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Nov 13th 2019

Celebrating Edwin Hubble, Legendary Astronomer

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Edwin Hubble was born in Missouri on Nov. 20, 1889. He served in both World Wars and earned a doctorate in astronomy from the University of Chicago. He’s most famous for his research at the Mount Wilson Observatory in California that revolutionized the field of astrophysics.

His work as an astronomer provides the foundation for modern astronomy, and his legacy continues to grow as today’s scientists use the telescope that was named in his honor to make new discoveries about the universe.

Edwin Hubble’s Biggest Contributions

Hubble’s research confirmed an expanding universe, which provided the foundation for the Big Bang Theory. Using Mount Wilson’s Hooker telescope — the largest telescope available at the time — he observed space and found evidence to back his theories.

Galaxies

Hubble proved that other galaxies existed outside of our home in the Milky Way by taking photos and comparing the brightness of stars, according to Biography.com. He estimated the size of Milky Way. (There had been no idea of its size at the time).

Hubble estimated that the Andromeda “Nebula” was nearly 900,000 light-years away from the Milky Way, and therefore was its own galaxy. It has since been renamed the Andromeda Galaxy and proven to be 2.48 million light-years away.

Hubble Sequence

He is also famous for creating the Hubble sequence, a classification system for galaxies that has been used since 1926. Hubble’s sequence sorts and characterizes or classifies galaxies by their shape. Although it is a basic classification system, it’s still used almost a century later.

Redshift

According to Space.com, Hubble was the first astronomer to describe the “redshift” phenomenon and tie it to an expanding universe. When an object such as a star moves away from us, its wavelengths get longer, so we perceive the light as becoming red. As it moves toward us, the light appears to become bluer, as its wavelengths get shorter and correspond with the blue end of the rainbow (or, in astronomy speak, the “visible light spectrum”).

Space.com explains that wavelengths of light can stretch or crunch together depending on the relative position of objects. Astronomers can use redshift to measure the speed and distance of objects in space.

Hubble observed that galaxies were moving away, with larger redshifts for the most distant galaxies. He demonstrated that the farther a galaxy, the faster it was moving away from Earth. It ultimately proved that the universe is expanding. Today’s astronomers regularly use modern telescopes to study redshift, but during Hubble’s time, it was revolutionary.

According to Biography.com, in 1929, Hubble and his colleague Milton Humason published research that showed that a galaxy’s redshift is proportionate to its distance from another galaxy.

Big Bang Theory Support

Their research supported the theory that galaxies come from a central point of origin. Scientists have cited Hubble and Humason’s work as evidence that helps prove the Big Bang Theory — one of the most popular theories on the universe’s origin, which was first suggested by Georges Lemaître in 1927, according to Biography.com.

Hubble Space Telescope

It’s fitting that the most powerful telescope in the sky is named after Edwin Hubble. According to NASA, the Hubble Telescope was the first major optical telescope to be placed in space. The telescope’s images of deep space confirm what Edwin Hubble’s research suggested about galaxies and the universe, and provide images that give physical evidence for theoretical concepts. Scientists have used the Hubble Telescope to observe distant stars and galaxies and the planets in our solar system.

When the Hubble Telescope deployed in April 1990, it was the most significant advancement in astronomy since Galileo’s telescope.

Hubble’s Legacy

Astronomy has changed since Hubble’s glory days, but his contributions are still at the core. In 2011, astronomers used redshift to verify Einstein’s theory of general relativity. In 2018, the International Astronomical Union renamed Hubble’s law as the Hubble–Lemaître law, according to EarthSky.

According to Live Science, 90 years after Hubble and his colleagues demonstrated that other galaxies are speeding away from the Milky Way, scientists are still working to better understand the expansion of the universe. In 2018, astronomers used the Hubble Telescope to observe that the expansion is even faster than expected. The same researchers also found that more distant reaches of the universe seem to be expanding less quickly than closer galaxies. Scientists are now trying to understand this relative slowdown, which could be caused by dark energy, dark matter, or another phenomenon that we haven’t discovered yet.

Soon, astronomers will have a new tool for studying our ever-expanding universe. The Hubble Telescope will soon be joined by an even more powerful research tool, the James Webb Space Telescope. But as we move on to the next generation of astronomical discoveries, Edwin Hubble will remain a legend in the field.

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