Exam 20: Galaxies and the Foundations of Modern Cosmology

Process of Science: Describe how scientists measure the distances to galaxies,starting with how they measure the distances of the nearest stars.Be sure to include enough detail so that someone who does not know the jargon of astronomy can still understand your explanation.

What is Hubble's law?

Which of the following is true about irregular galaxies?

Why are white dwarf supernovae more useful than massive star supernovae for measuring cosmic distances?

Massive-star supernovae and white-dwarf supernovae work equally well as standard candles for measuring cosmic distances.

Which of the following types of galaxies are reddest in color?

Which of the following best describes the status of the Milky Way in our Local Group of galaxies?

How was Edwin Hubble able to use his discovery of a Cepheid in Andromeda to prove that the "spiral nebulae" were actually entire galaxies?

Summarize the links in the distance chain that allow us to estimate distances to the farthest reaches of the universe.

Briefly explain why we think white-dwarf supernovae are useful for measuring cosmic distances.

If we went back in time 10 billion years,how would we expect a plot of galaxy luminosities against colors to change?

What does Hubble's law tell us?

Process of Science: How we can test that a so-called "standard candle" is indeed standard?

Why can't we see past the cosmological horizon?

What is the most accurate way to determine the distance to a nearby galaxy?

Current estimates place the age of the universe at about

How did Edwin Hubble measure the distance to the Andromeda Galaxy?

There are more large spiral galaxies than there are large elliptical galaxies.

Cosmological redshift is the result of

Elliptical galaxies are more likely to be found in clusters than are spiral galaxies.