Explain the difference between radial and transverse velocities
What will be an ideal response?
Radial velocity is found from Doppler shifts, and measures speed along our line of sight. Transverse velocity is motion across our line of sight, and requires both the apparent angular proper motion and knowledge of the parallax and distance.
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What is meant by reversible heat transfer?
What will be an ideal response?
All the following statements about known extrasolar planets are true. Which one came as a surprise to scientists who expected other solar systems to be like ours?
A) Some of the planets orbit their star more closely than Mercury orbits the Sun. B) Most of the planets are quite massive—much more like Jupiter than like Earth. C) Most of the planets orbit stars that are quite nearby compared to the scale of the entire Milky Way Galaxy. D) In some cases, we've found more than one planet orbiting the same star.
The more baryons there are in the universe (a higher density of baryonic matter), the lower the ratio of deuterium to hydrogen is. Therefore, if Harry measures a higher ratio of deuterium to hydrogen than Sally, Harry infers
A) a higher density of baryons than Sally. B) the same density of baryons as Sally. C) a lower density of baryons than Sally.
In the Drake equation (Number of Civilizations = NHP × flife × fciv × fnow), what do we mean by fnow?
A) the fraction of planets with civilizations at the present time (as opposed to only in the past or future) B) the fraction of planets in the galaxy on which a civilization could theoretically develop right now C) the fraction of civilizations in the universe that currently are sending messages to us D) the fraction of all species ever to exist that we currently are aware of