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the longer the period of pulsation for the Cepheid, the more massive and luminous the variable giant star is
True or False RR Lyrae stars pulsate, but with shorter periods and lower luminosiites than cepheids
True or False It is harder to map the structure of the Milky Way in visible wavelengths than with radio and infrared waves
Harlow Shapley mapped the Milky Way using the period luminosity relationship for RR Lyrae stars
T/F 21-cm radio waves allow us to map the distribution of hydrogen in spiral arms on the opposite side of the Galaxy
The orbit of the solar system around the Galaxy is similar to that of a planet, almost circular and in the galactic plane
Which is the correct description of the Sun's location within the Milky Way
above the disc and about one-third of the galactic radius from the center
The Galactic Year is the time for our solar system to orbit the Galaxy; it is about
225 million years
Detailed measurements of the disk and central bulge region of our Galaxy suggest our Milky Way is a
barred spiral galaxy
Which sequence of formation is best, oldest to youngest
Globular clusters, open clusters, OB associations
Describe our location in the Milky Way
he Milky Way's outer spiral arms, known as the Orion Arm or Local Spur. The Sun lies between 25,000 and 28,000 light years from the Galactic Centre.
What do the orbits of Populations I and II stars tell us about the formation of the Milky Way?
the metallicity of the star
How and when did the Miky Way Galaxy form?
The milky way was formed by stars gases and dust . The milky way also started as a black hole and stars dust and gases gathered around the black hole. When? with our current astronomical knowledge, scientists predict it was approximately 1 billion years after the big bang
T/f Irr II galaxies may be the result of a collision, or close encounter, of two normal galaxies
T/f While our Magellanic Clouds are irregulars, the two companions to Andromeda are both ellipticals.
T/f When observing a quasar, we are probably looking at a stage of evolution in the very early universe.
There is evidence that a collision between a spiral and an elliptical galaxy has produced a radio galaxy.
Which property is common to spiral galaxies?
on-going star formation and emission nebula in the arms
The Milky Way is often considered to be an intermediately wound, barred spiral, which would be type ________ according to Hubble.
What is true of the Local Group?
The milky way and the andromeda galaxy are two of the largest members of the local group.
Why does the Cepheid distance method fail us beyond about 20 Mpc?
Even with the HST, the most luminous Cepheids are too faint to be seen beyond.
What is the nearest huge cluster of thousands of galaxies, to which the Local Group may belong?
The energy radiated by a typical quasar requires that its black hole accrete about
Ten solar masses a year
Not only does the central engine of active galaxies and quasars require a black hole, but also ________ to provide the radiate energy.
an accretion disk of infalling matter
When mass is accreted into a black hole, how much total mass-energy can be radiated away?
The whole of its gravitational potential energy
Who invented the galaxy classes, and what three major groups did he invent? Which telescope did he use?
Edwin hubble. ellipticals, lentriculars and spirals. Hubble space telescope
To which portion of the Milky Way are the Magellanic Clouds most similar? Why?
the closest similarity would be to the arms of the Milky Way - the Magellanic Clouds themselves are small irregular satellite galaxies of the Milky Way and contain many of the same features found in the spiral arms - nebulae, star clusters, supernova remnants, etc
Head-tail radio galaxies reveal their motion through the intergalactic gas with a tail like structure
When galaxies collide, the large scale galactic structure if affected, but the individual stars are not
Our theories of galaxy formation are just as well developed and tested as are our theories of star and planet formation
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