How Can I Know that the Earth is Spherical?

Yet more celebrities come out and say they believe the Earth is flat
-- Rob Waugh for Metro.co.uk
Tuesday 21 Feb 2017 3:14 pm

There's are at least two simple solutions to this stupidity. You can do them yourself!

1. Friend's word
   1. Get a reliable friend whose word you trust. Make sure that both of you have working cell phones. Set them to international communications.
   2. One of you then flies to a spot supposedly around the globe. For example, it might be 8am where you are in New York and supposedly 3am in Hawaii.
   3. You know that the sun has risen in New York. What's it doing in Hawaii?
   4. Confirm each other's observations by using a video chat such as facetime.
   5. Talk to your friend about which of you is deluded or how flying on an airplane must be time travel or ... maybe the earth is spherical after all!
   6. If you have lots of friends around the planet, set up a google group video conference call and compare the locations of the sun, moon and stars while talking to each other.
   
   
   • google: time zones new york hawaii
   • Current Local Time in New York, New York, USA
   • Current Local Time in Honolulu, Hawaii, USA
2. Repeat the experiment of Eratosthenes. google: greek mathematician earth is round
3. Force the person who convinced you that the earth is flat to do these simple experiments.