Chapter 12

Front 1

Which of these galaxies is most likely to be oldest?

Back 1

A galaxy observed at a distance of 5 billion light-years

Front 2

Which set of star-position measurments most likely shows the largest parallax shift for nearby stars?

Back 2

Measurments made by 6 moths apart

Front 3

If earths orbital radius doubled in size,

Back 3

the parallax shifts of nearby stars would double in size

Front 4

If all the stars on the main sequence of a star cluster are typically one-hundredth as bright as their main-sequence counterparts in the Hydas Cluster, then that clusters distance is

Back 4

10 times the hydas distance

Front 5

Which kind of object is the best standard candle for measuring distances to extremely distant galaxies

Back 5

A white dwarf supernova

Front 6

If you observe two cephid variable stars to have the same period and one is brighter than the pther

Back 6

the brighter one is closer

Front 7

If you observe two cephid variable stars to have different periods and the birghter one has a longer period

Back 7

there is not enough info to determine which star is closer

Front 8

When ultraviolet light from hot stars in very distant galaxies finally reaches us, it arrives at earth in the form of

Back 8

visible light

Front 9

Why do virtually all the galaxies in the universe appear to be moving away from our own?

Back 9

Obvservers in all galaxies see a similar phenomenon due to the universes expansions

Front 10

If you observe the redshifts of galaxies at a given distance to be twice as large as they are now, the value you would determine for hubbles constant would be

Back 10

twice its current value

Front 11

What would you estimate for the universes age if hubbles constant were 11 kil. per sec per million light-years?

Back 11

28 billion years

Front 12

When we observe a distant galaxy whose photons have treaveled gfor 10 billion years before reaching earth, we are seeing that galaxy as it was when the universe was about

Back 12

4 billion years old