ASTRO (Science) FINAL EXAM 6
QUESTIONS CORRECTLY ANSWERED
What's the sequence of events that we think leads to the formation of an
elliptical galaxy?
1.When large galaxes merge, they can form an elliptical galaxy.
2.Immediately after the merger, the higher densities of gas and dust trigger a
period of rapid star formation
3.This population of new stars results in a wave of supernovae. The
supernovae explosions push all the star-forming material (free gas and dust)
outwards. From then on, it is then too low density to form new stars.
4.All of this occurs before the friction can help the galaxy settle into a disk
shape.
Protogalactic clouds collapsed to form irregular galaxies, that flattened into
spirals. Galaxies began to merge. Minor mergers preserve spiral structure;
major mergers lead to elliptical galaxies
What was the subject of the "Great Debate"?
the nature of the spiral nebulae and the universe
Who won the debate and what were the main points of contention?
Shapley "won" the debate but, ultimately, Curtis was right
Shapley argued that the Milky Way was the entire universe and the spiral
nebulae were within it
, Curtis argued that the spiral nebulae were "island universes" like then Milky
Way
What is the difference between Cepheids and RR Lyrae stars, when using
them asstandard candles?
Cepheid stars, like RR Lyrae pulsate in a regular way. However, Cepheids are
giant stars and cover a range of luminosities.
What role did Cepheids play in settling the "GreatDebate"?
Edwin Hubble used this technique to measure the distance to Andromeda. His
measurements gave a result of about 1.6 million light years.
What are the major members of the Local Group?
What is their eventual fate?
The Local Group has two large galaxies (the Milky Way and M31), one
medium galaxy (M33) and dozens (maybe hundreds) of dwarf galaxies
the Milky Way and Andromeda will merge into one galaxy
What are the differences observed between Active galaxies and normal
(quiescent) galaxies?
active galaxies are just like regular galaxies, only with an incredibly bright
core
What do we mean when we say "Dark Matter"?
matter that cannot be seen, it is nonluminous
What is a "galaxy rotation curve"
plot of the orbital speeds of visible stars or gas in that galaxy versus their
radial distance from that galaxy's centre
What, in a general sense, is thought to comprise Dark Matter?
non-baryonic matter, weakly interacting massive particle
is dark matter thought to be black holes, planets, sub-atomic particles?
QUESTIONS CORRECTLY ANSWERED
What's the sequence of events that we think leads to the formation of an
elliptical galaxy?
1.When large galaxes merge, they can form an elliptical galaxy.
2.Immediately after the merger, the higher densities of gas and dust trigger a
period of rapid star formation
3.This population of new stars results in a wave of supernovae. The
supernovae explosions push all the star-forming material (free gas and dust)
outwards. From then on, it is then too low density to form new stars.
4.All of this occurs before the friction can help the galaxy settle into a disk
shape.
Protogalactic clouds collapsed to form irregular galaxies, that flattened into
spirals. Galaxies began to merge. Minor mergers preserve spiral structure;
major mergers lead to elliptical galaxies
What was the subject of the "Great Debate"?
the nature of the spiral nebulae and the universe
Who won the debate and what were the main points of contention?
Shapley "won" the debate but, ultimately, Curtis was right
Shapley argued that the Milky Way was the entire universe and the spiral
nebulae were within it
, Curtis argued that the spiral nebulae were "island universes" like then Milky
Way
What is the difference between Cepheids and RR Lyrae stars, when using
them asstandard candles?
Cepheid stars, like RR Lyrae pulsate in a regular way. However, Cepheids are
giant stars and cover a range of luminosities.
What role did Cepheids play in settling the "GreatDebate"?
Edwin Hubble used this technique to measure the distance to Andromeda. His
measurements gave a result of about 1.6 million light years.
What are the major members of the Local Group?
What is their eventual fate?
The Local Group has two large galaxies (the Milky Way and M31), one
medium galaxy (M33) and dozens (maybe hundreds) of dwarf galaxies
the Milky Way and Andromeda will merge into one galaxy
What are the differences observed between Active galaxies and normal
(quiescent) galaxies?
active galaxies are just like regular galaxies, only with an incredibly bright
core
What do we mean when we say "Dark Matter"?
matter that cannot be seen, it is nonluminous
What is a "galaxy rotation curve"
plot of the orbital speeds of visible stars or gas in that galaxy versus their
radial distance from that galaxy's centre
What, in a general sense, is thought to comprise Dark Matter?
non-baryonic matter, weakly interacting massive particle
is dark matter thought to be black holes, planets, sub-atomic particles?
