UKAstroNut's video: How Do We Know The Earth Is Round

Thousands of years ago, Greek philosophers and mathematicians worked out that the Earth must be round. But, there are still some people today who believe that it is flat. So, what are the key pieces of evidence that the world we live on is round? Twitter: https://twitter.com/UKAstroNut Facebook: https://www.facebook.com/UKAstroNut Website: http://www.ukastronut.co.uk Image credits: By The original uploader was Zhaladshar at English Wikisource - Transferred from en.wikisource to Commons., Public Domain, https://commons.wikimedia.org/w/index.php?curid=2681838 By Wmeinhart - Foto wurde mit einem Panoramaprogramm aus drei Fotos zusammengesetzt, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=124261 By NASA / Bill Anders - http://www.hq.nasa.gov/office/pao/History/alsj/a410/AS8-14-2383HR.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=306267