Why Space Itself May Be Quantum in Nature - with Jim Baggott

Loop quantum gravity aims to unify the theories of general relativity and quantum mechanics, as explained by Jim Baggott.

Quantum gravity is the holy grail for modern theoretical physicists – a single structure that brings together the two great theories of the 20th century: quantum mechanics and general relativity. One widely-known solution is string theory, which emerged from particle physics. In this talk, Jim Baggott will describe the other approach known as Loop Quantum Gravity. This theory starts from general relativity, borrows many ideas and techniques from quantum mechanics, and predicts that space itself is quantum in nature.

Jim Baggott is an award-winning science writer. He trained as a scientist, completing a doctorate in chemical physics at the University of Oxford in the early 80s, before embarking on post-doctoral research studies at Oxford and at Stanford University in California.

This talk was filmed at the Ri on 12 February 2019.

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[doronron]

I've watched RI lectures since I can't remember (I'm 64). Jim carefully talked his presentation through in such a way that I heard and could digest every word. Perhaps the sound effects weren't necessary, but otherwise he managed to avoid any other dramatic concessions. For an interested layman, I've never seen a better lecture on this or any other subject. Thank you.

[allurbase]

If you already listened countless talks about general relativity you can skip to 38:00

[AndyinMokum]

As a layman, I found your lecture fascinating. The sound effects were quite alarming; especially for someone who's profoundly deaf in one ear. What sounds I can hear, are extremely distorted and Dalek like. Needless to say, I jumped quiet a few times 🤣.


I'll have to watch the video a few more times. Some of the concepts you introduce, are really hard to get one's head around. They simply don't comport to our everyday perception of space and time. As I said, the lecture was fascinating, thank you for sparking my curiosity 😀.

[MrTommy]

I guess the first half rehash is unavoidable, but the second half was highly effective in guiding me towards a better understanding of the big picture. Cheers to all involved in producing this little gem !

[anthonyowen]

Interesting lecture, but spoiled by very silly and totally unnecessary audio 'effects'. Luckily they are mainly during the first ten minutes and only make one appearance later on, but the presentation would have been improved if they had never been used at all.

[RogerRosenquist]

He has a wonderful talent for making these extremely difficult concepts (somewhat) understandable while putting the listener at ease about not totally understanding it.😊

[garyrafiq]

The closed captions (subtitles to you Brits) are great and error-free! Thank you, Royal Institution, for the captions, and the caption representation of the sound effects is helpful. Nothing wrong with those sound effects if they make the lecture interesting.

[icourant]

1:06:58 Time is a human concept. Space is not. Your saying that what we did come up with to make something understandeble is the real thing, and space is not. You say there is only time, no space... Yeh right. In physics its still space-time that is real. Thousands and thousands of people worked on that for years and years. And you. And you alone came up with a theorie telling all those people are wrong.... To say it in quantum terms... What is the properbility of that being right! :)

[impCaesarAvg]

Jim mentions the Queen Elizabeth Engineering Prize as being awarded 'today'. The award to Parkinson, Spilker, FrueHauf, and Schwartz was announced 12 February 2019. This lecture and that announcement were simultaneous -- unless you're moving very fast.

[AwesometownUSA]

Jim “Don’t look for them, you won’t find them” Baggott

[steveray]

"To see a World in a Grain of Sand And a Heaven in a Wild Flower, Hold Infinity in the palm of your hand And Eternity in an hour." William Blake

[Robyzed]

WOW Dr. Baggott, thank you so much for the crystal clear explanation. I see Smolin changed his mind about Time, much to Professor Rovelli's annoyance, I suppose. Furthermore, as a layperson, I just hope one day to see string theorists and LQG supporters publicly confront each other, comparing ideas instead of filling square meters of blackboard with math....as I must confess I'm still unable to understand the substantial differences between the two approaches to the problem.

[Biga]

47:00 knot quantum gravity could possibly be the greatest misleading physics term if they went with that.

[SirRelith]

This was such a fantastic explanation. I've watched several videos on loop quantum gravity and I believe this one to be the best so far.

[davidwright]

If there's one thing that gets me mad, Jim, it's 'Don't worry about ...', since usually, that's exactly where I do want to go. Not understanding it, means it's what I need to find out about. That aside, an interesting and well-presented talk; thanks. And yes, Jim, I've bought several of your books, the latest included. Be bold, bloody and brave with the next one - and put the damn math in!! I'm sure I'm not the only one with that feeling. Hawking's editor who said every equation halves the sales, was an - ok, let's just say, was misguided.

[BeyondWrittenWords]

55:24 'a single proton contains about 10^65 quantum of volume'. Quite a lot. And proton is small as hell.

[KilgoreTroutAsf]

For those familiar with history of physics, loop quantum gravity starts at 36:00

[kindlin]

Save yourself a half hour and skip ahead to 35:46, if you already have a cursory understanding of special relativity, general relativity and the inception of Quantum Mechanics.

[TheDavidlloydjones]

The Chinese "south-pointing chariot, " 指南车, works off a differential gear and the assumption that the Earth is flat.
If it worked perfectly it wouldn't operate the way suggested by the graphics at 38:00. In real life, it stops working after more than a few kilometres of bumpy road.

[ikaeksen]

Reason why we dont understand the universe : we see from our time dimension electrons moving extremly fast arround the atoms. But if we where able to travel to the atom, time would move extremly slow. Same with us being in this time demension looking at one universe up, where each galaxy moves slow (1 galaxy=1 atom, black hole is that atom neucleus)..If we where living in this higher dimensional universe up, we would see this galaxyatom moving fast.