What chiefly dictates the intrinsic color of a galaxy, separate from distance effects?
Answer
The types of stars currently dominating its population
The actual, or intrinsic, color of a galaxy is determined by the makeup of its stellar population at the time the light is emitted. If the galaxy is dominated by massive, short-lived, hot stars that are burning through their fuel rapidly, these stars emit intensely in the blue and ultraviolet regions, yielding a blue intrinsic color. Conversely, if the massive stars have already died off and the galaxy is populated mainly by aging, less massive stars, such as red giants, the galaxy will inherently possess a reddish or yellowish cast. This stellar composition acts as a cosmic clock, signaling the galaxy's stage in its life cycle.
Related Questions
What stellar population primarily dictates a galaxy's vibrant blue appearance?What physical process stretches light waves leading to the phenomenon of redshift for distant galaxies?What two distinct physical phenomena can cause a galaxy to appear red?If a galaxy has a measured redshift value of z=3, by what factor has its light wavelength been stretched?What foundational relationship did Edwin Hubble establish concerning galaxies based on redshift measurements?What chiefly dictates the intrinsic color of a galaxy, separate from distance effects?Which celestial object is explicitly mentioned as exhibiting a blueshift due to approaching the observer?Why are powerful infrared instruments like those on the James Webb Space Telescope essential for observing the very first galaxies?How did the light forming the Cosmic Microwave Background (CMB) achieve its current microwave frequency?When astronomers analyze a galaxy spectrum, how is the known wavelength of spectral lines like hydrogen used to calculate distance?