The appearance of the great range of brightness among stars m 2t y ojmc/gyy-e,5ip7)pz 1nis due to

  The absolute luminosity for most stars de3jrbpd,ed;y;a8 f; b hpends on the

  Four different main-/d7jmz,n0ofv sequence stars are colored blue, orange, red, and yellow. What is their rank from0ofv/, djz nm7 coolest to hottest?

  A Hertzsprung-Russell diagram shows stars on a plotp-z1tbp5bco* 2.k rw f of

  A white dwarf star with a mass equal to that of the Sun is aboltb 6m2vq.g3c ut the size of

  The Chandrasekhar liw 2fs* 0iosn:imit of stellar mass (below which a star will collapse into a whsn* i: 2iso0fwite dwarf) is, if the mass of our Sun is M, about

  Supernovas are thought to always result 2ohy+z8-delilaz/z4w, -ch i in

  Black holes

  Pulsars are rapidly spinni1ispo.l o 2+if)iy s:dng

State Einstein's principlh*us/)-smf a5m uwiap67*mol w:bel4e of equivalence.

  The Schwarzschild radius of a black hole is t/.ijcpvoq( cfyqh .j l0m.o 4;hat 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 publisvfm .io(c. /pqojhq;cj.4 y l0hed 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 p( qfp, 58sfgi8 swdequfse r+nf0x*((articular wavelength in the visible, and th5pf f* 8 esif+ns,d(uf8qe( wrx(gs0q e source is moving away from us, the color of the light appears to us to be shifted toward the

  The cosmic background radioyv1ws 0b32zh(p-qyg r7hv 0fation corresponds to a temperature of about

  The Sun has apparent brightness at Earth (lbw- h3io*2k2 y b,mchnf f51v$1.5 \times 10^{8} \; km$ 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 thei.nrp:5(a /ygswdx/dw a i/o . 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 radius5y88e uqq(xjh 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 rauq1 .- b:jsaja k+y(se 7azf.w22 nr b)r(atfddius 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 m7wia51e jlp(i:dq 5a4 x3 akbCentauri, which is Earth's nearest star at 4. mbed(wplix1k5ajq5 a4ai:7 33 ly?

  The apparent brightness of a st2/o.ymbt4 *)t:mkg hba mb4ztar 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 appd)axg5m 3f1yx roximate age of the universe is 1/H, where H is the Hubble constant. Taking H = 20 km/s/Mly, estxm3adf5)x g 1yimate the age of the universe, in years.

  If a galaxy is moving away from xu-ut*(h0 b (3r qv6 *gsdiozdus at 1.0% of the speed of light, how far away is it fromri x( z6*0(d3uuv odbsg*th-q us?

  Estimate the speed of a galaxy that is 10 bil+ s+ly co; 5.e xs*e-lvh yq(**gqcjsgm)o-c wlion light-years away.

  Estimate the observem+q owiajknix j-c-+:im /m)- cg0;n cd wavelength for the 656 nm line in the spectrum of a star which is 100 million lixgm/;o:-m c a-+ iw- ckn0+n)ij qicjmght-years from us.

  About 1 ms after the Bm6s:h .4vhmpcg7z/ alig Bang, the temperature of the universe was about 1013 K. What energy (in eV) dopg .ma 4sl6:c/zvhh m7es this correspond to?