ASTRO 101 QUESTIONS AND ANSWERS
Melanoheliophobia - Answers - An irrational fear of black holes
What are the three main attributes of photons? - Answers - Frequency, Wavelength,
Energy
If a photon's frequency is increased by a factor of two, what happens to its wavelength?
- Answers - Its wavelength decreases by a factor of two
If a photon's wavelength is increased by a factor of two, what happens to its frequency?
- Answers - Its frequency is decreased by a factor of two
If a photon's wavelength is increased by a factor of two, what happens to its energy? -
Answers - Its energy is decreased by a factor of two
What is weight? - Answers - Weight is the apparent force due to gravity as something is
pulled against a planet's surface
If a thing is initially at rest, what happens to its kinetic energy as it is gravitationally
pulled toward a massive object - Answers - Its gravitational potential energy is changed
into kinetic energy
When does an object have "escape velocity"? - Answers - Escape velocity is when an
object has enough kinetic energy to escape a gravitational field
What is a dark star? - Answers - A dark star has a surface escape velocity equal to the
speed of light
The regions of the electromagnetic spectrum in order of increasing energy - Answers -
Radio, infrared, visible, ultraviolet, x-rays, gamma rays
What is incandescence? - Answers - The emission of electromagnetic radiation from a
hot body as a result of its temperature.
What is luminescence? - Answers - The emission of light by a substance that has not
been heated, as in fluorescence and phosphorescence.
What is the Doppler effect? - Answers - The Doppler effect occurs when a source of
sound or light is moving relative to someone observing it
If a light source moves toward you, what would you observe? - Answers - You would
observe blue-shifted light
You observe that light from a star has a longer wavelength than expected. What is a
possible explanation? - Answers - The star may be moving away from you
,What effect does gravity have on light? - Answers - Gravity bends the path that light
follows
Two stars are near each other, and experience gravitational force between them. What
happens if the distance between them is decreased by a factor of two? - Answers - The
gravitational force increases by a factor of four
Two stars are near each other, and experience gravitational force between them. What
happens if the mass of one star is increased by a factor of two? - Answers - The
gravitational force increases by a factor of two
Two stars are near each other, and experience gravitational force between them. What
does Newton's third law say about them? - Answers - The stars each experience the
same force, but in opposite directions
What is the relationship between a dark star and a black hole? - Answers - A dark star
with a stable surface does not exist in nature, while a black hole with an event horizon
at the same place as the dark star's surface exists and can be observed.
What phenomena might black holes help explain? - Answers - Dark matter, dark energy
What is the event horizon of a black hole? - Answers - The event horizon is the radius
within which light cannot escape a black hole
What is a star? - Answers - A star is a self-gravitating body of gas which is massive
enough to sustain fusion
What is hydrostatic equilibrium in a star? - Answers - Hydrostatic equilibrium is when
gas pressure balances gravity
What is luminosity? - Answers - Luminosity is a measure of the light emitted by a star
What is apparent brightness? - Answers - The observed brightness of a star
What is the phenomenon where stars produce light based on their heat? - Answers -
Blackbody radiation
What are differences between fusion and fission? - Answers - Fission is when a nucleus
is split, and fusion is when nuclei merge
What is one direct piece of evidence for fusion in the Sun? - Answers - The streams of
neutrinos flowing outwards from the Sun's core
Where does the energy from fusion come from? - Answers - The energy from fusion is
created by the conversion of mass to energy through the equation E=mc^2
, Which term describes the situation when an element is unable to release energy
through either fission or fusion? - Answers - The iron catastrophe
Identify the three methods of energy transfer. - Answers - Convection, conduction,
radiation
Name the regions of the sun in their order from inward to outward. - Answers -
Thermonuclear core, convective zone, photosphere, chromosphere, corona
If you see the spectrum of a distant star and it appears as a rainbow of colours with
missing, dark lines, what could that mean? - Answers - There is an element in the
photosphere of the star, which absorbs light with the same colours as the missing lines
What causes main sequence turnoff? - Answers - A star runs out of hydrogen fuel and
its core contracts while its outer envelope expands
What happens when a star collapses to the point that its core is composed of iron? -
Answers - The star can no longer get energy from fusion, and will die
Which is a technique for finding the age of a cluster of stars? - Answers - Map the
cluster on a Hertzsprung-Russell diagram and see what types of stars have
disappeared from the main sequence
How old is the Sun? - Answers - 5 billion years old
Put the steps of the Sun's evolution in chronological order from 1 to 3 - Answers - 1)
fuse hydrogen into helium at its core 2) run out of hydrogen and become a red giant 3)
shed outer layers in a nebula and become a white dwarf
What stops a white dwarf from collapsing? - Answers - Electrons in the core producing
degeneracy pressure that stops the white dwarf from collapsing
What causes a white dwarf to collapse, releasing the energy to explode in a Type Ia
supernova? - Answers -
What causes a core-collapse supernova? - Answers - A core-collapse supernova is
caused by the collapse of a star with a high enough mass that it forms an iron core
What can be produced when a high-mass star dies by core-collapse supernova? -
Answers - A black hole, A neutron star, A nebula
What is degeneracy pressure? - Answers - Degeneracy pressure is the resistance of
certain particles to being in the same place and energy state
Melanoheliophobia - Answers - An irrational fear of black holes
What are the three main attributes of photons? - Answers - Frequency, Wavelength,
Energy
If a photon's frequency is increased by a factor of two, what happens to its wavelength?
