• ## Don’t believe Neil Tyson or B.o.B. Calculate the Circumference of Earth with Your Pen Pall.

OK, so it has come to my attention that the great Neil deGrasse Tyson has engaged on twitter with a recording artist called B.o.B. about whether the Earth is flat or spheroidal. Which is simultaneously the reasons why love and hate Twitter. I won’t go into why B.o.B. thinks what he thinks, or how he is wrong or why Neil Tyson cares to engage the matter. What I will do is show you how to figure it out for yourself. Below are some resources that will help you discover the nature of Earth all by yourself.

## Eratosthenes

First: the geometric nature of Earth was first estimated by Eratosthenes some 2000 years ago in Egypt. Conspiracy theories weren’t invented until the middle ages (5th to 15th centuries), according to wikipedia.Â Eratosthenes calculated the circumference of the earth to within about 100 miles of the real circumference with nothing more than simple tools and knowledge. Here’s how Eratosthenes did it:

You can do the same with a few simple tools. Here is a great step by step method for you and a friend in some distant city to partner up and calculate the circumference of the earth from Science Buddies.org.

Eratosthenes figured it out all on his own but he had to do it on a certain day (the summer solstice) and relate his observations to what he knew about shadows another city (Syene)about 500 miles away. Here’s a good illustration of that:

And for more in-depth math on the matter, check out this video from Kahn Academy.

## The Real Flat Earth Conspiracy Theory

So to my eyes, the Earth is spheroidal, unquestionably. At least according to basic geometry. Unless the sun’s rays are not parallel…

The more you know, the less you tweet.

-M