Black plaque № 25288

San Antonio, TX, United States

Belgian Transit of Venus Observation Site. The year 1639 marked the first recorded observation of Venus crossing the sun. Sir Edmund Halley (1656-1742) later predicted that using data from such crossings, known as transits, scientists could precisely quantify the astronomical unit of distance and me

asure the size of the solar system. The transits of Venus predicatably come in pairs, eight years apart, approximately every 120 years. Scientists from around the world traveled to observation sites d

Listen to the audio guide for Black plaque № 25288 Free on WIP — starts by itself when you arrive, even with the screen off