The appearance of the great range of brightness among vbs ek,ppbu41 ) hd iir,n,.1pstars is due to

  The absolute luminosity for most sht2 s xt- 8,wb 6k fftk*1skxngu95sc4tars depends on the

  Four different main-sequeztpy0vh dw -4-nce stars are colored blue, orange, red, and yellow. What is their rank from coolest top4tdv0 w--yz h hottest?

  A Hertzsprung-Russell diagram shows s ug-f)*)ot-;f bufvn; z3w yigtars on a plot of

  A white dwarf star with a mass equal to that of the Sunfa(4h0m z jh2s is about the size of

  The Chandrasekhar limit of stellar mam7y/imfd 5xig j (atvq78 5skd7u 0a*fss (below which a star will collapse into a white dwarf) is, if the mass of our Sun is M( d5 7g7t duamvi i/5*qs fafx8yjm07k, about

  Supernovas are thought to alway/ig6zssgf*gg 0+:hdwib 65o5f n+ejls result in

  Black holes

  Pulsars are rapidly r)b(hmyoyqnq-7qcy)/3id: vspinning

State Einstein's principle of eq aa1m7m9 hx)f;ug(b6ckor2bp, w ,pwuz l2p3iuivalence.

  The Schwarzschild radius of a black xidnj+ u:g*w1hole is that 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 published his general relativity theory. It can be calculated fxgn+u d: w*ji1rom 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 wrc)1 + pxo2gmm.vs uy6wu1: x x*4jiasavelength in the visible, and the source is moving away from us, the color of the light apprv.s+ga6yu 4 juw:2 )imxcp mso*x11 xears to us to be shifted toward the

  The cosmic background radiatioch)) 9u t j8adq)jjy1jn corresponds to a temperature of about

  The Sun has apparent brightness at jcbe i/.af,, oEarth ($1.5 \times 10^{8} \; km$ 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 luminosi0ns d8vc+e g/bq+vli/ ; tazv9ty 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 has a mean xz lxua n grc:e680a+8radius 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 radiusyxa*rvveq7*v (. q o,b 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 Centacfsrt y-9o;.mp*1 txokw0, wjuri, which is Earth's nearest star at 4.3wo ,*wrfsp.xy1 0o9j-c ; tmkt ly?

  The apparent brightness of a star is )h56to inygc /,cbgy 0$1.0 \times 10^{-12} \; W/m^{2}$ and the peak wavelength is 600 nm. Estimate its distance from us.

  It can be shown that the approximate age of the uhr m5*gx isz/q8i* t6aniverse is 1/H, where H is the Hubble constant. Takintxh i g8iazsq /*r5*6mg H = 20 km/s/Mly, estimate the age of the universe, in years.

  If a galaxy is moving away nf e rh*s(x:uwf)o57y from us at 1.0% of the speed of light, how far away is it fef:5wuyxr( f)on7*sh rom us?

  Estimate the speed of a galaxy that is 10 billion lighsn3: f5ldwab: t-years away.

  Estimate the observed wavelength for the 654aydz8ofsi k6 wvien 6;z9p me06,1 gj6 nm line in the spectrum of a star which is 100 million light-years from us ms;id06ip e,4aoz69yzfv k6egwn 81j .

  About 1 ms after the Big Bang, the temperature of the universe was 2rv ,)8cpuohi8ao rr5 about 1013 K. What energy (in eV) does this correspond to?r8 ropovr,5a) h 8ui2c