Hubble's law

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/hubble-s-law

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 Hubble's law?1929
2. What is the primary discoverer?Edwin Hubble
3. What is the theoretical precursors?Alexander Friedmann (1922), Georges Lemaître (1927)
4. Why do galaxies move away from us?Because the space between them is stretching. As space grows, the galaxies are carried along, so they recede from each other.
5. How do scientists measure how fast a galaxy is moving?They look at the galaxy's light and see how much it shifts toward red. The more the shift, the faster the galaxy is moving away.

Cosmological Redshift: The stretching of light wavelengths due to the expansion of space itself between the source and observer.
Standard Candle: An astronomical object with a known intrinsic luminosity, used to measure cosmic distances (e.g., Cepheid variables).
Hubble Constant (H₀): The proportionality constant relating a galaxy's distance to its recessional velocity, representing the current expansion rate of the universe.
Hubble Time: The reciprocal of the Hubble constant (1/H₀), providing an estimate of the age of the universe.