The appearance of the great n-:d 0au+ kiatk ih-lp5ov) *nrange of brightness among stars is due to

  The absolute luminosity for most stars depends on 9hjk85e(ip arg6v h3 k*mk;setbi , 3qthe

  Four different main-sequence stars are colored blue, orange, red, and yellow. W/-z up.h)x7h6r xyot ahat is their rank from coolest to hottest?o7-xthhayz 6/.pu xr )

  A Hertzsprung-Russele*l,ox7 qhbq 2l diagram shows stars on a plot of

  A white dwarf star with a mass equal to ik,brtb*g5mehj ;( v-;:+vjjf jcjt )that of the Sun is about the size of

  The Chandrasekhar limit of stellar mass (below whicqkgn- mtq1+ izu,-l.:gzwcga7th* u9 h a star will collapse into a white dwarf) is, if the mass of our Sun is M,g1gc.wg, +hqt: i- zanmlqtu7z9-k u* about

  Supernovas are thoughdnm2g*3 /lvvt. - obost to always result in

  Black holes

  Pulsars are rapidly spinnid nxg2; . pdj(anyfk16ng

State Einstein's principle of equ/*5yk wer b4q7qj7kn vy8 mp(/ykcaj9ivalence.

  The Schwarzschild radius of a black hojz2ot-4y/ u 5w 0xkhss 6u e/5twn-uxile 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 be calculated from a star's moxx2iut5-0suhy4sn6we/ /k5j u-t zw ass 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 inl;hhzbps(ep/l1v, wqco / a ): the visible, and the source is moving a slwbl /hac()/:,ehpp o;qv 1zway from us, the color of the light appears to us to be shifted toward the

  The cosmic background radiation correk x io;j* ge0clvoi-60sponds to a temperature of about

  The Sun has apparent brightness at Eart3( 7a +dyzfpg4lky +bth ($1.5 \times 10^{8} \; km$ 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 the Sun (c)hvr9sh64iu*t*./ y -wkb qj hh tqo8$1.5 \times 10^{8} \; km$ 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 ;)ln)tuqf(j sdius 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 mendbj 4ztt, x3c9e.ec2an 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 nearestyp p3dw27kuom53c ln+ star at kcmnp2 3pduy35ol 7w+4.3 ly?

  The apparent brightness of a;ra+* dg w/n:auuef/v 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 uncnq. ;5ml/al2 w/do ftvhj2;tiverse is 1/H, where H is the Hubble constant. Taking H = 20 km/s/Mly, estimate the age of the uni/ tlhmodw2/ nj;2vl tca.5;qf verse, in years.

  If a galaxy is moving away from us at 1.0% of to bnswlk2ds0o; o (e5y0l(tr )he speed of light, how far away is it frobo ytsw(s 2oknl r(50do l)e;0m us?

  Estimate the speed of a galaxy that is 1lciv ,0dx:n (+kjgdb40 billion light-years away.

  Estimate the observed wavelength for the 656 nm ligjn8 dc9j4;djaj4zdx(f4dn 2 ne in the spectrum of a star which is 100 million n4dx jjdzjc 4gjd;n 2afd48(9light-years from us.

  About 1 ms after the Bgts+u(:a.d8sbetu j u wb 56ykra965dig Bang, the temperature of the universe was about 1013 K. What energy (b 5ay6g:t a5swd8etjb(96uu+d ur.ksin eV) does this correspond to?