Astronomy Astronomy Galaxies and the Milky Way 1 — Questions and Answers
Question 1: What type of galaxy is the Milky Way?
- Barred spiral galaxy (Correct answer)
- Elliptical galaxy
- Irregular galaxy
- Lenticular galaxy
Correct answer: Barred spiral galaxy
The Milky Way is classified as a barred spiral galaxy, with a central bar-shaped structure from which spiral arms extend outward.
Question 2: What is the name of the supermassive black hole at the center of the Milky Way?
- Sagittarius A* (Correct answer)
- Cygnus X-1
- M87*
- NGC 4993
Correct answer: Sagittarius A*
Sagittarius A* (Sgr A*) is the supermassive black hole at the center of the Milky Way, with a mass of about 4 million solar masses.
Question 3: How long does it take the Sun to complete one orbit around the Milky Way's center?
- About 225 million years (Correct answer)
- About 26,000 years
- About 1 billion years
- About 13 million years
Correct answer: About 225 million years
The Sun orbits the Milky Way center once every approximately 225-250 million years, a period sometimes called a 'cosmic year' or 'galactic year.'
Question 4: What are the two largest satellite galaxies of the Milky Way?
- Large and Small Magellanic Clouds (Correct answer)
- Andromeda and Triangulum
- Canis Major and Sagittarius Dwarf
- Fornax and Sculptor Dwarfs
Correct answer: Large and Small Magellanic Clouds
The Large and Small Magellanic Clouds are the two largest satellite galaxies of the Milky Way, visible to the naked eye from the Southern Hemisphere.
Question 5: What is the Andromeda Galaxy's designation in the Messier catalog?
- M31 (Correct answer)
- M33
- M81
- M101
Correct answer: M31
The Andromeda Galaxy is cataloged as M31 in Charles Messier's catalog and is the nearest large spiral galaxy to the Milky Way.
Question 6: What is the approximate diameter of the Milky Way?
- About 100,000 light-years (Correct answer)
- About 10,000 light-years
- About 1 million light-years
- About 500,000 light-years
Correct answer: About 100,000 light-years
The Milky Way's disk is approximately 100,000 light-years in diameter, though its dark matter halo extends much further.
Astronomy Astronomy Galaxies and the Milky Way 1
What type of galaxy is the Milky Way?