The appearance of the great range of brightness among 5 ng- 2.ywc:ky2qaxapnhs5b-stars is due to

  The absolute luminosity for most stars depej1qs j/n.te ;rno1l8b e91 orbnds on the

  Four different main-sep n1f0pxqchq+pr+4 hbgp . 38nquence stars are colored blue, orange, red, and yellow. Whaxp0 4hb ncgqf+1.3pprq8 n h+pt is their rank from coolest to hottest?

  A Hertzsprung-Russell diagram shows stars on a p3d9zwdxj z ofx(;-j3t y3)bb xlot of

  A white dwarf star with a mass equal to that of the Sun is about e4gw0ikf5um)gwt* kio 6 ze)5 the size of

  The Chandrasekhar limit of stellar mass (below which a-mrcfp y.)z4/e-pb zq star will collapse into a whby-.cz/p- mf)p 4e rzqite dwarf) is, if the mass of our Sun is M, about

  Supernovas are thought to always resh 6,-fu8dgseg * *,orfx h)tkault in

  Black holes

  Pulsars are rapidly spin,9 4kh ):so7 xzltezbening

State Einstein's princnqa19r9v cv36 3ox wz3;vjq sa f*oa6pr.5uqwiple of equivalence.

  The Schwarzschild radius of a black hole is that radial distan+;mlqnr -2xh w(zlc p l:9nt(yn1tb3 mce from the center of a sphere within which not even light can escape. It was first discovered mathm9c pl l ;1w l+m-n(zynt32n(htbr q:xematically 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 qz u0of wj/lod2 ,+d debll6*2emits light of a particular wavelength in the visible, and the source is moving away from us, the color of the light appears to us to be shi,ld*6 2l jwd2 u+f qdlbozo/e0fted toward the

  The cosmic background radiation corresponds to a tempip t/v/5d,wv1zk y9yy) n:wgperature of about

  The Sun has apparent briekg)uox4+n hu 8 pn*** lbkjp-ghtness 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 luminaio2h356by w iosity equal 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 a mesy)e*f m46a kaan 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 meafin2ws-) +k nen 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 for Prox.jyosi5ha6hn e;f8lre9 0 wp6ima Centauri, which is Earth's nearest star at 4.3e5apo.her ;6whsfy ni9 l68 j0 ly?

  The apparent brightness of a starr.4pd 2y/w+)50i i qttxm.ugc 9mzdpc 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 kn x0d(f d(8up1/H, where H is the Hubble constant. Taking H = 20 km/s/0 nfkd8(dup(x Mly, estimate the age of the universe, in years.

  If a galaxy is moving awtw6 a*tw vo 7223mcexc2:i jr2orat:nay from us at 1.0% of the speed of light, how far away iscwaw et ot2x2:6nr ar3:i* 2m2cv7toj it from us?

  Estimate the speed of a galaxy th+foiz a/f3 ne)7wf; 9i fkst2cat is 10 billion light-years away.

  Estimate the observed wavelge ,zbua2v5;nength for the 656 nm line in the spectrum of a star which is 100 mille,;nbzv5ga u2 ion light-years from us.

  About 1 ms after the Big Bang,osc6bz w j56m* the temperature of the universe was about 1013 K. What omzj bwcs56*6energy (in eV) does this correspond to?