What is the critical density?
Group of answer choices
the density of a black hole
the minimum density needed for nuclear fusion in stars
the density of a gas cloud that is about to form a new star
the density that is just enough to slow the expansion of the Universe to zero eventually
Flag question: Question 2Question 21 pts
About when did helium form in our Universe?
Group of answer choices
1 second after the Big Bang
3 – 4 minutes after the Big Bang
4.5 billion years after the Big Bang
380,000 years after the Big Bang
Flag question: Question 3Question 31 pts
In an open universe…
Group of answer choices
the universe expands forever
galaxies will get so far apart it will be hard to see them anymore
the average density is less than the critical density
all of these answers are true
Flag question: Question 4Question 41 pts
Who first observed the cosmic microwave background radiation?
Group of answer choices
Caroline and William Herschel
Newton and Galileo
Turner and Hooch
Penzias and Wilson
Flag question: Question 5Question 51 pts
What did Einstein add to his theory of general relativity because he thought the universe could not be expanding?
Group of answer choices
Hubble’s law
the cosmological constant
the speed of light
curved spacetime
Flag question: Question 6Question 61 pts
If you use the reciprocal of the Hubble constant, then what is the approximate age of the Universe?
Group of answer choices
4.5 billion years
2 billion years
70 billion years
14 billion years
Flag question: Question 7Question 71 pts
Where did matter come from in our Universe?
Group of answer choices
conversion from an equal amount of dark energy
the collision of high energy photons
the merger of two galaxies
nuclear fusion in stars
Flag question: Question 8Question 81 pts
In order to have a “big crunch” in the universe, the average density of matter must be…
Group of answer choices
less than the critical density
greater than the critical density
none of these answers are correct
equal to the critical density
Flag question: Question 9Question 91 pts
What was the temperature of the Universe three minutes after the Big Bang?
Group of answer choices
1 billion K
15 million K
6000 K
100 million K
Flag question: Question 10Question 101 pts
What is the current blackbody temperature of the cosmic microwave background radiation?
Group of answer choices
2.73 K
10 million K
30 K
3000 K
What term do astronomers use to describe whatever is responsible for accelerating the expansion of the Universe?
Group of answer choices
spectroscopy
dark energy
relativity
dark matter
Flag question: Question 2Question 21 pts
About when did helium form in our Universe?
Group of answer choices
380,000 years after the Big Bang
4.5 billion years after the Big Bang
1 second after the Big Bang
3 – 4 minutes after the Big Bang
Flag question: Question 3Question 31 pts
What is the current blackbody temperature of the cosmic microwave background radiation?
Group of answer choices
3000 K
2.73 K
30 K
10 million K
Flag question: Question 4Question 41 pts
In an open universe…
Group of answer choices
all of these answers are true
galaxies will get so far apart it will be hard to see them anymore
the average density is less than the critical density
the universe expands forever
Flag question: Question 5Question 51 pts
What is the critical density?
Group of answer choices
the density of a gas cloud that is about to form a new star
the density of a black hole
the density that is just enough to slow the expansion of the Universe to zero eventually
the minimum density needed for nuclear fusion in stars
Flag question: Question 6Question 61 pts
What did Einstein add to his theory of general relativity because he thought the universe could not be expanding?
Group of answer choices
the speed of light
curved spacetime
Hubble’s law
the cosmological constant
Flag question: Question 7Question 71 pts
If you use the reciprocal of the Hubble constant, then what is the approximate age of the Universe?
Group of answer choices
2 billion years
4.5 billion years
14 billion years
70 billion years
Flag question: Question 8Question 81 pts
Who first observed the cosmic microwave background radiation?
Group of answer choices
Penzias and Wilson
Caroline and William Herschel
Turner and Hooch
Newton and Galileo
Flag question: Question 9Question 91 pts
In order to have a “big crunch” in the universe, the average density of matter must be…
Group of answer choices
equal to the critical density
less than the critical density
none of these answers are correct
greater than the critical density
Flag question: Question 10Question 101 pts
Where did matter come from in our Universe?
Group of answer choices
nuclear fusion in stars
the merger of two galaxies
the collision of high energy photons
conversion from an equal amount of dark energy
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