Author Question: How do scientists estimate how old the universe is? A) They look up the answer in a book. B) ... (Read 74 times)

skymedlock · **on:** Jul 27, 2018

How do scientists estimate how old the universe is?

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

Question 2

The greenhouse effect makes Earth warmer than it would be otherwise by about

A) 30 K. B) -16 K.
C) 15 K. D) There is no greenhouse effect.