The appearance of the great range of brightness among noetgv)py 1(qc 2 tl86stars is due to

  The absolute luminosity j, odh 3xxaj/io fd0;9for most stars depends on the

  Four different main-sequence stars are colored blue, orange, red, and yelg4wm-yay+62a *okkn w low. What is their rank from cooleskm-a6y2wok gy4w +* nat to hottest?

  A Hertzsprung-Russell diagr*l ip9/d 2hcdlam shows stars on a plot of

  A white dwarf star with a mass equal to that of the Sun is about the sizelzeb0;y+v7c w2wlx 9g of

  The Chandrasekhar limit osha7 y78yh4vmd 8k3u qf stellar mass (below which a star will collapse into a white dwarsv a47y h8kdh3mu 7q8yf) is, if the mass of our Sun is M, about

  Supernovas are thought to always result 6jou4r ;2)kmu0fzorj in

  Black holes

  Pulsars are rapidly sp 3j1pof wix4/guvy-q9owf4h+inning

State Einstein's principle of eq;s+o t73bli1wwfci,* z*gyo d99hsmi. y r)gjuivalence.

  The Schwarzschild radius of a black o +d3yil n53tr 5h 4hyxqam;r:hole is that radial distance 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 relativh 4qn:i+3hl5md35ory yxr;at ity 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 visible, an*6o,z960zb oerco)8epday jv d the source is moving away from us, the color of the lighoe6zpcobo9z v d,a)e *60jry8 t appears to us to be shifted toward the

  The cosmic background radiation corresponds to a temperature of abo3ur j: tl8ch5lut

  The Sun has apparent b:61i ttd-zkhg pudnouq846 g* rightness 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 luminostink-6h7r k +c j;h(uhity 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 ao1 exwf p3nt.r jw;-w5 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 p- gio f ov/z6urt.1v:,fq2 yaradius 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, which is Earth's nearest stacm(k0xh 7 )2gug mv434dmnlki r al0n4vimm7gxhk3gc)m( d 2uk4t 4.3 ly?

  The apparent brightness of a star is 5pf c ezy91u+m$1.0 \times 10^{-12} \; W/m^{2}$ and the peak wavelength is 600 nm. Estimate its distance from us.

  It can be shown that the approximate age of the universe is ,)qn*3cd uwhep a*q h/1/H, where H is the Hubble constanwn p ,/qd*h c3uaqe*)ht. Taking H = 20 km/s/Mly, estimate the age of the universe, in years.

  If a galaxy is moving away fromdgxhy2 (xfqjt/ 98z)w us at 1.0% of the speed of light, how far away is it from usy) h /zwgf(9 txxq82dj?

  Estimate the speed of a galaxy 8x/k z t6vbeb4that is 10 billion light-years away.

  Estimate the observed wavelength for the 656 nm line in the s 8u1wxz2dk*g z dh*)mkpectrum of a star which is 100 kd)k *gx 1z u*dmwh28zmillion light-years from us.

  About 1 ms after the Big Bang, the temperature of the universe was abo*/ra u:wse*bt0kyj x;ut 1013 K. What energy (in eV)**xwy 0;t/bes juk:r a does this correspond to?