Exam 19: The Expanding Universe

The spectrum of a galaxy is observed to have an Hα emission line at a wavelength of 856.3 nm.What is its distance if the Hubble constant is 70 km/s/Mpc? Note that the rest wavelength of the Hα emission line is 656.3 nm.

If you found a galaxy with an Hα emission line that had a wavelength of 756.3 nm,what would be the galaxy's distance if the Hubble constant is 70 km/s/Mpc? Note that the rest wavelength of the Hα emission line is 656.3 nm.

If there were more baryons in the universe immediately after the Big Bang,then the abundance of __________ in stars and galaxies would be higher.

The inverse of the value of H₀ is a:

If the spectrum of a distant galaxy is observed to have a calcium K absorption line that occurs at a wavelength of 500.4 nm,what is this galaxy's distance if the rest wavelength of this absorption line is 393.4 nm? Assume the Hubble constant is 70 km/s/Mpc.

The value of the scale factor R_U depends inversely on the value of redshift z.

Which of the following was NOT created as a result of Big Bang nucleosynthesis?

Which distance indicator can be used to measure the most distant objects?

In the Great Debate of 1920,Curtis argued that spiral nebulae were individual galaxies,while Shapley argued spiral nebulae must be part of the Milky Way because the Milky Way was very large in size.

Why are some galaxies' spectra blueshifted rather than redshifted?

The standard Big Bang theory successfully predicts that the fraction of helium by mass in the primordial universe was 2 percent,similar to what it is in the Sun.

When we measure distances to very faint galaxies with Type I supernovae,the accuracy of the measurement is only as good as that of the calibration of Cepheid stars.

The spectrum of a galaxy is observed to have an Hα emission line at a wavelength of 928.7 nm.What is its redshift? Note that the rest wavelength of the Hα emission line is 656.3 nm.

If the Hubble constant had a value that was half of its current measured value of 70 km/s/Mpc,the age of the Universe would be about

Type I supernovae have an absolute magnitude of −20.If you discover a Type I supernovae in a distant galaxy that has an apparent magnitude of 22,then how far away is this galaxy?

Astronomers have known that galaxies are separate entities outside of our own for roughly the last:

Astronomers use galactic redshift as a measure of:

The CMB contains photons left over from the epoch in the universe's history when electrons recombined with nuclei.

The cosmic microwave background radiation was emitted when the universe had a size about 1/1000 of today's value.What was the temperature of the microwave background radiation when it was emitted?

What is the interpretation of a redshift larger than 1?