SHAKESPEARE was wrong when he described Julius Caesar as "constant as the northern star", because the brightness of the North Star is variable, changing by a few per cent every four days. But the Bard will be right next year when the star's brightness will become constant, predict astronomers (New Scientist, Vol 138, No 1875).

The North Star's brightness varied by 10 per cent for most of the 20th century, but in the early 1980s, Armando Arellano Ferro in Canada discovered that the star's light variation had dropped to 5 per cent.

Astronomers Don Fernie, Karl Kamper and Sara Seager of the University of Toronto, Canada, have now found that the star's variability has plummeted further to only 1 per cent and predict it will stop pulsating in 1994.