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When is noon?
Posted by Rhett Allain on May 25, 2010 I was at the zoo this weekend, it was fun but hot. Somewhere near the middle, there was a sun dial. The cool thing (well, I think sun dials are cool anyway) was that the shadow was pointing about to the “12″. I looked at my watch and it said 1:05 PM. What is up…
RP 7: Cool things the Greeks did in astronomy
Posted by Rhett Allain on December 28, 2009 One of things I like to think about in science is “how do we know that?” It is interesting how one thing builds on another. This is a story of how the Greeks estimated the distance from the Earth to the Sun (an important idea in the development of the model of the solar system).…
When is the Sun directly overhead?
Posted by Rhett Allain on January 22, 2009 Question: When is the Sun directly overhead? (assume you are in the United States of America) Common Answers: Everyday at noon. On the summer solstice (June 21ish) Answer: For continental U.S. the answer is never. Since the Earth’s rotation axis is tilted 23.5 degrees with respect to its orbital motion around the Sun, one would…