What is a Circular Orbit?

@GlassAxe- @Geosynchronous orbit and geostationary orbit are orbits that rotate around the Earth at the same speed as the Earth turns. A geosynchronous orbit can move in oscillations relative to the north and south directions, but matches the speed of the Earth's spin. For example, a satellite that is in a circular geosynchronous orbit about the earth would appear to move north and south to an observer standing stationary, but would not appear to move east or west.

A geostationary orbit is a type of geosynchronous orbit, but is completely stationary to the observer. A satellite that follows a geostationary orbit would appear completely stationary to a stationary observer. This type of satellite would essentially hover over the same spot on the earth, moving directly in stride with the planet.

Now the question is how this relates to real life. A communication satellite would use a geostationary orbit because it would allow the antennae on the ground to simply point at the satellite while remaining stationary. If communication satellites were geosynchronous but not geostationary, ground based antennae would need to shift from pointing northward to pointing southward throughout the day. This would lead to a requirement for powered antennae that would significantly increase the cost for our phone bills.

What is geosynchronous orbit?

@georgesplane- The simplistic answer as to why the Earth's orbit is elliptical is twofold. The first reason is because of the gravitational pull of other planets and the moon. The second reason is because of the past bombardment of debris that created the planet and that occasionally still bombard the planet

The reason that the Earth's orbit is so circular really has to do with chance. By chance, all of the planetismal parts that collided to create the Earth averaged together to create a nearly circular orbit. This chance makes the circular orbit that we enjoy on Earth very rare. For this reason, it is hard to find other planets in other solar systems that could possibly support life. Not only do the space collisions that make up a planet need to average to create a circular orbit; the planet must also be a distance from the sun that falls within a biological sweet spot. This sweet spot is the distance where the temperature not too hot or cold for water to form and life to thrive.

If the Earth's orbit were not nearly as circular as it were, the seasons would be much more extreme, making it very hard for complex life forms to adapt and survive. An elliptical orbit would lead to hotter summers and colder winters.

Finally, what the article stated and what you have been taught regarding the seasons are both right. The shape of a planets orbit along with the tilt of the planet dictates the seasons. The varied tilt of the Earth combined with the ellipse of the Earth’s orbit creates the seasons. For example, a planet with a stationary tilt and a circular orbit would have regional climates rather than seasons.

Why is the Earth's orbit elliptical? Why is the earth's orbit the most circular orbit in our solar system? Is it rare to have a circular orbit? What would happen if the earth's orbit was not as circular? In other words, why would the earth be less habitable if it had a more elliptical orbit?

The article stated that the eccentricity of the Earth's orbit plays is responsible for the seasons, but I was taught that the tilt of the earth is responsible for the seasons. Which is right? I thought this article was very informative, but I would like to understand the importance of a planet's orbit and the properties of a circular orbit in better detail. I am not very well versed in physics or calculus, so please respond in somewhat layperson's terms. Thank you wiseGEEKS!