Astro*Dictionary
by Michael Erlewine

1 article for
"Lebedev, Pyotr Nicolaievich"

(lay'beh-dev)

(1866-1912) Russian physicist.

In 1901, he was able to observe and measure the pressure exerted by light, using very light mirrors in a vacuum. This result explains why the tails of comets point away from the Sun, regardless of whether the comet is approaching or receding from the Sun.