1. Which of the following methods can be used to find the distance from us to a star outside our galaxy? Choose all that apply.
(a) Parallax.
(b) Using luminosity and temperature from the H-R diagram and measuring the apparent brightness.
(c) Using supernova explosions as a "standard candle."
(d) Redshift in the line spectra of elements and compounds.
2. The history of the universe can be determined by observing astronomical objects at various (large) distances from the Earth. This method of discovery works because
(a) Time proceeds at different rates in different regions of the universe.
(b) Light travels at a finite speed.
(c) Matter warps space.
(d) Older galaxies are farther from the Earth than are younger galaxies.