In this engaging discussion, Brian Cox, a renowned particle physicist and science communicator, delves into the enigmatic Planck length. He explores why this tiny scale is pivotal to our understanding of the universe, serving as a boundary where gravity and quantum mechanics intersect. Brian highlights the challenges of observing at this level, discussing the implications of fundamental constants like the speed of light. Prepare to venture into deep cosmic mysteries and discover how these measurements shape our grasp of reality!
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Planck Length As A Fundamental Scale
Brian Cox argues the Planck length (~10^-35 m) emerges from measured constants and is fundamentally meaningful.
He frames it as a derived measurement, not an arbitrary number.
question_answer ANECDOTE
Human-Based Units Are Arbitrary
Brian Cox explains historical units like the meter and foot originated from human body measurements.
He emphasizes these reflect biology, not deep properties of the universe.
insights INSIGHT
Fundamental Length From Constants
Combine the speed of light (c), Newton's gravitational constant (G), and Planck's constant (h) to build Planck units and a length.
That calculation yields the Planck length, roughly 10^-35 metres.
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"It's a very, very beautiful calculation, but it's the best example I know of the relationship between these rather abstract quantities perhaps and something that you can look at in a telescope."
What happens when you try to look too closely at the fabric of the universe? When we gaze at a Planck length, a scale so small that even light becomes useless for observation, physics pushes back.
The Planck length is not just a tiny number, it’s a boundary where gravity, quantum mechanics, and relativity collide. Physicist Brian Cox explains why the measurement is a portal to the deep structure of reality, and why going beyond it may break the boundaries of our understanding.
Chapters:
0:00 Introduction
0:45 The importance of measurements
2:40 What are the fundamental quantities?
7:20 How important is the Planck length?
9:20 Why you can’t approach the Planck length
10:30 A theory with more dimensions
13:00 What keeps a star from collapsing?
14:42 The uncertainty principle
17:36 The Planck mass
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About Brian Cox:
Brian Cox obtained a first class honors degree in physics from the University of Manchester in 1995 and in 1998 a Ph.D. In High Energy Particle Physics at the DESY laboratory in Hamburg. He is now Professor of Particle Physics at the University of Manchester, The Royal Society Professor for Public Engagement in Science and a Fellow of the Royal Society.
Brian is widely recognized as the foremost communicator for all things scientific, having presented a number of highly acclaimed science programs for the BBC watched by billions internationally including ‘Adventures in Space and Time’ (2021), ‘Universe’ (2021), ‘The Planets’ (2018), ‘Forces of Nature’ (2016), ‘Human Universe’ (2014), ‘Wonders of Life’ (2012), ‘Wonders of the Universe’ (2011) and ‘Wonders of the Solar System’ (2010).
As an author, Brian has also sold over a million books worldwide including ‘Black Holes’, ‘Universal: A Guide to the Cosmos’, ‘Quantum Universe’ and ‘Why Does E=mc2?’ with co-author Professor Jeffrey Forshaw. He has set several world records for his sell-out live tours, including his most recent tour Horizons which has taken in venues across the globe.
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