Module 19.5

N = R*×fp×ne×fl×fi×fc×L
where

N=Number of communicating civilizations in our galaxy
R*=Average rate of star formation in our galaxy
fp=fraction of stars that have planets
ne=average number of habitable planets in each planetary system
fl=fraction of habitable planets that actually develop life
fi=fraction of life-supporting planets that develop intelligent life
fc=fraction of intelligent species that develop technological civilizations
L=the average length of time that a technological civilization
broadcasts signals
Module 20.4
p = (six month shift)/2
(Pay careful attention to the wording of the question.)

d = 1/p
To get the distance in parsecs, divide one by the parallax angle (AKA the heliocentric parallax).

To get the distance in light years, multiply the distance in parsecs by 3.3.

Module 20.5
To get the total proper motion multiply the arc seconds per year by the number of years.

Module 21.1
Velocity = distance/time


Whatever you multiply the frequency by, divide the wavelength by the same thing.

Module 22.1

Whatever you multiply the distance by, divide the apparent brightness by the square of that.

Absolute brightness = Apparent brightness at a distance of 10 parsecs.

Module 22.2

For every 5 you add to the magnitude, divide the brightness by 100.

Module 22.4

d = 10DM/5×10 parsecs.
  1. Subtract the absolute magnitude from the apparent magnitude
  2. Divide the result by 5.
  3. Raise 10 to that power.
  4. Multiply the result by 10 parsecs.