What is the name for the sun's crossing of the celestial equator, which happens twice a year?

On January 23, 1968, which country seized the USS Pueblo and detained its crew, accusing them of espionage? Thucydides began writing the history of which war when it broke out in 431 BC, and even served as a general in it? For his work developing nuclear-powered submarines, which admiral was known as the "Father of the Nuclear Navy"? Which singer co-wrote "Only the Lonely" and offered it to Elvis Presley before recording it himself? Which river flows more than 600 miles through Montana and Alberta before joining the Missouri? Lodgepole and ponderosa are types of which tall tree? Which Italian food brand, founded in Lucca in 1865, is best known for olive oil but also sells pasta sauces and frozen… Which cooking method roasts meat, such as a whole chicken, on a slowly turning spit?