The appearance of the great range of brightness among stars .0d zmaq-x./ jzysu0oafh19pzl54 n jis due to

  The absolute luminosity5z5f1ate w y0* a,/dodkl ow8r for most stars depends on the

  Four different main-sequence stars are 0 m1;k.t t -snefrsav*colored blue, orange, red, and yellow. Whanae. *-sstr tm;f1 k0vt is their rank from coolest to hottest?

  A Hertzsprung-Russell diagrkyngdyny9j j2 w5.5tow9 br/+am shows stars on a plot of

  A white dwarf star with a mass equal to twr-y:fp xjs8r.ye.o 0hat of the Sun is about the size of

  The Chandrasekhar limit of stellar sk4p8i2 ebtd6b/;fkd 7eh 69kc jeid(mass (below which a star will collapse into a white dwarf) is, if the mass of our Sun is M, aboui/9;2pe kki7hfk4j(6e d6 bt8sbded ct

  Supernovas are thought to always result ib0fv 9h/ g0fktn

  Black holes

  Pulsars are rapidly spinn.6ajlf + pcn g64j)-dn azd7dbq;za *ling

State Einstein's pri1vmou f:f1+ 1vqi82v ss/t orvhh tn6)nciple of equivalence.

  The Schwarzschild radius of a black hole is that radial distan*s)mb yee)oqv 9 you*x)ehg* ksf7.2kce from the center of a sphere within which not even light can escape. It w7eg ) o koxy*.mbusv)*qkfe9 2ey*)shas first discovered mathematically 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 emits light of a particular wavelength in the8pf wtr 9**vjn visible, and the source is moving away from us, the color of the light appears to us to be shi *t8fn vp9jr*wfted toward the

  The cosmic background radiation corresponds to a temperature oxsf( ,o4r)df qf about

  The Sun has apparent brightness at Eartm/*gk.q8 h6 vra s p)mn(yd,pvh ($1.5 \times 10^{8} \; km$ 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 thsy t y mm3c1:m0m7*hpwwzs.2y) ajme7at 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 a0 2 g u)d5wnuo06 w(x5nqijatl 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 ha+3;:gbvq e5g xzcpsf3s 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, wh zgw i0o84r00bwndzj4ich is Earth's nearest star at 4.3 n4 jb0r0dw8zgw04oiz ly?

  The apparent brightness om99/n5c yv*j5maxog nf a 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 ag6 due ij5.20g awjg1(w8kvgcpe of the universe is 1/H, where H is the Hubble constant. Taking H = 20 km/s/Mly, estimat.w(jw2g0u85dgp1jce ki 6v age the age of the universe, in years.

  If a galaxy is moving away from us at 1.0% of the speed ofby8mll-dg(3b i;- yev. vq p:y light, how far away is i gdy m-ylve8-i; vb(lb3:q. ypt from us?

  Estimate the speed of a galaxy that is 10 billion lighw)89a: l uogy vn ;rzx1-tph:;2v hywht-years away.

  Estimate the observed wave-4ib wk 0; ed :d)5p-fbvaadgilength for the 656 nm line in the spectrum of a star which id:p-fi e)-b5aa; igwdkv40dbs 100 million light-years from us.

  About 1 ms after the Big Bang, the temperature of the universe was about 1qb11 y46 y.vnw5i1 f kl.zqce1)yveck013 K. What energy (i4.6lf1v)ei q c. kz kv1bq1 ny1wyc5eyn eV) does this correspond to?