Final Review Flashcards
What is the most abundant element in the solar system?
Hydrogen
What is the primary reason for the flat, disk-like shape of the solar system?
Angular momentum conservation during the solar nebula’s collapse
Which planet in the solar system has the highest axial tilt?
Uranus
What distinguishes a dwarf planet from a regular planet?
Dwarf planets have not cleared their orbits of other debris
Which planet has the largest mountain in the solar system, Olympus Mons
Mars
What is the significance of the asteroid belt in understanding the solar system’s history?
It is evidence of a planet that never formed
What type of planet is most likely to have a thick hydrogen and helium atmosphere?
Jovian Planet (Gas Giant)
Which of the following is NOT a defining characteristic of terrestrial planets?
A) High density
B) Thin atmospheres
C) Few or no moons
D) Extensive ring systems
D) Extensive ring systems
Why is Mercury’s surface heavily cratered?
Lack of an atmosphere to protect it
According to the evolutionary theory of the solar system, why are the inner planets rocky
and the outer planets gaseous?
The sun’s heat caused lighter elements to evaporate in the inner solar system
Which terrestrial planet has the densest atmosphere?
Venus
What is the main reason Venus experiences a runaway greenhouse gas effect?
High levels of Cardon dioxide in its atmosphere
Which terrestrial planet has the largest known volcano in the solar system, Olympus Mons?
Mars
Which planet has the slowest rotation period, with one day lasting longer than its year?
Venus
What geological features dominate Venus’s surface?
Vast plains of volcanic rock
Why does Mercury have such extreme temperature variations between day and night?
It has no atmosphere to retain heat
Which terrestrial planet is most similar to Earth in size, mass, and density?
Venus
Which terrestrial planet shows evidence of water in its past, including dry riverbeds and polar ice caps?
Mars
Which planet has the Caloris Basin, one of the largest impact craters in the solar system?
Mercury
Why does Venus lack a magnetic field?
Its slow rotation prevents the generation of a dynamo effect
What is the primary component of Jupiter’s atmosphere?
Hydrogen
Which Jovian planet has the most extensive and complex ring system?
Saturn
What is the Great Red Spot on Jupiter?
A storm system that has lasted for centuries
What gives Uranus and Neptune their blue color?
Methane absorption of red light
Which Jovian planet’s axis rotation is tilted at 98 degrees, causing it to essentially roll along its orbit?
Uranus
What is the primary reason Saturn’s rings are so visible compared to those of other planets?
Their high reflectivity due to water ice
What is unique about Saturn’s moon Titan?
It has a thick atmosphere, primarily composed of nitrogen
Which Jovian planet has faint rings that were only discovered after observations with spacecraft?
Jupiter
What is the Roche limit?
The distance at which tidal forces prevent objects from accreting into a moon
Which planet was discovered using mathematical predictions before it was observed directly?
Neptune
What is the Kuiper Belt?
A region of icy bodies beyond Neptune
What is the primary characteristic that distinguishes a dwarf planet from a planet?
Dwarf planets have not cleared their orbital path of debris
Which Dwarf planet is the largest in the Kuiper Belt?
Pluto
Which of the following is true about the asteroid belt?
A) It lies between Jupiter and Saturn
B) It contains several moons of Earth
C) It lies between Mars and Jupiter
D) It was formed from a single destroyed planet
It lies between Mars and Jupiter
What causes the tail of a comet to always point away from the sun?
Interaction with the solar wind
What is the primary composition of a comet’s nucleus?
Ice and dust
What is the primary source of most meteoroids?
Broken pieces of comets and asteroids
What is a meteor?
A fragment of an asteroid or comet entering Earth’s atmosphere
What is the largest known asteroid?
Ceres
What is the difference between the Kuiper Belt and the Oort Cloud?
The Kuiper Belt lies closer to the sun, while the Oort Cloud is much farther away
What is the primary source of energy in the sun?
Nuclear fusion of hydrogen into helium
What is the approximate temp. of the sun’s core?
15 million K
Which layer of the sun is responsible for most of the light we see?
Photosphere
What causes the sunspots to appear dark compared to the surrounding photosphere?
They are cooler regions caused by magnetic field disturbances
Which of the following is a feature of the sun’s corona?
It is visible during a total solar eclipse
What is the approximate period of the sun’s sunspot cycle?
22 years
What is the solar wind?
A stream of charged particles ejected from the sun’s corona
What happens in the sun’s core to maintain hydrostatic equilibrium?
Radiation pressure from nuclear fusion balances the force of gravity
What is a coronal mass ejection?
A massive burst of solar wind and magnetic fields from the sun’s corona
Why is the temp of the sun’s corona hotter than the photosphere?
Magnetic heating processes transfer energy to the corona
What is the most common method used to determine the distance to nearby stars?
Parallax
If a star has a parallax angle of 0.3 arcseconds, calculate its distance in light years.
1/ parallax angle in arcseconds
Then equivalent conversion with 1 parsec = 3.26 light-years
1/0.3 = 3.33
3.33 pc * 3.26 ly/ 1 pc = 10.86
What does the Hertzsprung-Russell diagram plot?
Luminosity vs. temperature
What is the spectral class of a star primarily based on?
Its surfact temp
What type of stars are found in the lower right region of the HR Diagram?
Cool, dim stars
A star has an apparent magnitude of 6 and another star you are comparing it to has an apparent magnitude of -6. Which one seems brighter? How much brighter?
