Archive for December 5, 2017

12/05/2017 – Ephemeris – A flat Earth, come on, really?

December 5, 2017 Comments off

Ephemeris for Tuesday, December 5th. The Sun will rise at 8:03. It’ll be up for 8 hours and 58 minutes, setting at 5:02. The Moon, 2 days past full, will rise at 7:35 this evening.

Last Friday night I gave a talk to the Grand Traverse Astronomical Society about the world view of mostly ancient peoples. They uniformly believed in a flat Earth. This includes the world of the Bible. The Greek geographer Eratosthenes calculated the circumference of the Earth way back in the third century BC. A flat Earth would normally be the conclusion of a person who never went more than a few hundred miles from home, especially in an east-west direction. However if one went north or south, the stars would slowly change. Head south and new stars would appear above the southern horizon, and in the north, stars that would never set would now set. Polaris would drop lower in the North. The round Earth is the simplest explanation.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.


Here’s an extension from my notes:

Those who profess to believe in a flat Earth tend to be Christian and believe that the Bible is literally true even to the physical description of the world found in its pages. Therefore the basis for the flat Earth is the Bible.

While there are those who have always believed in a flat earth, Eratosthenes pretty much put killed that notion in the 3rd century BC when he found that there was a 7.2 degree difference in the altitude of the Sun at local noon on the summer solstice between Syene and Alexandria in Egypt. The distance between the two cities was about 800 km, and 7.2 degrees is 1/50th that of a circle, so the Earth would have been 50 X 800 or 40,000 kilometers or 25,000 miles* in circumference. This of course meant that the Earth was round! The units he used were stadia, whose exact length has been in doubt.

Flat earth theories started to proliferate in the mid-19th century when most of the Earth’s coastlines had at least been mapped, though the polar regions had yet to be breached.

Zetetic Astronomy. Earth not a globe! An experimental inquiry… by Samuel Birly Rowbotham, 1865
Zetetic Cosmology: Conclusive evidence that the world is not a rotating-revolving-globe, but a stationary flat pane circle, second edition, by “Rectangle”, 1899. Rectangle is a pseudonym of T. Winship
These can be found on

The latest reincarnation of the Flat Earth Society was started in 2013.  Their web page and wiki is here:

Flat Earth

The Flat Earth by Trekky0623 at English Wikipedia, placed in the Public Domain.


  • North Pole in the center.
  • The firmament rotates around it.
  • There is no South Pole.
  • There are impassable mountains in Antarctica at the end of the Earth.
  • Wouldn’t the Sun be always up for everybody?
  • Apparently, the Sun orbits over the flat Earth in circles between the Tropic of Cancer and Tropic of Capricorn to produce the seasons.
  • The Sun is 3000 miles away and is only about 30 miles in diameter.
  • It shines like a spotlight over the earth.
  • The moon is somewhat lower than the sun and can cause solar eclipses.
  • The flat Earth’s shadow cannot cause a lunar eclipse, since the Moon is on the same side of the Earth as the Sun. The eclipse is caused by a “shadow object” that we can’t see that comes between the Sun and the Moon.

It boggles my mind how anyone in this day and age, who travels a lot cannot believe that the Earth is a spheroid. Maybe no one looks up anymore. Perhaps I’m just an oddball astronomer who like to look up and see the stars shift as I move south or north. In fact I plan on it when I travel.

* corrected this value from the original post