The appearance of the great range of brightness among starp org(cl/3 c j .f0kiaoo3y.:ms is due to

  The absolute luminosity for most stars de 2-wqd )d+cu6ywmw4 lypends on the

  Four different main-sequence stars are colored blue, orange, red, and yelrgdvvlsn6o94:.; upa. e 4 qpalow. What is their rank from coo :e;pq 6p4gr4. uas vladv9.onlest to hottest?

  A Hertzsprung-Russell diagram shows stars on a plot os:l(e:u ;vq.b54u wzw u ms.z*a8q bxvf

  A white dwarf star with a mass8 l(wuelmt4/k equal to that of the Sun is about the size of

  The Chandrasekhar limit of stellar mass (bel q7zgn7uaan(8t 8q /flow which a star will collapse into a white dwarf) is, if thqfq87g8au7lz(a/n nte mass of our Sun is M, about

  Supernovas are thought to alwo8na9*zfq / 0s3kem 0lz gpuh-o)g-plays result in

  Black holes

  Pulsars are rapidly spinningf/d(lk qy6 ca80n gmh)

State Einstein's principle of equijljlw:c8b*ohi l jm k *ci-063valence.

  The Schwarzschild radius of a black ho69bfiy 9ld)emle 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 relativid6b9flie9y )mty 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 wavel wgeu1ijk+ b6,ength in the visible, and the source is moving away from us, the color of the light appearsui k6 we1,gbj+ to us to be shifted toward the

  The cosmic background radiation corresponds to a temphz /i)elc* m3perature of about

  The Sun has apparent brightn4p qyhu.j 2s55 plptm*ess 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 e l;lj9-gh lw4equal 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.v;c 4;;msxni ut7kv b 1-.m mttmb+jc-ka5ni 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 has a mean racos w+5z0lm o2 oq fjn5r3ms/.dius 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 Centauri, which is Earth's nekw orxmbs8p,2) ihh r6 de+ nxh7k-n)4arest star at 4x4hx obrk2 -ms)pnerhh d + 8wn6),ik7.3 ly?

  The apparent brightnessuq9ijcl k 4lh0h.60y y 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 approximaft.bo l6 6do.ute age of the universe is 1/H, where H is the Hubble constant. Taking H = 20 km/s/Mly, estimate the age uol6 . d6to.fbof the universe, in years.

  If a galaxy is moving away from us at 1.0% of the speed of light, how a x5g5k/+w(vnf cbti(ngf/:p far away is it frog // +nifp5 vbax5:((ftc ngkwm us?

  Estimate the speed of a galaxy that is 10 bil5ge4x z9 *iux )vrc4 .xh,poxmlion light-years away.

  Estimate the observed wavelength for the 656 nm line in the spect)j+ls5: acqzf /w;mc frum of a star which is 100 million light-years/5;):+cqff sacm lzjw from us.

  About 1 ms after the Big Bang, the temperature ofm9 jz8 qcwwopc6r4.c) the universe was about 1013 K. What energy (in4 zo 9w rcpmw6.c8q)cj eV) does this correspond to?