Questions and Answers
Galaxies are classified according to:
Spiral arms have _____ stars than the rest of the disk has.
Which of the following contributes the largest percentage of total mass of a spiral galaxy?
Currently, stars form in:
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A rotation curve plots ______ versus distance from the galaxy center.
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Spiral structure in a disk can be created by:
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In the context of spiral galaxies, Kepler's laws could be used to estimate:
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The existence of supermassive black holes at the centers of massive galaxies is:
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The reason all quasars are very distant is that:
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Astronomers determine the radius of an AGN by measuring:
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An E7 galaxy is more spherical than an E0 galaxy.
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A spiral galaxy's dark matter is distributed spherically.
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Dust does not shine in visible light, so it is considered dark matter.
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Most of the mass of a galaxy is in stars.
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AGNs are small but extremely luminous.
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Which of the following galaxy types has a spherical bulge and a well-defined disk?
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Which of the following galaxy types describes a galaxy shaped like a rugby ball?
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For a galaxy, the term morphology refers to:
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If all the stars in an elliptical galaxy traveled in random directions in their orbits, the elliptical galaxy would be type:
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In spiral galaxies, stars form primarily in the spiral arms:
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Dark matter is different from normal matter because:
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Astronomers know that dark matter is present in galactic halos because the speeds of orbiting stars _____ far from the center of the galaxy.
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Luminous matter includes:
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The differences among various types of AGNs are caused by:
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If a Seyfert galaxy's nucleus varies in brightness on the timescale of 10 hours, then approximately what is the size of the emitting region?
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Study Notes
Galaxy Classification
- Galaxies are classified primarily by shape.
- Spiral arms contain more stars than the rest of the disk.
- Dark matter contributes the largest portion of a spiral galaxy's total mass.
Star Formation and Structure
- Star formation predominantly occurs in spiral galaxies.
- A rotation curve represents the relationship between orbital speed and distance from a galaxy's center.
- Spiral structures can arise from star formation, bar-shaped bulges, or interactions with other galaxies.
Kepler's Laws and Galaxy Mass
- Kepler's laws can help estimate the mass of a galaxy based on the motion of stars.
Black Holes and Quasars
- The existence of supermassive black holes at galaxy centers is widely accepted within astronomy.
- Quasars are extremely distant due to the evolution of the universe.
- The radius of an active galactic nucleus (AGN) is determined by the amount of light emitted.
True/False Statements Insights
- E7 galaxies are less spherical than E0 galaxies.
- Dark matter in spiral galaxies has a spherically distributed profile.
- Dust doesn't emit visible light, categorizing it as dark matter.
- The majority of a galaxy's mass is not found in stars; instead, dark matter plays a significant role.
- Active Galactic Nuclei (AGNs) are compact yet very luminous.
Galaxy Types and Characteristics
- Barred spiral galaxies are characterized by a spherical bulge and well-defined disk.
- E5 galaxies have a rugby ball shape.
- Morphology refers to a galaxy's shape and the motion of its stars.
Galactic Dynamics
- Random stellar orbits define elliptical galaxies, classifying them as type E7.
- In spiral galaxies, stars mainly form in spiral arms due to the density increase.
- Dark matter differs from normal matter in that it neither emits, absorbs, nor scatters light.
Galactic Observations
- Orbiting star speeds increase as their distance from the galactic center grows.
- Luminous matter includes stars, dust, and gas collectively.
- Variations in AGN types are influenced by host galaxy type, black hole size, dark matter amount, and viewing angle.
Seyfert Galaxy Characteristics
- A Seyfert galaxy with a nucleus that varies in brightness over 10 hours indicates an emitting region of approximately 20 AU.
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Description
Test your knowledge with this quiz focusing on Chapter 20 of astronomy. The questions cover key concepts such as galaxy classification, star properties, and the mass composition of spiral galaxies. Enhance your understanding of these astronomical phenomena.
