Cosmology

Question 1

What is the luminosity absolute magnitude relationship?

Answer 1

M1 - M2 = -2.5log (L1/L2)

Question 2

What is the luminosity inverse square law?

Answer 2

f = L/(4pi d^2)

Question 3

What is hubbles law?

Answer 3

V = Ho d

Question 4

What are the equations that relate hubbles law, and redshift?

Answer 4

• change in wavelength/wavelength = z/c

- d = zc/Ho

Question 5

What is the equation for the total velocity of a galaxy in the sky?

Answer 5

Vobs = Vh + Vpec

(If the object is coming towards you - Vpec and away + Vpec)

Vh = hubble velocity

Question 6

The scale factor equations

Answer 6

r(t) = r(to) R(t)

Question 7

What is the equation that relates the scale factor to the Hubble factor?

Answer 7

H(t) = derivativeR(t)/ R(t)

Question 8

Redshift and the scale factor

Answer 8

z + 1 = R(tobs) / R(t)

Question 9

Pressure to density equation

Answer 9

P = wpc^2

Question 10

Critical density equation

Answer 10

Pcrit = 3H^2(t)/ 8pi G

Question 11

Age of the universe

Answer 11

to = 1/Ho

Question 12

Temperature at different ages of the universe

Answer 12

To = T(z) / z + 1

Question 13

The Schwartzchild radius

Answer 13

Rs = 2GM/ c^2

Question 14

Velocity and escape velocity

Answer 14

• v^2 = GM/R

- vesc = sqrt GM/R

Question 15

Rotation curves

Answer 15

v(r)/c = change in wavelength(r)/ rest wavelength

Question 16

Inclination equations

Answer 16

• vobs = vrot sin(i)

- cos(i) = b/a