The appearance of the great range o6c m,6 ca0sc 4hu.0deigmjtg-f brightness among stars is due to

  The absolute luminosity (7 uowm2la*sa for most stars depends on the

  Four different main-sequence s ru7y5 iu8rew+f,n9i7+c ebe vtars are colored blue, orange, red, and yellow. What is their rank from co8re ,riciv u9 n+7uwbe+ e5fy7olest to hottest?

  A Hertzsprung-Russell diagram shows star lw)j(bz)jeuhj3gp7 1s on a plot of

  A white dwarf star with a mass equal to that + 9vpz /bzsf)sof the Sun is about the size of

  The Chandrasekhar limit of stellar mass (below which a star will collapse intt) 3-t (ivuiifo a white dwarf) is, if the mass of oi vif)3( tut-iur Sun is M, about

  Supernovas are thought to always re;m/79xp hysmb sult in

  Black holes

  Pulsars are rapidly spinning hnc24xm0 )*5h fnxjdk

State Einstein's principle cs*ma x7tt)8 jk4mmdy;mg q .5of equivalence.

  The Schwarzschild radius of a blackj*ug7b mhw(x 4 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 relativity theory. It can b7xwg(4juh *m 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 partij 3y3l.d xz5 4w3j*dse1slexi cular wavelength in the visible, and the source is moving away from us, the color of the light appears to us to be shiftexe.3is4 *3d5ly jzw31j sedx ld toward the

  The cosmic background radiation corresponds to a temperature of +/, 4h+wrlqamxzzgul .oaj g(r a 71i9about

  The Sun has apparent brightness at Earth (( 6/hfoz0othluy9viky ,/*f:,bz t xu$1.5 \times 10^{8} \; km$ 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 lumin/j npn01jkwim6f/b 0w osity 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 a m4ov. -9 -rbfakyo ip4bean 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 ha uyy (wl.g*ids6.) lnjuk qi;(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 nearest star ,t laz 2.( bund 1,buiq)4/ituumu m:gat 4.3 ly i muutbu q,4:n/m 1 bta(di,g)u.2zul?

  The apparent brightness of a sta/w:beqv602j cym z/zdr 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 tz di9-+n+3iekhl w -mbhe universe is 1/H, where H is the Hubble constant. Taking H = 20 km/s/Mly, estimate the age of the universe, in yeb- mhni3l- i++9wdzke ars.

  If a galaxy is moving away from us at 1.0% of the speed of lig wtsobe 22vn+me7 /t1qv1er2z8r lpn1ht, how far away is it fr z8n+vr2mwp2 rl1e1nes te2qo/1 btv7om us?

  Estimate the speed of a gala0g1+)qy mrphw xy that is 10 billion light-years away.

  Estimate the observed wavelength for tl.a 857q1f)ua fxsvk mhe 656 nm line in the spectrum of a star which is 100 million ligq5s8.mka vfx alu7)1fht-years from us.

  About 1 ms after the Bizem uik4)zsqe0nf958zat z 1/g Bang, the temperature of the universe was about 1013 K. What energy (in eV) does this corre)nz9qizkz ema5z 81te0/sf4uspond to?