The sun, Mars, Jupiter, or even stars that are tens of billions of light years away. They all have one thing in common: they’re round. But asteroids can come in all sorts of strange shapes. So what is the reason that most objects in the universe are spherical?
If you are a person who likes, wonders, and is interested in astronomy. There must have been a time when I looked up at the sky and asked, Why is it round?
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The answer is something we are familiar with in our daily lives: ‘gravity’. Isaac Newton said that the more mass an object has, the more The force of gravity will also increase.
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Gravity is what makes most objects in the universe round. Since the Big Bang 13.8 billion years ago, this force has caused all particles to gradually coalesce into tiny globules.
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Then it increased in size. The matter that gathers together will try to fall as much as possible into the center until they find a point where they can’t fall any further.
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“Gravity pulls all matter towards the center of gravity,” said Brono Merin, astronomer and head of the European Space Agency’s Center for Science Information. “Every part of matter tries to get as close as possible to the center of gravity.”
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Gravity causes higher points to be pulled down. and points below it are filled in. Finally, a shape in which all points of gravity are equally balanced is a ‘sphere’, a shape in which all points on the surface are the same distance from the center.
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Even so, it is a force that can create stars. But it is a relatively weak force.
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Many small objects in space escape this gravitational pull. This is because it doesn’t have enough mass to create enough gravity. To attract matter to come together to form a sphere. This is the reason why asteroids are not round.
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Scientists estimate that the diameter of the object to form a sphere would be at least 400 kilometers.
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This number is for icy objects only. If the object is made of something stronger such as stone or steel, the size will have to be greatly increased.
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Another interesting thing about gravity on stars is that it determines the height of things on the planet’s surface.
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Examples on Earth such as Mount Everest When the earth’s tectonic plates move towards It will push this peak higher and higher, but it will also increase its weight. It is this weight that makes gravity have a greater effect on it.
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The earth will pull the mountains down into the earth. which again limits the height of Everest This is a competition between the strength of the tectonic plates and the Earth’s gravity.
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If our world was made entirely of oceans Everest will no doubt sink into the center. and make every point on the earth have the same gravitational force in balance again. becomes a perfect sphere
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But our world spins. Centrifugal force causes the diameter at the equator to ‘bulge’ out.
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This makes our world not truly round. It becomes like a circle with the equator slightly raised. Scientists have measured it and shown that this is indeed the case.
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by the length of the diameter at the equator (from left to right) is equal to 12,756 kilometers, but the diameter from pole to pole (pole-to-pole diameter, top to bottom) is equal to 12,714 kilometers, and if the faster the star spins, the more it will ‘bulge’ out.
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A clear example is Saturn. It has a diameter of 120,500 km at the equator, but its diameter from pole to pole is 108,600 km, a difference of nearly 12,000 km.
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All of this is the reason that Why are most objects in the universe round? They are affected by a fundamental thing called gravity that we are familiar with every day.
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Searched and edited by Witit Borompichaichartkul
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