HW 16

A  Hubble’s law alone implies that as the distance of a particular galaxy increases with time, it moves away from us progressively faster; in other words, it’s accelerating away from us.

B  Hubble’s law can be used to determine the lookback times of distant galaxies – that is, how far back in time we are seeing them.

C  If Galaxies Luke and Yoda both satisfy Hubble’s law, and Galaxy Luke’s distance is three times Galaxy Yoda’s distance, then Galaxy Luke is moving away from us three times faster than Galaxy Yoda.

D  Despite the expansion of the Universe, pairs of galaxies can still sometimes move toward each other and even merge together.

A  Astronomers can learn about the evolution of galaxies with images of the same galaxies taken by Edwin Hubble in the early 20th century.

B  Our Milky Way Galaxy and the Andromeda Galaxy are likely to form an elliptical galaxy at some time in the future.

C  At least some galaxies formed from the joining together (merging) of small groups of stars.

D  In the past, there existed a population of small, blue, irregular galaxies that have either merged together or faded from view.

E  Most elliptical galaxies formed within the first few billion years after the big bang.

A  none of these

B  stars, protons, neutrons, electrons

C  dark energy

D  dark matter

A  Filaments of galaxies surround voids that have no or very few galaxies inside.

B  Each cluster of galaxies is the same size.

C  Super-clusters expand outward from a Big Bang source.

D  Super-clusters are uniform & homogeneous across the universe.

A  gravity

B  supernova explosions

C  gas & dust

D  ignition

A  transition

B  sequence

C  lookback

D  rotation

A  FALSE

B  TRUE

A  TRUE

B  FALSE

A  FALSE

B  TRUE

A  FALSE

B  TRUE

A  TRUE

B  FALSE