How Eratosthenes calculated the Earth’s circumference

In 240 BC, the Greek astronomer, geographer, mathematician, music theorist and librarian Eratosthenes of Cyrene (c. 276 BC – c. 195/194 BC) calculated the circumference of the Earth without even leaving Egypt. Here’s how: Eratosthenes knew that at local noon on the summer solstice (at the time of the longest day, about 21 June in […]

Alternative Seven Wonders Of The World

The “Seven Wonders of the World“, describes seven great constructions known in the Hellenistic period – that’s why they are also known as the “Seven Wonders of the Ancient World”. In fact, in the Hellenistic era, each famous traveler had his own version of the list, but the best known and earliest surviving was from […]

What if a nuclear bomb hit your city?

On August 6, 1945, during World War II, an American Boeing B-29 Superfortress bomber named “Enola Gay” dropped the world’s first deployed atomic bomb codenamed “Little Boy” over the Japanese city of Hiroshima. The bomb exploded with 15 kilotons of TNT (63 TJ) of energy and caused horrendous destruction to the city. Approximately 66,000 people […]