The appearance of the gremms0 6ed d17wf7: oexhat range of brightness among stars is due to

  The absolute luminosity for most stars depends on the+vsf2 mv;e-v 0,otqk.x kryy*

  Four different main-sequence stars are colored blue, orange, red, an 3mvqitr*2jbw9wr 89 ly2b+eed yellow. What is their ra93rbr*9jtewiveq2l +wy 82bm nk from coolest to hottest?

  A Hertzsprung-Russell diagram shows stars on a plo8 ko1xf erlp5z d6oz:5t of

  A white dwarf star with a mass equal to that of the Sun is about the size 5mlww:ne5 n/g4 hgr 6mof

  The Chandrasekhar limitj kqy ;w8vyn ;4m:eua( of stellar mass (below which a star will collapse into a white dwarf) is, if the mass of our Sq:8uekw;;naymjy4( v un is M, about

  Supernovas are thought to always resul(3jvb)1 pu5cp wkx *wvfns+;pt in

  Black holes

  Pulsars are rapidly spin ifmz-ghzqp: wnuwxr 4 k65, br8a.o2/ning

State Einstein's principlegbw)uxd .4i5b of equivalence.

  The Schwarzschild radius of a black hole is that radial distance frox:a zx(to dykb/4dgf ,g3m)5(j kdz)um the center of a sphere within which not even light can escape. It was first discovered mathematically by Schwarzschild in 1916 afted: 5mxa3(zt/b g kkf(x jz)g,ou)y4d dr 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 li8p m+t qp 52wnasdo:0x1k2xo jght of a particular wavelength in the visible, and the source is moving away from us, the color of the light ax2wjponx a q:+2o 0 dk8p1st5mppears to us to be shifted toward the

  The cosmic background radiatio/ lmj8u2bm 2k4a d3aft:3 zauan corresponds to a temperature of about

  The Sun has apparent brigh;aki pz;2 z*ewtness at 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 lu.akdx; )h dx7-:jrs hxminosity equal 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 haso1s hcfd.x5eg (jc4p dvc:0axy *.8z w a 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 of6ch8 ic ;yva/e $1.5 \times 10^{8} \; km$. 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 f)0 rdk (c m0zvu2p-oykor Proxima Centauri, which is Earth's nearest star at 4.3 luz)rm02-povk(yd ck 0 y?

  The apparent brightness of a stajv,5 ua9p yg4l zxbo :e:5qbf3r 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 apg6 k1ue35t.(zvfb9 py58 rjn.mzrobg proximate age of the universe is 1/H, where H is the Hubble constant. Taking H = 20 km/s/Mly, estimate the age of the uny5r o 9n5rb1zzg.ku tpfj8mg .36e(bviverse, in years.

  If a galaxy is moving away f *u yf0e; ac4 4tdg6vks9swjh*rom us at 1.0% of the speed of light, how far away is it frog u4w9jsa*c 4sh*d;ekv 6fyt0m us?

  Estimate the speed of a galaxy that is 10 bila;-q k pd4l;lkumn r7zs;1(to lion light-years away.

  Estimate the observed wavelength for the 656 w t/g r9t 7l pa2uekw,(nf7r5cnm line in the spectrum of a star which is 100n,p7wrra tule5g(t 9/2cf7wk million light-years from us.

  About 1 ms after the Big Bang, the temperature of the universe was aj( d 0:8zjr3cri-86 eycrps-w vln)f gbout 1013 K. What energy (in eV)-gf( -i)peczr3n8sv6r0 cd:wryj 8l j does this correspond to?