What evidence suggests that the Milky Way contains dark matter?
A) We observe clouds of atomic hydrogen far from the galactic center orbiting the galaxy at unexpectedly high speeds, higher speeds than they would have if they felt only the gravitational attraction from objects that we can see.
B) We see many lanes of dark material blocking out the light of stars behind them along the band of the Milky Way.
C) We see many dark voids between the stars in the halo of the Milky Way.
D) When we observe in different wavelengths, such as infrared or radio, we see objects that don't appear in visible-light observations.
E) When we look at the galactic center, we are able to observe a large black hole that is composed of dark matter.
A
You might also like to view...
The density of ice is about 900 kg/m3, and the density of water is about 1000 kg/m3. A cubic block of ice one meter on a side floats in water. Assuming that the lowest square face of the cube is horizontal, the height of the block above the water line is
A. 0.2 m. B. 0.9 m. C. 0.5 m. D. 0.8 m. E. 0.1 m.
A uniform solid sphere rolls without slipping along a horizontal surface. What fraction of its total kinetic energy is in the form of rotational kinetic energy about the CM?
What will be an ideal response?
What is the energy of a photon that has the same wavelength as a 24 eV electron? (h = 6.63 × 10^-34 J×s, me = 9.11 × 10^-31 kg)
a. 24 eV c. 3.5 keV b. 14 × 10^-16 eV d. 5.0 keV
Aluminum alloys are readily deformed into shape because they have the _________-centered-cubic crystal structure.
Fill in the blank(s) with the appropriate word(s).