This day in . . . 1845

French physicists Louis Fizeau and Leon Foucault took this first successful photograph of the Sun on this day in 1845. They used the relatively new method of photography known as daguerreotype photography and managed to capture sunspots upon the Sun's surface.

Fizeau was also the first person to develop a terrestrial method of measuring the speed of light where previous estimates had been made by astronomical means. His value of 315000 km/s is not too far removed from the modern estimate of 299700 km/s.

Foucault was also working on the speed of light, although separately after the two had a falling out. He showed that light travels faster in air than it does in water. These two were great physicists, born within 5 days of each other, going to the same school and working together at the Paris observatory. What a shame they fell out - who knows what else they may have discovered as two great minds together.