Why are all planets round?
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Why are all planets round?
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You asked us, "Why are all planets round?"

In a nutshell? Gravity.

We all know what gravity is, right?

It's what makes apples tumble from trees and people fall flat on their faces, and,
well, the bigger an object is, the stronger its gravitational field.

Planets are pretty big, so gravity acts on them as a strong force, pulling everything together towards their center and the resulting shape is a sphere.

Now, planets aren't actually perfectly round - they've got a bit of what you might call a spare tire.

You see, planets spin around their axes and the force generated by the spinning works against gravity and causes a planet to bulge out at its equator.

Join the club, planets.

Source URL: https://www.tweentribune.com/article/tween78/why-are-all-planets-round/

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CRITICAL THINKING QUESTION
Why aren't planets perfectly round?

• sebastianr-6-bar
12/03/2015 - 11:39 p.m.

Planets are perfectly round because of the gravitational pull on the planet which results in a sphere. If the gravitational pull on planets wasn't as strong would they still be a sphere or would their shape start to deform?

12/04/2015 - 12:15 a.m.

Though it may seem like it at first, planets are not perfectly round. Because planets spin on an axis, the force created by spinning works against the gravity and "causes a planet to bulge out at its equator."
I found this article interesting. Though I already knew the answer to this question, I felt like it was explained in a way that made it easier for people who don't know why planets are round understand at least a little bit.

• carlym-4-bar
12/04/2015 - 12:46 a.m.

Planets aren't perfectly round because of the way that the plants spin on its axis. It creates bulges by the equator. It says, "You see, planets spin around their axes and the force generated by the spinning works against gravity and causes a planet to bulge out at its equator." This quote explains why planets aren't perfectly round.
I enjoyed this article because I didn't know why planets were round.

• josiec-1-bar
12/04/2015 - 12:46 a.m.

Planets are not perfectly round according to the article because, " They have got a little bit of what you call a spare tire, ... planets spin around their axes causing the planet to bulge out at it's equator." This is an example of why planets are not all perfectly round because they have a bulge at the equator. My opinion is that gravity will always have a force on solid objects because of the law of gravity that affects us every day and it is also why we are not floating into space.

• jilliand-3-bar
12/04/2015 - 01:06 a.m.

Planets are not perfectly round because they spin around their axes and that force works against gravity making it uneven at the equator. In paragraph seven, the text says, "You see, planets spin around their axes and the force generated by the spinning works against gravity and causes a planet to bulge at its equator." Since the planet is wider around its equator, it is not a perfectly round. I thought this article was interesting because I did not know that the spinning force of the planet was stronger than gravity.

• oliviam-6-bar
12/04/2015 - 01:36 a.m.

The main reason why planets are not perfectly round is that "their axes and the force generated by the spinning works against gravity and causes a planet to bulge out at its equator."(p. 7)

Since the force of gravity is not strong enough to resist the force of spin, the planets end up getting smushed at the equator.

• samanthao-ver
12/04/2015 - 10:12 a.m.

That is a good question, why are planets round? Well the gravity is pushing everything toward the center so that is what is making it a sphere.

• mathiasl-2-bar
12/04/2015 - 11:44 a.m.

It says in the article that the planets bulge out at its equator which makes the not perfectly round. then it says that the planets have a stronger gravitational pull which makes the planets in a sphere

• roberto-ver
12/04/2015 - 01:10 p.m.

That is a very good question, why all planets are round. No one really knows why. Most of the planets were created hundreds of years ago. I think that is the biggest mystery in the world.

• maxx-ver
12/04/2015 - 01:30 p.m.

I was surprised that all planets aren't completely spherical