The appearance of the great range of brigu /yj,uw 2chymn w524qhtness among stars is due to

  The absolute luminosita74 -tv4yasvb, fk:jl y for most stars depends on the

  Four different main-sequence stars are coloreme *0n15ydnol -v8hfod blue, orange, red, and yellow. What is their rank from coolest 5e ody n0n8-h*1omflvto hottest?

  A Hertzsprung-Russell diagram.qoo5vc1 8n vf shows stars on a plot of

  A white dwarf star wi km5d wgv zl( gruk3+v800fl92pt1kkkth a mass equal to that of the Sun is about the size of

  The Chandrasekhar limit of stellar mass (below dv4zw4d*w; zj 2pedhn( ec d76which a star will collapse into a white dwa;4nj7zw vedw2 ( cepdd h6dz4*rf) is, if the mass of our Sun is M, about

  Supernovas are thougx8cyy z 4dev9 v)-7crwht to always result in

  Black holes

  Pulsars are rapidly spd (idnu;f)p0b inning

State Einstein's principle of equivalenll6jkgncooc. +;.z0b ce.

  The Schwarzschild radius of a black hole is that radial disi6v5(mwxdx) *iomkr 3ru*w ik+8 p(v htance 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 can be calculated frohvp r5 *)*wiwxvi3i8+dmumkxo((6r km 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 sourcuby4qeq.1qslk1 , q /ce emits light of a particular wavelength in the visible, and the source is moving away from us, the color of the light appears tqb1 qqe /ys,ucqk1.4l o us to be shifted toward the

  The cosmic background radiation correspond d3cou3 1vuf chrql4)5 q3.feqs to a temperature of about

  The Sun has apparent brightness at Earth (pxy 983c b4d rdr+8upcn.;bva$1.5 \times 10^{8} \; km$ 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 eqeoco50ij0 t ).sv1ix vd8brz-ual 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.sopc0(55hrkuy c t3,tau+ 0yc8zu 7cu 0yhxl 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)m2t/ez /gy to9fy mb3t(gg*8hg,cu i 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, which is Earth' -7c0fot v 6::l+ng7yayhvnegs nearest star aggnav:ovfct7yn6ey7- 0+ l:h t 4.3 ly?

  The apparent brightness of 5uer 85 t(iwb wqowf/1 vs,)t0hq t3wha 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 uni r.wsxgi.l 2x vk/r/:fverse is 1/H, where H is the Hubble constant. Taking H = 20 km/s/Mly, estimate the age of the lv2.r.wxsk xg r i:f//universe, in years.

  If a galaxy is moving away from us at 1.0% of the speed of 8l1w: efy +pec:ox:ms light, how far away is it f+:o8lfeecpx:s1 :my w rom us?

  Estimate the speed of a galaxy that is 10 billion light-yeatny38be 39ff 9p xtlm:;7 l,(acejkh urs away.

  Estimate the observek3*c,7z)jzj mfqaer v 9s4nh )d wavelength for the 656 nm line in the spectrum of a star which is 100 million light-years )k4jvr)m3n h,z* z79 jafsceq from us.

  About 1 ms after the vj4;yjj 9 zwff 7+lucw9o- k3yBig Bang, the temperature of the universe was about 1013 K. What e4 v9 3y;fj97jfw okw zu-lc+jynergy (in eV) does this correspond to?