C = 3x10^8 m/s MSun = 2x10^30kg Radius of Earth: 6378.1km G = 6.67x10^-11 (m^3 / Kg S^2) K = 9x10^9 (kg m3 / C^2 s^2) Lsun = 3.8x10^26 W1 AU = 1.5 x 10^8 km1 AU = 4.85 x 10^-6 Pc1LY = 9.5x10^15

1:

• a
• 158nm = V / (3x10^8) m/s

V = 4.74 x 10^7 m/s = 4.74 x 10^4 km/s Ho = 75 km/s/mpc (4.74 x 10^4) / 75 = 632 mpc = 632000000parsecs

• b.
• 32x10^8 = 10^((17.8-M)/5))

(17.8-M)/5 = Log(10)(6.32x10^8) M = -((Log(10))(6.32x10^8)(5) - 17.8) = -3.16x10^9 Wolfram alpha gives me [-26.2].

• c.

100^((M1-M2)/5) = L2/L1100^((4.76-(-26.2))/5) = L2/1 Log100 L2 = (6.192) L2 = 6.192 / Log100 =3.096 Wolfram alpha gives me 2.42 x 10^12.

• d.

D = 10^((m-M+5)/5) pc D = 10 m = x M = 2.42 x 10^1210 = 10^((m-(2.42x10^12)+5)/5) m - 2.42x10^12 +5 / 5 = Log10 10 m - 2.42x10^12 +5 = Log10 50 m = 2.42x10^12

2:

• a
• b
• c

3:

• a

29:1 Galaxy is 30x brighter than it should be if it were made of 1Msun/1Lsun stars.

• b

29:129(1/0.001):129000:1

4:

• a

Fg = GMM/d^2 Fg = (6.67x10^-11)(2x10^30)(50)/6378100^2 Fg = 163961991.9 N

• b

Fq = KQQ/d^2 Fq = (9x10^9)(2x10^30 x 5x10^7)(50 x 5x10^7)/(6378100^2) Fq = 5.53 x 10^43 N

• c

Fq / Fg = 3.38 x 10^35 Fq is (3.38x10^35)x greater than Fg. This makes sense, since we don't fall through the earth.

5:

• a

B = L/D^2 B = 3.8x10^26 / (1.5x10^11)^2 B = 16888.9 W/m^2

• b

B = L/D^2 B = 3.8x10^26 / (9.5x10^15 x 10^10)^2 B = 4.21 x 10^-26 W/m^2

• c
• 9 / 4.21x10^-26

=4x10^29

• d

4x10^29 / 10^22 =4x10^7 [1 / (4x10^7)]th of the amount needed. Makes sense because sun is brighter than space.

6:

• a

Google: Radius: 50000LY A = (pi)r^2 = 7.85x10^9 LY^2

• b
• 85x10^9 / 10 000

=7.85x10^5 LY^2 / Civilization

• c
• 85x10^5 = (pi)r^2

r = 500LY d = 1000LY

• d
  • a Nothing changes
  • b 7.85x10^9 / 100 = 7.85x10^7 LY/Civ
  • c 7.85x10^7 = (pi)r^2
    • r = 4998.7
    • d = 9997.4 LY

7: P = 10000 W r = 150m A = 70685.8 m^2 d = 100 LY = 9.5x10^17

10000 / 100^2 = 1 W/m^2 Max: 70685.8 w

P = 10000 W r = x a = x d = 70000 LY

10000 / 70000^2 = 2.04x10^-6

• 7x10^-24

8:

• a

m = 100 million KG ke = (1/2)m(v^2) Ke1 = 0 Ke2 = 50millionkg(0.1 x 3x10^8)^2 Change in KE = 4.5x10^22

• b
• c
• d