Multiple Choice
How do scientists estimate how old the universe is?
A) They measure the speeds and distances of galaxies, and calculate the time it took for them to travel that distance.
B) They measure the abundances of radioactive elements in meteorites, and use their half- lives to calculate the age.
C) They look up the answer in a book.
D) They measure how fast the Sun is losing energy, and how much energy it has to lose.
E) They make a guess; no one really knows how old the universe is.
Correct Answer:

Verified
Correct Answer:
Verified
Q16: Briefly explain how the Sun generates energy.
Q45: An astronomical unit (AU)is .<br>A)the current distance
Q46: How many galaxies are there in the
Q48: How long does it take our solar
Q49: Stellar and galactic crowding: The comparison of
Q51: How many seconds are in one year?
Q52: The Earth has a radius of about
Q53: Place the following items in order of
Q54: Which of the following statements does not
Q55: If the entire galaxy (with a diameter