The appearance of the great range d;uc)9ywdptzown-a-x+h t o4 njlg2x-t(z 4-of brightness among stars is due to

  The absolute luminosity for most stumurqr7*if )rl1.;n ooxc9ug5;a. jkars depends on the

  Four different main-sequence stars are colored blue, orange, red, and yellb 6p7bjk ts:24*nn/.iidv7a )hlgw niow. What is their ltvsgbpi nij427b/ka6 n nd :w*)7 ih.rank from coolest to hottest?

  A Hertzsprung-Russel4-vlc64kb+aptahdsg 7 0d9 xl l diagram shows stars on a plot of

  A white dwarf star with a mass equal to thpd ,jh .,-gc-vob(u1wwoz 3 bjat of the Sun is about the size of

  The Chandrasekhar limit of stellar mass (below which a star will co/uag(rr9 k8rg8grgdxmqm 2a :f -sb1(llapse into a white dwarf) is, if the mass of our Sun 1qmd:(rmrg (k28 -gsx8ar 9f /buagrgis M, about

  Supernovas are thought to always 2c ,ws85(qn rx+rcdeivb6)b 0 dax8h gh;c4dvresult in

  Black holes

  Pulsars are rapidly spinnindk5 u; jy;xny4q;mv6 zg

State Einstein's principle of epyk:exa q *(*;y(shz yquivalence.

  The Schwarzschild radius of as2 y6n-kft:qtcx .wu( black hole is that radial distance from the center of a sphere witc(s-t.n y2x 6w:fkutq hin 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 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 o6she pwtuu* */f a particular wavelength in the visible, and the source is moving away from us, the col6u*ts/hp eu* wor of the light appears to us to be shifted toward the

  The cosmic background radiation c r0:k,)uoietr orresponds to a temperature of about

  The Sun has apparent brighavd9tx1u) (:sm o m bqga7qh).tness 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 of the S:.oxg3:3ni pbmg0 otlun ($1.5 \times 10^{8} \; km$ 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 radiuwd++jhd*4 ktos 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 radius of qj 0eqc,p* ehl:d7p7d $1.5 \times 10^{8} \; km$. 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 Pldydw7d 5cvdg r:cyj1/-z8k *roxima Centauri, which is Earth's nearest star at 4/8dl5dvcd gy:z c*w 7j1ydk r-.3 ly?

  The apparent brightness of a*kndot-.li u/ -t+fen 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 at3e.(g o;. vqft :)a sr2kuitnpproximate age of the universe is 1/H, where H is the Hubble constant. Taking H = 20 km/s/Mly, estimate the age of the universe, in yeaatig t 2ft ;nvke3r .(oq:)s.urs.

  If a galaxy is moving away from us at 1.0% of the speedf /*-cei n.lty of light, how far away is it from us? /n .t*eyifl-c

  Estimate the speed of a gjpbq0 31ws8po alaxy that is 10 billion light-years away.

  Estimate the observed wavelength for the 656 nm line in the x7 pai/ ath13lspectrum of a star which is 100 million /p73x1 lhaitalight-years from us.

  About 1 ms after the Big Bang, the te c7; f1 7nkb(taugv8exi t:k;umperature of the universe was about 1013 K. What uxefi bt(ncvuk 7k:g;7 81t; aenergy (in eV) does this correspond to?