Hi I’m Harlow Shapley..

..and I’m Heber Curtis..

..and we are

ASTRONOMERS..and we are

ASTRONOMERS!

In the 1920’s astronomers has identified faint, fuzzy objects through their telescopes which they called nebulae. Some of these objects looked spiral-shaped, some were just blobs. This started what became known as the Great Debate, What were they? Where were they? Enter Shapley and Curtis…….

Shapley’s Argument…..Based upon my work at the Mount Wilson Observatory I firmly believe that:1. The Universe is one gigantic galaxy

100,000 parsecs across.2. The Sun and Solar System are far from

the centre of the galaxy.3. Nebulae are huge clouds of gas and dust

and are actually part of the Milky Way galaxy.

Curtis’ Argument…..Based upon my work at the Allegheny Observatory I firmly believe that:1. The Universe is made up of many

galaxies.2. Our galaxy is smaller than Shapley

suggests (only 10,000 pc).3. The Spiral Nebulae are other very

distant galaxies, completely separate from the Milky Way.

The Great Debate…I’m right.

No, I’m right.

No, I’m right.

No, I’m right.

No, I’m right.

No, I’m right.

Actually, in a way, they’re both right!

Edwin Hubble!Edwin Hubble! Wow!

Yes, that’s right it’s me, Edwin Hubble the founder of Observational Cosmology! My observations of Cepheid variable stars in the Andromeda Galaxy lead me to the following conclusions:1. Shapley was right that the Solar System is far from the centre of our

Galaxy but Curtis was right that there are many galaxies.2. Curtis was also right about spiral nebulae, my observations showed that

they are very far away.

..and we are

ASTRONOMERS

Thanks Edwin. We realise now that we were both right and your excellent observational skills

and pursuit of the scientific method have shamed us both into calling a truce, putting

aside our differences and becoming friends. As they say ‘per ardua ad astra’! Cheerio!