Podcast
Questions and Answers
What happens to an atom when an electron is completely detached from it?
What happens to an atom when an electron is completely detached from it?
What is a requirement for an object to be considered a dwarf planet in our Solar System?
What is a requirement for an object to be considered a dwarf planet in our Solar System?
How much smaller is the distance between the Sun and the nearest star compared to the distance between the Milky Way and Andromeda?
How much smaller is the distance between the Sun and the nearest star compared to the distance between the Milky Way and Andromeda?
Why can we study how galaxies evolve?
Why can we study how galaxies evolve?
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What is the age of the most recent information we can get about a star 50 lightyears away?
What is the age of the most recent information we can get about a star 50 lightyears away?
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What are the correct standard units of mass, distance, and time?
What are the correct standard units of mass, distance, and time?
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What is the duration of this examination?
What is the duration of this examination?
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Where should you record your answers?
Where should you record your answers?
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What is the consequence of arriving late to the examination?
What is the consequence of arriving late to the examination?
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Why must you remain silent in your seat during the last 15 minutes of the examination?
Why must you remain silent in your seat during the last 15 minutes of the examination?
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What is the consequence of writing on the question paper?
What is the consequence of writing on the question paper?
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What is the purpose of showing your student card to the exam invigilators?
What is the purpose of showing your student card to the exam invigilators?
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What is the unit of mass commonly used in astronomy?
What is the unit of mass commonly used in astronomy?
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Why does the Solar System not expand apart due to the expansion of the universe?
Why does the Solar System not expand apart due to the expansion of the universe?
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What is the difference in the gravitational pull of a black hole and a normal star with the same mass on a planet orbiting them at the same distance?
What is the difference in the gravitational pull of a black hole and a normal star with the same mass on a planet orbiting them at the same distance?
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What is the speed of light emitted by a spaceship moving towards you at 1/3c?
What is the speed of light emitted by a spaceship moving towards you at 1/3c?
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How can we measure the speed at which galaxies move?
How can we measure the speed at which galaxies move?
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What is the implication of the universe expanding on the Solar System?
What is the implication of the universe expanding on the Solar System?
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What would happen if we suddenly turned off gravity in the Milky Way?
What would happen if we suddenly turned off gravity in the Milky Way?
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What is the Doppler Effect?
What is the Doppler Effect?
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How can we determine the distance to a galaxy that contains Cepheid variable stars?
How can we determine the distance to a galaxy that contains Cepheid variable stars?
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What happens to an object's mass as it approaches the speed of light?
What happens to an object's mass as it approaches the speed of light?
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What can we conclude from the fact that all distant galaxies are redshifted?
What can we conclude from the fact that all distant galaxies are redshifted?
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Can we measure the motion of galaxies like we do for stars?
Can we measure the motion of galaxies like we do for stars?
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What happens to the light received from a distant star moving away from us compared to light from our Sun?
What happens to the light received from a distant star moving away from us compared to light from our Sun?
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What must occur to an electron in orbit around an atom's nucleus for it to emit a photon?
What must occur to an electron in orbit around an atom's nucleus for it to emit a photon?
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What is the correct order of the fundamental forces from strongest to weakest?
What is the correct order of the fundamental forces from strongest to weakest?
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Why do observers moving at different constant velocities see time pass at different rates?
Why do observers moving at different constant velocities see time pass at different rates?
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What is the result of an electron jumping from a higher energy orbit to a lower energy orbit around an atom's nucleus?
What is the result of an electron jumping from a higher energy orbit to a lower energy orbit around an atom's nucleus?
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What can be said about the light emitted from our Sun and an identical distant star moving away from us?
What can be said about the light emitted from our Sun and an identical distant star moving away from us?
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Study Notes
Units of Measurement
- The correct standard units of mass, distance, and time are kg, m, and s.
Black Holes
- A black hole and a normal star with the same mass will exert the same gravitational pull on a planet orbiting them at the same distance.
Speed of Light
- The speed of light remains constant regardless of the motion of the source or observer.
- If a spaceship moves towards you at 1/3c, the speed of the light emitted by the spaceship, as measured in your frame of reference, is c.
Galaxies
- The distance between the Sun and the nearest star is smaller than the distance between the Milky Way and the nearest large galaxy, Andromeda, by a factor of roughly 100,000.
- We can study how galaxies evolve because the further away we look, the further back in time we see.
Dwarf Planets
- To be considered a dwarf planet, an object in our Solar System must orbit the Sun and be close to a round shape.
Atomic Physics
- If an electron is completely detached from an atom, the atom is ionized.
- When an atom emits a photon and creates an emission line, one of the electrons in orbit around the atom's nucleus has to jump from a higher energy orbit to a lower energy orbit.
Gravity
- If gravity were suddenly turned off in the Milky Way, the galaxy would fly apart.
- The theory of general relativity shows that gravity is not a force, but rather the curvature of spacetime.
Relativity
- As an object approaches the speed of light, its mass approaches infinity.
- The theory of special relativity shows that observers moving at different constant velocities will see time pass at different rates due to the fact that everyone agrees on the speed of light.
Stars
- We can determine the distance to a galaxy that contains Cepheid variable stars by using the period-luminosity relation.
Forces
- The correct order of the fundamental forces, placing the strongest first, is strong, electromagnetic, weak, and gravity.
Universe Expansion
- Because all distant galaxies are redshifted, we know that the Universe is expanding.
- If the universe is expanding, the Solar System will not eventually expand apart due to its own gravity holding it together.
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Description
Take this midterm exam to test your knowledge on astronomy topics, covering 30 multiple-choice questions in 50 minutes. The quiz is designed for students of Dr. Robert Cockcroft's ASTRON 2B03 course at McMaster University. Evaluate your understanding of the course material and identify areas for improvement.
