astronomy ch 26 quiz

How were astronomers able to determine that the spiral nebulae were actually distant galaxies?

Edwin Hubble discovered a Cepheid in M31 and determined its distance to be well outside of the Milky Way.

The redshifts of Galaxy A and Galaxy B have been measured. The redshift of Galaxy B is twice that of Galaxy A. Which is moving away faster?

Galaxy B

The redshifts of Galaxy A and Galaxy B have been measured. The redshift of Galaxy B is twice that of Galaxy A. Which galaxy is farther away and by what factor?

Galaxy B is twice the distance of Galaxy A.

The first to actually predict that the universe was expanding and estimate the expansion rate was....

Georges Lemaitre

Which of the following is not a valid designation for a galaxy in the Hubble classification system?

SaB

There are many types of galaxies, but the most massive galaxies are going to be....

ellipticals.

Hubble's Law is important because ....

it showed the universe is expanding.

Galaxies have stars of varying ages, but the stars of elliptical galaxies are typically....

pop 2

In an expanding universe, what exactly is expanding?

spacetime

Which one of the following cannot be used to estimate the distance to galaxies?

trigonometric parallax

Examples of astronomical objects that can be considered standard candles (or bulbs) are....

1. Cepheid variable stars 2. type Ia supernova 3. planetary nebulae

The Tully-Fisher relation...

1. is used to measure distances to galaxies. 2. provides a fairly accurate estimate of a galaxies luminosity based upon its rotational velocity. 3. only works for spiral galaxies.

Which of the following are true concerning Hubble's Law?

1. not constant over time 2. experimentally confirmed the prediction of Lemaitre. 3. consequence of an expanding universe.

The diameter of a typical spiral galaxy might be something like....

100,000 light-years

If the Hubble constant is 20 km/s/million-light-years and a galaxy is known to be at 100 million-light-years, what would you expect the galaxy's recessional velocity to be?

2000 km/s

Hubble's Law (also known as the Hubble-Lemaitre Law) can be restated as:

The more distant a galaxy, the faster it is receding.

The first person to photograph redshifted spectra of galaxies was....

Vesto Slipher

An SBc galaxy in the Hubble classification system would have...

a barred spiral shape with loose arms.