And at last I see the light, And it’s like the fog has lifted. And at last I see the light, And it’s like the sky is new. And it’s warm and real and bright, And the world has somehow shifted. All at once everything is different, Now that I see you.
Today is the 340th anniversary of the determination of the speed of light:
By timing the eclipses of the Jupiter moon Io, Rømer estimated that light would take about 22 minutes to travel a distance equal to the diameter of Earth’s orbit around the Sun. This would give light a velocity of about 220,000 kilometres per second in SI units, about 26% lower than the true value of 299,792 km/s.