The appearance of the great range of brightness amongjo/ 86p fg 8qoad9/ex,jgtu,r stars is due to

  The absolute luminosity for mos kx:r :*rlh jlq lixg.:yp,5l8t stars depends on the

  Four different main-sequence stars are colored blue, orange)uhif a.mq4e:, red, and yellow. What is their rank from coolest to hottemh:4f.aiq e)ust?

  A Hertzsprung-Russell diag/: pwlxfw e vq,blp5z0p;w8j3ram shows stars on a plot of

  A white dwarf star with a mass equal to tbg.*6od3 zq z .dhojt3hat of the Sun is about the size of

  The Chandrasekhar liwepp3b)he u+ojt1 )go* 7da0 mr 3,gelmit of stellar mass (below which a star will collapse into a white dwarf) is, if the massdopolh u )e1je)brpg*37 0e,agm 3w+t of our Sun is M, about

  Supernovas are thought /euq,21 mmnvotfc dcgg;,i/ 1 to always result in

  Black holes

  Pulsars are rapidly s-mqik5(e5o7+s hp ,pqmwbltcz d 1q38pinning

State Einstein's principle of.qcmj9 *, bzoh/ty2-mr7t sxe equivalence.

  The Schwarzschild radius of a black hole is that radial distance froa)g,ubf g:/ rbm the center of a sphere within which not even light can escape. It was first discovered mathematically by Schwarzschild in 1916 after Einstein pubg gafbr :,/u)blished 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 wavelength in the visible, andk4 // u6ug lvpoqte1t6 the source is moving away from usgp1/vkl/6ettu o 64uq , the color of the light appears to us to be shifted toward the

  The cosmic background radiation corresponds to a temperame)bx w9bo1+p*bwv :fture of about

  The Sun has apparent brightnesnp/ i0:s;wv(w ymlue,s 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 equab:o2 x apxgt* 4b;8sixl 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 vm8zsnpqn*bt/u 9 m.0 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 km?

  The Earth's orbit has a mean radius o/ )hbn fwmh,1(0 gveatf $1.5 \times 10^{8} \; km$. 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, whi/ a/ep (1qhre;x gi3eich is Earth's nearest star at 4.31e/rpaq3ee;i(gix h/ ly?

  The apparent brightness of a s:cri ( zxppw 7i..yoj2tar 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 of27dt4hjfo2 xn the universe is 1/H, where H is the Hubble constant. Taking H = 20 km/s/Mly, estimatj 7hnft2ox d42e the age of the universe, in years.

  If a galaxy is moving away from us at 1.0% of the spz4 ro tsdt+ wjv3 l)1x3ims8wd1*r.oueed of light, how far away is it frwdorzvw o)38xl14 +3*is1 dt rmusjt.om us?

  Estimate the speed of a galaxy that is 10v /9k,zz tg..tuvk; x*.ufosx billion light-years away.

  Estimate the observed wavelength for the 656 nm line in the spectrum of a s;6u:n/)1tgxw mn p gzltar which is 100 million liwz /n:1xg; lg)6u mntpght-years from us.

  About 1 ms after the Big Bang, the temperature of the universe was aboutqq4+ec(nll:h4n v(egev x6b: 1013 K. What energy (in eV) do+vc(h xqq6lele4ebvn (g ::n4es this correspond to?