ASTO Final Exam Flashcards
What type of light we use to see the center of the Milky Way?
X-ray, Infrared, and radio waves are the best to look into the milky way.
What can you see when viewing X-ray?
Only the more extreme objects.(white dwarfs, neutron stars, and stellar-mass black holes)
What is a globular cluster?
clusters that
form so many stars that they are
gravitationally bound even after the
gas is depleted.
What’s bound to happen to the satellite galaxy orbiting the Milky way.
They get ripped apart by tidal forces.
How are large galaxies formed.
They are formed through Galaxy mergers.
What does a elliptical galaxy look like?
Elliptical galaxies are galaxies that have no
disk and appear as spheroids or overloids. With little gas.
With the hubble constant what is the milky way.
The milky way is a SBa or a SBb (spiral barr)
What makes an irregular galaxy?
Galaxy merging causes these weird galaxies.
What piece of evidence show we have dark matter.
Bullet clusters
What does mass to light ratio measure.
how much more a
galaxy weighs than the amount of light it
produces.
What is dark matter mass to light ratio?
0
What type of galaxy has the old stars.
elliptical
What type of galaxy has the highest mass?
Spiral galaxies
What galaxy has the biggest diameter?
Spiral galaxies
How do we measure distant galaxies?
By calculating its red shift.
What spectrum is used to measure the redshift?
Redshifts are determined by
looking at common absorption
lines in the spectrum.
Z=v/c What are these
Z = redshift
c= speed of light
v= radial velocity
Why are galaxies moving
away from us?
Because the universe is expanding.
What percentage of the universe is Dark matter?
27%
What percentage of the universe is ordinary matter?
5%
What percentage of the universe is Dark energy?
68%
What percentage of the universe is stars?
<1%
What was the cause of the universe.
The big bang
What does dark energy do to the universe?
Makes the universe expand faster.
What is the Hubble constant today?
68 km/s/Mpc
What is the thought of dark energy?
The best guess is that dark energy is has a
constant density in the Universe over time.
What will happen to the universe if matter dominates?
the universe will collapse.
What will happen to the universe if dark matter dominates?
The universe will expand infinitely fast.
At the beginning of the universe why weren’t photons and electrons formed.
because the temperature was to hot.
What allowed photons and electrons to form?
As the universe expands it cooled. within a few second they were able to form.
What happens to a free neutron?
Because it is unstable it decays into a proton.
What happened to electrons as the universe cooled?
The moment the
Universe cooled enough
for electrons to join
protons and form atoms,
all the trapped light
escaped.
What is the CMB?
Cosmic Microwave Background
What is inflation?
that the
Universe started small and then
expanded very fast.
What is a peak in the universe?
These are over dense areas that get smaller and more dense.
What are voids in the universe?
These are areas that expand and get even less dense.
What is the Dark age of the universe?
The period between the CMB light and the first star is
called the Dark Age of the Universe and cannot be
observed.
What is the Reionization era.
matter was ionized before recombination.
What is Photoevaporation?
where
light adds enough heat or
momentum to cause atoms to
escape a gravity well of a galaxy.
What happens to a galaxy after photoevaporation.
Galaxies fail to form stars for a long time, if ever.
what is the cosmic noon.
this was the peak of star formation in the universe.
What is the cosmic dawn.
This is the start of star formation at the start of reionization.
What makes most of the Milky ways mass.
Dark matter halo
What is the largest local cluster?
The Virgo cluster
Super cluster
The Virgo supercluster
An even larger super cluster?
The Laniakea that contains four superclusters.
What is the single point in the Laniakea Supercluster are all attracted to?
The great Attractor/
