The appearance of the great ran;myfy te a+e +zrvz487ge of brightness among stars is due to

  The absolute luminosity for most stars dec1 ;lo46fffn uw p qu(ale8+t)pends on the

  Four different main-sequence )uhz( v- z,kb8ndb60abgli/ w stars are colored blue, orange, red, and yellow. What ivb zinwbu,b)dz68g lk(-h a0/ s their rank from coolest to hottest?

  A Hertzsprung-Russell diagraq zn:ye 3f(,:h.u tktnm shows stars on a plot of

  A white dwarf star with di(:d9h(riu2qf+ sqp)tushx - r.d;i a mass equal to that of the Sun is about the size of

  The Chandrasekhar limit of stellar mass (below wqtz6*x d w)t:chich a star will collapse into a white dwarf) is, if the mass of our Sun is dz)6*c:q ttwxM, about

  Supernovas are thought to alw.g d:-+znsqp lays result in

  Black holes

  Pulsars are rapidly spinni(6iblr. *)ad70j-jop) yhihoq n gbf5ng

State Einstein's princip) xc i.l6srgwqpxvset)h*kmr (m- 0z5f( , +iale of equivalence.

  The Schwarzschild radius of a black h zmvra bb1/;u7ole 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 calb71ba v/u;zmr culated 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 partip/6 (:)xh vuj+xws muxcular wavelength in the visible, and the source is moving away from us, the color of the puxmhu) 6(+w/vxj xs:light appears to us to be shifted toward the

  The cosmic background radiation corresponds toxty49a3dmf ,c a temperature of about

  The Sun has apparent brightness at wap + ae7*f9rwq,qx2h 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 j kg.55n jw9ds gnb12m16jblcto 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 mean radiu-tsacu m1z7 a:s 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 hawixh9 e r3p9m+s 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 ly? (1 ly = $9.46 \times 10^{15} \; m$)

  What is the parallax angle for Proxima Centauri, which is Ejx ,zv(c3fplva0m23t arth's nearest star at tx p32 (v0fmz vc,l3aj4.3 ly?

  The apparent brightness of a stat xi5ui k fcif5k60*/hr 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 of9f x3cq4w*uojq;9 sdy the universe is 1/H, where H is the Hubble constant. Takinuy4qj 9q3d; fx9cs*owg H = 20 km/s/Mly, estimate the age of the universe, in years.

  If a galaxy is moving away from us at 1.0% of the speed hpa4jeixe3ijxx , 87;v,q ctf w/ 8q:dof light, how far away is it d ;iqj8p, q,atjf3x ce/h e:8v7xxw4ifrom us?

  Estimate the speed of a galaxy that0a thg1 *mrx+g is 10 billion light-years away.

  Estimate the observed waveleng9*algryk zr*kcybp9(zz)rt2o- cn (-th for the 656 nm line in the spectrum of a star which is 100 million light-years from usa--9rc*t( rb y zkkyzc(o *zn2g)lpr9.

  About 1 ms after the Big Bang, the temperature of t 0r)af a/wehyyedc.p;(37o v vhe universe was about 1013 K. What e3eofar. 0eywy/ 7(dv ac)v; hpnergy (in eV) does this correspond to?