The appearance of the great range of brightnesh wtos nj0iwg4tinh7 *0,e2y;s among stars is due to

  The absolute luminosity for most stars depends on the(-*qg y4(ky,c nwlhvg

  Four different main-sequence stars are colored blue, ofdj06 o( isd;prange, red, and yellow. What i( s;6od0i dpfjs their rank from coolest to hottest?

  A Hertzsprung-Russell dia-ql mshyb5l1)z/s: mhgram shows stars on a plot of

  A white dwarf star with a mass equal to that of the Sund 2l.a: ./wzzup rqfx; is about the size of

  The Chandrasekhar limit of stellar mass (below w+ lf,;arcb( kzs )u7bta5f9,6v ydmo04 lrmjzhich a star will collapse into a white dwarf) is, if the mass of oz 45 ;7,c+rvj, a tblm 9mbsoyuz0(dfrf kal6)ur Sun is M, about

  Supernovas are thought to always r- 3 zmh /mfs jb6fam4c7p/ca3uesult in

  Black holes

  Pulsars are rapidly spinn8f/ba pvhts7prj f;1y4p+k1j7 eai1ging

State Einstein's principle of eqq6g k s ste:2rirt+vac95g*u*uivalence.

  The Schwarzschild radius of vo3 o ibu6rzx(lb3. m-a black hole is 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 star's mass M b 3 vxru(io3- o.lmzb6as: $R = 2GM/c^2$. 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 wavelength in the ).w/qji20 ais 5wuyhpm97j kcvisible, and the source is moving away w0j2s uq97c/a .y jhimw5ki)pfrom us, the color of the light appears to us to be shifted toward the

  The cosmic background radiationele/:fqt-j. p( he-v,saj07ksap 2uh corresponds to a temperature of about

  The Sun has apparent brightness at Earth kly ed7atccdm gy9wf2 65el6hw224 f+($1.5 \times 10^{8} \; km$ 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 th p7.e5d)9 9nnvdgnim9u v2 ktoat 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 radius obod 8,sy4h xq,f $1.5 \times 10^{8} \; km$. 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 f46/j i2lbp9bkujt x-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 fre d- 5;- sx-ggjbko7tor Proxima Centauri, which is Earth's nearest star at 4.3ob5;ge-rjx sgd7 kt-- ly?

  The apparent brightness oegxpc j *tq59)i i)2bbf 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 universe is 1/H, where ui71x 1z2irq6rf3du j H is the Hubble constant. Taking H = 20 km/s/Mly, estimate the age of the universe, in 1 7ud 3jr xfrquz2i6i1years.

  If a galaxy is moving away from us at 1.0% of the speed ofla ti7da.hcslm(3; b1 light, how far away is it f731a(la;tl . hm dbcisrom us?

  Estimate the speed of a galaxy that is7pzdt)ab. jcxgi e(2. 10 billion light-years away.

  Estimate the observed wavelei- xct 61nzaj72vm)e ength for the 656 nm line in the spectrum of a star which is 100 million tzxneij72eac6vm 1 -)light-years from us.

  About 1 ms after the Bi2;(pqr p,vmppw; k/v.1z cobbv 1wph)g Bang, the temperature of the universe was about 1013 K. What energy (in eV) does v(ppzcq. mpr ;wvv2 ,hb1p;k)1bpw/o this correspond to?