The appearance of the great range of brightn82 ew8f*p mqan5wmzl9ess among stars is due to

  The absolute luminosity for most stars depends on t rk ;+okzipo2.he

  Four different main-sequencu + mio1cx;jgx:3nkb.e stars are colored blue, orange, red, and yellow. What is:j+xmgibc3x 1u nko; . their rank from coolest to hottest?

  A Hertzsprung-Russell dit 36, n fem)f6 reczkeqx1tr,0agram shows stars on a plot of

  A white dwarf star with a fylw d6*o 0v-wu,id1y 0veaf4mass equal to that of the Sun is about the size of

  The Chandrasekhar limit of stellar mass (below w2p br.n5s2lmqqj g.h31elkf:hich a star will collapse into a white dwarf) is, if the.52ln:3mql.2 pj1qh ksr bfg e mass of our Sun is M, about

  Supernovas are thought to always result in;))lgcxhzvqoj5c 4;wl fkttt - :5i:j

  Black holes

  Pulsars are rapidly srh9up / jy4nd/pinning

State Einstein's principle of eqh5d/ phosuhy-y ob; sv90fp ))uivalence.

  The Schwarzschild radius of a black hole is that radial8/x i l9ja2ctm 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 2mit9jlx c8/a 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 wave ll7edc0 6 .urf0hn/hulength in the visible, and the source is moving away from us, the color of thef6uu/hndcrl0 hl7e.0 light appears to us to be shifted toward the

  The cosmic background radiation corresponds to a temperature o e9;wwwr.kxzzp0/ ;*9 slaoxj f about

  The Sun has apparent brightn (dt ntt+v .f : m(:4s/phfd5nix-awwiess 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 luminosity equal *a yyzs qeexd)c93x+nx nf 85,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 a mean rag,1(3uy49 hbjavi vxwdius 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 appli4 5*u;m3 c+dyt qk 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 ly? (1 ly = $9.46 \times 10^{15} \; m$)

  What is the parallax angle for Proxima Centaz2vrv uqkzgzs; :; )d*uri, which is Earth's nearest star at );*r;vqud kvzsz 2g :z4.3 ly?

  The apparent brightness qv zoig eyq4b )o2,2rz(,p1o jzxe v,0of 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/-rky r.pm2c9)h( kxqf1 ivskoj, c),lH, where H is the H(ohm)f ki rp1qsc2lj. )r,k vcyxk 9-,ubble constant. 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 speed ofob6 vb7n ;llknqk+2 o9 light, how far away is it from us?n6o7bql;k vl2o+ 9kbn

  Estimate the speed of a galaxy that isp8.*hy+ ug o oqbhv*j( 10 billion light-years away.

  Estimate the observedtoal4t 6 q83l,qe* ztw wavelength for the 656 nm line in the spectrum of a star which is 100 million ligh*w8634qql tetozl,a tt-years from us.

  About 1 ms after the Big Bang, the temperature of the universe was about 1013 K*l sjm19d.p v)zvnp90+zckn 1e v ;ega. What energy (in eV) does this correspond t s pv)+ 90 1ec pzjd.kg1;vnn9*zmlaveo?