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349

Mount Wilson
Observatory

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349

Mount Wilson
Observatory

OLogy Series
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Less than 100 years ago, many scientists thought that our Milky Way galaxy was the entire universe. Then, in the 1920s, astronomers at California's Mt. Wilson Observatory forever changed this view of the universe. Using the world's largest telescope, Edwin Hubble and his team discovered the first galaxies beyond our own. Then they found that other galaxies were moving away from us, the first solid evidence that the universe is expanding.

The Hooker telescope at Mt. Wilson was the largest telescope in the world for 40 years. Its 100-inch mirror allowed the telescope to:

magnify objects more than smaller telescopes

shine more light than smaller telescopes

collect more light than smaller telescopes

Are you right?

Correct!

The larger a telescope's mirror, the more light it collects, and the more information it gathers from objects in space. The Hooker telescope gave scientists a clearer view into the universe, letting them study distant objects in detail that were once too faint to see.

Mt. Wilson Observatory is on a mountaintop outside of Los Angeles. Observatories are often placed on mountains because:

the cold air protects the telescopes

the view is clearer in the thin atmosphere

the telescopes are closer to space

Are you right?

Correct!

Light from distant objects is less distorted in the thin atmosphere, so telescopes can see them clearer. Mountaintops are also usually in remote areas, far from the air pollution and bright lights of large towns.

The Andromeda galaxy had never been seen before astronomers viewed it from Mt. Wilson Observatory.

Fact
or
Fiction
?

Fiction

Andromeda is visible without a telescope. But astronomers at Mt. Wilson were the first to recognize that it was a galaxy and not a spiral nebula, a cloud of dust and gas.

Edwin Hubble could tell that distant galaxies were moving away from us because they got smaller over time.

Fact
or
Fiction
?

Fiction

As galaxies move away, their light waves stretch out, like sound waves from a passing train. Hubble could measure the change in a galaxy's light waves to calculate its speed.

Location: Mount Wilson, San Gabriel Mountains, near Los Angeles, California
Founded: 1904 by George Ellery Hale
Claim to Fame: held the world's largest optical telescope for 40 years
Major Discoveries: sunspots, first galaxies, expansion of the universe
Cool Fact: The route to the top of Mt. Wilson was so steep and dusty, mules had to carry materials to build the observatory and its telescopes.

Image credits: © AMNH.