so tell me Neil is the earth flat? we
have video from space of the rotating
spherical earth. the earth is round. thank
you for joining us on this episode.
This is a cartoon
but what's odd is there are people who
think earth is flat right but recognize
that the moon is round Mercury Venus
Mars Jupiter Saturn Uranus Neptune and
the Sun are all spheres but earth is
flat
that's not something doesn't square
that's a job right okay plus in my
latest book mmm your latest book is
called astrophysics four people in a
hurry well we just where we didn't plant
the book I have an entire chapter titled
on being round and it's an exploration
of how all the laws of physics and the
accounting of energy as processes unfold
in the universe how that conspire to
make things round so it favors the speed
favors a sphere yes and if it's
something is not a sphere it's a little
bit flattened you can ask what's landed
and you find out oh it's rotating real
fast right so then it gets a little
flattened because of that right and so
almost everything in the universe is
either spheres or slight distortions of
a sphere for some other thing that's
happening to it I mean we can just see
how the the universe favor spheres so
its nature right basic nature universe
it has fairness to the people who want a
flatter yes let's be fair to those in
Columbus's day there was surely a flat
earth contingent yes
columbus predates the era of
experimental checking of any idea you
might have not a peer-reviewed a kind of
just let just say whatever yourself you
know what i believe that elephant poop
will cure cancer there you go that's
right wrote a paper about it like to
read it here it is right right so it was
a tool till Francis Bacon Galileo 1600s
where the idea that if you're going to
say something and you think what you're
saying is true then no matter how
obvious you think it is that it's true
you should still test it doctor there
could be something fooling you in one
way or another so if you want to say
earth is flat then for example
lunar eclipses what's a lunar eclipse if
your face is the brilliant Sun thank you
and this is Earth and the moon is over
here the Sun is always casting Earth's
shadow into space it's always there no
matter what right obviously okay it's
just a shadow it's a channel the moon
shining on blackness yeah a shadow in
darkest shadow and so so the moon
occasionally passes through that shadow
and if you see the shape of Earth's
shadow on the moon it is always round
always round if earth were flat
sometimes you get like a flat shadow all
right and we've never seen a flat shadow
right in fact it is a segment of a arc
of a circle
no matter the orientation of the moon
and the Sun and the only thing that
makes a perfectly circular shadow would
be something that's perfectly circular
perfectly spherical yes so the only
thing that makes a perfect circle shadow
every single time is a perfect sphere
okay no matter what angle and where as a
disc it would only make a perfect circle
if you lined it that way and then they
have to look at the face of the disc in
order to get the circle Greeks knew this
right all the lunar eclipses had they
said oh my gosh we must be in a round
earth this is thousands of years before
Columbus exactly so now if the earth is
round how big is earth you might want to
check for that there's a famous
experiment conducted by Eratosthenes
Bethany ever touched the knees in the
two cities in the old world and one of
them they knew that at 12:00 noon on a
particular day of the year that the Sun
was directly overhead and you can see
the bottom of a well okay you don't run
around looking at the bottoms or wells
no you net because the light doesn't
take it's just doesn't get down it
doesn't get down it how can we use this
observation to see if Earth's surface is
curved we needed another well turns out
we can't see the bottom of both wells at
the same time what might explain this
well they're two possible explanations
first we could have a flat earth with
the Sun that's small and close by so
that the light hits the second well at
an angle or second we could have a
curved earth with a Sun that's big and
far away so that all the light comes in
parallel but only one well at a time is
lit all the way to the bottom turns out
with just two wells there's enough
wiggle room for both explanations to fit
our observations
Eratosthenes only had two wells but what
if he had added a third with a third
well it doesn't matter where the Sun is
no flat earth model can explain the
angles of all three shadows but the
spherical model explains it all all
three angles with ease and to do this
experiment you got to measure the angles
Greeks had the angles yeah okay in fact
geometry translates to earth measurement
so one last thing which should be
obvious okay if you pay attention and
think about it if you send a ship
straight to the horizon it eventually
begins to disappear until it's no longer
visible beyond your horizon right and
you should ask yourself what kind of
surface would produce that result if
it's con ocean has a ramp they just like
going down seafarers knew this right and
so would however flat they would have
imagined the earth to be they couldn't
they couldn't have accepted to be
completely flat because otherwise you
would never not see the ship okay
also if I just tell you chuck walk due
east okay right and don't ever stop
right I just turn around my chair and
face this way and eventually you're
gonna come back right and you'll
probably be about 150 years old
cuz I am no Forrest Gump that is that
long that would take me to run the earth
for me the fact that there's a rise flat
earthers there's evidence of two things
okay long one we live in a country that
protects free speech that's actually
kind of Awesome and two we live in a
country with a failed educational system
whoo that one hurt our system needs to
train you not only what to know but how
to think about information and knowledge
and and and and evidence if we don't
have that kind of training you'd run
around believe anything anything
anything and if you're interested in
learning more about the earth the Sun
and how the fact that we're rolling
through space at what do i what is this
17,000 miles per hour is that what we're
going for that number out of your you
know what I pulled it from so you should
consider all of this and consider
chucking out brilliant whether you are
an adamant defender of the Earth's
curves mm-hmm or a professional
scientist or a lifelong learner
brilliant helps you master concepts of
math science and engineering through
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