The appearance of the great range of mhs6oyo3judq k*i1j8rv),:p m6q pu3 brightness among stars is due to

  The absolute luminosw/9 nsk; /jhq0qsowil ,fz i+an79, geity for most stars depends on the

  Four different main-sequence stars are colored blue, orange, red, ani. fd ulnfq43,(mef ;ud yellow. What is fmu( unfd,l f .qie34;their rank from coolest to hottest?

  A Hertzsprung-Russell diagram shows stars on a plot oo**i 5so*yo qvf

  A white dwarf star with a mass equal to that of the Sun is about the size o9wsji :e13wz ,aqf;awyyr. h*f

  The Chandrasekhar limit of stellar mass (below which a sta i9mppsprm9f9f2 ,s.)o4dsjxr will collapse into a white dwarf) is, if th9piosx99mm4 rp.fsd2 p, fj) se mass of our Sun is M, about

  Supernovas are thought to alzb/ y w/atau*l:7jo+n ways result in

  Black holes

  Pulsars are rapidly spin zbwixx8vm(*,ning

State Einstein's principle qqp)v8tnajvd trd0) 9f ,01 hnof equivalence.

  The Schwarzschild radius of a black hole ami+8,by: f d jd01zugis that radial distance from the center of zu y d0ga+8b1f ,i:djma 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 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 wa24iezo :( 5axrmtl7ukvelength in the visible, and the source is moving away from us, the color of the light appeli(um r 4ek2xz75 to:aars to us to be shifted toward the

  The cosmic background radiation corresponds to a temperatu)xvjv5+xn938 -9v.e gujleo f6gx tture of about

  The Sun has apparent brightnej.bmqpo: nz.yv , (:hhss at 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 toh.izb c; a)lm8 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 ha0f+ 7s)8c)m/ ptmatck l, qswus a mean 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 har98hi e/kbd 2/h)fxojs a mean 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;o0ruz+dj t:x Centauri, which is Earth's nearest star at 4.3 ly t duo0+zj;:rx?

  The apparent brightness of 27m:fodjs l g1 -zhi5wa 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 universe is 1/H, whe37f namhij (6iu8 djc)hhy 7q5re H is the Hubble constant. Taking H = 20 km/s/Mly, estimate the age of the universehiud7j57ma )3n 6 8yhfqihjc (, in years.

  If a galaxy is moving away from us at 1.0% of the 3ls2y q;qjxh o*t24kpazn)1tspeed of light, how far away isysoz;3jn4 2 ahk1lptq2qt)*x it from us?

  Estimate the speed of a gal3 jadw16-i59 nncgw k*x1sz*zwnaz x;axy that is 10 billion light-years away.

  Estimate the observed wavele*k w yeb6bp*f+ngth for the 656 nm line in the spectrum of a star which is 100 million f b6bp**wkey+ light-years from us.

  About 1 ms after the Big Bang, the temperaturedh9xm oy:y3n9a 79d jl of the universe was about 1013 K. What energy (in eydo9l3n7m:j d 9xa9yh V) does this correspond to?