The appearance of the great range of brightnessv-e4 cf8 qmhj;xm57cv among stars is due to

  The absolute luminosityaom:jj18sblu26 .mnhr b53qj for most stars depends on the

  Four different main-sequence stars are cu5 mfohl + 1(cqnx9o,abvmb;9olored blue, orange, red, and yellow. What is their rank frco(9bx 5 u,vf ;+lmqamobhn19om coolest to hottest?

  A Hertzsprung-Russell diagrams ttl h,50m ;fsa4sdao46jxf1 shows stars on a plot of

  A white dwarf star with a mass equal to that of the Sun is about the size ,x+ (wa5blr+mf cnk4zof

  The Chandrasekhar limit of stellar mass (below which a star q)j dx )3n5e /ul lu4c2noy*nlwill collapse into a white dwarf) is, if the mass ofouy5 3jlx4lq2 elcn)*) n/udn our Sun is M, about

  Supernovas are thought to always rec qxc.7/razh;+m,uznyz0q7esult in

  Black holes

  Pulsars are rapidly sp.3-f6nvlhzgjv 3o0nx inning

State Einstein's princi aj 13edt d:wqgb.l 989mwa,wiple of equivalence.

  The Schwarzschild radius of af71t3c 1jgk- wy (pvsfum9g; r black 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 publishe19 yj rk f1fggm7s;uv c-tp(3wd 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 lightn8y/p p6x1pl fj.op8j of a particular wavelength in the visible, and the source is moving away from us, the color of the light app/.p 68x 1jpoyf lnj8ppears to us to be shifted toward the

  The cosmic background radiatio8 u,47q1qcnt8rq8uxp; b lppgn corresponds to a temperature of about

  The Sun has apparent bri6b rlfp m/:b 6m*c .jhq*f7jhfghtness 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 tak 08j,x/ l,exvafzix*v9 jt r9rg;)mhe 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 mean raez o*ivpz+ qi 0k++-wgdius 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 tofs87pabm :*s 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, which is Earth's nearesta) *q*7hal8mpio xob+ star at 4.3b oqi*a7p 8o)h xm+*al ly?

  The apparent brightness of a starpw 8u3b2uzj4 t 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 approximavov8 cim./9on te age of the universe is 1/H, where H is the Hubble constant. Taking H = 20 km/s/Mly, estimate the age of the universe, in yv 9vc.oi8mon/ears.

  If a galaxy is moving away from us at 1.0% of the speed of light, how far a1ug1, gxns: kyway is it from u 1k,x1s:ygu gns?

  Estimate the speed of c4cfik);li1) yv zpq7 ) dlu)ka galaxy that is 10 billion light-years away.

  Estimate the observed wavelength for the 656 nm line in the spewbpbsncp19*.lkl 17 tctrum of a star which is 100 1 9s *1tppkb. cl7nwlbmillion light-years from us.

  About 1 ms after the Big Bang, th)hx0w ,;brb kv+n.kape temperature of the universe was about 1013 K. Whaxa+)wp;h.rb0 k knbv, t energy (in eV) does this correspond to?