How would the solstices and equinoxes change if the earth's orbit were circular instead of elliptical. explain how a circular orbit would effect seasonal changes?

Answer 1

Seasons, solstices and equinoxes are related to the angular tilt of the Earth's axis of rotation as compared to the ecliptic, which is the plane of the Earth's orbit. They have nothing to do with the elliptical orbit of the Earth.

The Earth's orbit is an ellipse, but it is very nearly circular; the eccentricity is only about 3%. If the Earth's orbit were perfectly circular, we probably wouldn't notice any difference.

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The Solstice or equinox would not change. These are related to the tilt of earth.

Earth is at its closest to our star during December and January, at about 91 million miles, and farthest during June and July at 93 Million miles.

While a perfect circular orbit would not effect your questions it would also be very unlikely that it would ever occur.

As a thought experiment, If there were only Earth and our star, as each orbited while Earth is small in comparison would still pull at the star a small amount.

The Star and earth would be orbiting each other.

Given that objects have mass,

Given mass is attracted to mass,

I do not know of a method other than computer modeling,

to map the orbital patten of our star moving with all of the planets influence.

This is why I do not think it could ever be possible to have a perfect circular orbit.

It would be very complex

Answer 2

A lot would depend on "How much?" additional tilt and eccentricity of the orbit. The Earth's axis of rotation is currently 23 and change degrees "tilted" to the ecliptic, the plane of the Earth's orbit around the Sun. If the angle increased to 30 degrees, it probably wouldn't make all THAT much difference; the temperate zones would be somewhat expanded while the polar weather would become a little more extreme.

Earth's orbit around the Sun is an ellipse, but with only about 3% eccentricity; it's nearly circular. The Earth is at perihelion - closest to the Sun - on January 4 (plus or minus a day, depending on the cycle of leap years) and is at aphelion around July 2. The difference in the distance is only about a million miles or so. If the Earth's orbit were made more eccentric, swinging closer to the sun and farther away, it could easily render the Earth uninhabitable. Over the course of the last 3 million years or so, we've had wild swings between warm weather and ice ages. (We're currently near the peak of one of the warm periods.) Scientists studying human DNA and evolution have calculated that during the last ice age (with a push from a whopping HUGE volcanic eruption!) the human population was down to perhaps 100 breeding pairs of humans. We very nearly became extinct, 70,000 years ago.

An extended winter caused by moving 20 or so million miles away from the Sun could easily finish the job.

Answer 3

Without doing any complex calculations, we can say that the dates of any given equinox

or solstice might move a day one way or another, but the positions of these points in the

sky wouldn't change at all.

Answer 4

While the Earth's orbit is not exactly circular, it's so close that you can't tell it from a circle by eye. Making it a perfect circle would have only a very small impact on the seasons (the fact that the Earth is actually closest to the Sun in early January should give those who live in the Northern hemisphere some idea of how little the shape of the orbit matters).