Henrietta Leavitt and Cepheid Variables

Henrietta Swan Leavitt discovered a relationship between the period and brightness of Cepheid variable stars, which allowed astronomers to measure distances in space. This discovery led to Edwin Hubble's realization that the universe is expanding, fundamentally changing our understanding of the cosmos. The video also explains how to observe Delta Cephei, a notable Cepheid variable star.

What was the main impact of Henrietta Swan Leavitt's discovery on astronomy?

• It changed the understanding of the universe's scale.

• It helped in identifying new planets.

• It led to the discovery of black holes.

• It improved telescope technology.

What was Henrietta Leavitt's role at Harvard College University?

• She was a professor of astronomy.

• She taught courses on galaxy formation.

• She analyzed photographic plates to find variable stars.

• She developed new telescope lenses.

What is a unique feature of Cepheid variable stars?

• They have a constant brightness.

• They have a unique light curve signature.

• They are the largest stars in the universe.

• They are only found in the Milky Way.

How did Henrietta Leavitt's discovery help in measuring distances in space?

• By using the speed of light.

• By observing the color of stars.

• By determining the period of Cepheid variables.

• By measuring the temperature of stars.

What was Edwin Hubble's significant finding using Cepheid variables?

• The existence of black holes.

• The expansion of the universe.

• The presence of life on other planets.

• The discovery of new elements.

What was the initial belief about the Andromeda galaxy before Hubble's discovery?

• It was a black hole.

• It was a distant star.

• It was a newly formed planet.

• It was a part of the Milky Way.

Where is Delta Cephei located?

• In the constellation Andromeda.

• In the constellation Orion.

• In the constellation Cepheus.

• In the constellation Ursa Major.

What is the period of variability for Delta Cephei?

• 10 days

• 5.4 days

• 20 days

• 2.5 days

How can one observe the variability of Delta Cephei?

• By measuring its temperature.

• By tracking its brightness over several days.

• By using a radio telescope.

• By observing its color change.

What is the apparent magnitude range of Delta Cephei?

• 1.0 to 2.0

• 2.5 to 3.5

• 4.5 to 5.5

• 3.5 to 4.5