Accelerating expansion of the 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/accelerating-expansion-of-the-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. Who discovered Accelerating expansion of the universe?1998
2. What is the key observational method?Analysis of Type Ia supernovae light curves and redshifts
3. What is the primary driver of acceleration?Dark energy
4. What does it mean that the universe is stretching faster and faster?It means that space itself is getting bigger at an increasing speed, so galaxies move away from each other more quickly over time.
5. How did scientists discover that the universe is expanding faster?They looked at distant Type Ia supernovae, which shine with a known brightness, and found they were dimmer than expected, showing they were farther away than a slowing universe would predict.

Redshift: The stretching of light waves from objects moving away from an observer, indicating expansion.
Cosmological Constant (Lambda): A term in Einstein's field equations representing the energy density of empty space.
Equation of State: A thermodynamic relation linking pressure and energy density, used to describe cosmic components.
Cosmic Microwave Background (CMB): The faint afterglow of the Big Bang, providing a snapshot of the early universe.