Spiral galaxy

High school (ages 12+)
Space & Astronomy

Name:

Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/spiral-galaxy

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. What is the star formation mechanism?Density waves in spiral arms compress interstellar medium, initiating OB star formation
2. What is the galactic bar prevalence?Approximately 60-70% of nearby spiral galaxies exhibit a central stellar bar
3. Why do spiral arms look bright?The arms are density waves that squeeze gas and dust together. This makes the gas collapse and form young, bright OB stars that light up the arms.
4. How do spiral galaxies make new stars?In the spiral arms, the waves compress gas and dust, causing it to collapse under gravity. The collapse creates new, massive stars that shine brightly.

Density Wave Theory: A model explaining spiral arms as regions of increased stellar and gas density propagating through the galactic disk.
Interstellar Medium (ISM): The matter and radiation that exist in the space between the star systems of a galaxy.
Galactic Bar: An elongated structure of stars extending from the central bulge of a spiral galaxy.