Curtis, Shapley and Hubble. Show that peoples views and ideas about space have changed over time Consider how we know so much about space when it.

The Great Debate

The Great DebateCurtis, Shapley and Hubble1ObjectivesShow that peoples views and ideas about space have changed over time

Consider how we know so much about space when it is so big and things are so far away?

Explain how/why differing scientific views become an accepted scientific theory.2

With the knowledge on these slides..Answer the questions on the worksheet in as much detail as possible3The Greeks (~ 10AD) The Earth is at the Centre of the Universe; Sun, moon, planets and stars orbit the Earth

4Copernicus (1543)Sun is at the centre of the Universe

He had observed the movement ofthe planets - this backed up histheory! BUT the Church disagreedThey believed that God must have put the Earth at the centre

I dont think so!!!5Galileo Galilei (1610)Not everything orbits the Earth

He observed 4 of Jupiters moons and he noticed that they orbited around Jupiter

He confirmed Copernicus view: not everything had to orbit the Earth!

6Kepler (1618)Observed all the planets and developed laws to confirm that they all follow circular orbits

This too agreed with Copernicus theory

7Newton (1686)

He developed the ideas about gravitation that we use today

He explained the positions and the orbits of the planets8Why have our views about the Earth in space changed?9Why have our views about the Earth in space changed?The development and technological advancement of the telescopeGreat TelescopesYou can see heaven from here

The Hubble Telescope (seen from the space shuttle Discovery)

20th Century: Curtis v ShapleyThe Great DebateWho were Heber Curtis and Harlow Shapley?What were there differing views?When did this debate happen?Which view was correct?And what role did Edwin Hubble play in all this?

The Great Debate: 26 April 1920The basic issue under debate was whether:

the distant stars seen from Earth were relatively small and were part of our own Milky Way galaxy OR they were separate galaxies but appeared to be so small because they are so far away!What Harlow Shapley thoughtIn the Great Debate Shapley said that the Sun was not at the centre of the Milky Way galaxy, and thought that the Milky Way galaxy contained the entire Universe.What Heber D Curtis thoughtIn the Great Debate Curtis argued that some of the small stars seen from Earth were in fact distant galaxies so far away that they were outside the Milky Way

Hubbles roleHe settled the argument !

HOW?Hubbles roleHe settled the argument !

He identified stars in a separate galaxy (the Andromeda galaxy) and showed that the distance to this galaxy was far beyond the edge of the Milky Way galaxy

He used a huge 2.5m land based telescope on Mount Wilson (USA) to see this far! In the 1920s this was the largest telescope in the world (1oo inch)Mount Wilson telescope

18Hubble space telescope (1990)2.4-meter (7.9ft) mirror!

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