Type Ia supernova
This is important because the brightness of type Ia supernovae was thought to be essentially uniform, making them useful "standard candles" in measuring distances in the universe. Such an aberrant type Ia supernova could throw distances and other scientific work into doubt; however, the light curve characteristics of SN 2003fg were such that it would never have been mistaken for an ordinary high-redshift Type Ia supernova.