How the planets get their spherical shape

In summary, planets get their spherical shape from the force of gravity. This is due to the concept of hydrostatic equilibrium, where a celestial body will assume a shape that balances gravity and pressure. While some theories suggest planets formed from explosions, most current theories state that they condense out of stellar nebulas. An experiment with particles in space showed that they naturally form into a spheroid shape. The geometry of a sphere makes it the most stable shape against the force of gravity. However, factors like spin can cause slight deviations from a perfect sphere.
  • #1
lalu
2
0
how the planets get in spherical shape if the they are formed by a big explosion ?
 
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  • #2
Spheres of matter are the most stable shapes when pitted against the relentless force of gravity.

- Warren
 
  • #3
lalu said:
how the planets get in spherical shape if the they are formed by a big explosion ?

and they weren't formed by a big explosion :)

google accretion disk and solar system formation

cheers
Dave
 
  • #4
Planets get a spherical shape from gravity. Once a protoplanet (Baby Planet) reaches a certain radius, gravity crushes it into a spherical shape.
 
  • #5
The key concept you're looking for is hydrostatic equilibrium. If a celestial body is massive enough, its gravity will cause it to assume the optimal shape which balances gravity and pressure. This is a spheroid.
 
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  • #7
If I remember correctly, there was an experiment with particles in the space station (wasn't it salt?) and the particles formed together in a spheroid shape.

It is natural.
 
  • #8
I thought that planets needed an explosion (shockwave) to be formed out of nebulae... for example an explosion would allow a condensate (not like the boson ones) to be formed -as an origin of initial gravitational attraction- and thus the whole gas around would start "falling" into that and form the planet.
Due to the geometry of a sphere, it's the most favorable (energetically) shape to be formed... of course it's not a perfect sphere (for example the spin makes it more like an oval).
 

1. How did the planets form into a spherical shape?

The planets formed into a spherical shape due to the force of gravity. As dust and gas particles came together to form the planets, the force of gravity pulled them towards the center, creating a spherical shape.

2. Why are some planets perfectly spherical while others have an oblong shape?

The shape of a planet is determined by its rotation and speed of rotation. A faster rotation will cause the planet to bulge at the equator, resulting in an oblong shape. Additionally, the composition of the planet can also play a role in its shape.

3. Can a planet's spherical shape change over time?

Yes, a planet's shape can change over time due to external forces such as collisions with other objects or internal changes such as changes in mass or composition.

4. What role does the planet's size play in its spherical shape?

The size of a planet plays a significant role in its spherical shape. Smaller planets have less gravity, which may result in a more irregular shape. Larger planets have stronger gravity, pulling them into a more spherical shape.

5. Are there any other factors besides gravity that contribute to a planet's spherical shape?

Besides gravity, the planet's composition and rotation also play a role in its spherical shape. The internal structure and materials of a planet can determine its overall shape, while the speed and direction of rotation can affect its oblateness or bulging at the equator.

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