crossed by a multitude of absorption lines
The great spiral nebula in Andromeda has a continuous spectrum
crossed by a multitude of absorption lines. The spectrum is a
very close approach to the spectrum of our Sun. It is clear
that this spiral nebula is widely different from the
bright-line or gaseous nebulae in physical condition. The
spiral may be a great cluster of stars which are approximate
duplicates of our Sun, or there is a chance that it consists,
as Slipher has suggested, of a great central sun, or group of
suns, and of a multitude of small bodies or particles, such as
meteoric matter, revolving around the nucleus; this finely
divided matter being visible by reflected light which
originates in the center of the system.
