1.Is it possible to see the cosmic microwave background radiation with your nake
ID: 1514656 • Letter: 1
Question
1.Is it possible to see the cosmic microwave background radiation with your naked eye? With a visible light telescope?
a.The cosmic microwave background radiation has been cosmologically redshifted to present-day wavelengths in the microwave range. Thus they cannot be seen with the naked eye or with a visible light telescope.
b. The cosmic microwave background radiation was released when the first stable hydrogen atoms were formed. Thus, this radiation includes Balmer transitions that are in the visible range. But this is a very small portion of the entire spectrum, so the visible spectrum will be very dim.
(2) What does it mean to say that the universe is dark-energy-dominated?
a.This means that the density of dark energy is larger than the density of radiation or of matter in the universe.
b.This means that the fraction of dark energy in the universe is changing more rapidly than the fraction of radiation or matter.
c.This means that the gravitational pull on Earth is influenced more by dark energy than by matter or by radiation.
(3) What happened when the universe changed from being matter-dominated to being dark-energy-dominated?
a.The universe began to expand.
b.The expansion rate of the universe began to accelerate.
c.The universe ceased to expand.
d.The expansion rate ceased to accelerate.
Explanation / Answer
1-a
1. It is not possible to see the cosmic microwave background radiation with your naked eye or With a visible light telescope because
The cosmic microwave background radiation has been cosmologically redshifted to present-day wavelengths in the microwave range. Thus they cannot be seen with the naked eye or with a visible light telescope
2. a
the universe is dark-energy-dominated means
the density of dark energy is larger than the density of radiation or of matter in the universe.
3.b
when the universe changed from being matter-dominated to being dark-energy-dominated
The expansion rate of the universe began to accelerate.
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