The appearance of the great range of brightness among stars is due r.ut 8g,.j3mywu+cbh;l l/ mato

  The absolute luminosity for most stars depends o /fs0)kls)+ ckqrs8 sfn the

  Four different main-sequence stars are colorrz4e.w ;s+ yod.xne: hed blue, orange, red, and yellow. What is their rank from coolee ..sh d+own e4:xr;zyst to hottest?

  A Hertzsprung-Russell diagram shows stars on)sescu js7 (p8v 222bmmlof4e a plot of

  A white dwarf star with a mass equal to that of the Sun is abouta1jc5 mknd+a 1 the size of

  The Chandrasekhar limit of stellar mass (bvp sr:8rx.64ytjyd0 w l :ya:melow which a star will collapse into a whid .y v6a8x:: yprs0wltym j:4rte dwarf) is, if the mass of our Sun is M, about

  Supernovas are thought to alw y4*urdfbed6 pv4n1wkx3m 3 )kays result in

  Black holes

  Pulsars are rapidly spinnhay5bb.e *)ad-.al+ k gd1ouping

State Einstein's principle of equiv4zth 65ticc sw 7hk6)nalence.

  The Schwarzschild radius of7 dm9d1+zsps hp.algpl m )8ts:w7 c9o a black hole is that radial distance from the center ofwd9h s+ lptc1d ).so p9z7sm78:gpa lm 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: $R = 2GM/c^2$. 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 wa5g, bfwm)tb 7uvelength in the visible, and the source is moving awamgt, ub7)f5 bwy from us, the color of the light appears to us to be shifted toward the

  The cosmic background radiation ckk5 vz pmz,r qux58,9porresponds to a temperature of about

  The Sun has apparent brightness at Eak 9tm;g w8 5hzd2mr+slrth ($1.5 \times 10^{8} \; km$ 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 equalt z, k7ws,kosg5l:p5w 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 anqn e66dr 44++ uhzoeuazp t62 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 a mean radius ./nm7ei o:a e eylte5+k7kx(cof $1.5 \times 10^{8} \; km$. 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 Pp veo.g1g ji0t813knm 4ram( qroxima Centauri, which is Earth's nearest star at 4.3ptk.rvq( 0nmjg e 4a i3g1m81o ly?

  The apparent brightness of a skbubv:ga/-n ,tar 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 thatqf+hq zy7fr3 * the approximate age of the universe is 1/H, where H is the Hubble constant. Taking H = 20 km/s/Mly, estimatqr* zfhfy7+3q e the age of the universe, in years.

  If a galaxy is moving away from us at 1.0% of the speed e,n:oko c59g22vpx w9t)a kmuof light, how far away is it from u2 nxut9:apok5wmoe 2cv9gk ),s?

  Estimate the speed of a galaxy that is 10 billion light-years /-fzr/ o*xy ifj3d6(n vuv0mdaway.

  Estimate the observed wavelength for the 656 nm line vg 5 5gotlguiu wqoa md;o(.na 75/9;uin the spectrum of a star which is 100 million d (ao9ao5u5wnt g. ; mu o/gqu5lgv7;ilight-years from us.

  About 1 ms after the Big Bang, the temperature of the universe was about t(f+8dxb* )cvs zv (x.fkx2pi 1013 K. What energy (in eV) does this correspo*. +zxfxv8v(d xskcp)tif(b2nd to?