Video Infoblog: 1/137 - Physics' Greatest Mystery

13 Sept 2023

Unlock the mysteries of the universe with the fine structure constant! Join us as we delve into the intriguing world of 1/137, a number that defines our existence and challenges our understanding of physics.

Transcript

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[Music]

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they say that the only certainties in

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life are death and taxes but science is

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full of constants which we can be sure

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of there's the speed of light in a

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vacuum the gravitational constant the

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plank constant and the elementary charge

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to name just a few but of all the

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constants in the universe there is one

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that excites physicists more than any

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other it has sometimes been jokingly

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referred to as the answer to life the

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universe and everything but it's not a

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42 it's 1

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137th if we're being technical it's 1 in

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137.0 35 999 084 but 137 is close enough

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this number shows up everywhere in

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quantum physics and it became an

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obsession of many of the founders of

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quantum mechanics it's a number that

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Richard fean described as being one of

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the greatest damn mysteries of physics

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and a magic number that was written by

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the hand of God Paul durra called it the

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most fundamental unsolved problem in

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physics and Wolf Gang Paulie stated when

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I die my first question to the devil

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will be what is the meaning of the fine

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structure constant so what exactly is 1

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137th how is it discovered why is it so

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damn

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[Music]

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important so the fine structure constant

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also known as the Summerfield constant

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is a fundamental constant of physics

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that quantifies the strength between

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charged particles and the

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electromagnetic force the discovery of

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this constant began in 1887 when Albert

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mikkelson and Edward moley took precise

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measurements of the hydrogen atom

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Spectrum while elements shift energy

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levels in their orbit around the nucleus

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they emit photons with specific energies

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by breaking that energy up into specific

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wavelengths of light we can produce the

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Spectrum for that particular atom and

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atoms of each element have their own

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unique Spectrum but as we gained the

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ability to take even more precise

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measurements it was discovered that

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there were a couple of problems first

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the energies measured in the Spectrum

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analysis didn't quite line up with the

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expected values from our calculations

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this meant that something in our

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equations had to be off moreover it was

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discovered that each line in the

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spectrogram was actually two separate

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lines that were very close together

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these pairs of nearly identical lines

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are known as fine structures in a 1916

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paper German physicist Arnold samfield

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observed that the difference between

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these two lines was always a multiple of

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a specific number he named this number

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the fine structure constant denoted by

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the Greek letter Alpha and the number

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was represented by the equation that's

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on the screen now this formul actually

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includes some of the constants that we

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already mentioned e is the elementary

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charge Epsilon Subzero is the electric

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constant H bar is the reduced plank

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constant and C is the speed of light and

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Pi is of course just Pi since these are

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all constants we can plug their values

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in and we get approximately 1 137 that

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by itself wouldn't necessarily be enough

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to excite physicists the whole point of

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these constants is that they show up in

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equations like this all the time what

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interested physicist so much was that

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1100 37th is the only thing we get now

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there's a glaring emission in that

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answer which is the lack of units of

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measurement C is expressed in me/ second

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and ear is expressed in columns but all

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of the units and measurements in this

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equation cancel out making the fine

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structure constant dimensionless it's

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just a number making it more similar to

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Pi than to the other constants in that

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equation while it isn't the only

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dimensionless constant in physics it's

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the one that has most captivated

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scientists imaginations most of the

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other dimensionless constants are just

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the weights of various types of quarks

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and leptons and such which are far more

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useful than they are interesting and if

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the fine structure constant only showed

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up as the difference between these pairs

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of spectral lines it likely would have

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been little more than a funbit of trivia

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however as studies in quantum physics

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progress the number began to appear

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everywhere this number began showing up

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in countless different equations

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governing light and matter that's how

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the number was discovered but despite

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over A Century of physicists obsessing

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about it was still no closer to

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understanding its significance so why

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does

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137th appear to be the most important

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number in quantum physics while the fine

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structure constants has its specific

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uses there's no obvious reason that this

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number would continue to show up in as

