The appearance of the be(;p*j3do,zx8 jk .as4vdkzlc og0+great range of brightness among stars is due to

  The absolute luminosity for most wnp jm8rm+;5k stars depends on the

  Four different main-cw- qrs5p zi6 ;a0)qcisequence stars are colored blue, orange, red, and yellow. What is their rank from coolest to hottest?cai -)pqrzc06 q;is5w

  A Hertzsprung-Russell diagram shows stars on a plot oslxl/kq+cmc-*6v 1 ,lfii1t l f

  A white dwarf star with a mass equal to thanrwjhm8 q-t ,d7s+qago o9 kp5v4 )qj*t of the Sun is about the size of

  The Chandrasekhar limit of stellar mass (below which a star will collapse ij5ocn 9 0kcntkoy:1-nnto a white dwarf) is, if the mass of our Sun is M,jon5c -o9cnykn:0k 1t about

  Supernovas are thought tocz- p1 :f.dboi always result in

  Black holes

  Pulsars are rapidly spinn kpr9zrn73j qa hy 4p/buc.a+/ing

State Einstein's prin do/e /hzbgj:/ciple of equivalence.

  The Schwarzschild radius of a black hole is that radial distance from the centsbnle f;u-3b)p6 (f dfer 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 tbb fslp6n)( d3 u;fe-fheory. 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 ligvv;hs l4hx-d7 ht of a particular wavelength in the visible, and the source is moving away from us, the color of the lixv; dhl7h4-vsght appears to us to be shifted toward the

  The cosmic background r5s:3kedcezdoe6pnz3gsu-j c.i )2 q .adiation corresponds to a temperature of about

  The Sun has apparent brighp76 apo7c9 jh4;:9gu kjh(:peuwq ukwtness 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 th3sd4efw c)i- ge 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 ra)pre(us3) kxff7kl j( dius 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 radiusk 8ca, j3wkon+7l ;myj2tfa7n*hd 5 ua 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 starsi)+xu ; y8 p)52fryfn ks,a4zghc5as at 4.3 ly?hp y;,ns5 2 4f)uyks+5szaa fgxir8)c

  The apparent brightness9k-,zs7+wfd:j. hn ngn ym86mp.gg cd of a star 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 ar j4w3h-ijch;p7on 2 universe is 1/H, where H is the Hubble constant. Taking H = 20 km/s/M -aohwipj jh;4n732 crly, estimate the age of the universe, in years.

  If a galaxy is moving away from ufs p0u-ztg0ag8q4viv c8. ;*nbw;ynbs at 1.0% of the speed of light, how far away is it fz p-;cs vb;.u4 t0 a ggq8b0nvi8wnfy*rom us?

  Estimate the speed of a galk wr *wkws 9y5d1n:o3aaxy that is 10 billion light-years away.

  Estimate the observed wavelength fo9n2,*f ((iqb kocbpdf5 iwi*y r the 656 nm line in the spectrum of a star which is 100 million light-yearfn2pii(5bb,o *wd ic ky 9*f(qs from us.

  About 1 ms after the Big Bang, the temperature of the uc09jfs b.j, nkniverse was about 1013 K. kjj. 9sf 0n,cbWhat energy (in eV) does this correspond to?