Galaxy cluster

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/galaxy-cluster

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. How heavy is the Galaxy cluster?10^14 to 10^15 solar masses
2. What is the category?Largest known gravitationally bound structures in the universe
3. What is the key principle?Gravitational binding of galaxies, hot intergalactic gas, and dark matter
4. Why do galaxy clusters have so much hot gas?The gas between the galaxies is heated to millions of degrees by the cluster’s gravity, so it glows in X‑rays.
5. How do scientists know galaxy clusters have dark matter?Galaxies inside a cluster move too fast to be held together by visible matter alone, and the cluster’s gravity bends light from distant galaxies, showing extra mass.

Intergalactic Medium (IGM): The diffuse plasma filling the space between galaxies within a cluster, heated to millions of degrees.
Virial Mass: The total mass of a gravitationally bound system calculated from the velocities of its components.
Gravitational Lensing: The bending of light from distant sources by the gravity of massive foreground objects, used to map mass distribution.
Hierarchical Structure Formation: A cosmological model where large structures form from the merging of smaller ones over time.