Optics. Ole Ryomer

you are: Optics

The First real certificate of finiteness of a velocity of light the Danish astronomer has received in 1675 Ole Ryomer (1644-1710) of supervision of seeming divergences between the moments of eclipses of companions of Jupiter. Still Galilej has opened that at Jupiter four companions (now it is known much more), moving in the same plane, as a planet, round the Sun. Thus, as the planet rejects the huge shade, each companion should become covered by this shade at each turn; both companions, and a planet are visible, certainly, only thanking otra-0. Ryomer zheniju a sunlight.

Eclipses of companions of Jupiter should be observed in various seasons according to relative position of the Earth and Jupiter. It has been found that the interval between eclipses accepts the maximum and minimum values through time intervals approximately in six months. The difference between these two values was absolutely doubtless - nearby 30 sek, and eclipses occurred often enough - each 42 hours so it was possible to see gradual change of an interval.

As rotation of the Earth cannot bear any responsibility for irregularities of movement of companions of a remote planet, Ryomeru needed to be assumed that the explanation lies in a final velocity of light. In time between two eclipses the Earth passes about 5 million in km; 15 sek - the maximum deviation from the average period is, should be, time necessary for light for passage of such distance, and, hence, a velocity of light should be slightly less 320 thousand in km in second

It was the first definition of size which as we know now, is one of the major physical constants. Being stated thus, work of Ryomera seems rather prosaic: as if he has simply noticed that any other person could notice. Actually supervision of Ryomera is a scientific feat, opening. Newton when wrote the ' Optics ', without hesitation recognised that Ryomer has measured a velocity of light.