Planet Earth as we currently understand is :

• A planet which orbits around the Sun at the centre of our Solar System
• Rotates at a time interval we call a day
• Orbits around the sun approximately every 365.25 days
• Has a Moon which orbits around the Earth approximately every 29.53 days
  
• Is affected by gravitational forces interacting between the Sun, Moon, Planets and their moons within our Solar, plus influences from outside our solar system

In general, the Earth (including its atmosphere) is finite in regards to its total mass and composition of elements. Changes can occur when :

• Objects such as meteors enter our atmosphere or crash into our planet
• Energy from the sun (and maybe further afield) is converted into mass
• Energy (possibly in the form of radiation) or objects (space craft etc) escape the confines
  
• Elements within the confines of Earth are transformed by energy from one form to another (eg gas to liquid, on chemical compound to another, vegetation to flesh, flesh to vegetation and all the other marvels which contribute to what we call "life")

Gravitational forces move gases and liquids around the earth. Solids are moved in a variety of ways without interference by creatures including :

• Winds blowing dust
• Heavy rains moving soil
• Tides moving sand
• Ice floes
  
• Volcanoes
• Tornadoes, hurricanes, tsunamis, tidal waves resulting from natures activities

Creatures influence the movement of mass from one place to another in many ways including :

• Growing crops that take mass out of the soil, encapsulate water and gases and moved to another location
• Consuming vegetation (and flesh)
  
• Construction taking materials from one place to use in another
• Mining
• Burning fuels releasing them from their solid liquid or gaseous form into the atmosphere
• Migration by creatures of all kinds

Movements, however small, influence the Earth's balance.

Spinning objects are influenced by a change in mass or the positioning of mass (that's why we have our tyres balanced with counterweights).

Nature is marvellous! If there is movement of mass that changes the balance of the earth, gases and liquids flow from one position to another as a self correcting balance mechanism. The centre of balance may change, but at least the planet doesn't wobble out into outer space.

Ponder This  ...

How much does the movement of mass (eg people, other creatures, plants and raw and manufactured materials) affect the earth's balance and aspect in relation to its orbit around the sun. Do specific locations subsequently experience a change in the amount of energy received from the sun?