Questions and Answers
What are the three types of galaxies?
Spiral galaxies, Elliptical galaxies, and Irregular galaxies.
How did the Milky Way form?
Galactic bars developed when stellar orbits in spiral galaxy became unstable and deviated from a circular path.
What is the Hubble Classification Scheme?
The grouping of galaxies according to their shape.
What are the three main types of galaxies that Edwin Hubble categorized?
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What is the difference between barred spiral and spiral galaxies?
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What is the name of the diagram that Hubble created to classify the three different galaxies?
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What is the shape and structure of an elliptical galaxy?
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What is unique about an irregular galaxy?
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What galaxy has little or no gas and dust?
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What is the most popular galaxy in the universe?
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What is a galaxy cluster?
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What proved that there were hundreds to thousands of galactic clusters?
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What super cluster is the Milky Way part of?
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What group is the Milky Way part of?
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What does Hubble's Law state?
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What is the equation to get the recession speed?
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What is the evidence of the universe expanding?
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What is an active galaxy?
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What are the jets of energy called that blast out from the black hole?
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How do you know when a galaxy is active by looking at the electromagnetic spectrum?
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Study Notes
Types of Galaxies
- Three main types: Spiral, Elliptical, Irregular.
- Spiral galaxies feature rotating disks of stars and gas with distinctive spiral arms.
- Elliptical galaxies appear oval or circular and lack spiral arms.
- Irregular galaxies have no defined structure.
Formation of the Milky Way
- Developed from galactic bars due to instability in stellar orbits within a spiral structure.
Hubble Classification Scheme
- Categorizes galaxies based on their shapes and structures.
- Edwin Hubble's classification includes Elliptical, Barred Spiral, and Spiral galaxies.
Barred Spiral vs. Spiral Galaxies
- Barred spiral galaxies possess a central bar structure from which spiral arms extend, unlike standard spiral galaxies.
Hubble's Tuning Fork Diagram
- A visual representation created by Hubble for classifying galaxies into different categories.
Structure of Elliptical Galaxies
- Characterized by the absence of spiral arms and disks, often appearing oval or cigar-shaped.
- Typically contain little to no gas and dust.
Characteristics of Irregular Galaxies
- Lack a fixed shape or structure, making them unique among galaxy types.
Galaxy Clusters
- Groups formed by many different galaxies sharing a gravitational bond.
Evidence from Hubble Deep Field
- The Hubble Deep Field image demonstrated the existence of hundreds to thousands of galaxy clusters.
Milky Way's Supercluster and Group
- The Milky Way is part of the Virgo Super Cluster and belongs to the Local Group.
Hubble's Law
- States that galaxies move away from the Milky Way, with their speed directly proportional to their distance.
Recession Speed Calculation
- Calculated using the formula: Recession Speed = Hubble's Constant x Distance.
Evidence of Universe Expansion
- Redshift observations indicate that the farther a galaxy is, the more it shifts towards red, suggesting increased speed of recession.
Active Galaxies
- Defined by their high-energy centers, indicating significant emissions.
Quasars
- Jets of energy that project from supermassive black holes at the centers of active galaxies.
Identifying Active Galaxies via Electromagnetic Spectrum
- Active galaxies exhibit wider and gradual emission and absorption lines in their electromagnetic spectrum patterns.
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Description
Explore the fascinating world of galaxies through this quiz, which covers the main types: Spiral, Elliptical, and Irregular. Learn about the Hubble classification scheme and the differences between Barred Spiral and standard Spiral galaxies. Test your knowledge on the formation of the Milky Way and Hubble's Tuning Fork diagram.