Exam 25: Cosmology: The Origin and Evolution of the Universe

Measurement of structure in the cosmic microwave background radiation has recently indicated that we live in a flat universe between a closed and an open universe, and yet the measured density of detected matter and radiation is only 20% to 40% of the critical density required for a flat universe. In what form is the other 60% to 80% of the "matter" likely to be?

What value for the Hubble constant is obtained from the observations of the ESA Planck satellite?

If the Hubble constant is found to be 25 km/s/Mly, what would then be an upper estimate for the age of the universe?

When the universe was about 24,000 years old, the radiation density had decreased to the point where it was equal to the matter density, yet it was only many years later that atoms formed. What happened to make possible the formation of atoms?

Within which time frame from the initial Big Bang is it felt that the present laws of physics completely fail us, because time and space as we know them did not exist?

The future of our universe-continuous expansion or eventual contraction-can be determined by observing the rate at which cosmological expansion is changing because of gravitational attraction between masses in the universe. How would this effect of deceleration be measured in terms of the Hubble relationship between speed of recession (graphed vertically) and distance (graphed horizontally)?

What does z = 0 mean?

When we view a quasar with a redshift z, this means the wavelengths of light emitted from the quasar have been shifted by z = Δλ \ λ₀. This wavelength shift is:

Figure 25-13 of Universe, 11th ed., shows temperature variations in the cosmic microwave background. Dark areas in the image correspond to regions where the photons were gravitationally redshifted when they left the early universe. Suppose we point a telescope at one of these regions now. What would we expect to see?

The first 10^-43 seconds of the age of the universe, during which time matter was so compressed that all known science fails us, is called the:

The question asked in Olber's paradox of cosmology is:

What was Einstein's cosmological constant, denoted by the Greek letter lambda, intended to represent?

If there is no dark energy, what is the future of the universe? (See Figure 25-18 of Universe, 11th ed.)

In which of the following areas of scientific study will we never be able to follow the scientific method in repeating the observations of several different "samples" in order to verify the generality of the conclusions?

If the uncertainty in the Hubble constant H₀ = 73 km/s/Mpc is 10%, leading to values of between 65.7 km/s/Mpc and 80.3 km/s/Mpc, what is the corresponding range in the estimated age of the universe?

As we look at more distant regions of space, we see those regions as they existed at earlier times, but our farthest views are blocked by a "wall"-beyond which the universe is opaque. What event occurred at the time marked by this wall?

Studying the pattern of temperature variations in the early universe (see Figure 25-13 of Universe, 11th ed.) tells us something about the sound waves existing at that time. This, in turn, has given us information about all of the following EXCEPT the: ​ ​

The 2.7-K cosmic microwave background radiation comes from:

By what factor has the universe expanded since the time of recombination?

Is there an advantage in using redshift z to describe the distances to faraway galaxies?