The appearance of the grl ;yq+jmne*z)xrt/ny6x ; elvp6np- : eat range of brightness among stars is due to

  The absolute luminosity for most stars 5qx.mwy(i( ckdepends on the

  Four different main-6*e /o ag xumswej sp4.ay851fsequence stars are colored blue, orange, red, and yellow. What is their rank ex18 awsgjs6p5 .m 4u*feoya/ from coolest to hottest?

  A Hertzsprung-Russell diagram shows q5ffq1i*2c1yh6c chsstars on a plot of

  A white dwarf star with a m4/ jw ,vby9vsshuf, qy - jv4h2u0(wpbass equal to that of the Sun is about the size of

  The Chandrasekhar limit of stkb2 3e38 fdycm34bgr aellar mass (below which a star will collapse into a white dwarf) is, if the mass of our Sun is M, ak8 ma23r3f3bdc g 4byebout

  Supernovas are thought cna8 3 8+d*riuw 7phyqto always result in

  Black holes

  Pulsars are rapidly s7903mxdnvhzj:iy v8 x3tc3pikdz n./pinning

State Einstein's principle oekz/d4i)bf*2o9jjeq83 xuegh8 u va/ f equivalence.

  The Schwarzschild radius of a black hole is that radial distad n6-7nk o3sxk9gf/* c k0uewance 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 b6-kcxkk*fo0enan s7 39 dw/uge 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 e( )w;- x;y rotdone 6zzt-vlm,mits light of a particular wavelength in the visible, and the sylz;wor v6m)d ;zn,t xeot(--ource is moving away from us, the color of the light appears to us to be shifted toward the

  The cosmic background radiation corresponds to a temperature of j1di m(d7d:zm about

  The Sun has apparent brightness (2m np4h czcq/rgtft-dxu+)6at 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 to that of thev:xu*;fm zo2.sw 9e pk 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 mean4iagt .xk-wx qu2r11r+i +jqm4 hnh iww9n()k 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 mea+6exll44nd q 4jh/ zvz.2xzq+(m kluvn 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 Earth's nearifenr t9hzm5m7j k8 m/c9mq40pbs k73est star at 4.3 kb7jf9 nmec3rztm/p m 0k87 s9mqh45ily?

  The apparent brightness of as)x7cx2i lti c .f09id p j)/fb7 xfkr5c9ug,y 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 ug-hbjj91 ebh i41ekv .niverse is 1/H, where H is the Hubble constant. Taking H = 20 km/s/Mly, estimate the age of the universeh4.g1 hvi1kebbj j-9e , in years.

  If a galaxy is moving away from us at 1.0% of thb: rgrd+s 6oaft9o g/,e speed of light, how far away is it fgobsot ,d/g 6rf:9ra+ rom us?

  Estimate the speed of a galaxy that is6eds5sg2*qkxuhd 0a2 xll .n5 10 billion light-years away.

  Estimate the observed wavelength for the 656 nm line in the spect t7pe*74sc7d us2nh8lm:cjb hg(llc- rum of a star which is 100 million lights7nlp7hc(2-eb:htglmu sdc 7cl 8*j4-years from us.

  About 1 ms after the Big Bang, the temperaturp36an0p 4j 3 -vn/rkqq( umpfge of the universe was about 1013 K. What energy (in eV) doesppa4/p0k-6jrmn(nu g qf3q3 v this correspond to?