The appearance of the great rani7.fqn8sdo v5n .os6wge of brightness among stars is due to

  The absolute luminosity for most stars depends on 9 c9 v nie92ipkk0p,ththe

  Four different main-sequence starp(9 qr/ta+uq4py0 jbrs are colored blue, orange, red, and yellow. What is their rank from coolest q0(ytr p / 4jr+upbaq9to hottest?

  A Hertzsprung-Russell diactid(8lfragm6-xh t2 b94 ,twgram shows stars on a plot of

  A white dwarf star with 37n+atl,+e t*j xamo1/hro +fsj3 bsda mass equal to that of the Sun is about the size of

  The Chandrasekhar limit of stellar mass (below which a star willi 12zjgrd f5(s collapse into a white dwarf) is, if the mass of our Sun i51rf ids(z gj2s M, about

  Supernovas are thought t6m u i;/r1myupo always result in

  Black holes

  Pulsars are rapidly spin4 lpuje56 zf h01tk;yaning

State Einstein's principle of 39hbkr sqan7+yd63pu equivalence.

  The Schwarzschild radius of a black hol,oe 3wtnms( u/uqb- 6 *e-btdse is that radial distance from the center of a sphere within which not even light can escape. It was first discovered mathematically bybuu, ds3 ( t-qe-t*os/n embw6 Schwarzschild in 1916 after Einstein published his general relativity theory. It can be calculated from a 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 waved v35(h:m-rwnkqx8 5xw y;xfglength in the visible, and the source is moving away from us, the color of the light appears to us to be dwgfm5n: q hx;x(rv8y-w 3x5kshifted toward the

  The cosmic background radiation corresponds to a temperature of a hxnk3sb*-h07hk , mbhbout

  The Sun has apparent brightnek/3r p1tv.bp8 km 00j mx*qoqbjkt-1iss at Earth ($1.5 \times 10^{8} \; km$ 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 lu paucv4z,f6* nminosity equal 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 f57b,vvpz(dwtv g :)ss 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 hagtyxy jgz 6gr0r6 p8.07nqrown 3gmv4 tlv1;6s a 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 angle for Proxima Centauri, which is Earth's nzyj) x,cz0 xx7earest star at 4.3 lyzxy 7j0cx,zx )?

  The apparent brightness of a st6.abyt3z 9j vn dv:q/gar is $1.0 \times 10^{-12} \; W/m^{2}$ and the peak wavelength is 600 nm. Estimate its distance from us.

  It can be shown that the approximate age of the universe is 1/H, where H iqv2qr52 / :b1vbe kjebs the Hubble constant. 25 jvev:bqrbk 2/bq1 e Taking H = 20 km/s/Mly, estimate the age of the universe, in years.

  If a galaxy is moviny2pihgb n2rh m8r4+w*g away from us at 1.0% of the speed of light, how far away is it m48yn b*+wr2phr 2gihfrom us?

  Estimate the speed oj+ mjec g*:.7c.s vrnwf a galaxy that is 10 billion light-years away.

  Estimate the observed wavelength forb e2 k5wl2hpf(ohd ./s the 656 nm line in the spectrum of a star which is 100kh5ped b 2.wf2 l/s(oh million light-years from us.

  About 1 ms after the Big Bang, the temperature of xxeppip/4 ;v9 the universe was about 1013 K. What energy (in eV) does this correspp;x9 p/ 4xveipond to?