The appearance of the great range ofycb(+y v9:m dkhb 8*becy4c1 t brightness among stars is due to

  The absolute luminosity for mostr7jge (:xle(t stars depends on the

  Four different main-seq 1+duc6qq((x)s )4bxnm xvz cyuence stars are colored blue, orange, red, and yellow. What is their rank from cx 6cq(m1n)xd4uvscy (z q)xb+oolest to hottest?

  A Hertzsprung-Russell diagram s ;; jypwd-d,+mo /k,;pqkje tkd5hi( ohows stars on a plot of

  A white dwarf star with a mass equal to that of the Sun is about the size ofa-h5me um w5 5v;)uitd

  The Chandrasekhar limit of stellar mass (below which a star wic 9ge fdg35fiz2ooqv*x() 4a qll collapse into a white dwarg 3f i * xq425gze)vf9cqaood(f) is, if the mass of our Sun is M, about

  Supernovas are thought to always result ial. s8g i3j2pon

  Black holes

  Pulsars are rapidly spin:. qiv4w(e ughning

State Einstein's princim7 n kz gi.0109e3chxwsvyd9 tple of equivalence.

  The Schwarzschild radius of a black hole is that radi xhveb-z 89n/eal distance from the center of a sphere within which not even light can escape. It was first discovered mathematically by Schwarzschild in 19e vn-bh/z89 xe16 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 2lezz)q8wyl)atbgq -6 gq3c;gd v)h; a particular wavelength in the visible, and the source is moving away from us, the color-thggd;a2g6z bl8z vcqe)l)3q)w y;q of the light appears to us to be shifted toward the

  The cosmic background radiation corresponds to a tempe.+kv8p*ufnd i3i zt 7xze4k (krature of about

  The Sun has apparent brightness at Eargqlw4 ; 9byxa0th ($1.5 \times 10^{8} \; km$ 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 thatuitk- 2+m.cx(6 vejfc 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 0wyq zb5 be0z.,)y3l;ggd l fcof $1.5 \times 10^{8} \; km$. 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 radiue)iw-i6i gjv- oh,q,ms 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 Proxujtdnu 2e*w-eer.: z*xlt 10gima Centauri, which is Earth's nearest star aj *er*wu :-unz. t10 te2glexdt 4.3 ly?

  The apparent brightness of a star ii pvv/6hlczzm e6 -v0)s $1.0 \times 10^{-12} \; W/m^{2}$ and the peak wavelength is 600 nm. Estimate its distance from us.

  It can be shown that the approximate age of the *lo 8 b;ztq)jiuniverse is 1/H, where H is the Hubble constant. Taking H = 20 km/s/Mly, estimate the age of the univers * ilb8qt);joze, in years.

  If a galaxy is moving away from us at 1.r)bguw+kr3 td7 ( imt.0% of the speed of light, how far away is it fromu+7 md) k.(t trb3wirg us?

  Estimate the speed of a galaxy that is 10 billion 3/ b.a1lout o8d.lefslight-years away.

  Estimate the observed +hy ge* b(doc*wavelength for the 656 nm line in the spectrum of a star which is 100 million light-years*( eyc gb+o*hd from us.

  About 1 ms after the Big Bang, the temperature of the universe was about 101kmvkp2 s *:it/3 K. What:2spi/vtk* mk energy (in eV) does this correspond to?