What do we mean by the main-sequence turnoff point of a star cluster, and what does it tell us?
A) It is the spectral type of the hottest main-sequence star in a star cluster, and it tells us the cluster's age.
B) It is the mass of the most massive star in the star cluster, and it tells us the cluster's size.
C) It is the point in a star cluster beyond which main sequence stars are not found, and it tells us the cluster's distance.
D) It is the luminosity class of the largest star in a star cluster, and it tells us the cluster's age.
A
You might also like to view...
A neutron bouncing off a heavy nucleus loses speed. If it instead bounces off a light nucleus it loses
A) less speed. B) more speed. C) the same amount of speed.
Compared to optical telescopes, radio telescopes are built large because
A) radio waves have very long wavelengths. B) radio waves are absorbed by the atmosphere. C) atmospheric turbulence is more of a problem. D) they're less expensive to make than optical telescopes. E) radio sources are harder to find.
The largest plutons are called ______________
Fill in the blank(s) with correct word
What are the two possible explanations for not seeing something glowing brightly along every line-of-sight?
I) The universe is infinite in size and infinitely old, but dust absorbs starlight from far away stars. II) The universe has a finite number of stars. III) The universe is changing in some way as to prevent us from seeing an infinite number of stars. A) I and III B) II and III C) I and II