The appearance of the gre*w9wz o-- ,wqe. ftzfkat range of brightness among stars is due to

  The absolute luminosity for mos7skx f)ms og5;8htm* u0 1qonmt stars depends on the

  Four different main-sequence stars are bff t.7a8ijg/ colored blue, orange, red, and yellow. Whatgfa8f7i./tj b is their rank from coolest to hottest?

  A Hertzsprung-Russell diagram shows stars on a plot ofce- gzml+*8 tf

  A white dwarf star with a mass equal kyeu q dz/5imjle7j 0wb8ii4-f* j* :hto that of the Sun is about the size of

  The Chandrasekhar limit of stellar mass (belowj; 2)ohkbkr,b which a star will collapse into a white dwarf) is, if the mass of our Sun is M, abo bkk)j;,bro2hut

  Supernovas are thought to always result 0n x+uf ,f,m 2zc6liqnin

  Black holes

  Pulsars are rapidly sau k-x3xl/ 2mv7po38ylsw c3 ds b;br+pinning

State Einstein's principle of equiv+ cn xw7n6haix3xw(e,w u r3)halence.

  The Schwarzschild radius of a black hole ioz;5 s (4u,q-g8ueumzp u a3xfs that radial distance from the center of a sphere within which not even light can escape. It was first discovered mathematically by Schwarzschild in 1916 after Einstein published his general relativity theory. It can be calculated from a,o-z8ua xp(uu 5 4f3e;zusq gm star's mass M as: $R = 2GM/c^2$. Take the radius of both stars A and B as the Schwarzschild radius. If the mass of star A is twice as much as the mass of star B, the average density of star A, compared to star B will be

  When a distant source emits light of a particular waveleng8qag gdh* +j4ei.wuy0 th in the visible, and t*i qdga4y e hu+g8jw.0he source is moving away from us, the color of the light appears to us to be shifted toward the

  The cosmic background radiation corresponds to a temperature of sa 4dib+8 chth dak*z)r/ 2,frabout

  The Sun has apparent brightness at Ej) c1i0kzrplq0c jc( 7arth ($1.5 \times 10^{8} \; km$ away) of B. What would be the apparent brightness of the Sun at Pluto, which is $6.0 \times 10^{9} \; km$ from the Sun?

  A star has absolute luminosity equa2. ppnz8 pl2jwl to that of the Sun ($1.5 \times 10^{8} \; km$ from the Earth) but is 10 pc away from the Earth. By what factor will it appear dimmer than the Sun?

  The Earth's orbit has a mean radiu)*wee8 irsc s,:s6vdgs of $1.5 \times 10^{8} \; km$. Over a six-month period, the apparent position of a particular star varies by $0.00014^{\circ}$ due to parallax. How distant is the star, in km?

  The Earth's orbit has aep lcga v cm:fr8)8*5p*mw8 bl mean radius of $1.5 \times 10^{8} \; km$. Over a six-month period, the apparent position of a particular star varies by $0.00014^{\circ}$ due to parallax. How distant is the star, in ly? (1 ly = $9.46 \times 10^{15} \; m$)

  What is the parallax 6 ;us e70leeesd3sa/z angle for Proxima Centauri, which is Earth's nearest star at 4.3 ly?ze es/u;a s 0dese67l3

  The apparent brightness of a star isnh q61d /-j1chrj , tnbz/chn5 $1.0 \times 10^{-12} \; W/m^{2}$ and the peak wavelength is 600 nm. Estimate its distance from us.

  It can be shown that the approximate 6mn9h93jjov3n w*ji7np g ij6age of the universe is 1/H, where H is the Hubble constant. Taking H = 20 km/s/Mly, estimate the age of the universe 6v*h3p9iow n7 36jjjj9nng im, in years.

  If a galaxy is moving away from 5nk g1yb nu uf5zod41-us at 1.0% of the speed of light, how far away is it from 5nnk1yg51z-udfu 4o b us?

  Estimate the speed of a galaxy that o v uvu.,n oqdhmjtx;;7mm0+, c3,mulis 10 billion light-years away.

  Estimate the observed wavelength for the 656 nm line in the spectrum of a sta-,f f kf-qke57kx zd4cr which is 100 mild fk-54kze7fc, kqxf-lion light-years from us.

  About 1 ms after the Big Bang, the temperature of the univ9f39qztl (vp uerse was about 1013 K. What energy (in eV) does this cop9qu3vzf 9(l trrespond to?