Astronomy Chapter 29
The first satellite (spacecraft with instruments) to measure and confirm the cosmic microwave background was the:
COBE (COsmic Background Explorer)
The two scientists who first discovered the cosmic microwave background radiation were:
Penzias and Wilson
Where in space did the expansion of the universe begin?
everywhere at once
When do astronomers now think that the "dark energy" began to accelerate the expansion of the universe?
several billion years after the Big Bang
Scientists speculate that the properties (laws) of the universe must be the way they are because if they were significantly different, we would not be here to think about them. This idea is called
the anthropic principle
According to our modern theories, the geometry of the entire universe (all of space-time) may be curved or warped. This is a pretty bizarre notion; what other discovery in astronomy has helped us believe that space may be able to curve or warp?
the properties of black holes
One of the things that our current "standard model" of the Big Bang Theory doesn't explain is
why the temperature of the cosmic microwave background is so uniform throughout all of space
The model of the universe that involves an enormous increase of scale during a very short time in the early universe is called:
the inflationary universe model
Why did Einstein introduce the cosmological constant into the equations of his General Theory of Relativity when describing the universe?
Einstein's equations required the universe to expand or contract; he could not imagine or accept it doing either one, so he put a factor in to stop it from moving
The standard bulbs (standard candles) that made it possible for astronomers to discover the acceleration in the expansion of the universe were
Type Ia supernovae
At first, right after the Big Bang, the universe was too hot for nuclei and electrons to combine into the kinds of neutral atoms that are familiar to us today. How soon after the beginning did it become cool enough for neutral atoms to form?
a few hundred thousand years
If you want to check on what conditions were like in the universe a few hundred thousand years after the Big Bang, what sort of instrument would it be best to use:
a satellite with infrared and microwave telescopes on board
In the very distant future, given our best model of the accelerating universe, what will the universe look like?
all the stars will die and the galaxies will be dark
In our modern view of the expansion of the universe, we understand that it is space that is stretching; individual galaxies don't speed away from each other as if they were rockets. In that case, why do galaxies show a red-shift?
as space stretches, the waves of radiation in space also stretch and their wavelength increases
Which of the following statements about dark matter is FALSE:
astronomers have a pretty good idea what the dark matter is made of
Which of the following statements about the early universe (as envisioned by the standard model of cosmology) is FALSE?
at the very beginning, the energies were so great that the universe was actually contracting for a while
Today, we believe that only a small number of elements were actually formed during the Big Bang. Which of the following was NOT one of these:
carbon
Which of the following is the Earth not located in?
globular cluster M-13
How does a period of extremely fast inflation very early in the history of the universe explain the observation that the geometry of the universe looks flat (not curved) to us?
inflation increased the size of the universe so much that the resulting universe looks flat from any point of view
If we include the effects of deceleration in our calculations of the age of the universe, the age we get is:
less than the Hubble time
Based on many surveys of the average density of matter in the universe (regular matter and dark matter), astronomers now conclude that the average density of the universe is
less than the critical density
In describing the universe using his equations of general relativity, Einstein assumed that it was isotropic (the same in all directions.) What recent observations have confirmed that the universe is isotropic on the large scale?
measurements of the 3-degree cosmic background radiation
Which of the following did NOT happen during the first few minutes after the Big Bang?
some very massive early stars formed
When we determine the age of the universe using the Hubble Time, what important simplifying assumption goes into our calculations?
that the expansion of the universe has been happening at the same rate - neither speeding up or slowing down
Which of the following is pretty good evidence that the universe began with a Big Bang?
the 3-degree cosmic microwave background radiation
The reciprocal of the Hubble constant (1/H) is a rough measure of the:
the age of the universe
After the Big Bang, in order for the universe to become transparent to light and other electro-magnetic radiation, what had to happen?
the density of the universe had to decrease (to 1000 nuclei per cubic centimeter or less)
Recent observations indicate that the universe is expanding faster today than it was a few billion years ago (that, in other words, the expansion of the universe is accelerating.) What kind of observations have led astronomers to this surprising conclusion?
the measurement of galaxy distances using Type Ia supernovae
What is the strongest known force in the universe?
the strong nuclear force
