What's eating the universe? - with Paul Davies

What are the unexplained riddles of the universe? Award-winning physicist Paul Davies talks you through the strange enigmas that have preoccupied cosmologists from ancient Greece to the present day.

Laying bare the audacious research that has led us to mind-bending solutions, Paul will tell you how we might begin to approach the greatest outstanding enigmas of all.

Paul Davies is a theoretical physicist, cosmologist, astrobiologist and best-selling science author. He has published about 30 books and hundreds of research papers and review articles across a range of scientific fields. He is also well-known as a media personality and science populariser in several countries. His research interests have focused mainly on quantum gravity, early universe cosmology, the theory of quantum black holes and the nature of time. He has also made important contributions to the field of astrobiology, and was an early advocate of the theory that life on Earth may have originated on Mars. For several years he has also been running a major cancer research project, and developed a new theory of cancer based on tracing its deep evolutionary origins. Among his many awards are the 1995 Templeton Prize, the Faraday Prize from The Royal Society, the Kelvin Medal and Prize from the Institute of Physics, the Robinson Cosmology Prize and the Bicentenary Medal of Chile. He was made a member of the Order of Australia in the 2007 Queen's birthday honours list and the asteroid 6870 Pauldavies is named after him.

This talk was filmed at the Royal Institution on 21 September 2021.

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[deborahrobinson]

As always, Paul Davies is brilliant, communicative and charming in a highly informative lecture. Thank you.

[ksmit]

If I listen to this 10 times, I might have a 1/100th of the knowledge it takes to understand the topic. Hoping it subliminally soaks in(since I watch during my lunchtime nap).

[SteveBakerIsHere]

f-sub-l from the Drake equation can at least be considered. Biologists seem to believe that the first self-replicating molecule was probably RNA. We can look at the shortest known sequence of RNA in the most primitive bacteria. We can estimate the density of amino acids in the oceans of early universe (and amino acids are rather common in the universe) - we can estimate the reaction rate at which amino acids randomly collide with each other and estimate the probability of a self-replicating RNA molecule just happening to appear by chance in a liter of water over a second. If we multiply our best estimate for the amount of water in the oceans of an earthlike planet by the best estimate for the number of such planets and multiply by the amount of time since the oceans formed on a typical planet appeared, we can get a VERY rough estimate of f-sub-l.

I have tried doing that - using the best numbers I can find - and the result is that life is EXCEEDINGLY unlikely to have appeared anywhere in the universe by pure random collisions of amino acids. So unless we can find a MUCH simpler self-replicating molecule - or some means of stacking the odds in favor of a self-replicator, then f-sub-l is far, far too small - and we are alone in the universe.

(In detail - the length of that minimal self-replicator as a specific string of N amino acids is critical because there are 26 amino acids - so probability of a random sequence of amino acid collisions making that exact chain is 26 to the power N...so the longer the chain has to be - the VASTLY less likely it is to have happened).

The simplest sequence known to exist in nature is a bacterium called Carsonella Ruddii, with just 160, 000 base pairs. But 26 to the power 160, 000 is a crazy large number! Even if we imagine some reason why the four standard base pairs might dominate the oceans - 4 to the power 160, 000 is still far too big - given the size of the visible universe.

So to my mind - the most critical piece of knowledge we need to answer the "Are we alone?" question - is a matter for the BioChemistry people to answer: "What is the shortest sequence of amino acids that will self-replicate?"

But if the entire universe is infinite - then no matter how long the odds, life is certain - and there is (for sure) alien life somewhere - and now the only question is what are the odds that it exists within the observable universe?

[anaryl]

Such an excellent, understated delivery. I've watched this several times before bed, Paul certainly brings a dulcet tone to such a violent topic.

[demibee]

A great presentation where he freely admits we haven't figured it all out, but this is what we think so far.

[BassGoBomb]

Just to join all those saying what a wonderful thing it is that we still have lectures like this and the Royal Institution itself. And, thank you Paul Davies

[ericlawanderson]

Paul Davies' lectures are as wonderful as his books. My favorite thinker and explainer of big ideas in the Solar System.

[anialiandr]

We used to use Paul Davis’ videos about quantum physics back in the 90s in our linguistics master courses to teach students laterality . Great teacher ❤

[DrJanpha]

I first listened to Paul Davies' talk about the universe some twenty years ago. As enchanting to listen to as ever, Sir...

[brucewilliams]

The very best explanation of modern cosmology that I have ever heard. Professor Davis wins the award for clearest explanation and analogy of science. Bravo RI.

[lacostejr]

Dr. Paul Davies and Sir Roger Penrose have almost the same PUBLIC SPEAKING VOICE 💯... I was listening to this lecture at 2 a.m., waiting to fall asleep, so I wasn't watching. I was just listening, and I kept thinking it was Sir Roger Penrose lecturing Cosmology!

It is always a pleasure to listen to lectures in Physics, Mathematics, and Cosmology. I spend all my free time Pondering our origins, consciousness, and time... Cheers 🙏

[UserNameWasCensored]

I came here looking for an acoustic guitarist. I left with the average intelligence of a Nobel prize-winning physicist.

[bobaldo]

Very well delivered lecture! Thanks for making it available.

[bloodmoney]

our universe is like a cartoon I've seen of Homer Simpson, when he stood beside a green hedge, then he slowly backed into it, disappearing into the hedge.

[jameslyons]

What a great day it is! To hear this lecture has made it so!

[donquixoteupinhere]

Great lecturer! Thanks for making this kind of quality content available to anyone with internet access!! Long may it continue!

G'day from Australia
Very interesting lecture.
Cheers

[johncostigan]

Somehow I am reassured by Paul Davies lecture that it's a useful step forward to at least know what I don't know.

[marksakowski]

Universe doesn't need people to understand it. It is understandable by itself.

[siggesaltens]

Sigge Dr. Saltensø :Thank you Paul : I've been following You now for the majority of 77 year. Time is a Point. And there I stand, so help me, God, and watch You aproaching me.