SCIENCE

So, a Twitter spat between astrophysicist Neil deGrasse Tyson and rapper B.o.B over the flat Earth theory has turned into a full-blown rap battle. (NPR)

Watch Neil deGrasse Tyson’s StarTalk to see what B.o.B. is up against.

Teachers, scroll down for a quick list of key resources in our Teachers’ Toolkit.

All the images in this gallery come from NASA’s Earth-observing satellite Suomi NPP. Can you spot California’s Central Valley? What Mexican mountain chain cuts through the center of the image? Image courtesy NASA/NOAA/GSFC/Suomi NPP/VIIRS/Norman Kuring

All the images in this gallery come from NASA’s Earth-observing satellite Suomi NPP. This one showing the striking differences in the landscapes of the icy Arctic, deserts of Africa and southern Asia, and the green, green grass of Europe. (Compare this image of the Arctic Circle with the diagram provided by the Flat Earth Society.) Image courtesy NASA/GSFC

All the images in this gallery come from NASA’s Earth-observing satellite Suomi NPP. Can you spot how the swirling storms of the southern Indian Ocean differ from the hurricanes of the North Atlantic? (Think about the Coriolis effect.) What rivers help create Africa’s lushly verdant central region so clearly visible in this image? Image courtesy NASA/NOAA

All the images in this gallery come from NASA’s Earth-observing satellite Suomi NPP. Can you understand why Australia is sometimes called the “island continent”? Can you spot the microcontinent of Zealandia peeking out from the clouds in the southeast? Image courtesy NASA/NOAA

All the images in this gallery come from NASA’s Earth-observing satellite Suomi NPP. You’re familiar with the Blue Marble. Well, here’s the Black Marble—a nighttime image showing the city lights of Asia. What is the brightly lit, heavily urbanized city-state north of Australia? What cities do the networks of the Indian subcontinent connect? Why do you think eastern China is more brightly lit than western China? Image courtesy NASA Earth Observatory/NOAA NGDC

Discussion Ideas

• Why is rapper B.o.B. picking a fight with astrophysicist Neil deGrasse Tyson?
  • B.o.B. is disputing science. He seems to believe the flat-Earth model of our planet’s shape. The leading theory of modern flat-Earthers is that Earth is a flat disc, surrounded on all sides by an ice wall (Antarctica) that holds the oceans back. (Here’s a model.)
  • Neil deGrasse Tyson is a scientist—specifically, he’s an astrophysicist who is very familiar with spherical planets.

• How do we know the Earth is round?
  • Here are 10 good reasons, some of which you can test on your own, with a little help from a classroom in another state or country.
    
  • 10: All the other planets and stars we’ve ever seen have been spherical. In fact, being spherical is part of the definition of a planet. Read about it here.
  • 9: Day and night happen at different times on different places on Earth. Use our fun activity to help students understand how time zones work.
  • 8: The Coriolis effect means that ocean currents and hurricane winds are deflected to the right in the Northern Hemisphere, to the left in the Southern. Learn why this indicates a curve here.
  • 7: Three 90-degree angles make a triangle on the Earth’s surface, but not a flat surface. Learn more about the geometry of spheres here.
  • 6: The sun appears lower and lower in the sky as you travel away from the Equator. Prove this yourself, by getting in touch with a school a couple hundred miles north or south of you. Cue up the video to about :56 for instructions on what to do next.
  • 5: The positions of the stars changes as you go north or south. This is crucial for celestial navigation—investigate how one 20th-century explorer used celestial navigation to travel the world.
  • 4: People circumnavigate the world sailing in one direction! Read about some of them here.
  • 3: Sunsets, ships, and even buildings sink below the horizon. Learn more about this deceptively important concept here.
  • 2: The shadow of the Earth can eclipse the moon. See the phases of a lunar eclipse here.
  • 1: Astronauts from NASA and other space agencies have seen the Earth, and we have countless images of our planet from space. Learn more about one of the most famous here.

• How long have we known the Earth was round?
  • At least as far back as ancient Greece. Students of Pythagoras (500 BCE) knew the Earth was round, Aristotle (350 BCE) explained the world was round, and Eratosthenes (240 BCE) even calculated the circumference of the Earth. Learn more about Eratosthenes here.

• B.o.B. seems to bring up a good point: “The New York City skyline is clearly visible from Harriman State Park’s Bear Mountain, 60 miles away. If Earth were a ball 25,000 miles in circumference, viewing from Bear Mountain’s 1,283-foot summit, the Pythagorean theorem determining distance to the horizon being 1.23 times the square root of the height in feet, the NYC skyline should be invisible behind 170 feet of curved Earth.” So why is the iconic Manhattan skyline visible from Bear Mountain?
  • Neil deGrasse Tyson points out that “Earth’s curve indeed blocks 150 (not 170) ft of Manhattan. But most buildings in midtown are waaay taller than that.”

TEACHERS’ TOOLKIT

NPR: Neil DeGrasse Tyson Gets Into A Rap Battle With B.o.B Over Flat Earth Theory

Nat Geo: StarTalk videos

Minute Physics: Top 10 Reasons Why We Know the Earth is Round

Nat Geo: 240 BCE: Eratosthenes Measures Circumference of Earth

LiveScience: Are Flat-Earthers Being Serious?