- Answers - Its wavelength decreases by a factor of two
If a photon's wavelength is increased by a factor of two, what happens to its frequency?
- Answers - Its frequency is decreased by a factor of two
If a photon's wavelength is increased by a factor of two, what happens to its energy? -
Answers - Its energy is decreased by a factor of two
What is weight? - Answers - Weight is the apparent force due to gravity as something is
pulled against a planet's surface
If a thing is initially at rest, what happens to its kinetic energy as it is gravitationally
pulled toward a massive object - Answers - Its gravitational potential energy is changed
into kinetic energy
When does an object have "escape velocity"? - Answers - Escape velocity is when an
object has enough kinetic energy to escape a gravitational field
What is a dark star? - Answers - A dark star has a surface escape velocity equal to the
speed of light
The regions of the electromagnetic spectrum in order of increasing energy - Answers -
Radio, infrared, visible, ultraviolet, x-rays, gamma rays
What is incandescence? - Answers - The emission of electromagnetic radiation from a
hot body as a result of its temperature.
What is luminescence? - Answers - The emission of light by a substance that has not
been heated, as in fluorescence and phosphorescence.
What is the Doppler effect? - Answers - The Doppler effect occurs when a source of
sound or light is moving relative to someone observing it
If a light source moves toward you, what would you observe? - Answers - You would
observe blue-shifted light
You observe that light from a star has a longer wavelength than expected. What is a
possible explanation? - Answers - The star may be moving away from you
,What effect does gravity have on light? - Answers - Gravity bends the path that light
follows
Two stars are near each other, and experience gravitational force between them. What
happens if the distance between them is decreased by a factor of two? - Answers - The
gravitational force increases by a factor of four
Two stars are near each other, and experience gravitational force between them. What
happens if the mass of one star is increased by a factor of two? - Answers - The
gravitational force increases by a factor of two
Two stars are near each other, and experience gravitational force between them. What
does Newton's third law say about them? - Answers - The stars each experience the
same force, but in opposite directions
What is the relationship between a dark star and a black hole? - Answers - A dark star
with a stable surface does not exist in nature, while a black hole with an event horizon
at the same place as the dark star's surface exists and can be observed.
What phenomena might black holes help explain? - Answers - Dark matter, dark energy
What is the event horizon of a black hole? - Answers - The event horizon is the radius
within which light cannot escape a black hole
What is a star? - Answers - A star is a self-gravitating body of gas which is massive
enough to sustain fusion
What is hydrostatic equilibrium in a star? - Answers - Hydrostatic equilibrium is when
gas pressure balances gravity
What is luminosity? - Answers - Luminosity is a measure of the light emitted by a star
What is apparent brightness? - Answers - The observed brightness of a star
What is the phenomenon where stars produce light based on their heat? - Answers -
Blackbody radiation
What are differences between fusion and fission? - Answers - Fission is when a nucleus
is split, and fusion is when nuclei merge
What is one direct piece of evidence for fusion in the Sun? - Answers - The streams of
neutrinos flowing outwards from the Sun's core
Where does the energy from fusion come from? - Answers - The energy from fusion is
created by the conversion of mass to energy through the equation E=mc^2
, Which term describes the situation when an element is unable to release energy
through either fission or fusion? - Answers - The iron catastrophe
Identify the three methods of energy transfer. - Answers - Convection, conduction,
radiation
Name the regions of the sun in their order from inward to outward. - Answers -
Thermonuclear core, convective zone, photosphere, chromosphere, corona
If you see the spectrum of a distant star and it appears as a rainbow of colours with
missing, dark lines, what could that mean? - Answers - There is an element in the
photosphere of the star, which absorbs light with the same colours as the missing lines
What causes main sequence turnoff? - Answers - A star runs out of hydrogen fuel and
its core contracts while its outer envelope expands
What happens when a star collapses to the point that its core is composed of iron? -
Answers - The star can no longer get energy from fusion, and will die
Which is a technique for finding the age of a cluster of stars? - Answers - Map the
cluster on a Hertzsprung-Russell diagram and see what types of stars have
disappeared from the main sequence
How old is the Sun? - Answers - 5 billion years old
Put the steps of the Sun's evolution in chronological order from 1 to 3 - Answers - 1)
fuse hydrogen into helium at its core 2) run out of hydrogen and become a red giant 3)
shed outer layers in a nebula and become a white dwarf
What stops a white dwarf from collapsing? - Answers - Electrons in the core producing
degeneracy pressure that stops the white dwarf from collapsing
What causes a white dwarf to collapse, releasing the energy to explode in a Type Ia
supernova? - Answers -
What causes a core-collapse supernova? - Answers - A core-collapse supernova is
caused by the collapse of a star with a high enough mass that it forms an iron core
What can be produced when a high-mass star dies by core-collapse supernova? -
Answers - A black hole, A neutron star, A nebula
What is degeneracy pressure? - Answers - Degeneracy pressure is the resistance of
certain particles to being in the same place and energy state
