Galaxy groups and clusters

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-groups-and-clusters

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 groups and clusters?Dark matter constitutes 80-90% of the total mass in galaxy clusters
2. What is the intracluster medium (ICM)?Hot, X-ray emitting gas filling the space between galaxies in clusters
3. What is the formation paradigm?Hierarchical structure formation within the Lambda-CDM cosmological model
4. What is a galaxy group and how many galaxies can it have?A galaxy group is a collection of up to about 50 galaxies. Our own Local Group has around 54 galaxies, including many small dwarf galaxies.
5. What makes galaxy clusters different from galaxy groups?Galaxy clusters are much bigger and denser, holding hundreds to thousands of galaxies. They also contain hot gas that glows in X‑rays and are the largest structures bound by gravity.

Lambda-CDM Model: The standard model of cosmology, describing a universe dominated by dark energy and cold dark matter.
Gravitational Lensing: The bending of light from distant objects by the gravity of massive foreground objects, used to map dark matter.
Baryonic Matter: Ordinary matter composed of protons and neutrons, which forms stars, planets, and gas.