On November 21, 1676, the Danish astronomer Ole Rømer discovered the speed of light. Space History Archives👉 https://space-com.visitlink.me/oPoIC4 Before Rømer figured it out, scientists thought that light travels instantaneously, or infinitely fast. Rømer disproved this almost by accident when he was studying Jupiter's moon Io. He was trying to figure out how long it takes Io to orbit Jupiter in hopes of using it as a cosmic clock. He watched Io disappear behind Jupiter and reappear on the oth