WorksheetsASTR-1303 Module 3 Review
Total questions: 45
Worksheet time: 15mins
What is the primary factor determining the type of stellar remnant (white dwarf, neutron star, black hole) a star leaves behind?
Rotation speed
Initial mass
Chemical composition
Presence in a binary system
A white dwarf is primarily composed of what elements?
Hydrogen and Helium
Iron
Carbon and Oxygen
Neutrons
What force supports a white dwarf against gravitational collapse?
Thermal pressure
Neutron degeneracy pressure
Electron degeneracy pressure
Magnetic pressure
The Chandrasekhar Limit (~1.4 solar masses) refers to the maximum mass of which object?
A main-sequence star
A neutron star
A white dwarf
A black hole
A nova occurs when what happens on the surface of a white dwarf in a binary system?
Carbon fusion ignites
Helium fusion ignites
Hydrogen fusion ignites
The star collapses into a black hole
What force supports a neutron star against gravitational collapse?
Thermal pressure
Electron degeneracy pressure
Neutron degeneracy pressure
Strong nuclear force
Approximately how large is a typical neutron star?
The size of the Earth
The size of the Sun
The size of a city (~10–20 km)
The size of Jupiter
According to General Relativity, gravity results from which phenomenon?
A fundamental force mediated by gravitons
The curvature of spacetime by mass
Electromagnetic interactions
The strong nuclear force
The boundary around a black hole beyond which nothing can escape is called the:
Singularity
Accretion disk
Ergosphere
Event horizon
The process by which tidal forces stretch an object falling into a smaller black hole is called:
Accretion
Gravitational lensing
Spaghettification
Time dilation
Long-duration gamma-ray bursts are thought to be associated with which events?
Merging neutron stars
Novae
Supernovae of very massive stars forming black holes (hypernovae)
Merging white dwarfs
What instrument first detected gravitational waves from merging black holes and neutron stars?
Hubble Space Telescope
Chandra X-ray Observatory
Very Large Array (VLA)
LIGO (Laser Interferometer Gravitational-Wave Observatory)
What is the approximate diameter of the Milky Way's galactic disk?
1,000 light-years
10,000 light-years
100,000 light-years
1,000,000 light-years
Stars in the galactic halo primarily orbit the galactic center in which manner?
Circular orbits within the disk plane
Randomly oriented, elliptical orbits
All in the same direction, perpendicular to the disk
They do not orbit the center
The mass of the Milky Way inside the Sun's orbit is estimated primarily using:
Counting visible stars
Gravitational lensing
The Sun's orbital velocity and distance via Newton's version of Kepler's third law
Measuring the brightness of the central bulge
By which process does the Milky Way recycle gas from stars into the interstellar medium and back into new stars?
Galactic cannibalism
The star-gas-star cycle
Dark matter interaction
Gravitational settling
Hot, million-degree bubbles of gas in the interstellar medium are primarily created by:
Planetary nebulae
Supernova explosions and powerful stellar winds
Accretion disks around black holes
Molecular cloud collapse
Which electromagnetic radiation is most useful for mapping atomic hydrogen gas in the Milky Way's disk?
Visible light
X-rays
21-cm radio waves
Gamma rays
Where does most star formation occur in the Milky Way?
In the halo
In the central bulge
Uniformly throughout the disk
In cold, dense molecular clouds
Spiral arms in galaxies like the Milky Way are best understood as:
Fixed structures made of the same stars over time
Jets of material from the central black hole
Density waves causing gas compression and star formation
Illusions caused by dust lanes
Compared to stars in the disk, stars in the galactic halo are generally:
Younger and more metal-rich
Older and more metal-rich
Younger and metal-poor
Older and metal-poor
Approximately how many galaxies are estimated to be in the observable universe?
1 million
1 billion
100 billion
1 trillion
Which type of galaxy is characterized by a disk, bulge, spiral arms, and ongoing star formation?
