Earth–Sun distance changes from slippery equation to single number.
Without fanfare, astronomers have redefined one of the most important distances in the Solar System. The astronomical unit (au)
— the rough distance from the Earth to the Sun — has been transformed
from a confusing calculation into a single number. The new standard,
adopted in August by unanimous vote at the International Astronomical
Union's meeting in Beijing, China, is now 149,597,870,700 metres — no
more, no less.