The appearance of the 1p4g csfwm hav5,1+ys great range of brightness among stars is due to

  The absolute luminosity forc;9-dh)ugw vie0ex1f most stars depends on the

  Four different main-sequence stars armx0o15d2 bf cle colored blue, orange, red, and yellow. What is tb x 5c1dofl0m2heir rank from coolest to hottest?

  A Hertzsprung-Russell diagram shows stars on a plot +yo3q rshdd;tf07.lsof

  A white dwarf star with a mass equal f2n xyp g/0s-k+afip,to that of the Sun is about the size of

  The Chandrasekhar limit of stellar mass (below which9gc)-o aoku 7)wrlpa6xqvd: , a star will collapse into a white dwarf) isa6-gd7 akr,q)poxc:ow )ul 9v, if the mass of our Sun is M, about

  Supernovas are thought to always result in3r0)dc 0 onrb bwr, 4z7npdw(n

  Black holes

  Pulsars are rapidly dw md8uil)(o;9l ovp ;spinning

State Einstein's princip88) -ruk. tgo 8hj(irdaiid0dle of equivalence.

  The Schwarzschild radius of a black hole ia)m3w )lb4uob j1ubq kh8v9r:s 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 relativity theory. It can be calculated from a star's mass M as j)3albqvmbur9 8o ku:4hwb )1: $R = 2GM/c^2$. 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 in4pa/ 3fnret .mn-d* 7lyc+stom b. q0l the visible, and the source is mo m+c b*l4r0s deoamq np7-nt.yf.3 t/lving away from us, the color of the light appears to us to be shifted toward the

  The cosmic background radiati:tf d 3.:;glvfoz o :eav:8stion corresponds to a temperature of about

  The Sun has apparent brr-x3 s hw8ghgtc4+ ah6nq8h 2iightness 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 65c mth+0vg6ut5qbgg9 +azce 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 has9t6ei,wl/hk0 ooqccyk )vl)d y; yb/ , 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 km?

  The Earth's orbit has ilkqfpd. 42 aj7;.4dw3ft srya 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 jr2zii.x;2 m mfor Proxima Centauri, which is Earth's nearest star atmm z.jii22rx ; 4.3 ly?

  The apparent brightness of a star is 3cfl*u1p vog3 $1.0 \times 10^{-12} \; W/m^{2}$ and the peak wavelength is 600 nm. Estimate its distance from us.

  It can be shown that the approximate ag d9nw0.4key05 tp oxwme of the universe is 1/H, where H is the Hubble constant. Taking H = 20 km/9w 50p o4eykwd0mtx n.s/Mly, estimate the age of the universe, in years.

  If a galaxy is moving away from us at 1.0% of the sper 78ki+ ex7 fcdqsbnl l.do;7,ed of light, how far away is it fromeicb.qkrdlnf77x, ;+7dl8s o us?

  Estimate the speed of a galumywm3ol9;d l5 ; hi*kaxy that is 10 billion light-years away.

  Estimate the observed wavelength for the 656 nm linej t (,,cx*fkd (ognh;h in the spectrum of a star which is 100 million lig,t o;gdjfk,h( c( hxn*ht-years from us.

  About 1 ms after the Big Bang, the temperature of the 9so pu90v f8hr9warls9 3*ibn universe was about 1013 K. What energy (in eV) d80awb ni o*9uhl 93s9frpv9rs oes this correspond to?