Why do we say that the Doppler technique gives the planet's ...

[clmills979]

Why do we say that the Doppler technique gives the planet's minimum mass?
 
  A) The size of the Doppler shift that we detect depends on whether the planet's orbit is tilted.
  B) The size of the Doppler shift that we detect depends on knowing the star's mass, which can be very uncertain.
  C) Extrasolar planets are always increasing in mass.
  D) Doppler measurements are very difficult, producing noisy data that often cause astronomers to underestimate a planet's mass.

Question 2

Which lunar feature most resembles the Moon's original crust?
 
  A) Valleys
  B) Craters
  C) Maria
  D) Bright rays
  E) Highlands

[jrpg123456]

Answer to Question 1

A

Answer to Question 2

E

[clmills979]

Thanks for the timely response, appreciate it

[Joy Chen]

Gracias!