
StarTalk @StarTalkRadio
#OTD 1/7/1610: Galileo wrote a letter describing 3 of Jupiter's moons for the first time - he 1st described them as "fixed stars" but quickly realized they were satellites w/later observations (where he also found the 4th Galilean moon): https://t.co/RGgFExWRSl https://t.co/uliCHblJau — PolitiTweet.org