Curtis

Definition

Curtis refers to Heber Doust Curtis, an American astronomer who played a significant role in the early 20th-century debate about the nature of spiral nebulae. Curtis advocated for the idea that these nebulae were actually separate galaxies beyond the Milky Way, which was a foundational concept for understanding quasars and active galaxies.

5 Must Know Facts For Your Next Test

1. Heber Curtis participated in the Great Debate of 1920 against Harlow Shapley.
2. Curtis argued that spiral nebulae (now known as spiral galaxies) are independent galaxies outside our own Milky Way.
3. The resolution of this debate helped pave the way for Edwin Hubble's discoveries about the expanding universe.
4. Curtis used data from observations made at Lick Observatory to support his arguments.
5. His work laid important groundwork for the later discovery and study of quasars, extremely luminous active galactic nuclei.

Review Questions

• Who did Heber Curtis debate in the Great Debate of 1920?
• What was Curtis's main argument regarding spiral nebulae?
• How did Curtis's position influence future astronomical discoveries?

Related terms

Great Debate: A famous scientific debate between Heber Curtis and Harlow Shapley regarding the nature of spiral nebulae and the scale of the universe.

Edwin Hubble: An American astronomer whose observations confirmed that spiral nebulae are indeed separate galaxies, leading to the theory of an expanding universe.

Quasar: An extremely luminous active galactic nucleus, powered by a supermassive black hole at its center.