How Does Light Actually Work?

the newly born Universe buzzed and

frothed with Boundless Energy even after

the Raging furnace of the first few

minutes had died away temperatures

Universe wide were more than 100 million

de for thousands of years this Primal

heat burned a cosmos of plasma a super

hot mix of particles and radiation until

one day it changed

forever that day arrived when the

universe was almost 400,000 years old

and had cooled to about 3,000 Kelvin in

this now comparatively tepid soup lone

electrons met lone protons and finally

could stick together forming the first

atoms but this was not all for as each

electron and proton bound together a

small amount of energy was released a

packet of energy that raced away the

cosmic speed limit the speed of light a

particle of energy born in the formation

of a hydrogen atom a particle we call a

photon a particle of light

itself this Photon was far from the

first but as the universe began

transitioning from plasma into neutral

gas light could then for the first time

stream freely through its reaches and so

our photons long long journey

began it headed out first into the

universe's Dark Ages a time before the

first Stars burned a time before the

first galaxies formed in the Eerie

Darkness gravity pulled on mass to mold

the first seeds of cosmic structure but

the photon sped on and noticed nothing

eventually the first Stars burst into

life around it massive and Bloated these

ancient Suns burned themselves out in a

cosmic blink of an eye as the first

super giant black holes grew rapidly

between them as they e devoured Mass but

the photon sped on and noticed nothing

the first galaxies began to assemble the

sky lit up with the fires of uncountable

young Stars across the cosmos as they

began to fuse the initial hydrogen and

helium atoms into heavier

elements but the photon sped on and

noticed

nothing Millions steadily turned into

billions of years and as galaxies grew

and matured eventually the intense light

of young Stars began to settle the

photon's journey could have potentially

lasted forever into eternity but after

almost 14 billion light years of travel

a large spiral galaxy steadily came into

view its Destiny was set near a small

blue dot orbiting a small white star

after crossing the last few thousand

light years the photon collided with a

piece of metal part of a telescope built

by humans and orbiting near the planet

Earth the photons energy was completely

absorbed energizing electrons and

registering on

detectors but as the photon vanished

from existence its billions year-long

Journey complete it still simply did not

notice because to the photon itself

the journey never took place 13.8

billion years of cosmic time disappeared

in an

instant yet how can this be light has

existed in the universe from its

earliest moments and will continue to

exist long after humanity and the stars

are shred to dust but just how does it

work and how can it seemingly last

forever and perhaps most importantly

what even is

it light is fast it only takes 0.13

seconds for it to circulate the entire

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educational content on

[Music]

YouTube light had played a pivotal role

since the cosmos's very beginning in

these earlier times it had only existed

for the very briefest of moments

slamming into speeding particles before

it had a chance to travel anywhere one

piece of light dying as another was born

however our parcel of light was born

into a very different very transparent

Universe with the cosmic Maelstrom of

the Big Bang finally abated our Photon

could begin its immense Journey

unhindered as it traveled many

generations of stars led to our sun and

billions of years after humans began to

walk on the surface of our small rocky

planet and So eventually as our Photon

was a couple of thousand light years

distant from Earth those humans began to

wander all men by Nature desire to know

an indication of this is the Delight we

take in our senses and above all others

the sense of sight this most of all the

senses makes us know and brings to light

many different between

things the ancient Greeks wondered if

light emanated from the eyes touching

and feeling the world around us but

clearly there are times when it is dark

when we can't see anything so they

concluded light must be something

external something captured by our eyes

Islamic scientists went on to unravel

the properties of light finding rules of

reflection and the magnification

properties of glass lenses light was

clearly a natural part of the universe

around

us but it took the coming of the

Scientific Revolution and a fight

between two giants of science for

light's deepest secrets to be finally

uncovered the year was 1652 and Dutch

physicist astronomer mathematician and

allround genius Christian haggens was

exploring Optical phenomena he had noted

how light traveled through lenses and

bounced off mirror surface surfes and

was particularly interested in the

phenomenon of refraction where the path

of light is bent when it passes from one

medium to another haggens noticed that

light was often split into the colors of

the rainbow by his instruments and

sometimes strange patterns of dark and

light would be produced clear evidence

to him that light was some sort of wave

some sort of traveling oscillating

phenomenon oscillations can be found

throughout nature from planetary orbits

to vibrating electrons but let's start

with a simple

picture think of a child on a

swing as they swing their position

oscillates from one position to the next

and then back again just like a pendulum

that drives the regular ticking and

talking of a grandfather clock when

oscillations act in unison but slightly

out of Step waves are formed a stone

thrown in a flat Pond pulls the water

down with it but the water bounces back

this splash of water pulls on its

neighbors inducing them to oscillate

which in turn pulls on their own

neighbors these oscillations fan out

across the pond as a steadily Rippling

pattern of waves waves are everywhere

from sound waves csing in the air to

ocean water waves driven by the wind and

moon seismic shifts can generate violent

and destructive earthquakes in our

planetary crust whilst similar waves

Ripple in the atmosphere of the Sun and

other

stars and so light seemed also to be a

wave but this left an obvious question

if light is a wave just what was doing