the orbit theory (newly consructed)

The orbit theory has been formed largely by observation.The first part of the theory admits  that the universe is expanding as astronomists have observed.However since it is impossible to determine how fast or slow; it assumes that the universe is expanding slowly.So the earth is moving faster than the sun as it has been agreed.But still at a not a great velocity in terms of the differential between the sun and the earth.In other words, the earth is only moving slightly faster than the sun.Consequently there is not a great deal of force in this dimension.
The centrifugal force keeps the earth at an almost constant distance from the sun.This is the earth's orbit.However the differential force with the sun does pull it out of orbit slightly. The orbit is elliptical in nature.Pulling it out of orbit in the long side of the  ellipse  will pull it out at the pointed part, or the end, as well.The shape of the elliptical orbit will tend to correct itself over time.It is believed that the centrifugal force is stronger  than the differential velocity and be more important for a body the size of the earth.
This change in the orbit has caused  the change in temperature.This is easy to observe because when the earth moves from summer to winter the earth has moved through it's orbit.This change in temperature has been caused by the earth moving through it's elliptical orbit.There has been an increase in overall earth temperature over the last several decades but it is possible that the orbit will correct it's shape and return to it's old shape.This will bring world temperatures down again.