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The Sound of Science - 'How many galaxies are in the universe?'


The Sound of Science - 'How many galaxies are in the universe?'

Welcome to The Sound of Science from WNIJ and NIU STEAM. It’s a weekly series explaining important STEM concepts. Today’s hosts are Jeremy Benson and Newt Likier.

We have a question here from Ohm, who asks “How many galaxies are in the universe?”

The answer to this question starts with an astronomer named Edwin Hubble. You’ve probably heard of the Hubble Telescope, which until recently was the largest space-based telescope in orbit around the Earth.

Edwin Hubble was the first person to discover galaxies outside our own. He also discovered that all the galaxies he detected were moving away from one another, providing evidence that the visible universe is expanding.

Before Hubble, many of what we now call galaxies were thought to be clouds of interstellar gas and dust known as nebulae. Hubble identified a method to determine how far away these objects were, and in doing so, he realized that some of these objects were much too far away to be part of our own Milky Way galaxy. Those distant objects turned out to be entire galaxies of their own.

This was huge for the world of astronomy. Hubble had basically changed the way everyone saw the universe. After his discovery, a lot of people had Ohm’s question too.

There are so many galaxies out there that getting an exact count would be impossible. Instead, scientists use math to estimate the total number. The most common method is to count the number of galaxies we can find in a small section of the sky. Then we can use that info to extrapolate an estimated amount for the entire sky. Using this method, astronomers currently estimate the total number to be around 100 million.

However, NASA just launched the James Webb space telescope in December of 2021. The Webb space telescope is much more advanced than the Hubble. With the Webb telescope’s improved views, some astronomers expect that estimate may double as we begin to detect even fainter galaxies.

Thank you for your question, Ohm!

This has been the Sound of Science on WNIJ. Where you learn something new every day.

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