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WorksheetsAstro 1500 Final Exam review Part 2 (Exam 3 and onwards)
Total questions: 29
Worksheet time: 39mins
Why are black holes black?
They're so hot, the light appears to us as black
It's just a area where there isn't anything
The escape velocity of a black hole is greater than that of light
They are actually a bright green color
How can we know the age of a star cluster?
By looking at number of blue and red stars and their turnoff point
By looking at the size
By looking at the density of stars
Guessing
Black hole A has a mass 3 times larger than black hole B, what is the ratio of their event horizons' radii? (R_A/R_B)
1/3
3
1/9
9
When standing near a massive object (such as a black hole), will time move faster, slower, or the same speed (from the perspective of an outside observer)?
Faster
Slower
The same
What is the only type of black hole we have an image of?
Supermassive Black hole
Intermediate Mass black hole
Stellar mass black hole
Primordial black hole
Which of the following pressures is overcome first as a star evolves towards its end point?
Electron Degeneracy Pressure
Neutron Degeneracy Pressure
Pressure from Nuclear Fusion
A large star (10-25 solar masses), will become what at the end of it's life?
White Dwarf
Neutron Star
Black hole
White hole
In astronomy, a standard candle is most useful to help us measure an objects ...
Radius
Color
Luminosity
Temperature
Where do we normally find elliptical galaxies (more so than spiral galaxies)?
In areas crowded with galaxies
In areas with not many galaxies
Orbiting spiral galaxies
Elliptical galaxies are purely theoretical
What percent of the entire universe (not just the milky way) is dark matter?
5%
27%
73%
95%
Neutron stars are very very dim in the visible portion of the spectrum, how would you find neutron stars?
Look at the edges of galaxies
Look for pulsars (a type of neutron star)
Look for really big stars and then wait
Find a large neutrino source and look there
Galaxy Clusters have gas inbetween galaxies with velocities much higher than the observed escape velocity of the cluster. What explains this?
Dark Matter, creating more mass than observed
Lots of galaxies too faint to observe, that add up to the needed mass
The gas will escape eventually, it just hasn't yet
The gas is actually in the foreground
Due to the expansion of the universe, what can we expect from a galaxy that is farther away from us (compared to one that is closer)?
It will be moving away faster
It will look to be stuck in place
It will be more heavily blueshifted
It will be moving away slower compared to closer galaxies
What is out best evidence for the existence of dark matter in the milky way?
There are large areas of extinction in the milky way
Stars at the center of the milky way orbit around something we cannot see
The rotation curve is not what we expect it to be
We have no evidence, it is purely a theoretical guess
True or False: With our current observational techniques and understanding of physics, we can predict and measure what happens inside of a black hole.
True
False
A star doesn't collapse from gravity due to the pressure from fusion. Why does the universe not collapse from gravity?
Because black holes resist the gravity from the universe
Because gravity doesn't work on scales that large (the stuff is too far apart)
Because the universe is expanding
Because Prof. Simon said so.
What is a main cause of large scale structures in the universe?
The differences in the CMB scaling up
Inflation turning quantum fluctuations into large structures
Big Bang Nucleosynthesis
There is no large scale structures in the universe, it completely uniform
What is the shape of the universe we live in?
Closed and curved
Open and Flat
Open and curved
We have no idea but are working to find out
What is the Hubble Sphere?
The sphere around a black hole that indicates the point at which light cannot escape
The distance from us at which objects are moving away at the speed of light
The sphere around the universe preventing it from getting too big
The special chair Hubble used at his telescope
If a significant amount of matter was added to the universe (creating a much higher density), which "ending" might happen?
Big Ripple
Slowly Expanding and cooling off (heat death)
Big Rip
Big Crunch
True or False: Exoplanets are actually very common in the universe (Pictured: The planet "Earth")
True
False
What are astronomers looking for when they see if a planet is in the habitable zone?
A planet that has a period of 1 yr is in a stars habitable zone
A planet with an atmosphere
A planet that has intelligent life to tell you whether it is habitable or not
Ability to have liquid water
Which type of galaxy is often found in the center of large clusters?
Sbbc galaxies
Elliptical Galaxies
Sc Galaxies
Irregular Galaxies
Why did astronomers introduce the concept of Dark Energy?
The universe expanded slower in the past than expected
Einstein thought the universe should be curved
We see galaxies spinning faster than we expect
We observed some mysterious energy that doesn't interact with light
Galaxies far away, in all directions, appear to be redshifted. Why did this first cause alarm for astronomers?
Because it means that every telescope is tuned wrong
Because this proves Newton wrong
It suggested that we are possibly at the center of the universe
It didn't cause alarm, it is expected in a finite, constant universe
What is a major conclusion from the Drake Equation?
Life in the universe is likely abundant
Life in the universe is likely rare
Life in the universe is primarily carbon-based
Any life is impossible
What is the cosmic microwave background?
The radiation from everybody running microwaves in their houses
The light that was emitted when the universe was 3000 K
The light from many many old M type stars
The unchanging background signal of the universe
How many accretion disks does the average black hole have?
1
2
3
15 or more
Find the Schwarzschild radius for the sun, which has a mass of 2⋅1030 grams. Give answer in meters. ( G=6.67⋅10−11m3/kg⋅s2 , c=3⋅108m/s )
About 3 meters
About 3000 meters
About 300,000 meters
About 30 billion meters
