The appearance of the great range of brightness among 7u ;- mb o))7 6bpyzizupa5qhpg+qtx +stars is due to

  The absolute luminosity for most starsa ,yqqd*471kx3 jrv f-k mua8u depends on the

  Four different main-sequence stars are colore8 9h+9vu f7 z; umz2km-ut+nir*patied blue, orange, red, and yellow. What is their rank from coolest to hotte9ituzk+nuut*8i 92rmv hfzm pe+a7 -; st?

  A Hertzsprung-Russell diagram shows stars,(n5dt uixk eyfr 7*68ajto4s on a plot of

  A white dwarf star with a mass equal to that of thy 63e1d.w ntgke Sun is about the size of

  The Chandrasekhar limit of stellar mass (below which a star wiw20o)ml oh3 v8big1b jll collapse into a whwi l)bo2o0mvjg3 h1 b8ite dwarf) is, if the mass of our Sun is M, about

  Supernovas are thoug;udso usi( mo(4 .1kpf..zsab ht to always result in

  Black holes

  Pulsars are rapidly spinninzv-e7v. pt m32 u,yj0xtq wti4q ak97ig

State Einstein's principle of ed8(xhuf2i8p oi)- a ooquivalence.

  The Schwarzschild radius of a black hole is that radial disfwm:/d -w 1urbtance 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 calculat1-r u bfm:/wwded 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 particulagp;;ek 5 vaqy6r wavelength in the visible, and the source is moving away from us, th;5kqa p 6;eyvge color of the light appears to us to be shifted toward the

  The cosmic background rad4c3u+g z 5zip cq,mbn-iation corresponds to a temperature of about

  The Sun has apparent brightnessa.l d5u:yne9ze7*ydv iz 7aac-m, )st 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 l2 -i zs/r;l(davjszq0n pu2u-up;5 hto 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 4kzg mci o5k;n3/gx ,na 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 has a meakp,j; )w nct8lsr +/lqn 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 Proxim a2 i ,l phbz35f+-+oy(kjenska Centauri, which is Earth's nearest star ap i+ohz3-ajb(ky l 2,5fse+n kt 4.3 ly?

  The apparent brightness.dg b*iy. nl7o of a 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 an/lguc+58rt3eh * l, abat uw-ge of the universe is 1/H, where H is the Hubble constant. Taking H = 20 km/s/Mly, estimate the age of the universe, in ygtc3,e h/85a lt*nab uwu+r-l ears.

  If a galaxy is moving away from us at 1.0% of the speedu l3q w 9xbwhud8m+,m9 of light, how far away is it from us?uml 93+m9,bwux wqdh8

  Estimate the speed of a galaxy that is 10k)jz uz/)abf vux8sa-xb+91o billion light-years away.

  Estimate the observed wavelexkp9kk1 / cec4ngth for the 656 nm line in the spectrum of a star which is 100 million light-years fro9c4k 1/ pxkkcem us.

  About 1 ms after the Big Bang, the temperature of the universe 0u fml4o5fe yat;9d1mwas about 1013 K. What energy (in eV) does te0;5 ml 9a ft4d1mfuyohis correspond to?