-6 seems brighter
2.25^6 = 129.75 difference
Apparent Magnitude
How they look from the real position from Earth
Absolute Magnitude
Brightness at 10 pc
Which of the following is true for a red giant star?
A) It is cooler than the Sun
B) It is smaller than the Sun
C) It has a higher surface temperature than the Sun
D) It is fainter than the Sun
It is cooler than the sun
What is a binary star system?
A system with two stars orbiting a common center of mass
What is the relationship between a star’s mass and its lifetime?
More massive stars live shorter lives because they burn fuel more quickly
What does the term main sequence refer to?
A relationship between a star’s luminosity and temp for most stars
What is the primary component of interstellar matter?
Hydrogen
Which type of nebula glows due to the ionization of hydrogen by nearby hot stars?
Emission nebula
What triggers the collapse of a molecular cloud to form stars?
Gravitational attraction overcoming internal pressure
What is the role of dust in interstellar space?
It absorbs and scatters light, making distant stars appear dimmer
What type of star forms from the collapse of a molecular cloud?
A main-sequence star
What is the primary reason star formation occurs in molecular clouds?
They are dense and cold enough for gravity to dominate
What is the significance of the Orion Nebula for studying star formation?
It contains protostars in various stages of formation
What prevents stars from continuously accreting material once they form?
Stellar winds and radiation pressure
What is the primary fuel for a low-mass star during its main sequence phase?
Hydrogen
What happens when a low-mass star exhausts the hydrogen in its core?
The core contracts, and the outer layers expand into a red giant
What is the helium flash in a low-mass star?
The sudden fusion of helium in the core
What is the primary product of helium fusion in a low-mass star?
Carbon and oxygen
Which type of pressure supports a white dwarf against further collapse?
Degeneracy pressure of electrons
What is a planetary nebula?
An expanding shell of gas ejected from a red giant
What happens to a low-mass star after it expels its outer layers as a planetary nebula?
It becomes a white dwarf
Why can’t a white dwarf support fusion in its core?
Degeneracy pressure prevents further heating
What is the approximate upper mass limit for a white dwarf?
1.4 x mass of the sun (the Chandrasekhar Limit)
What marks the end of a low-mass star’s red giant phase?
Helium fusion stops, and the outer layers are ejected
What type of stars make up the majority of the main sequence stars in the galaxy?
Low-mass stars
What is the fate of a low-mass star’s core after it becomes a white dwarf?
It cools and dims over time
What is the ultimate fate of a white dwarf that has no more fusion?
It becomes a black dwarf
What is the evolutionary path of a low-mass star from birth to death?
Protostar → Main sequence → Red giant → Planetary nebula → White dwarf
What happens to a low mass stars luminosity as it enters the red giant phase?
It increases significantly
Why do low mass stars have longer lifetime than high mass stars?
They burn their fuel more slowly
What is the primary fuel for massive stars during the main sequence phase?
Hydrogen
What happens when a massive star exhaust its core hydrogen supply?
It contracts, and helium fusion begins
What element marks the end of fusion in the core of a massive star?
Iron
What causes a supernova explosion in a massive star?
The sudden collapse of the core
What is the Chandrasekahr Limit, and how does it relate to massive stars?
The mass above which a white dwarf collapses into a neutron star or black hole
What are the two possible remnants left behind by a massive star after a supernova?
A neutron star or a black hole
What is the typical size of a neutron star?
10 to 20 km
What is a pulsar?
A rapidly spinning neutron star, emitting beams of radiation
What is the event horizon of a black hole?
The point beyond which nothing, not even light, can escape
What causes a neutron star to become a black hole?
When it’s mass exceeds the the Tolman-Oppenheimer – Volkoff limit
What type of supernova is associated with the death of a massive star?
Type two
What is the role of neutrinos in a supernova explosion?
They carry away most of the energy from the explosion
What is the approximate mass of a black hole formed from a typical massive star?
3 to 10 masses of our sun
What is a gamma ray burst, and how is it related to the deaths of massive stars?
A burst of radiation caused by the collapse of a massive star into a black hole
Why can’t fusion of elements heavier than iron release energy in a stars core?
Fusion of heavier elements requires more energy than it releases
What is the approximate diameter of the Milky Way galaxy?
Hundred thousand light years
Where is the sun located within the Milky Way?
In the disk, about 27,000 light years from the center
What evidence supports the existence of dark matter in the Milky Way?
The rotation curve of the galaxy remains flat, a large radius
What is the primary method used to determine the structure of the Milky Way?
Radio observations of neutral hydrogen, ( 21 cm line )
Recent observations have revealed a vast structure of young stars in gas in the Milky Way, known as
The Radcliffe wave
Which type of galaxy is characterized by a lack of spiral arms in a smooth, featureless appearance?
Elliptical galaxies
What is the significance of the Hubble tuning fork diagram?
It categorizes galaxies by their morphology
What is a quasar?
An extremely luminous active galactic nucleus
The discovery of the South Pole wall in 2020 revealed:
A vast structure of galaxy is stretching 1.4 billion light years
The James Webb space telescope’s observations have challenged previous theories by discovering:
Galaxies with mature features existing only 300 million years after the Big Bang
What does the cosmological principle state?
The universe is homogeneous and isotropic on large scales
What is the significance of the cosmic microwave background radiation?
It provides a snapshot of the early universe
What does Hubble’s law describe?
The relationship between a galaxy distance and its recessional velocity
The concept of dark energy was introduced to explain:
The accelerated expansion of the universe
Recent data from the Gaia spacecraft has provided:
A detailed 3-D map of the Milky Way
Spectral Type of Earth
G2
