Astro 001 Exam 4
In the symbol for Hubble type galaxy, SBc, the "B" denotes....
The presence of a bar
According to models of galaxy formation, which stars formed first?
The spheroidal population
We see the most distant galaxies as they were when the universe was...
1-2 billion years old
What is a starburst galaxy?
A galaxy with a very high rate of star formation
Which of the following is false?
A nova is more luminous than a supernova
What is a quasar?
A very luminous source due to a black hole at the center of a galaxy that is quickly growing
What technique for measuring distance can you use to discover Hubble's Law?
Cepheid variables in galaxies and white dwarf supernovae
Which of the following is not true about dark matter?
Dark matter & dark energy are 2 aspects of the same phenomenon
What's the difference between an E0 & and E7 galaxy?
E7 has an oval shape and E0 is circular
What type of galaxy can result from collisions between galaxies?
Elliptical or irregular
Why do stars in the halo have almost no heavy elements i.e. C, N, O?
Halo stars formed before these elements were made
Where are open clusters found?
In the disk
Where do stars form in the galaxy today?
In the disk
Why do we think there's a lot of dark matter in clusters of galaxies?
Individual galaxies are moving so fast they couldn't be held together gravity of visible matter & gravitational lensing lets us measure mass we can't see
In what part of the spectrum are starburst galaxies brightest?
Infrared
Compared to spiral galaxies, elliptical galaxies have...
Less gas, redder colors, and less new star formation
How do we know that the universe's expansion is speeding up?
Look at objects from different times in the past to see how expansion changes
How do you measure the mass of the super massive black hole at the center of the Milky Way?
Look at the orbits of nearby stars & apply Kepler's 3rd law
What happens to planets when their galaxy collides with another galaxy?
Nothing because the space between stellar systems in a galaxy is greater than their size
What are the differences between open star clusters and globular star clusters?
Open clusters are less concentrated, younger, and have fewer stars
Which has the events correct from early to late?
Quark soup, protons form, nucleosynthesis, recombination, star formation
Which properties of spiral galaxies allow us to subclassify them?
Size of bulge and extent of spiral arms
Which force is responsible for holding the nucleus together via gluons?
Strong
What happens because of recombination?
The cosmic microwave background is produced
What is Hubble's Law?
The faster a galaxy is moving, the farther away it is
What kind of gas cloud can collapse & form stars?
The gas cloud must have a mass that exceeds the Jeans mass so that gravity overcomes the internal pressure in the cloud
How did conditions differ from the present era when the universe was young?
The universe was hotter, more dense, and smoother
How could universe be accelerating, despite gravitational pull of all matter in it?
There could be a new force or property of space that affects the universe on its largest scale
Where is the center of the universe?
There is no center of the universe, expansion is happening everywhere
How have astronomers interpreted the unexpectedly fast rotation of galaxies?
There must be a lot of dark matter whose gravity can be felt but not seen
What three fundamental particles are you made of?
Up quarks, down quarks, and electrons
How many types of fundamental particles exist?
30
What is the mass of the black hole at the center of the Milky Way?
4 million solar masses
How many up quarks are in Helium-3?
5
About how long does it take light to cross the Milky Way galaxy?
About 100,000 years
What does our galaxy look like?
All the above; large disk with spiral arms & relatively flat & thin, clouds of dust & gas in spiral arms, old yellow stars found at center bulge, old stars & globular clusters located in spherical halo
How do you measure the speed of a galaxy relative to you?
Doppler shifts
What parameters do Hubble's law relate to each other?
Galaxy recession velocity and distance
What forms in nucleosynthesis?
Most of the Helium-4 in the Universe
What fundamental particle makes up a Hydrogen-1 atom?
One proton, one electron
