Why does earth remain in its orbit?

Answer 1

because all the earths plates are constantly moving, this means while some plates are moving apart creating new land under the sea, other plates are sliding over one another, so one plate sinks down into the Earth's mantle.

~Underwater mountain chain

~Seafloor spreading takes place

~Old crust is being swallowed up into trenches

~The amount of crust always stays the same

Answer 2

Considered in terms of land-terrain, the earth's total surface-area does not in fact stay the same from period to period. With the constant battering of water and wind and other erosion factors, along with the contrasting build-up of new land through water recession and silt-deposits at river-mouths, among many other forces, there is a continual (if also typically small) adjustment in the overall magnitude of the Earth's surface from day to day.

Answer 3

Simple Answer:

Earth is pretty much the same size, volume and mass, has it has been since it was formed billions of years ago. (See the caveat at the end.)

There is very little mass added to Earth and very little mass has been lost from Earth for billions of years.

The volume of the Earth also changes very slowly as a result of cooling and solidification of the molten core. This is so small, there do not appear to be realistic estimates of this effect, but there are some ridges formed on other planets that are conjectured to be a consequence of the planet shrinking due to core solidification.

More Explanation:

The only way we get new mass now is particles that come to us from outer space. If we get hit by an asteroid, meteor or comment, then that add mass, but for the last few billion years there have not been many of these. Yes, there have been some very large explosions due to asteroids and comets, but even then these were only a few tons or even if they were a hundred times larger, the mass was still an insignificant amount compared to the mas of Earth. In total, about 15 million kilograms of meteoroids and space dust enter Earth's atmosphere each year and that is not even a trillionth of a percent of the mass of the Earth

The only two ways we lose mass now is by thermal escape (Jeans mechanism) and stripping off of the atmosphere, mostly by solar wind. We are normally protected from the solar wind by the Earth's magnetic field, but that has flipped around in the past probably hundreds or thousands of times and when that happens, the Earth can lose this protection for a few years or few centuries. Even then, the normal solar wind would not strip off much of the atmosphere in just a century. Currently, the largest loss of mas is the loss of the lightest atoms, hydrogen and helium.

While the average speed of a gas molecule is determined by temperature (KE=3/2kT), some atoms are moving much faster and some slower. The very tiny number of light atoms moving fast enough to escape from Earth do so at the highest altitudes of the atmosphere. This is the Jeans mechanism. The current rate of loss is about three kilograms of hydrogen and 50 grams of helium per second.

In the very early phases of the formation of the Earth, things were different. Constant bombardment by asteroids, meteorites and comets was adding mass all the time. Indeed, some theories say that most of the water on Earth was delivered by comets. After the first few hundred million years, this slowed down a lot and by now, almost no new mass is added by comets and meteorites.

Caveats:

(a) In the first few hundred million years there is reason to believe that there was a great change in the mass of the Earth do to a collision with another planet. There is something called the "Giant Impact Hypothesis" that says the Earth's moon was formed when another planet collided with Earth back then. In recent years, the newest data has actually further supported this idea and it is becoming accepted as a very likely explanation of how the Moon got here. Earth would have lost a great deal of mass, much of which is now the moon.

(b) In the next few billion years, the Sun will go through a red giant phase and strip the atmosphere and oceans from Earth and then, even more problems may occur.

(c) There may, of course, be some cataclysmic event such as another collision with a giant asteroid or Earth's magnetic field may decide to turn off or Earth my be fried by a giant solar flare or more. Those would bring unpredictable changes to Earth's mass.

Answer 4

It's the gravity of the sun vs gravity of the moon

the sun is farther away, the moon is very close.

the gravity of other planets might also have a significant effect.

Answer 5

Because of the tectonic plates in its core an because it is a basic solid, earth can't grow any bigger than it already is now. It is physically impossible.puuppy

Answer 6

While new sea floor is being made at mid ocean ridges, old sea floor is consumed at subduction zones. These two processes balances each other out.

Answer 7

Gravitatinal force of Sun keeps the earth in its orbit mainly.

Answer 8

Rocks don't grow.