OCR Text |
Show Velocity of Light. The first determination of the velocity ve-locity of light was made by Romer in 1676. The method was based upon the observation of the eclipses of Jupiter's satellites, phenomena of frequent recurrence re-currence and easy of observation. Assuming As-suming that light required time wherein where-in to move from place to place through space, the interval between successive eclipses would appear too short when the earth is approaching Jupiter and too long when the earth is receding therefrom. Romer found in his observations obser-vations that such was the case and that the interval was conditioned by the rate of speed at which the earth changed places relatively to Jupiter. From these constants Romer computed that light expended about sixteen and one-half minutes in crossing the earth's orbit. From this is deducsd a velocity of about 186,500 miles a second. sec-ond. Harper's Weekly. |