Observable universe

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/observable-universe

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 Observable universe?Approximately 1.5 x 10^53 kg
2. What is the radius of observable universe?Approximately 46.5 billion light-years
3. What is the age of universe?Approximately 13.8 billion years
4. Why can we only see a part of the universe?Because light travels at a finite speed, we can only see objects whose light has had time to travel to us. The universe is about 13.8 billion years old, so light from farther away hasn't arrived yet. This creates a natural boundary called the particle horizon.
5. How far can we see in the observable universe?The edge of the observable universe is about 46.5 billion light‑years away. That means we can see objects whose light has traveled that far. The light we see from the cosmic microwave background was emitted when the universe was very young, but those objects are now much farther away.

Comoving Distance: The distance between two objects that accounts for the expansion of the universe.
Isotropic: Having a uniform appearance or properties in all directions.
Particle Horizon: The boundary in spacetime beyond which events cannot affect an observer.
Redshift: The stretching of light waves towards longer, redder wavelengths due to expansion or gravity.