The appearance of th+vc ,k 7bhkp+ee great range of brightness among stars is due to

  The absolute luminosity for most6lf p 89fb+fh,s uyn)u stars depends on the

  Four different main-sequence stars are colored ht00; srrkfwea193z1caagmj; 7mp f 5blue, orange, red, and yellow. What is their rank from coolest to hf01c0 ea5r7zm13jpgrak ;sw ha; m9ftottest?

  A Hertzsprung-Russell diagram shows stars -( +3cj usizjlon a plot of

  A white dwarf star with a ma8:a.lsbte;fd )a/ xhp ss equal to that of the Sun is about the size of

  The Chandrasekhar limit of stellar massb, (gc/fr2e xh (below which a star will collapse into a ecxg f(b/rh 2,white dwarf) is, if the mass of our Sun is M, about

  Supernovas are thought to alwaysx mq3kokj5 4x; result in

  Black holes

  Pulsars are rapidly spinning- /mn pm/wfflnj*5y ix 9nxi+2

State Einstein's princiht)fabqn fn s+:p09:7 se9wqlple of equivalence.

  The Schwarzschild radius of a black hole is that radial distancukmln,0sn u/2 e 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 belum/0 2nkuns , 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 emits8fbn)j4s1s4wy 3 vs4kc6 sm):gh cifu light of a particular wavelength in the visible, and the source is moving away from us, the color of the light appearg:)3i4j w 6vs48cku1mnf) bsfcs4s hy s to us to be shifted toward the

  The cosmic background radiation corresponds to a temp;p o75n; fcchferature of about

  The Sun has apparent brightness at )ei 5 jh7 ziw:wy.t)0jgmc.oi*rmz 8eEarth ($1.5 \times 10^{8} \; km$ 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 luminl3ia3ik.qqc.l (vcpdqv1n;) osity 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 q7.hdg5 s(k jp 8lw0x;)qqz3,xz2t yd)gudvomean 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 o b6 k1gpoc5b fff7,cz:f $1.5 \times 10^{8} \; km$. 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, whil6w:7 ft65jp*:cg+ohq1w zg dn14m og dlg1zmch is Earth's nearest star at 4.3 ly?+wmd:hzldtgm66 g*15jc gqw:onl1z1op gf7 4

  The apparent brightness of a st0 p2+p.v cddvrar 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 a+;4o-xrpuokf-zuwu5 gu, u))vce9rw 0cfm ,rpproximate age of the universe is 1/H, where H is the Hubble constant. Takinkufwz ufo)m4cev9r; gu ),, -0r-cwxur+5 opug H = 20 km/s/Mly, estimate the age of the universe, in years.

  If a galaxy is moving away from us at 1.0% ofrwx;k7th u5* c the speed of light, how far away is it fc5u;tr w7khx *rom us?

  Estimate the speed of a gar,5vkl odw)0.a2vu fu laxy that is 10 billion light-years away.

  Estimate the observed wavelength for the 656 nm line+z.enilsqn: 5 in the spectrum of a star which is 100 mill: 5zlnie s+qn.ion light-years from us.

  About 1 ms after the Big Bang, the temperature of the universe w8(foov7 )9ngv( m vos7 lw,hdhas about 1013 K. What energy (in eV) does this)8mhofg77(,ol vs ovd 9w(nh v correspond to?