Most of the galaxy is made up of...
are galaxy interactions and collisions common?
If two galaxies collide, what is the chance of the stars colliding?
chances are they would not collide
variable stars & how they extend the distance ladder
a variable star is a star thats luminosity changes over a short period of time. by measuring the time it takes to pulsate we can determine the distance
Why are spiral arms so bright?
Because that is where star formation occurs and the young stars are very bright.
Tully-Fisher relation & how it extends the distance ladder
based on redshift and blueshift in the arms of the spiral galaxies, you can judge the luminosity and therefore the distance
Which emits more energy, an active galaxy or a normal galaxy?
An active galaxy
The four characteristics of life
grow by eating, ability to react to changes in environment, reproduce & pass on genetic material to next generation, capacity for genetic change - evolution
Which element are organic molecules based on?
the universe looks the same in any direction
assumed property of the universe such that the number of galaxies in an imaginary large cube of the universe is the same no matter where in the universe the cube is placed
What causes the acceleration in the accelerating universe?
dark energy/cosmological constant
Three types of galaxy
ellipticle, spiral, irregular
galaxies are found in
clusters and superclusters
Huble's Law (V=Ho d)
rate at which a galaxy recedes is directly proportional to its distance from us
spectrum of a normal galaxy
looks like a regular blackbody curve
spectrum of an active galaxy
does not look like a regular blackbody curve
source of energy in active galaxies
supermassive black hole devouring material
no cool gas, no new stars, hot interstellar gas
new stars created, irregular in shape, cool gas, random orbit
light from quasar bending around an object in front of it and making it appear as if there is 2 Quasars
spiral galaxy formation
gas & dust clouds & stars combine, formation is slow, fast rotation causes gas clouds to flatten
elliptical galaxy formation
star formation fast, slow rotation
mutual attraction of galaxies
comes from emission from black hole, because of accretion disc spiraling toward black hole
Type of active galaxy whose emissions come from a very small region within the nucleus of an otherwise normal looking spiral system