Which of the following provides the strongest evidence that halo stars are older, on average, than disk stars?
A) Halo stars orbit in random directions, but disk stars have more ordered orbits.
B) There are no blue halo stars.
C) There are no red disk stars.
D) Theories of galaxy formation tell us that the halo formed earlier than the disk.
B) There are no blue halo stars.
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A beam of light in air is incident on a glass slab at an angle of incidence < 90°. After entering the glass slab, the beam of light
A) does not change its path. B) follows the normal to the glass slab. C) bends away from the normal drawn at the point of contact. D) bends closer to the normal drawn at the point of contact.
The measure of a material's capacity to transmit fluids is called the material's ______________
Fill in the blank(s) with correct word
The average orbital velocity in the Solar System is about _____
A) 10 km/s B) 20 km/s C) 30 km/s D) 40km/s
Most stable types of nuclei have an ______________ number of protons and an ______________ number of neutrons
a. even; odd b. odd; odd c. odd; even d. even; even