Jongjin Park
Until the early 1920s, the universe was made up of galaxies. However, Edwin Hubble, who was a lawyer, was the first to discover the existence of galaxies other than our own at the Mount Wilson Observatory. Until then, galaxy and universe meant almost the same thing, and in this universe there were hundreds of billions of galaxies like the Milky Way to which we belong. With Hubble’s discovery of galaxies, the universe grew exponentially overnight. Stars twinkling in the night sky. However, I thought the faintest thing was a nebula of stars. Hubble discovered that it is extragalactic outside the Milky Way galaxy. Suddenly, the universe has grown hundreds of billions of times.
Telescopes that use visible light are affected by layers of the earth’s atmosphere. So he decided to place a telescope outside the atmosphere, and named the telescope, which began working in 1990, the Hubble Space Telescope in honor of Hubble. However, the operation of the Hubble Space Telescope involved astronomical costs, so nothing could be done recklessly. Additionally, as the money poured into the dock, many people began to be skeptical of the Hubble Space Telescope.
In such a circumstance, some mad astronomer proposed to search some empty space without reason, and it was dismissed as nonsense. There was no need to do useless things like 10 days of observation with such expensive equipment, but anyway, what the Hubble Space Telescope discovered was a huge world in a corner of the universe that I thought was nothing. In one corner of the universe, around 3,000 galaxies have been discovered in a pinhole. There are a number of galaxies that are not captured by normal optical telescopes due to obstructions in the Earth’s atmosphere. This is the Hubble Deep Field. It’s like looking through a microscope at what appears to be nothing and discovering that it is full of bacteria.
As a result of the findings so far, it is estimated that there are at least around 250 billion galaxies in our universe. The Milky Way, to which we belong, is one such galaxy, and our Milky Way galaxy alone contains about 400 billion stars. So, how many whole stars exist in the universe? Multiply two astronomical numbers. By our human standards, that distance and number is infinite. That is, the actual calculation itself is meaningless.
Now, the James Webb Space Telescope, launched on Christmas Day last year, is sending back more great pictures from space as it orbits the point where the Earth’s and the sun’s gravities are in balance. With the development of space telescopes, the universe is growing and more galaxies are being discovered throughout the universe. For reference, the Milky Way galaxy to which our Sun belongs is 100,000 light years across. In other words, it takes 100,000 years at the speed of light to get from one end of the Milky Way to the other.
There is a star called the sun at the edge of the Milky Way, one of the galaxies in the universe, and we live on earth, one of the eight planets that revolve around the sun. We think we are very important to this universe, but you are welcome. Looking at the scale of the solar system, looking only at the Milky Way galaxy, or moving further, when we imagine the entire universe, our existence on Earth is so weak that it does not reach even one coronavirus that afflict us now. (Author)
Jongjin Park
