The appearance of the great 0ps/t6aamk 5k range of brightness among stars is due to

  The absolute luminosity for most stars depends on yopp.y( yh)p ja hp21*p7qq9othe

  Four different main-sequence stars are colored blue, orange, red, ao ( d0.9-kfw cegg9oag r8mgknm(5t5wnd yellow. What is their rank from coolestkm wwrkmocnfe 9 - (g8gog(t09g55da. to hottest?

  A Hertzsprung-Russell diagram shows stars oukc(8 gb:vt -v7dlwd (n a plot of

  A white dwarf star with a mass equal to that of the Sun is clvv;xrn qx4i2p4f8m/6s d gj0s4 ma3about the size of

  The Chandrasekhar limit of stellar mass (below which a stak *vi)a9,zd bv th-ph0r will collapse into a white dwarf) is, if the mass ofi)h *v -h0 ktp9vd,zab our Sun is M, about

  Supernovas are thought to always bekw/ o15jxthf i)7 n 7kb9j6cresult in

  Black holes

  Pulsars are rapidly spig - 0c+d b9sfa0r6rwbgnning

State Einstein's principle of equivalence,ioy3z :envfz,hxkr(k 4sk36.

  The Schwarzschild radius of h3f 0iu*yh;tr 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 Einstein published his general relativity theory. It 0ryhu ;it*f3hcan 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 e zad/ l p-qynn9,g9 rbl+d6lf6fi),ylmits light of a particular wavelength in the visible, and the source is moving away from us, the color of t a/ r 9p ynq-yb lfzdll96d6+,nlgi,)fhe light appears to us to be shifted toward the

  The cosmic background radiation corresponds to a temperature o3fzaufj0 -m7z f about

  The Sun has apparent brightness afm (d,bama-o -t 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 e:p1f-xw.szj7e kux 5the 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 zqjp) s9a4s;y 1,ggj za 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 meant- y(tkobzzmr9 .m+ +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 angle for Proxima Centauri, whichw4-39sbjcqhh fm d(8wt+y3 a*anvu .b is Earth's nearest star at 4.3 ly?qj.3w *an u f-dvayw+m4(8t93bc hs hb

  The apparent brightness ofg7ht-ya k5l m 6m5jgs+ 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 t9 aml.p/uu;wdy 8 8d/wr,lvbthe approximate age of the universe is 1/H, where H is the Hubble constant. ld/lm 98p,w8v.b yu t ;d/uwar Taking H = 20 km/s/Mly, estimate the age of the universe, in years.

  If a galaxy is moving away from us at 1.0% of the speelvj;0hxa)hoz/ 8r )t821tne;xfqq gr d of light, how far away is it fr2thq 0 z )8;t/n ergfolrxh; a8vq)x1jom us?

  Estimate the speed of a galaxy that is 10 billqc ;2 ej-qqod0ion light-years away.

  Estimate the observed wavelength for the 656 nm line in thek2zz 2,c:t* lzhum 0dh spectrum of a star whic2 hzzc z0l*t2 ,ukhm:dh is 100 million light-years from us.

  About 1 ms after the Big Bang, the temperature of the universe was about 1013 Kpc.t dr8t ff c5nu.4o7. What energy (in eV) does this corruf.t4rf5o8 t7. cdcnpespond to?