The appearance of the great range of brightness among starsio- rrop:l7tm6s .t 4s is due to

  The absolute luminosity for most stars depends on thd dz sj-t*jy1-e

  Four different main-sequence stars are colored blue, orange, red, and yellow8ld(j) hh9x qmu .fje(. What is their rank from coolest to hoj (x.e mhhjlf8u()d9q ttest?

  A Hertzsprung-Russell diagram shows stah v .-n1s0prny./kdpwrs on a plot of

  A white dwarf star with a mass equalvf2 tc9. *s ewyb,qc:e to that of the Sun is about the size of

  The Chandrasekhar limit of ste7w1( 4q l.lfzdpkvo)ozq0n;u llar mass (below which a star will collapse into a white dwarf) is,;v l dqz .0p f4l(n1)7wukzoqo if the mass of our Sun is M, about

  Supernovas are thought to always resultlj.euutz6a .4f q0 0/lvxbfm 6 in

  Black holes

  Pulsars are rapidly wro )8- lzl.;mc) wfmrspinning

State Einstein's principle of equiowr ;a0oj3sf 777.v/i9sibw t ucav7x valence.

  The Schwarzschild radius of a black hole is that radialz:ku5(g22+jc 2jny . vhinxyh distance from the center of a sphere within which not even light can escape. It was first discovered mathematically by Schwarzschild in 1916 after Einstei2vg+y(yh5 2kz2ni . uhxj:cjnn 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 the visibleseaxyk hu z-7 0go47(r, and the source is moving away from us, the color of the light appears to us to bz-useho0xr y7a k7(g 4e shifted toward the

  The cosmic background radiation corresponds to a temperature of yzh55i -m igd;vdp(v8 about

  The Sun has apparent brightness at 3kn.wq:);qjgb -7.tjd xxoua 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 b4 d5y,q)lvvh 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 meanq.7kakhiy v/(ic ba7g/ l+l7n 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 rwr*zy xqia* 6u7: j2xd ujwb95adius 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 fosjyn2dd e 1 dzsak 3.)j1awm66r Proxima Centauri, which is Earth's nearest star at 4.3 ly?6.sm1)dn6j w dad2eya s 13kzj

  The apparent brightness of a star i84e)xuxow)i s p7h .eis $1.0 \times 10^{-12} \; W/m^{2}$ and the peak wavelength is 600 nm. Estimate its distance from us.

  It can be shown that the approximate age of thef 57 5g zib.+gt0sj0fz1ynbsj universe is 1/H, where H is the Hubble co+tgf.bb5s n g57 fsz1j0z0yj instant. Taking 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 of light, how farcdflbwer:zr o;ffq1 t6;3* d+ away is er6fd*:zd;1ff ;+qwrtc l3boit from us?

  Estimate the speed of a galaxy thab-wzx5b bpfq9.w(eeck m7y92 t is 10 billion light-years away.

  Estimate the observed wavelength for the 656 nm line in the spectrum of a nq;o5cee 60*.* 1oveyxsgd9r s9cixx star which is 100 million lncq96yixe 1re. s0dgvo;*x xoec 5*9sight-years from us.

  About 1 ms after the Big Bang, the temperatu : d vu5 puhaw6.8hhmsu,.x7wure of the universe was about 1013 K. What energy (in eV) does this corres sx.7updw u,8a.muh5uh6:v hw pond to?