why is the earth round?

Answer 1

Because gravity sucks.

Really, I'm not joking.

Gravity manifests as a centropic force that attracts all objects with mass toward the center of mass.

This means that tiny particles have an attraction to each other and will clump together in free space. When enough particles and molecules clump together from this attraction, they eventually form larger masses that we call planets. Because gravity pulls or "sucks" matter toward the center of this mass, the shape inevitably becomes spherical.

("Spherical" is the correct three-dimensional term for "round" like a ball.)

Einstein's theories of gravity have been proven correct; specifically, that gravity "warps" the fabric of space / time.

In this respect, we can say that large massive bodies become spherical because of the "dent" in space that body occupies.

You can visualize this as a curved circular trough...

Imagine a roulette table... On the edge of the table is a trough for the roulette ball to spin around in. Even if the ball was not perfectly spherical when you initially spun it, after enough time, the friction of the trough would gradually round-off any eccentric irregularities.

In a very real sense, this is exactly what gravity does in space over vast stretches of time.

Now, it is important to point out that the Earth is not perfectly round. There are slight distortions of the Earth's spherical shape because of the rotational ( gyroscopic) forces on it as it spins at roughly 25 thousand miles per hour. There are also tectonic forces within the mantle and geological forces in the core that affect the overall "roundness." of our planet.

Obviously we have mountains and valleys and plains and moving oceans, so at no time can the planet be perfectly spherical. However, the shape is almost perfectly spherical because gravity attracts toward central mass and warps space / time into a conforming trough that "rounds" all massive bodies in space.

Now here is the really fascinating part!

We do not know exactly what gravity is or exactly what causes "mass." The LCH ( Large Hadron Collider) in Cern is scheduled to be operational this year! That is exciting news for us armchair physicists! One of the first orders of business for this amazing new apparatus is to check for "Gravitons" and the "Higgs Boson" the theoretical particle that transmits gravitational force. When they discover something, you can bet it will make science history. We are on the threshold of an exciting new era in physics!

Or not...

It may be that they confirm nothing and have to start theorizing all over from scratch. Either way, we will prove, partially prove or disprove modern theories of physics very soon!

In the meantime, no one can say with certainty exactly what gravity is. We do know how it manifests though. We DO understand the laws of gravity very well; so well that we can send satellites into orbit and men to the moon. But until we can confirm or disprove modern theories, all we can say for certain is, "Big planets are usually spherical because Gravity sucks!"

Answer 2

Its due to the mass. Once the mass of an object in space reaches a certain amount, the gravity is enough to deform solid structures (rock will bend and break). This will happen until all the holes in the rock are filled with rock from on top. All matter will be pulled toward the center. The issue with earth being slightly non-spherical is due to outward momentum caused by the rotation. So the equator (part of earth moving fastest) is actually a bit thicker because gravity has some more opposition there.

Answer 3

The Earth is not round! If the Earth were round it would be a two dimensional area. The Earth is a three dimensional volume. The correct question is: "Why is the Earth a sphere?", and the correct answer is that the Earth is not a sphere it is an oblate spheroid, since it is flattened at the poles and it bulges at the equator.

Answer 4

earth was , just like all planets, cosmic dust. due to the high gravitional force of sun, that dust starts to whirl, spin and turn around the sun.heavy metals felt down to the core and by time due to speed of rotation. earth has become round. in addition to the facto of internal gravity produced by the heavy inner core of earth moving in the liquid outer core.

Answer 5

The weak gravity force causes mass to accrete in an outward-gathering manner. All planets are thus spherical over time, during their birth, coalesced from less dense matter possessing weaker gravitational attraction than the parent body.

But why the sky is blue I'll never know. :)

Answer 6

gravity pulls all the different materials and elements in our earth together into a ball and holds it like that.

Answer 7

A real question. May I add to it.

Why is milk white ?

Answer 8

because all the heavenly bodies are like this.