Why are things in space spherical?

The Sun, Mars, Jupiter, or even stars tens of billions of light-years away. They all have one thing in common: they’re round, but asteroids can come in all kinds of weird shapes. What is the reason that most objects in the universe are spherical?

If you are someone who loves, wonders and is interested in astronomy. There must have been a time when you looked up at the sky and asked: Why is it round?

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The answer is something familiar to us in our daily lives: “gravity.” Isaac Newton said that the greater the mass of an object, the greater its mass. 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 material that clumps together will try to fall as far as possible into the center until it finds a point where it can fall no further.

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“Gravity pulls all matter towards the center of gravity. Every bit of matter is trying to get as close as possible to the center of gravity,” said Bruno Merin, astronomer and head of ESA’s Science Information Centre.

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Gravity causes higher points to be pulled down. 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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However, 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 force. This is because it does not have enough mass to create enough gravity. To attract matter to come together to form a ball. This is why asteroids do not rotate.

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Scientists estimate that the diameter of the object that will form a sphere will be at least 400 kilometers.

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This number is for icy bodies only. If the object is made of something stronger such as stone or steel, the size must be greatly increased.

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Another interesting thing about gravity on stars is that it determines the height of objects on the planet’s surface.

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Examples on Earth are like Mount Everest. When the Earth’s tectonic plates move towards it, it will push this peak higher and higher, but it will also increase its weight. This weight is what makes gravity have a greater effect on it.

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The Earth will pull the mountains into the ground. Which again limits the height of Mount Everest, and this is a competition between the force of tectonic plates and Earth’s gravity.

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If our world were made entirely of oceans Mount Everest would undoubtedly sink into the centre. And make every point on Earth that has the same gravitational force balanced again. It becomes the ideal field

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But our world revolves. Centrifugal force causes the diameter to “bulge” at the equator.

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This makes our world not really round. It becomes like a circle with the equator rising slightly. Scientists have measured it and shown that this is indeed the case.

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Along the diameter at the equator (left to right) is 12,756 km, but the pole-to-pole diameter (diameter from pole to pole, top to bottom) is 12,714 km, and if the speed of the star’s rotation increases, its “bulge” increases.

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A clear example of this is Saturn, as its diameter at the equator is 120,500 km, but its diameter from pole to pole is 108,600 km, a difference of approximately 12,000 km.

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All of this is why why are most objects in the universe round? They are affected by something basic called gravity which we know every day.

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Researched and edited by Witit Borompichaichartkul

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