>Astronomers have discovered a world only a little bit bigger than Earth, whirling around a bright star about 31 parsecs from our planet.
Parsec is one of those units that is difficult to remember if you just look at the conversion (1 parsec = 3.26 light years). If you remember how it's defined, however, it somehow becomes easier (for me anyway). One parsec is the distance at which one astronomical unit (AU, mean distance between earth and sun) spans one arcsecond in the sky. One arcsecond, in turn, is 1/3600th of a degree, and is approximately the width of a human hair from 20 meters away.
On a side note, if you think that's small, many stars in the night sky have apparent diameters measured in thousandths of an arcsecond.
Parsec is one of those units that is difficult to remember if you just look at the conversion (1 parsec = 3.26 light years). If you remember how it's defined, however, it somehow becomes easier (for me anyway). One parsec is the distance at which one astronomical unit (AU, mean distance between earth and sun) spans one arcsecond in the sky. One arcsecond, in turn, is 1/3600th of a degree, and is approximately the width of a human hair from 20 meters away.
On a side note, if you think that's small, many stars in the night sky have apparent diameters measured in thousandths of an arcsecond.