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many places as it does to date we don't

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actually have an answer for this 137 is

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a prime number that doesn't appear to be

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tied to any other mathematical constants

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and we have no real explanation for its

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origin that led many physicists down the

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fails path of numerology to try and find

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an explanation this was especially

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prevalent at the beginning of the 20th

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century when the fine structure constant

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was believed to be exactly 1 in 137

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rather than just approximately that

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number at one point English physicist

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Sir Arthur Edington argued that the

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number should be exactly 136 because he

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had calculated the number of protons in

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the universe to be 136 * 2 to the power

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of 256 it's no longer believed that

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those calculations have anything to do

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with one another but that's an example

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of the sort of superstition that some

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early Quantum physicists were dealing

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with currently there isn't any Theory we

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can use to predict the value of the fine

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structure constant it's the sort of

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constant whose value can only be

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determined by measuring it in

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experiments and we must just use that

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measurement to make other predictions

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about the universe without any

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understanding of why the value is the

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number that it

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is so we don't have any explanation for

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where this number came from but is the

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number even that important and the

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answer to that is absolutely yes as we

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said earlier Define constant structure

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quantifies the strength of the

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electromagnetic force everything we

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experience in our day-to-day lives is

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governed by the gravity or

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electromagnetism and life could simply

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not exist in the universe if that

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constant were even just slightly

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different if the number were higher or

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lower it would alter how tightly

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electrons were bound to their nuclei

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making atoms either smaller or larger

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currently the value is low enough

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meaning the electromagnetic force is

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weak enough that atoms are mostly filled

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with empty space electrons orbit far

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enough away to enable chemical bonding

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if the force was stronger then these

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chemical reactions may not be possible

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or at the very least all of chemistry

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would be dramatically different on the

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other hand if the fine structure

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constants were lower resulting in a

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weaker electromagnetic force electrons

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would orbit further away making atoms

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and molecules unstable it's estimated

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that if the constant were to change just

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4% in either direction the Stars

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wouldn't have been able to fuse carbon

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atoms together thus making Life as we

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know it impossible if the force became

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even weaker then Fusion wouldn't be

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possible at all all and there would be

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no stars like so many things in our

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universe the fine structure constant

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seems perfectly tuned to enable life of

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course there is the caveat these

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discussions always refer to Life as we

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know it and it's possible that a wildly

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different Universe would have wildly

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different types of life but again

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physics is full of all sorts of

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constants and what makes this one so

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particularly interesting is that it's

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dimensionless take the speed of life for

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example this is usually approximated to

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be 300,000 km a second though Some

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people prefer to use 100 8 6,000 m a

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second if you're feeling particularly

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soly you could even say that TR travels

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at 5.4 million furong per regulation

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hockey game in these cases the number

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itself is meaningless and it's just a

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byproduct of the units of measurement

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that we use to define it and when you

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consider that a kilometer is

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internationally defined as the distance

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that light travels in 1 300,000 of a

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second it creates this weird bit of

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circular logic within the definitions

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that's why the dimensionless aspect of

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the fine structure constant is so

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fascinating to physicists letter Pi it's

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a pure number that simply exists in

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nature without the need to be defined by

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any sort of human perspective it's even

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been argued that 137th is the perfect

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message to broadcast to aliens to show

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them that we are a form of intelligent

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life if we were to send them the

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gravitational constant we would also

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need to include an explanation of what

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the hell meter a second and a kilogram

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all are but 1 137th speaks for itself

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would probably once transmitted in

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binary instead of base 10 but if an

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advanced alien civilization were to

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receive that number is a message from us

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they would know that we had at least

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something of an understanding of quantum

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physics Okay so we've talked about how

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important the value of the fine

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structure constant is and the

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devastating consequences that could

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arise if it were changed even slightly

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however it's not quite as constant as

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we've made it sound thus far it actually

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changes increasing logarithmically as

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the relevant energy scale increases at

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the time of the big bang when the energy

