The appearance of the great range of brigbugma 3fofl9ws 6;dfh( 38,auhtness among stars is due to

  The absolute luminosity for mos5rxuy h 60 /y hrsr:f0ye0t4pit stars depends on the

  Four different main-sequence stars are colored blue, oran:41f stuww(l3f1uqe q ge, red, and yellow. What is th :wqqs1 13 4flftu(uweeir rank from coolest to hottest?

  A Hertzsprung-Russell diagram shows stars on a w 4k2:og y2lkv/)jxx ,i.n nwnplot of

  A white dwarf star with g mil- gh0gsjefs )*71a mass equal to that of the Sun is about the size of

  The Chandrasekhar limit of stellar mass (below which a st0 j3mpi /lu,n/ejkyahjwi0 e05 w m(t+ar will collapse into a white dwarf) p ia hley/j0 im/m+0u3,5t0wje k(wnjis, if the mass of our Sun is M, about

  Supernovas are thought to always *) a 1l-aygyjwresult in

  Black holes

  Pulsars are rapidly spic+- tpd+gwvtck m:;upczk;9 ,nning

State Einstein's principle of equiv9c 69 prqjujo tr..3ytz; fpaq,6h:ip alence.

  The Schwarzschild radius of a black hole is that radial jq +sm9vwt, 1f 6e h2a(qsikzkr8 y.z/is(5js distance from the center of a sphere within which not even light can escape. It was first discovered mathematically by Schwarzschild in 19. kkit /2fqi r8ssj5(sy,+sj9hm61w qezz(av16 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 wavelenk-rbu-f titx0 gs( g./yu ;b;cgth in the visible, and the source is moving away from us, the color of thirut; g;(/yk.0f-xg-bc s bute light appears to us to be shifted toward the

  The cosmic background radiation corresponds to a temperatmbx66a k1 6nbz i)ia+pure of about

  The Sun has apparent brightn/z 4cd xz(x,qu)lhp8a ess 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 luminosity equal to that 8n8d lnrpa, x r2ckldv.3/6cvj8 .pxbof 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 radius8j9ou/ j mcq rzch,vwl;,zuq 7).wqd4 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 a mean ro g3u6oba6b3xbs,0 s kadius 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 g:xh8;) l1jio-cq evwangle for Proxima Centauri, which is Earth's nearest star at 4.3lxijqgh-:v;e81 wco ) ly?

  The apparent brightness ok5m/f2lc8c +u w6)odehuvo3of a star 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 universene-u 8,7bg,tkpz 3axbq e35eg,mby- e is 1/H, where H is the Hubble constant. Takingy,mee ,3ee 3,ab-x7-zbq pgtubnk85 g H = 20 km/s/Mly, estimate the age of the universe, in years.

  If a galaxy is moving away from us at/ kpucu:l5wt* g15byj 1.0% of the speed of light, how far away isb uwy/uk lj5cp:5*t 1g it from us?

  Estimate the speed of a galax8 ek1e4b mn/czs)bbg3snr5 xd:g57cc y that is 10 billion light-years away.

  Estimate the observed wavelength for the 656 nm line in the spectrum of a stao3b -l 7m)m)lpwnd f8nr which is 100 million light-years fron bw7dl- mn)8)mlf op3m us.

  About 1 ms after the Big B-mg(5p0gw3h j/ xdgcz ang, the temperature of the universe was about 1013 K. What energ (jp/gwh0 -d53 ggcmxzy (in eV) does this correspond to?