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Follow the historical journey of our understanding of the universe, from Immanuel Kant's concept of 'island universes' to the discovery of galaxies like our own. Learn about the Great Debate, Edwin Hubble's groundbreaking measurements, and the Hubble Deep Field. Explore different galaxy shapes, such as spiral, elliptical, and irregular galaxies, as well as significant celestial bodies like Andromeda Galaxy and the Large Magellanic Cloud. Discover how modern telescopes reveal billions of galaxies, and ponder mysteries like Olber's Paradox. Unravel the cosmic mysteries and vastness of the universe through this engaging exploration.
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1755: Philosopher Immanuel Kant proposes the universe is filled with great wheels of stars - ‘island universes’ 1845: William Parsons identifies ‘spiral nebulae’
The Great Debate (1920): Harlow Shapley argued that the "spiral nebulae" were nearby gas clouds, and that the Universe was composed of only one big Galaxy. Heber D. Curtis argued that the universe is composed of many galaxies like our own • 1924: Edwin Hubble measures distances to the brightest spiral • nebulae • Supergiant stars in the spiral nebulae are so faint that they must be • far outside the Milky Way
Spiral Galaxies,.... ...elliptical galaxies,... ... and irregular galaxies
Galaxy Clusters and Large Scale Structure Virgo Cluster
A few hundred billion galaxies can be seen with • current telescopes • Sloan digital sky survey has mapped out the distribution of • galaxies in certain parts of the sky
Olber’s Paradox (1826) Why is the night sky dark?
Olber’s Paradox (1926) Why is the night sky dark?
Olber’s Paradox Why is the night sky dark? • The universe has an edge • The stars and galaxies ‘run out’ at some distance from us • The universe has a beginning First suggested by Edgar Alllen Poe in 1848