Let's Talk About: The Bright stuff Share with others: Pick a
star in the sky and ask yourself how bright it is. Brighter than
the one next to it, perhaps? And why is it so bright? If it
sounds simple, think again. It's a puzzle that astronomers say
our eyes alone cannot solve. In order to truly understand the
bright stuff, we need physics at the ready. The measure of a
star's brightness is referred to as its magnitude. Astronomers
arrange magnitudes on a scale in which dim stars are signified
by high numbers and bright stars by low numbers. A star with a
magnitude of less than zero is considered exceptionally bright.
Think of our sun. Nothing in the sky is brighter than the light
from our parent star. That is, if you're talking about its
apparent magnitude, which is the brightness of a star as viewed
from Earth. Because the sun is so close to us, it has the
highest apparent magnitude of all celestial objects: --26.7. But
while the sun is king by apparent magnitude, by absolute
magnitude it's not. Absolute mag