The appearance of the great ranqb w9 6e2(y5y) wfxyms6 1qcmkge of brightness among stars is due to

  The absolute luminosity tcv62(wt( uaik m:l;lfor most stars depends on the

  Four different main-sequence stars are colored ceff;5 cctbact o89, ,blue, orange, red, and yellow. What is their rank from coolo;,baecccc tff 8 95,test to hottest?

  A Hertzsprung-Russell s7e5r4p4 e9t xp0dqkwdiagram shows stars on a plot of

  A white dwarf star with a mass equal to that of bsw3uio .; iwc4l2ty/ the Sun is about the size of

  The Chandrasekhar limit of stellar mass (below which a star w,p2vs:c 2ufb2qao2 ih6dtr+ gill collapse into a white dwarf) is2dt2sig2r +au2o: q p,bhf6 vc, if the mass of our Sun is M, about

  Supernovas are thought to ali cg : u2m8a.5lood;g/vytzc4ways result in

  Black holes

  Pulsars are rapidly spty du v *u;.fa2;.jimkinning

State Einstein's principle ofi it5otp+ywp :lue x ndp+86lq2uv881 equivalence.

  The Schwarzschild radius of a black hole i.: aa*- k*wdx:gra4j-tfzfw bs that radial distance from the center of a sphere waa z* wwtj-f4 -*bgarkfd.::x ithin 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 wavelength in the vi-f p)vt /pni:nsible, and the source is moving away from us, the con: fivnp/) tp-lor of the light appears to us to be shifted toward the

  The cosmic background radiation corresponds to a temperature of a-,eqvcb 4k: rrbout

  The Sun has apparent brightness 6j31oev s ft1dat 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 t, m((fqoynfbop + :ga1o 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 radius of 3m/qlmgq3suz(-m* dq$1.5 \times 10^{8} \; km$. 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 r5 uiz u *ir8txq7io0i6adius 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, which o (u9m9ce. bznis Earth's nearest star a e(cmb9nz9 .out 4.3 ly?

  The apparent brightness of a star m gr .v0wn(c68y hx-mbwe 4gj*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/H, where.ep 6 nxlf6c7njf( l+p H is the Hubble constant. Taking H = 20 km/s/Mly, estimate the age of the xf jp76nelf ( +pnc.6luniverse, in years.

  If a galaxy is moving away from us at 1.0% of the speed of liwdy7m - 8;mxefght, how far away is it fx d7m;fe8wmy -rom us?

  Estimate the speed of a galaxy that is 10 billion lights,05i+e;zoqx.+di h jzkyi4u-years away.

  Estimate the observed wavelength for the 656 nm line in the spectrum of3 o o-rql 0jzcrh:9qpx+1lkl 2 a star which is 100 million light-yel-:or+r qq 2khp 91co03 xllzjars from us.

  About 1 ms after the Big Bang, the tem1,s0uiti* a5bnji fu) perature of the universe was about 1013 K. What energy (in eV) does this correspond to tj1bf,i0ausi n5 i*u)?