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slash real-life floor lights is about
the fastest thing that you can possibly
imagine think about how fast it seems
when you turn on a light switch in your
room and you see it instantly fill up
with lights or when you shine a
flashlight on something and the light
immediately appears on whatever you're
shining it acts it feels instant because
of our scale light moves so quickly that
it might as well be but when you move
out beyond our scale light get slower
and slower to the point where it quickly
seems to more resemble a snail rather
than you know light speed here's what I
mean light on earth seems really really
fast because earth is small light
travels at a speed of 299,792,458 meters
per second when in a vacuum which is
fast enough to completely orbit the
entire earth more than seven times in a
single seconds which looks like this
while it's happening
when you flip on a light inside of your
room the light probably moves fast
enough to reach across the entire room
in just one 500 thousandth of a second
which tamir human eyes basically feels
instant this is why instant
communication on the internet between
any two people on the earth's surface is
possible because earth is a small enough
place to where light speed basically
does mean the same thing as instants but
that all changes drastically when we
zoom out just a little far away from the
earth and get out into the rest of the
universe far from being instantaneous it
takes light 1.25 five seconds to cover
the distance between Earth in the moon
which has all kinds of weird
implications when the Apollo astronauts
were there there was a lag in
communication between them and Mission
Control back on earth because a message
from Mission Control would take 1.25
five seconds to arrive and then the
astronauts message will take 1.25 five
more seconds to come back for a total
message relay time of 2.6 seconds
round-trip so in the future when you're
trying to communicate on Facebook or
discord or whatever it is with someone
living on the moon you'll have to wait
at least two point six seconds after
sending a message
before you'd actually get a response and
it's all because of the limitations and
speed of light speed communication but
communicating with somebody on the moon
is still easy when compared with
somewhere else like say on Mars which is
a lot further away from us than the moon
is in the future when we have colonies
with thousands or even millions of
people living on Mars the sheer distance
away that Mars is is going to create
lots of weird and interesting
communication problems since Earth and
Mars have different orbits around the
Sun Mars varies pretty drastically in
her distance away from Earth on the
close end it takes light just over three
minutes to cover the distance which
isn't bad but on the far end it'll take
22 minutes in 24 seconds which makes
instant communication impossible if you
have a friend who lives on Mars and you
send them a message when Mars is
farthest away from Earth your message
will take over 22 minutes just to get
there and then whenever they get around
to responding to you it'll take over 22
more minutes just to get back to you
even if your friend on Mars responds
immediately when they get your message
it'll take about 45 minutes after you
sent it before you get a response and
that's the quickest response time
possible so nobody should really get
upset after not getting reply to for a
while by a Martian this is going to
become a big problem in the future and I
suspect it's going to cause human
civilization on Mars to gradually feel
more and more isolated and separated
from Earth the light just keeps getting
slower and slower the further we move
away from Earth the time it takes light
to reach a Jupiter from Earth is
anywhere between 33 to 53 minutes
meaning that when NASA has a probe in
orbit they have to wait for around two
hours sometimes just to process
information and send instructions to
correct a potential navigation error
meaning that Lightspeed instructions are
sometimes too slow to arrive in time to
fix the problem even light from the Sun
takes a while to reach us here on earth
generally around 8 minutes on average
which looks like this in real time it's
slow so slow in fact that if the Sun all
of a sudden just disappeared for
whatever reason we wouldn't even realize
it back here on
until eight minutes after it happens and
just forget about trying to maintain
instant communication at the outer
reaches of the solar system on Pluto
because it takes light over five hours
to get here from Earth and keep in mind
everything that we've talked about so
far is just within the confines of our
own solar system so light gets even
slower when we get even further out the
nearest other star to our Sun Proxima
Centauri is 4.24 light-years away from
the earth meaning yeah it would take
4.24 years for light from earth to reach
it so just imagine what it would be like
if we ever successfully managed to get
colonists or a probe out on a planet
there a single message between the
colony and earth would take almost a
decade to achieve because the Lightspeed
message would take 4.24 years each way
going back and forth to truly appreciate
how insane that is if there were a human
colony on a planet there right now they
would only just now be hearing about
news and memes from 2015 do you even
remember what was going on back then
Boeing had just unveiled the 737 max
Obama was still the US president brexit
hadn't been voted on yet everybody's
favorite educational YouTube channel
hadn't even been created yet and people
were arguing over what color that stupid
dress was it's blue and black it just is
so this would be the current state of
our planet that would be reaching the
residents of Proxima Centauri B in the
future it'll take 8 and a half years
just to get a response from somebody
there after you send them a message
if humanity's life expectancy remains
around 80 years in the future you'll
only be able to share a maximum of 9
messages in your entire lifetime with
somebody who lives around Proxima
Centauri B and that's what the fastest
form of light speed communication looks
like with just the closest star to us in
the universe let alone the billions and
trillions of stars and planets that
exist even further away from that the
speed of light is slower than you think
it is and it's too slow for our grander
ambitions and space we just haven't
really
developed to the point yet where it's
become a major problem for us but it
will happen eventually and we need to be
prepared for it the physics of lights
are complicated but even though light
moves slowly there's all kinds of things
that you can learn by looking at it you
can use the principle of parallax to
learn how far away a star is or you can
look at a star's luminosity to figure
out how hot it is and you can learn how
to do both of these things and so much
more right now in the astronomy course
that's offered over at brilliance it's
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