QUIZZES NATS
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York University *
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Course
1745
Subject
Astronomy
Date
Feb 20, 2024
Type
docx
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5
Uploaded by ProfMaskScorpion194
Quiz 14: · How does the Doppler shift or wobble method find planets around stars?
o it looks for periodic redshifting and blueshifting of spectral lines of a star
· Around which type of star were the first exoplanets discovered?
o pulsar
· A 'hot Jupiter' is a
o planet Jupiter-sized or larger orbiting its star closer than Mercury orbits the Sun
· The discovery of which object in the Kuiper belt prompted Mike Brown to re-evaluate Pluto's status as a planet?
o Eris
· Which nomenclature would be used to describe a planet orbiting the star 51 Pegasi?
o 51 Pegasi b
· Who discovered Pluto?
o Tombaugh
· Why is Pluto no longer considered a planet?
o It did not clear its orbit
· In the radial velocity method, the periodic redshifting and blueshifting of a planet's spectrum helps astronomers determine if a planet is orbiting a star
o False
· Who first observed a redshifted spectrum of a star?
o Huggins
· Multiple planets orbiting a star (other than the Sun) have not yet been detected
o False
Quiz 15: · The mass of an exoplanet can be determined using the transit method.
o False
· What do astronomers think needs to be present on a planet, in order to have the chance of finding extraterrestrial life?
o Water
· What is the ‘habitable zone’ around a star?
o Where the temperature of a planet could have liquid water
· The planet Kepler 22b could be covered with
o Water
· Why is it easier to detect planets around M dwarfs?
o They are fainter, it is easier to see transits
· Which nomenclature would be used to describe a planet orbiting the star 51 Pegasi?
o 51 Pegasi b
· Have any planets been found in their star’s habitable zone?
o Yes/True
· The radius of an exoplanet can be determined using the transit method.
o True
· How is the transit method used to find planets around stars?
o It looks for small dips in the brightness of a star
· What type of observations do astronomers make to use the transit method to find exoplanets?
o Astronomers take multiple images for this method
Quiz 16: · Diffuse nebulae are found around
o O stars
· The Sun will most likely end its life as a
o Planetary nebula
· What nebula is visible with the naked eye?
o All of the above (Andromeda galaxy, Orion nebula, and Large Megellanic Cloud)
· What type of spectrum does a nebula have?
o Bright line
· The reddish or pinkish emission from nebulae comes from which element?
o Hydrogen
· Planetary nebulae are found around
o White dwarfs
· What colour are reflection nebulae?
o Blue
· Which scientist was finally able to solve the mystery of what nebulae were?
o Huggins
· When a particle (like a free electron, atom or ion) collides with an ion in a nebula, it can transfer some of its ______________ to the ion. An electron in that ion then jumps to a higher energy level.
o Kinetic energy
· Which wavelengths are best to observe protoplanetary disks?
o Infrared
Quiz 17: · Black holes are defined as
o Objects with escape velocities greater than the speed of light
· What is the name of the most likely candidate for a stellar mass black hole in our galaxy?
o Cygnus X-1
· What is the name of the supermassive black hole at the center of the Milky Way Galaxy?
o Sagittarius A*
· What type of data were collected by astronomers which allowed them to discover the supermassive black hole at the center of our galaxy?
o Infra-red images taken over many years to measure changes in positions of stars orbiting the central object
· What did Eddington observe in 1919, which proved a prediction of Einstein’s theory of gravity?
o That the positions of stars were affected by the gravity of the Sun
· What marks the ‘edge’ of a black hole, beyond which nothing can escape?
o Event horizon
· According to Einstein’s theory of gravity, _____ get(s) warped by mass
o Spacetime
· How are stellar mass black holes created?
o During supernova explosions
· What occurred to enable the first detection of gravitational waves?
o A collision between 2 black holes
· What wavelengths were used to create the first ever image of a black hole?
o Radio Waves
Quiz 18:
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By comparing the apparent vs absolute brightness of a star, we can calculate the star's ______________
o
Distance
A Cepheid is an example of a ______________ star
o
pulsating variable
The absolute brightness of a Cepheid star directly relates to its _________
o
pulsational period
Shapley used the distances he derived for Cepheid stars, using the inverse square law, to deduce the size and structure of the Milky Way Galaxy. Where were these Cepheid stars located?
o
in globular clusters
Hubble's observation of a Cepheid in _______________ allowed him to settle the Shapley - Curtis debate
o
the Andromeda nebula
Hubble's Law can be show in a graph that plots (y vs x):
o
recessional velocity vs distance
Which is an implication for Hubble's Law?
o
the Universe is expanding
Which statement best describes Hubble's Law?
o
the farthest galaxies are moving away from us at the fastest speeds
What is dark matter?
o
unseen mass in the Universe, revealed by its gravitational effects
What is dark energy?
o
an anti-gravity force, causing the Universe to accelerate in its expansion
QUIZ 19:
The Big Bang is a description of the moment of creation of ____________
o
The Universe
Who thought that the Universe began as a ‘primeval atom’ and expanded with time to the
way it is today?
o
Lemaitre
What did Einstein consider to be his 'biggest blunder'?
o
Failing to believe the universe was expanding and thus has a moment of creation
At t=0 (exactly
), the Universe was
o
singularity
Just after
t=0, the Universe was
o
Pure energy
How was matter created in the early universe?
o
From the conversion of photons to particle – antiparticle pairs
What is the farthest visible object (or thing) in the Universe?
o
The cosmic microwave background radiation
The cosmic microwave background radiation is an echo that traces an important moment in the early Universe:
o
When it transitioned from being opaque to transparent to radiation
The cosmic microwave background radiation was detected
o
Accidentally, by Penzias and Wilson
The Sloan Digital Sky Survey map of the distribution of galaxies in the universe
o
Tells scientists their models for the Big Bang and how the universe evolved are largely correct