Multiple Choice
Which of these statements does NOT correctly describe the universe at the era of recombination?
A) The temperature of the universe was about 3 K.
B) The universe was about 380,000 years old.
C) The universe became transparent to radiation.
D) Electrons and protons combined to form neutral hydrogen atoms.
Correct Answer:
Verified
Correct Answer:
Verified
Q39: What appears to be the relationship between
Q40: If the Hubble constant is 75 km/s/Mpc,
Q41: When a gamma-ray photon undergoes pair production,
Q42: The Milky Way Galaxy is moving at
Q43: In modern particle physics, the proton and
Q45: What are the particles that make up
Q46: An elliptical galaxy in Boötes (shown at
Q47: Which of these BEST describes the universe
Q48: If the cosmological constant exists, what physical
Q49: Why did Einstein introduce his cosmological constant