The apparent magnitude (m) of a celestial object is a number that is a measure of its brightness as seen by an observer on Earth. The smaller or more negative the number, the brighter a star appears. The sun, at apparent magnitude of -27, makes it the brightest object in the sky. It is adjusted to the value it would have in the absence of the atmosphere. The brighter an object appears, the lower its magnitude value (i.e. inverse relation). In addition, the magnitude scale is logarithmic: a difference of one in magnitude corresponds to a change in brightness by a factor of or about 2.512.