The Cosmic Perspective - Measuring Cosmic Distances

If the orbital radius of the Earth were greater than its actual value, the parallax angle to nearby stars would be

Higher

If the orbital radius of the earth were greater than its actual value, the maximum distance a star could be away from earth

Higher than the actual upper limit

Stars that have the highest apparent brightness are

very luminous and nearby .

Massive-star supernovae are not good standard candles because

they have different luminosities

Which two things are needed to determine a standard candle's distance from earth

Apparent brightness and luminosity.

About how long it take for a radar pulse o travel round trip from Earth to Neptune and back again t earth?

8 Hours

A super nova is observed in galaxy 2000 million ligh years away. How long ago did the supernova occur?

2 billion years ago.

Which type of standard candle is the most appropriate for determining the distance to nearby galaxies

Cepheid Variables