BILL NYE: Is the earth flat or round? It's round, okay. Now, let's see. How do we go about proving that? MICHELLE THALLER: That's a hard thing for
me to even start talking about because there are so many proofs that the earth is round
it's difficult to know where to start. NEIL DEGRASSE TYSON: B.o.B., the rapper, I
have a video letter to him the transcript of which is in ""Letters From An Astrophysicist."" That rose to that level of attention because
he started saying 'I'm using laws of math and physics to show Earth is flat.' Those are fighting words. You're going to say using math and physics? That is an alarm to the Geekoverse that we
must rise up and counteract these forces from the dark side that are out there. THALLER: There are proofs all around you. It is not difficult to know that the earth
is round. So let's start from the simple to the slightly
more complicated. One of the things you can see yourself with
a pair of binoculars is if you actually go out to a lake and there are boats on that
lake the farther away a boat is, the more the bottom of the boat will disappear and
you'll basically just see the mast of the boat. And as a boat goes farther and farther away,
the last thing you will see is the very top of the mast of that boat, and that's because
the boat is actually going over the horizon that's curved. And that means that as it goes farther and
farther away you see less and less of the bottom of it and more of the top of that. You can see that with binoculars by an ocean,
by a lake. It's really easy. That wouldn't happen if the earth were flat. You would simply see the boat getting smaller
and smaller and smaller as it went farther away, but you'd be able to see the whole thing
with the same proportions. NYE: Go to the seashore. Go to a seashore and figure out if you live
on the East Coast figure out why you can't see Spain from the East Coast of North America. Just go to the middle of the Mississippi River
and look south. Why can't you see Louisiana. Why can't you see New Orleans. What's the problem there? Or the climb a tower or go to the top of a
hill or a mountain and you'll see a little farther, but you will not see to the other
side of the earth, places we know to exist. For example, I've been to London. I can tell you other people have. I've been to Vancouver, British Columbia and
you cannot see Vancouver, British Columbia from Boise, Idaho let alone from New York
City or Toronto or what have you. THALLER: Then there's some other proofs that
are a little more obscure but they're actually really lovely and one is to observe What happens
during a lunar eclipse. Now a lunar eclipse happens when the earth
casts a shadow on the moon. The moon actually goes dark. In fact if you've seen one you could actually
see the earth's shadow go across the moon. And when the moon is entirely in the earth's
shadow the moon looks like of dark and even kind of red colored. It's really, really beautiful. What's happening in that case is that the
sun is on one side of the earth. The earth is in the middle and it's casting
a shadow. The earth is casting a shadow on the moon. And as the shadow moves across the moon you'll
notice that the shadow is curved, it's round. So something like the Sun that's bigger than
the earth and is able to cast a shadow of the earth on the moon can actually show you
the shape of the earth. Aha, you might say, but could the earth be
a disk? Could it be flat but it's actually still shaped
like a disc, not like a sphere. There was a Greek scientist called Aristarchus
and what he noticed was that you can get a lunar eclipse at many different angles where
the sun is. Sometimes the shadow goes straight across
the moon. Sometimes it just kind of glances the moon
just a little bit is in shadow just on the top or on the bottom. From every different vantage point, every
different angle that the sun is casting a shadow you always get a perfectly curved shadow. The only shape that can cast a shadow that's
curved from any direction you put the light is a sphere. So people have known that the earth is spherical
for thousands of years. NYE: Look at pictures from space where you
see the earth as a sphere. Those pictures are not faked and I'll tell
you just if nothing else here's why you can tell they're not faked. Just to create the paperwork that NASA had
created, NASA in this one case. Just the paperwork to send anything out in
space. To send people into orbit or to send them
to the moon, that amount of paperwork would make faking it prohibitively expensive. No one could afford to generate that much
documentation. Then the other thing if you want to get into
this, if your friends are really serious, have them get on a boat or a ship and go out
at sea and you'll notice you can't see infinitely far. Furthermore if you get into it enough pick
up a book about navigation or go online and learn about navigation. A very, very important thing you have to take
into account when you try to navigate the ocean from a ship or a boat is how high you
are off the sea surface. The higher you are off the sea surface, the
farther you can see, the farther away the horizon is. THALLER: I actually said this to somebody
and I couldn't believe they'd never thought of it, but with binoculars you can see planets. You can see Saturn and Jupiter. You can see Mars with a telescope. The sun, the moon, everything else you see
in the solar system is a sphere. So we're the one thing that is different? And that actually made somebody who was more
interested in actually hearing information, that got them to think like you're right. Everything else we take a picture of is a
sphere. NYE: And you guys, come on. Everybody watches newscasts. You all use mobile phones. You all see airplanes fly around. You all go to see Ed Sheeran in concert one
day in London, another day in Melbourne, Australia. This all depends on our fundamental understanding
of the size of the earth and its shape with extraordinary precision. And if you want to get into it the earth isn't
quite a sphere. It's a little wuhh. Its spin is a little wuhh, stretched it, made
it slightly oblate as the saying goes. THALLER: And it's not okay to think that the
earth is flat. This is not a viable argument. I have friends who have been on the international
space station. They have orbited the earth once every 90
minutes. I have had personal experience with people
that have been up in space and can see with their own eyes that the earth is round. And, of course, we've taken all these amazing
pictures from space. They're so beautiful all those pictures of
the earth. So I don't really know what's going on right
now with this earth is flat thing. TYSON: In a debate what is the construct? It's typically two people and there's an audience
and you debate some opposite sides of some issue and then there's a winner of the debate. And everyone walks away reflecting on the
winner. So who wins a debate? It's often the person who's charismatic, who
may be charming that's related to charisma of course. Who had a good way with words, good vocabulary. And you can have someone who doesn't have
any of that who is speaking objective truths who could lose a debate. So then what is the point of the debate if
one of these points of view is objectively true? I will not enter a debate where I have the
objectively true side of an argument and the other person does not. That is something that should not be debated,
does not belong in front of an audience getting debated. You want to debate something? Debate political policy of what to do in the
face of climate change. Do you have carbon tax? Do you have solar panels? Do you subsidize them? Debate that. Don't debate something that is or is not objectively
true in this world. NYE: This is all susceptible to analysis,
but spend some time learning about navigation, tell your friends to spend some time learning
about navigation. Ahh. Navigation has changed the world by the way. What are you wearing? You're wearing stuff that came from another
part of the world on a ship. It didn't get here by magic. It got here through science. TYSON: I think it's important to combat people
who are claiming that they are using math, science, evidence and physics behind their
cause when, in fact, they either aren't or they're using it badly. That needs to be called out. Otherwise, if you just have a belief system
I don't really care. We live in a country that protects free speech
which usually also means free thought. You want to think Earth is flat, go right
ahead. But if you start influencing other people
who have power over other people and you have no foundation in objective reality it can
be dangerous. If you influence people or you yourself become
someone who has influence over legislation, laws, rules by which we all abide in society,
that's an unhealthy situation for civilization to be in. If your personal belief system which does
not have correspondence in objective reality starts becoming predominant in the thoughts
and hearts and minds of civilization. THALLER: It's not okay to say that the earth
is flat. This is some sort of strange denial. I don't know where it comes from and it's
something where I keep getting this question. We really need to put this question to bed
because we've known the earth is a sphere for a long time.
