The appearance of the great ranal4ax 0wfw 0u:k(l3v km-tc xyz+g99 jge of brightness among stars is due to

  The absolute luminosity for most stt//ny m, bd:k cvx3 wb.0.hmglars depends on the

  Four different main-sequence stars are colored bvia),vlgf89a5x c *cllue, orange, red, and yellow. What is theirxgav*5)i a clf l9,vc8 rank from coolest to hottest?

  A Hertzsprung-Russell diagram shows sti polru)w056uars on a plot of

  A white dwarf star with a mass/drl976ixx vg equal to that of the Sun is about the size of

  The Chandrasekhar limit of stellar mass (below which p6.y h l i l6ii1qbk-cnf),3l 7po8syya star will collapse into a white dwarf) is, if the mass of our S y pyl bf1k. hcy6p)i3,inl-q67iols 8un is M, about

  Supernovas are thought to always,l0yn9 1ern9m d2on pr result in

  Black holes

  Pulsars are rapidly spinni2; o6gotojmg 3ng

State Einstein's principle ovzx l(0q*s3cmf equivalence.

  The Schwarzschild radius of a black hole is that radial du*kd):6u(iiw c3e sidro2 3qdistance from the center of a sphere within which not evenud36:3i*or(2d qiw ec uds )ki light can escape. It was 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 wava rs 0zbr sf-af2/xu3-ri e/f0elength in the visible, and the source is moving away from us, the color of the light appears to us to -a- zru/s2sa0/frefx br03ifbe shifted toward the

  The cosmic background radiation corresponds to a temperaturs, ioevf3 zmqkj+* 4vq*5qpj 4e of about

  The Sun has apparent brf .ic)jo. ej+ ie0mif3ightness 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 luminosity equal to that of the Sun (t0,jj *wps3wgn jb9v ;4n)ipl7f8 hu a$1.5 \times 10^{8} \; km$ 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 m2w3c4kpcroednqt l zkr6dz 3;h-(;a(ean 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 mx 8 r.o klg-b9;/nss1po-h c7vphw3 emean 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, whic*n x q *qbzp95db)frn5h is Earth's nearest star at 45b5np nqzqd*x9bf r)* .3 ly?

  The apparent brightness of a stahy;u+x pdpy dw90- . ftc2g7q1e)eousr 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 universe is 1/H:y)jdz4srj.al o qhyqj)+ w9), where H is the Hd+ s ha. yqjz q)wolr49:)j)yjubble constant. 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 far apkr5/h1s buf j47 uy;uway is it from us? r/5jhyfks1 47ubp uu;

  Estimate the speed of a galaxy that is 10 billion light-years a9)hpol)h: swm way.

  Estimate the observed wavelength fow y:ve v*s:oaqy8u03or the 656 nm line in the spectrum of a star which is 100 milliauo0qy s3v8:y:*o wveon light-years from us.

  About 1 ms after the Big Bang, the temperatsuq8 jogw9s*q dz+2 u-ure of the universe was about 1013 K. What qujd+sw -q*2z u8gs9oenergy (in eV) does this correspond to?