confused science teachers

[burnzey boi]

the end of last month we had a quiz with our two science teachers, one of them were saying that the earth is on a tilt but goes in a straight circle, the other argued back that it goes in an eclipse. they were still fighting about it last time i saw them (quite funny actually!). i was wondering which one is true?

[VulcanRider]

From the US Naval Observatory website:
...The Earth's orbit is very close to being a perfect circle, but not quite. It is somewhat elliptical, which means that the distance between the Earth and the Sun varies over the course of the year. This effect is too weak to cause the seasons, but it might have some influence over their severity. The remainder of this page explains this possibilty.

Read all about it:
http://aa.usno.navy.mil/faq/docs/seasons_orbit.html

[Intrepid]

it's deffinaty elliptical, it alters the tempreature and lots of stuff, not by much, but it makes a difference.

[Bozos of Bones]

If teh altering of temperatures was caused by proximity to the Sun, then all places on earth would have equally starting seasons. It is no the case. The changing of teh seasons is caused by the Earth's tilted axis.

[Bungleau]

I agree partially, Bozos -- the differing seasons are caused by proximity to the sun, and because of the tilted axis, different parts of the world experience them at different times of the year. When it's winter, your part of the globe is tilted away from the sun. When it's summer, you're tilted toward it. The difference, although slight, is enough to give us the seasons.

If there were no tilt, then every part of the earth would maintain their season all year long. They wouldn't have the same season as other regions, but they wouldn't have any real variation. That's why the equatorial regions tend to remain warmer, and the polar regions tend to fluctuate more.

[Azred]

Quite right--our seasons are a result of the axis tilt of 23.5 degrees (.41 radians). The axis does precess, so in about 10,000 years the summer months we know now (July, August, etc) will be our winter months then.
All planets have an elliptical orbit, but the eccentricity of the Earth's orbit is very small, making our orbit nearly circular. Kepler proved this centuries ago.

[Ilander]

For the mathematically, physically, or scientifically minded, the Earth's orbital eccentricity is .0167

Note that the eccentricity of an orbit is defined as the ratio of the distance between the foci (center points of an ellipse, more or less) and the semimajor (longer) axis.

Note that if you actually draw an ellipse, to scale, with an eccentricity of .00167 , you would probably have a difficult time distinguishing it from a circle...in fact, only Neptune has a more circular orbit in our solar system.

On the subject of teachers...well, while they try, there are serious deficiencies in secondary education, and many corners are cut---and that's all I will say.