The appearance of the great range of brightness among stars kafzc/89a d x+is due to

  The absolute luminosit 9)y.owxefj ;uy for most stars depends on the

  Four different main-sequence stars are colored blue, orangep e1u3 xysxn)*+x )d vz8zxs1d, red, and yellow. What is the 3xeud 8d*xyn +)) xsxzp1s1zvir rank from coolest to hottest?

  A Hertzsprung-Russellk:*ny-y u)1) exzsi bh diagram shows stars on a plot of

  A white dwarf star with a mass equal to that of the Sun is about the size o7g-c6q j +c, f4gmmoaef

  The Chandrasekhar limit of stellar mass (below which a st cjbtax(z+ c2dz670 bpar will collapse into a white dwarf) is, if the mass of our Sun is M, about0c z(cda26jb7 +bpt zx

  Supernovas are thought th wqyhz q5gi :6dj3b27 kxdc53( h4zbl:g dv(lo always result in

  Black holes

  Pulsars are rapidly sp r 3ew6*v:h2vxii o(npy: 8qukinning

State Einstein's principle of equivalencek mx+9j 9j vkctj5y2zcfx 4;s8.

  The Schwarzschild radius of a black hole *ctk .r0h1,x k0 h2 oixssd4dwis 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 10x0,4 k.rxsoskhhw *ditc d2 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 ligh: fdpace(. b9yt of a particular wavelength in the visible, and the source is moving away from us, the color of tap c:ef9(dy b.he light appears to us to be shifted toward the

  The cosmic backgroundm39dqexc b+ z )1ysk6n radiation corresponds to a temperature of about

  The Sun has apparent brightness ate u rkpz xv2d.hj i*:24lr)pp5 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 the Su/eo9p*oal8beud6-s5f 3 a yo6p,b iy /fogiv3 n ($1.5 \times 10^{8} \; km$ 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 rc:wqmf 6sdi24 adius 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 ra-n2+na8upya k*gva8vk- e1m kdius 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 isf9gh+g(ag 5d)a xfnd4uf4bc4 Earth's nearest star at 4hu)45x9fb +aggadd4fg cf 4n( .3 ly?

  The apparent brightnessck x8sq3 h:vj1 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 ths/:gb2 yo: rwojw7na s l:+kc5:ed(coe universe is 1/H, where H is the Hubble constant. Taking H = 20 km/s/Mly, e7w5og/ kdo +s2:a rwej(lc :nbo:scy:stimate the age of the universe, in years.

  If a galaxy is moving away from us at 1.0% of the speed of light, a6z1v3 +p. i)vfwojwf how far away is it o)j3 1fvf +p6.w iwavzfrom us?

  Estimate the speed of a, os b(voxg m8o0ew7.jqo2ds2 galaxy that is 10 billion light-years away.

  Estimate the observed wavelength for the 656 nm line in the tdnn6 (n/ioaqy51h .nr , rj;hspectrum of a star wq onanhn r(n61/i, d;t jh5.yrhich is 100 million light-years from us.

  About 1 ms after the Big Bang, the tempera;mx7yq 9 (v4jtagfr2tture of the universe was about 1013 K. What energy (in eV) does thx4t2v;rq ( ty9a7gjfm is correspond to?