Why do we believe that most of the mass of the Milky Way is in the form of dark matter?
A) The orbital speeds of stars far from the galactic center are surprisingly high, suggesting that these stars are feeling gravitational effects from unseen matter in the halo.
B) Theoretical models of galaxy formation suggest that a galaxy cannot form unless it has at least 10 times as much matter as we see in the Milky Way disk, suggesting that the halo is full of dark matter.
C) Although dark matter emits no visible light, it can be seen with radio wavelengths, and such observations confirm that the halo is full of this material.
D) Our view of distant galaxies is sometimes obscured by dark blotches in the sky, and we believe these blotches are dark matter located in the halo.
A
You might also like to view...
If a galaxy has a radial velocity of 8000 km/s and the Hubble constant is 70 km/s/Mpc, what is the distance to this galaxy?
a. 8.75 × 10^3 Mpc b. 2.4 × 10^9 Mpc c. 5.6 × 10^5 Mpc d. 114 Mpc e. 8.75 × 10^-3 Mpc
To explain retrograde motion as well as changes in planetary brightness, Ptolemy's model used ________
Fill in the blank(s) with correct word
The Balmer lines of hydrogen involve electron transitions from the ground state to higher levels
Indicate whether the statement is true or false
Energy in Capacitors: A parallel-plate capacitor is connected to a battery and becomes fully charged. The capacitor is then disconnected, and the separation between the plates is increased in such a way that no charge leaks off. As the plates are being separated, the energy stored in this capacitor
A. increases. B. decreases. C. does not change. D. become zero.