The appearance of the great range kn dp 3zhd)e40of brightness among stars is due to

  The absolute luminosity f nmvpw g64*6o*g3vstzor most stars depends on the

  Four different main-sequence stars are colored blue, oranp myc:inm)1h +ge, red, and yellow. What is their rank from coolest to hottei +1 mcm)hpny:st?

  A Hertzsprung-Russell diagraci) v.-jbr+gq mx(1jcm shows stars on a plot of

  A white dwarf star with a mass equal to that odg iegy 4,kb.*h37vy u0d ybeq0.hhc/f 9ycf. f the Sun is about the size of

  The Chandrasekhar limit of r0/q :c-6usq l .cyzhhstellar mass (below which a star will collapse into a white dwarf) is, if t 0srq :6.zhq/lc -hyuche mass of our Sun is M, about

  Supernovas are thought vj//zevl-ghl ,6 e:bnto always result in

  Black holes

  Pulsars are rapidly ixtfh8pq uj8. e5ibn)/ q 7/exspinning

State Einstein's principle ofl 139/io fvlht:1vrc o equivalence.

  The Schwarzschild radius f0 u c2chx.xes+t4 0qxof a black hole 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 p0 sxxq2e+f4.0th ucxcublished 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 visib;z0idm1vfn . zle, and the source is moving away from us, the col. dm;fv nz01zior of the light appears to us to be shifted toward the

  The cosmic background radiatio-km 4-o uvon2vw gze1+d7hzhw3eh* 0 un corresponds to a temperature of about

  The Sun has apparent brightness at Earqw ty79hi oef*)lwa-0th ($1.5 \times 10^{8} \; km$ 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 luminosit-c4gc-qs0 vml 0x luo0y 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 radiufig3l:p62px in; t( mgs 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 meafq yo8ijk0vsga8hcav6wb o 3fo* mg; b*2b)27n 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 Cen2g d+ssf-a 1cbtauri, which is Earth's nearest star a-s1 abgc+2fds t 4.3 ly?

  The apparent brightness of a s +a n-k vp5pzmyg223o6bu8jg ztar 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, when,tk ub w*5x2tiu l+ut3 cpfwsry j7+/e5(0zyre H is the Hubble constant. Taking H = 20 km/s/Mly, estimate the age ofew+f52 tl(ti*ujuk +5nc bx 03uyp zr s,yt/w7 the universe, in years.

  If a galaxy is moving away from us at 1.0% of the speed of light, how 9bmwbi,t)4s bfar away is it 9ibsb4,b tw)mfrom us?

  Estimate the speed of a galaxy llp; (r* ua)wsthat is 10 billion light-years away.

  Estimate the observed wavelength for the 656 colfug 1nk0odb3j: 5 ips:g52nm line in the spectrum of a star whdgu:fko is055 bln231:op gj cich is 100 million light-years from us.

  About 1 ms after the Big Bang, the temps e,42(cl 3 /tmcgfisderature of the universe was about 1013 K. What energy (in eV) does this correspon/d,fe2i ssl4t( 3ccg md to?