The Milky Way Revealed
Galactic Recycling
Miscellaneous
Measuring Galactic Distances
Hubble's Law
100
How far is the Sun from the center of the galaxy?
What is more than halfway/two-thirds of the way?
100
Bubbles and superbubbles.
What are... 1) hot ionized gas around a star that went supernova and 2) many individual bubbles combined
100
The three major types of galaxies.
What are spiral galaxies, elliptical galaxies, and irregular galaxies?
100
Standard candle.
What is an object with known luminosity without first measuring its apparent brightness and distance that we can use to calculate distances to other objects?
100
This is what Hubble's law tells us.
What is that more distant galaxies are moving away at faster speeds?
200
How disk stars orbit.
What is they all have the same orbital velocity and they bob up and down because of the localized pull of gravity within the disk?
200
Galactic fountain.
What is when a superbubble breaks out of the galactic disk, expands in a blowout and the gas spreads outward and upward into the halo, but then falls back down into the disk only to repeat itself.
200
This is how galaxies are grouped together/the difference between the way spiral and elliptical galaxies are grouped.
What is...spiral galaxies are often in groups of a few dozen while elliptical galaxies are often in clusters which have hundreds or thousands of galaxies?
200
Main-sequence fitting.
What is a method used to find distances to objects by comparing clusters of stars on an H-R diagram?
200
This is what the inverse of Hubble's constant tells us.
What is the age of the universe?
300
How halo and bulge stars orbit.
What is they travel around the center in elliptical paths with random orientation and can swoop very high or very low without being affected by the disk's gravity?
300
The most abundant cool gas in a galaxy.
What is atomic hydrogen gas?
300
The difference between the disk population and the spheroidal population of stars.
What is the disk population has both young and old stars with heavy-element proportions of about 2% while the spheroidal population contains only old low-mass stars with low heavy-element proportions around 0.02%?
300
Period-luminosity relation for Cepheid variable stars.
What is the longer the period, the more luminous the star?
300
Lookback time.
What is the time it takes for a galaxy's light to reach us?
400
Where most of the galaxy's mass is.
What is in the halo?
400
This is why the star-gas-star cycle can't continue forever.
What is because gas gets locked permanently in brown dwarfs, white dwarfs, neutron stars, and black holes and eventually runs out?
400
This is what's in the center of the Milky Way Galaxy.
What is a source of radio emission called Sagittarius A* that we believe to be a supermassive black hole? However, Sagittarius A* does not have a strong X ray accretion disk like we expect black holes to have, but rather has flares of brightness when chunks of material fall in all at once.
400
Name some distant standard candles.
Cepheid variable stars, white dwarf supernovae, other galaxies
400
Cosmological redshift.
What is a redshift caused by the expansion of the universe stretching out the wavelengths of light?
500
How fast does the Sun orbit the galactic center and how long does each orbit take?
What is 220 km/s and 230 million years?
500
Spiral arms.
What are huge waves of star formation that propagate through the gaseous disk of a spiral galaxy?
500
Elliptical galaxies are more ___ in color than spiral galaxies.
What is red?
500
Tully-Fisher relation.
What is a relation that says the faster a spiral galaxy's rotation speed, the more luminous it is (because they both depend on mass), so then we can measure true luminosity from rotation speed and use that galaxy as a standard candle...?
500
The Cosmological Principle.
What is that distribution in the universe seems smooth and without center or edge?
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