The appearance of the great range of brightness among stars is dh-vrz0 kr5-z (3quunlue to

  The absolute luminosity for most stars depends 4.c,7wom cm1)fed;l8tjknv orh44 x g on the

  Four different main-sequence stars aro swkd6 h::nk6h 3tu39 uefi( y-v nz4a)v9hgwe colored blue, orange, red, and yellow. What is their rank from cof(ng6dhi:k9- )vswo4h6 3te9u whz3y vak :un olest to hottest?

  A Hertzsprung-Russell dw5qj +fsd ux0d:+l 0ct8jzoj,)/kc xj iagram shows stars on a plot of

  A white dwarf star with a mass equal to that of the Sun mcha4m*04+, 0qi mqgs( yctsais about the size of

  The Chandrasekhar limit of stellar mass (bel+c qiqphr)x30ow which a star will collapse into a white dwarf) is, if th3c)hx+ qirqp0 e mass of our Sun is M, about

  Supernovas are thoughup7dk0, z za3;orqsxd 7zpy 0:t to always result in

  Black holes

  Pulsars are rapidly spiy)t gyhcmm;f*,; c9ispjz p20nning

State Einstein's principle of equivall4b8hx x qs-npyv:e d( d6a1c,ence.

  The Schwarzschild radius oosg go ,* ;)z/guqu squ7pm+7bf a black 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 Einste+ ug*)7gqqsmo7o,zup;ub/g s in 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 sourcek5erurj tvd m 76:*3af emits light of a particular wavelength in the visible, and the source5e6 k3aft* d:ruvmj7 r is moving away from us, the color of the light appears to us to be shifted toward the

  The cosmic background radiation corresponds to a temperature of aboutmy/r l5lhbg8vrlnc 5qv7,7y0

  The Sun has apparent brightness atc(cg iifoy6sv y +o;8z1 y35kh 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 th l*kl;rf0sy1;iax 1pce 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 radizq37etn,g83of ptii3e l+ ho(us 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 tl+p38rwb b hu8c(y.n 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 an6z p405wtswfvnbhdzg ;+ +j/ngle for Proxima Centauri, which is Earth's nearest star at g0ps h4zv d/t5wbjwnn ;zf ++64.3 ly?

  The apparent brightness of7lw u jnx(-ef:om1wowj j3jg( e:5b8f 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 universe is 1/eo zjz:q3+ sc3H, where H is the Hubble constant. Taking H = 20 km/s 3ezz+3jqc s:o/Mly, estimate the age of the universe, in years.

  If a galaxy is moving away from ghql;b;o.8r8g *fwq j hm9c*q us at 1.0% of the speed of light, how far away is it from u g*fcbrhq8;go h9lmj;w*. qq8s?

  Estimate the speed of a galaxy that is 10 birlr a5)ygd 93dllion light-years away.

  Estimate the observed wavelength for the 656 nm line i,y mauuxlz205n the spectrum of a star which is 100 million light-years lamuyuxz 2,50 from us.

  About 1 ms after the Big Bang, the temperature of the universn-hi 8cd)) myi ;ws.mre was about 1013 K. What energy (in eV) does thic8 n)w.)syi m mrh-;ids correspond to?