2006-09-10 01:44:30 · 5 answers · asked by amal m 1 in Science & Mathematics ➔ Earth Sciences & Geology
it has to do with the tilt of the earth on its axis...during september and october (fall in the northern hemisphere) the northern hemisphere is moving further from the sun and the southern hemisphere is getting closer. the first day of winter is the shortest of the year and the first day of summer the longest.
2006-09-10 01:50:51 · answer #1 · answered by dan 4 · 1⤊ 0⤋
The USA is positioned further away from the earth during the winter months creating shorter days. The cause of the seasons is that the rotation axis of the Earth is not perpendicular to its orbital plane, but currently makes an angle of about 23.44° (called the "obliquity of the ecliptic"), and that the axis keeps its orientation with respect to inertial space. As a consequence, for half a year (from around 20 March to 22 September) the northern hemisphere tips to the Sun, with the maximum around 21 June, while for the other half year the southern hemisphere has this honour, with the maximum around 21 December. The two moments when the inclination of Earth's rotation axis has maximum effect are the solstices.
2006-09-10 08:52:24 · answer #2 · answered by Anonymous · 1⤊ 1⤋
The earth is like a ball with two pins stuck in opposite sides of it, one pin is the north pole and one the south. The line between these pins (poles) isn't straight up but on an angle. This angle stays the same as the earth moves around the sun during the year. So for half the year the northern half of the earth is pointed towards the sun (pointing "directly" towards it mid-summer) and the other half of the year it points away ("directly" in mid-winter) and the same is true of the southern half. When you are towards the sun, you get to see it for longer so have longer days, when you are away from it you get shorter days
If you are really near the pole that is angled toward the sun as it spins, you will be able to see the sun all day, if you are at the other pole, you will be in darkness all day.
As the poles swap between which points at the sun and which points away they reach a point where they don't point away from or towards the sun, (autumn and spring) at these times you get equally long days and nights.
2006-09-10 09:32:02 · answer #3 · answered by qatpoo 2 · 0⤊ 0⤋
Because the rotational axis of the earth tilts 23.5 degrees from the ecliptic and always points the same direction (i.e. toward Polaris, the north star) a person standing at a position 23.5 degrees north of the equator will see the sun straight up at noon on the summer solstice (about June 21). As the earth revolves about the sun the tilt (still pointed to the north star) of the earth puts more and more of the earth in the way of the sun, so that it SEEMS to rise less and less each day above the horizon at noon, until on about December 21 (the winter solstice) it's highest point is much lower, but directly above someone standing at 23.5 degrees south latitude (who will see it directly above his or her head).
2006-09-10 12:04:52 · answer #4 · answered by David A 5 · 0⤊ 0⤋
The earth's rotational axis is slanted 17degrees from the elliptical plane of its orbit around the sun. From the vernal
equinox to the autumnal equinox, the slant is towards the
sun in the northern hemisphere, thus exposing the north
to a longer day. Conversely in the other half of the year.
Convince yourself with a ball and flashlight in a dark room.
I did that when I was 13.
2006-09-10 08:53:43 · answer #5 · answered by albert 5 · 0⤊ 0⤋