Imagine the Universe!
Imagine Home  |   Ask an Astrophysicist  |  
Ask an Astrophysicist
Library of Past Questions

Milky Way and other Galaxies

First time visitors: Please be sure to read our main page!

  • Check out the resource links. These are the sites we often point to in answering your questions.
  • Browse through the library of questions below.

Resources for this Topic

  1. The Cosmos (

  2. Cosmos in a Computer (

  3. Galaxies (

  4. The MultiwavelengthMilky Way (

Library of Past Questions and Answers

    The Milky Way Galaxy (Our Own)

  1. How large is the Milky Way galaxy?

  2. Where is the Solar System located in the galaxy?

  3. What is our Sun's rate of speed in relation to the center of our galaxy? Is our galaxy moving as well?

  4. What is the age of the Milky Way compared to the Universe?

  5. How many stars (or what percentage) in our galaxy are 4.5 billion years old (age of the Sun) or older?

  6. What is the proof that the Milky Way is a barred spiral?

  7. Do you have any pictures of the Milky Way Galaxy from above?

  8. Why are far away galaxies visible to telescopes, but not the center of ours?

  9. Do you know where I can find information about mapping the Milky Way at different wavelengths?

  10. Are there more Pop I or Pop II stars in our galaxy?

  11. What do you know about the dwarf galaxy that is colliding with our own?

  12. Was the Milky Way galaxy once a Quasar?

    Other Galaxies - General

  1. How many galaxies are there in the Universe?

  2. What is the closest other galaxy to the Milky Way?

  3. Are the Magellanic Clouds moving away faster than we thought?

  4. What happens when galaxies collide?

  5. Can galaxies lose mass when they interact?

  6. Who first discovered the nature of galaxies?

  7. How do astronomers estimate the distances to other galaxies?

  8. How accurate are the published distances to other galaxies?

  9. What is the most distant known galaxy in the observable universe?

  10. Do all galaxies have large black holes at their center?

  11. What will happen to the Central Black holes when galaxies collide?

    Other Galaxies - Types and Sizes
  1. What different types of galaxies are there?

  2. What are lenticular galaxies?

  3. Why do galaxies have their different shapes?

  4. What type of galaxy is the most abundent?

  5. What is the average size of a galaxy?

  6. What are the sizes of the different types of galaxies?

  7. What is the nature of spiral arms in galaxies?

  8. How can elliptical galaxies exist soon after the Big Bang?

  9. How is a galaxy's size determined when it forms?

  10. What are Dark Galaxies?

    Clusters of Galaxies

  1. How are the Local Group of galaxies selected?

  2. Do we need teraflop and petaflop computers for calculating the evolution of clusters of galaxies?

  3. What is the Great Attractor?

Imagine the Universe is a service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA's Goddard Space Flight Center.

The Imagine Team
Acting Project Leader: Dr. Barbara Mattson
All material on this site has been created and updated between 1997-2012.

DVD Table of Contents
Educator's Index