Elliptical galaxy
Spiral galaxy
Lenticular galaxy
Irregular galaxy
Which type of galaxy contains primarily old stars, has little gas or dust, and shows no significant star formation?
Spiral galaxy
Barred spiral galaxy
Irregular galaxy
Elliptical galaxy
In the Hubble tuning fork diagram, what characteristic distinguishes Sa galaxies from Sc galaxies?
Sa galaxies have smaller bulges and looser arms
Sa galaxies have larger bulges and tighter arms
Sa galaxies are barred, while Sc galaxies are not
Sa galaxies are older than Sc galaxies
The Period-Luminosity relation is crucial for using which objects as standard candles?
White dwarf supernovae
Neutron stars
Cepheid variable stars
Globular clusters
Hubble's Law states that a galaxy's recessional velocity is directly proportional to its:
Mass
Luminosity
Distance
Age
Mergers between two spiral galaxies are thought to commonly result in the formation of which type of galaxy?
A larger spiral galaxy
An irregular galaxy
A lenticular galaxy
An elliptical galaxy
A galaxy undergoing an exceptionally high rate of star formation is called a:
Quasar
Radio galaxy
Starburst galaxy
Spiral galaxy
What is believed to be the power source for Active Galactic Nuclei (AGN) and quasars?
Intense star formation
Accretion onto a supermassive black hole
Merging neutron stars
Multiple supernovae
The relationship between the mass of a galaxy's central supermassive black hole and the mass of its bulge suggests what evolutionary scenario?
Black holes form before galaxies
Galaxies form before black holes
Black holes and their host galaxies evolve together (co-evolution)
There is no relationship between them
Which event marks the earliest time in the universe that we can directly observe via electromagnetic radiation?
The Big Bang itself
The end of inflation
The emission of the Cosmic Microwave Background (CMB)
The formation of the first stars
During which era of the early universe did hydrogen and helium nuclei capture electrons to form neutral atoms?
Era of Nucleosynthesis
Particle Era
Era of Nuclei
Era of Atoms
What are the two most abundant elements predicted to be formed by Big Bang Nucleosynthesis?
Hydrogen and Carbon
Helium and Oxygen
Hydrogen and Helium
Carbon and Iron
The theory of inflation was proposed to solve which problem(s) with the standard Big Bang model?
The flatness problem
The horizon (uniformity) problem
The structure problem
All of the above
Flat rotation curves of spiral galaxies provide strong evidence for the existence of:
Supermassive black holes
Dark energy
Dark matter
Gravitational waves
Gravitational lensing occurs when:
Light is bent by passing through a glass lens
Mass bends spacetime, causing light rays to change direction
Dark energy repels light rays
Magnetic fields deflect photons
Observations of distant Type Ia supernovae indicate that the expansion of the universe is:
Accelerating
Decelerating
Constant
Stopped
Based on current evidence, what is the likely ultimate fate of the universe?
It will recollapse in a "Big Crunch"
It will expand forever at an accelerating rate
It will reach a maximum size and become static
It will stop expanding and remain at its current size
Which type of supernova is used as a standard candle to measure cosmic distances?
Type Ic supernova
Type Ia supernova
Type Ib supernova
Type II supernova
What is the main evidence for the existence of dark matter in galaxies?
Flat rotation curves of galaxies
Unusual star colors
High rates of star formation
Presence of black holes
Which process is responsible for the creation of elements heavier than iron in the universe?
Supernova nucleosynthesis
Stellar hydrogen fusion
Big Bang Nucleosynthesis
Cosmic microwave background emission
Which component of the Milky Way contains the oldest stars?
The spiral arms
The halo
The bulge
The disk
What is the primary method used to determine the distance to nearby galaxies?
Measuring their redshift
Using Cepheid variable stars as standard candles
Counting the number of stars
Observing their rotation curves
Which phenomenon provides evidence for the presence of a supermassive black hole at the center of the Milky Way?
Rapid orbital motion of stars near the galactic center
Abundant star formation in the halo
Uniform distribution of gas in the disk
Presence of planetary nebulae
