Strange Universe: Venus leaves with a bang 7/2/23

Venus is now at its very brightest, at magnitude -4.7, which makes beginners wonder what that means. If Venus is the most brilliant starlike object, what can we compare it with? Well, summer’s brightest stars are magnitude zero and one, which makes them 100 times less luminous than Venus. The magnitude business started with an ancient Greek named Hipparchus, who assigned each star a different magnitude. Hear the buildup to using photometers and what how certain starts became visible with time.