Explanations 
Textbooks 
Exams 
GCSE 
IGCSE 
AS 
A Level 
International A Level 
University Admissions Tests 
Flashcards 
Vaia AI 
Notes 
Study Plans 
Study Sets 
Find a job 
Find a degree 
Student Deals 
Magazine 
Mobile App Chapter 21: Problem 20
In the Hubble scheme for classifying galaxies, what kind of galaxy is the Milky Way? a. elliptical b. spiral c. barred spiral d. irregular
Short Answer
Expert verified
c. barred spiral
Step by step solution
01
Understanding the Hubble Scheme
The Hubble Scheme is a classification system for galaxies introduced by Edwin Hubble. It categorizes galaxies into four main types: elliptical, spiral, barred spiral, and irregular.
02
Identifying Galaxy Types
Elliptical galaxies are smooth and featureless, spiral galaxies have a flat, disk-like structure with spiral arms, barred spiral galaxies also have a disk and spiral arms but with a central bar-like structure, and irregular galaxies lack a defined shape.
03
Characteristics of the Milky Way
The Milky Way has a disk structure with prominent spiral arms and a central bar, fitting the description of a barred spiral galaxy.
04
Selecting the Correct Option
Among the provided options (a. elliptical, b. spiral, c. barred spiral, d. irregular), the description of the Milky Way matches c. barred spiral.
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with Vaia!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Edwin Hubble
Edwin Hubble was an American astronomer who revolutionized our understanding of the universe. He is best known for developing a classification system for galaxies, known as the Hubble Scheme. Hubble's work showed that the universe is expanding, a discovery that led to the Big Bang theory. By categorizing galaxies based on their appearance, he helped astronomers identify and understand different galaxy types. The main categories in the Hubble Scheme are elliptical, spiral, barred spiral, and irregular galaxies. Hubble's work laid the foundation for modern astronomy. His contributions are still relevant to astronomers today.
Galaxy Types
Galaxies are categorized into four main types: elliptical, spiral, barred spiral, and irregular.
- Elliptical galaxies: These galaxies are smooth, featureless, and oval-shaped. They contain older stars and have little gas and dust, making star formation rare.
- Spiral galaxies: Characterized by a flat disk and spiral arms, these galaxies contain significant amounts of gas and dust, where new stars are born. They are vibrant and colorful due to the various stages of star formation.
- Barred Spiral galaxies: Similar to spiral galaxies, but with a central bar-shaped structure. The Milky Way is a barred spiral galaxy. The bar consists of stars and may channel gas into the center, possibly affecting the formation of new stars.
- Irregular galaxies: These galaxies lack a defined shape. They have significant gas and dust and are often sites of intense star formation.
Milky Way Structure
The Milky Way is our home galaxy and is classified as a barred spiral galaxy. It has several distinct parts:
- The Galactic Disk: This is a flat, circular region containing spiral arms filled with stars, gas, and dust. This is where most of the star formation occurs.
- The Galactic Bulge: At the center of the Milky Way, the bulge is an elongated, bar-shaped structure, rich with older stars.
- The Galactic Halo: Surrounding the disk and bulge, the halo contains old stars, globular clusters, and dark matter.
- Spiral Arms: Extending from the central bar, the spiral arms include regions of active star formation. These arms are bright and often contain young, hot stars, glowing gas nebulae, and star clusters.
Barred Spiral Galaxy
Barred spiral galaxies have a unique structure that sets them apart from regular spiral galaxies. Features include:
- Central Bar: Made up of stars, the bar extends from the nucleus and runs through the center of the galaxy. This structure can affect the movement of gas and stars within the galaxy.
- Spiral Arms: These arms originate from the ends of the bar and not directly from the nucleus. They often contain regions of active star formation.
- Examples: Many galaxies, including our Milky Way, are barred spiral galaxies. The bar can influence galaxy dynamics by channeling gas to the central regions, possibly fueling the growth of a central black hole and affecting the rate of new star formation.
- Evolutionary Insight: The presence of a bar might indicate a certain stage in the galaxy's evolution, showing how galaxies can transform over time.
