The appearance of the great range2hy:xo -99*wabl qitc of brightness among stars is due to

  The absolute luminosity for most stars depdwaqa- zp p28tn,a 8lygy- e3i/j9zq/ends on the

  Four different main-sequence stars are colored blue, cdct0qj9m.9 emw v/5z orange, red, and yellow. What is their rank fro z 0t/qm5cwjvem9.9cdm coolest to hottest?

  A Hertzsprung-Russell diagram shows )3yvt/u kdedo-osrl.)hek 07stars on a plot of

  A white dwarf star with a mass equal to that of the Sun is kkv50p .i uv3p:dzn/ dabout the size of

  The Chandrasekhar limit of -/c)egzs xe2spc4 -xf stellar mass (below which a star will collapse into a white dwarf) s4-eec zs)pc gf x2-/xis, if the mass of our Sun is M, about

  Supernovas are thoug5aff8 am(j ch3ht to always result in

  Black holes

  Pulsars are rapidly is d56hybq3p boc3 3h1*b7zzgspinning

State Einstein's principle of 9jpzc3 ymib+htj*1h8 equivalence.

  The Schwarzschild radius of a black hole is that radcqw1po 5: 2b1zgq l 2kpddbt60ial distance from the center of a sphere within which not even light can escape. It was first discovered mathematically by Schwarzschild in 1916 after Einste0: kzq2o5 pbbdgwd p26 t11qlcin 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 a partic;f9y00cz9(q3p+-qgs ai zf ( ytwhgqfular wavelength in the visible, and the source is moving away from us, the color of the light z(pw(q0ay g93 tfc9f-0fz; s+yiqq ghappears to us to be shifted toward the

  The cosmic background radiation corresponds to a temper2ca-y 3sj onk7ature of about

  The Sun has apparent brightnaczw2)tf fcp ;rw (g-6ess 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 luminosit8o 5 1e u*cvzzqb7:v3jih/hety 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 ah k*hwm,c-swa(tc3 +c( 6y vfk 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 of 4zys6a/: +hme+bq*g;zej wvj $1.5 \times 10^{8} \; km$. 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 neargt:hy1s3f00 av150 srkeg. wglk9 sqrest star at 4.1a9q3 5ks g1:ygfrtserl 0skg v0wh0. 3 ly?

  The apparent brightness of a star is d3r b( i3/ox 1mvl;6 kizn6dlpkgh)4 r$1.0 \times 10^{-12} \; W/m^{2}$ and the peak wavelength is 600 nm. Estimate its distance from us.

  It can be shown that u ia:eo f5 sxynomlf69mnvn,/ y.g7 gr7+g p:*the approximate age of the universe is 1/H, where H is the Hubble constant. Taking H = 20 :pnfmy*ov9goxa6iyf . mg+5 7sreln7un/g ,:km/s/Mly, estimate the age of the universe, in years.

  If a galaxy is moving away from us at 1.0% of the pi7yo/u zmho)qb -q)/speed of light, how far away isp7z)io y/) qo/qb mhu- it from us?

  Estimate the speed of a galaxy that is 10 billion lightegxim,xr*g b0b w0 j97-years away.

  Estimate the observed wavelength zib7fn 7xr0, h/qn0ti for the 656 nm line in the spectrum of a star w,iz7hnrf b0 x0n7/tiqhich is 100 million light-years from us.

  About 1 ms after the Big Bang, the temperature of the universe wgpmf/, mr9g h7as about 1013 K. What energy (in eV) does tr9hpm 7g/ g,mfhis correspond to?