Copper Quizzes Flashcards
What are the differences between open star clusters and globular star clusters
Open clusters are less concentrated, younger, and have fewer stars
Which of the following is FALSE?
a nova is more luminous than a supernova
What kind of a gas cloud can collapse and form stars?
The gas cloud must have a mass that exceeds the Jeans mass so that gravity overcomes the internal pressure in the cloud
What is the mass of the black hole at the center of the Milky Way?
4 million solar masses
How do you measure the mass of the supermassive black hole at the center of the Milky Way?
Look at the orbits of nearby stars and apply Kepler’s third law
About how long does it take light to cross the Milky Way galaxy?
About 100,000 years
What does our galaxy look like?
It has a large disk with spiral arms, and is relatively flat and thin
It has clouds of gas and dust in the spiral arms
Older yellow stars are found mostly in the central bulge
Old stars and globular clusters are located in a spherical halo above and below the disk
Why do stars in the halo of the galaxy have almost no heavy elements such as carbon, nitrogen, and oxygen?
Halo stars formed before those elements were made
Where do stars form in the galaxy today?
In the disk
Where are open clusters found?
In the disk
In the symbol for the Hubble type of a galaxy, SBc, the “B” denotes:
The presence of a bar
What happens to the planets in a galaxy when that galaxy collides with another galaxy?
Nothing, because the spaces between stellar systems in a galaxy is much larger than their size
Which properties of spiral galaxies allows us to sub classify them as Sa, Sb, or Sc?
Size of bulge and extent of spiral arms
Compared to spiral galaxies, elliptical galaxies have:
Less gas, redder colors, and less new star formation
What is the difference between an E0 and an E7 gas?
The E7 has an oval shape and the E0 is circular
You will see that the universe is almost 14 billion years old. That means that we see the most distant galaxies as they were when the universe was:
1-2 billion years old
According to models of galaxy formation, which population of stars formed first?
The spheroidal population
What type of galaxy can result from collisions between galaxies?
Elliptical or irregular
What is a starburst galaxy?
A galaxy with a very high rate of star formation
In what part of the spectrum are starburst galaxies brightest?
Infrared
What parameters do Hubble’s law relate to each other?
Galaxy recession velocity and distance
What technique for measuring distance can you use to discover Hubble’s law?
Cepheid variables in galaxies and white dwarf supernovae in galaxies
How do you measure the speed of a galaxy relative to you?
Doppler shifts
What is Hubble’s law?
The faster a galaxy is moving, the farther away it is
Where is the center of the Universe?
Universe?
There is no center to 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
Which of the following is not true about dark matter?
Dark matter and dark energy are two aspects of the same phenomenon
Why do we think there is a lot of dark matter in clusters of galaxies?
Individual galaxies are moving so fast that they could not be held together by the gravity of visible matter
Gravitational lensing lets us measure mass even when we can’t see it
How do we know that the universe’s expansion is speeding up?
We look at objects from different times in the past to see how expansion changes with time
How could the universe be accelerating, despite the gravitational pull of all the matter in it?
There could be a new force or property of space that affects the universe on its largest scales
What fundamental particles make up a Hydrogen-1 atom?
one proton, one electron
Which force is responsible for holding the nucleus together via gluons?
strong
What three fundamental particles are you made of?
up quarks, down quarks, and electrons
How many types of fundamental particles exist?
30
How many up quarks are there in Helium-3?
5
Which has the events in the right order, from early to late?
quark soup, protons form, nucleosynthesis, recombination, star formation
Now what happens because of recombination?
the cosmic microwave background is produced
What forms in nucleosynthesis?
most of the Helium-4 in the Universe
What is a quasar?
a very luminous source due to a black hole at the center of a galaxy that is quickly growing
How did conditions differ from the present era when the Universe was young?
the young Universe was hotter, more dense, and smoother