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scale was massively High the value of

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the fine structure constant would have

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approached one but since the universe

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tries to achieve the lowest energy State

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possible this value quickly dropped

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while there isn't any known reason why

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it didn't just fall to zero the constant

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instead seems to be asymptotic at 1

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137th as energy approaches zero which is

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good since we wouldn't exist if it

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didn't this detail is hugely important

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for the potential creation of a grand

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unified theory of physics and we've made

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a whole video about that if you'd like a

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more in-depth explanation but it's known

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that at high enough energy levels the

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electromagnetic force and the weak

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nuclear force act as a single force and

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the variable nature of the fine

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structure constant can help explain that

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in fact there are a lot of open

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questions regarding the formation of the

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universe and the standard model of

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physics that could potentially be solved

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by a variable constant and this has led

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to the controversial belief that the

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fine structure constant may actually be

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variable throughout time and space and

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the value of 1 137th is only true in our

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small pocket of the universe scientists

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got to work trying to prove that the

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constant could be variable in time and

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space rather than just a higher levels

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this was done using spectrographic

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analysis both of quazars because of

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their incredible brightness and with

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stars that are nearly identical to our

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own sun and the results have been

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astonishingly inconclusive analysis of

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solar twins showed no variation in the

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fine structure constant but to get

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proper readings from a star as

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unremarkable as our own son it needs to

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be relatively close if the theory is

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that the constant changes over time or

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in different parts of the universe

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getting readings from stars that are

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only hundreds or thousands of light

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years away wasn't very likely to show

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any real real difference in the first

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place however the results from the

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quazar are much more interesting because

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they allowed us to gather data from much

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further away in 1999 A team out of the

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University of South Wales claimed to

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discover the first variation in the fine

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structure constant by analyzing the

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Spectra of stars from 10 to 12 billion

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years ago the measured result was

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slightly lower than the value had

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previously measured it was a tiny

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difference but it was definitely there

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years later the same team tried again

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but this time they took measurements

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looking in the opposite direction what

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they found was a constant that was a

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tiny bit higher in that Direction now of

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course this still isn't conclusive the

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changes were small enough that they

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could have been experimental errors

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signal noise or they could have even

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been caused by gas clouds having a

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highly unusual ratio of isotypes

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furthermore it's a bit convenient that

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this team found the exact results they

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were looking for with different

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variations in different directions while

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other teams failed to find any variation

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in their measurements of the fine

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structure constants it's convenience but

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that doesn't mean it's wrong while the

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prevailing opinion is that the

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discrepancy was just signal noise the

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research has yet to be properly

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discredited currently we just don't have

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a definitive answer on exactly how

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constant the fine structure constant is

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though if it is variable through time

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and space this could have major

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implications so units measurements are

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an important part of most constants

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because they give us a frame of

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reference for the relationship

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represented by that constant the speed

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of light is the relationship between

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distance and time Plank's constant is

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the relationship between jewels and time

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and the gravitational constant is the

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relationship between mass distance and

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time so if the fine Str constants is

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dimensionless what is the relationship

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that this number is meant to represent

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Perhaps it is the relationship between

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these other constants and how they

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interact to create the universe around

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us or maybe it's just an arbitrary

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number with no particular meaning after

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all it's easy to make a formula using

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various constants that will be

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dimensionless like dividing the mass of

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a helium atom and the mass of a hydrogen

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atom but what makes the fine structure

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constant more intriguing than other such

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numbers is that it shows up everywhere

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it is literally the glue that holds the

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universe together because without the

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electron magnetic force you would just

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pass through other matter assuming the

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molecules in your body were even held

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together in the first place while we

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understand the importance of the

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constant as a measurable value that we

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can use in equations it's probably best

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not to continue to search for specific

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meaning in the number one 137th is just

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one of many random values that were

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selected at the beginning of the

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universe and the fact that every one of

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those random values happens to be

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exactly perfect for the creation of life

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is probably just a coincidence that we

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shouldn't worry too much about

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