:00], [25:13:00]. This concept was influenced by Ray Sax’s “flaking theorem” concerning gravitational waves and the curvature tensor, and Engelbert Schuking, who explained the conformal invariance of Maxwell’s equations and the importance of separating positive and negative frequencies [24:26:00]. These insights were crucial to the genesis of Twistor Theory [26:01:00].
Personal Anecdotes
Penrose recounts his first experience with geometry at around seven years old: when given spinach he disliked, he rearranged a round portion into a semicircle of the same volume to trick his nanny into thinking he had eaten half [02:54:00]. He admits that at the time, he misunderstood that volume and shape are distinct [03:51:00]. He also attributes much of his success to luck, being in the right place at the right time [23:56:00].