how come, earth moves app 20 deg along it's axis ,hence SUMMER & WINTERS?

Question

what gravitational force act on it?

I still havent got a satisfactory answer.
WHAT CAUSES THE 20 DEGREE TILT
ie. + & - 10degree , what force causes the poles to move forward and backward towards sun ? or in other words where the alternating tilting energy comes from?thanks upfront

OR AM I WRONG ALLTOGETHER,and the axis dose not swing every 6 month.

Answer 1

This is a tough one to answer without visual aids! Imagine a sphere (the Earth) orbiting another sphere (the Sun). The Earth, as well as orbiting the Sun, also spins on it's axis. If you imagine a basketball being spun on the ground, the point at the top of the ball looks like it's not moving. There's a similar point at the bottom of the ball. Connect these two non-moving points by a line and you have a line: that line is the rotation axis of the ball. The same applies to the Earth: the two non-moving points are the geographic north and south poles. Join these points together and you have the Earth's rotation axis.

If the rotation axis was perpendicular to the plane of the Earth's orbit around the sun, we would have no seasons. Instead, the rotation axis is tilted 23.5 degrees away from the perpendicular to the plane of our orbit. To think of it another way, the axis makes an angle of 90-23.5 = 66.5 degrees with the plane of our orbit.

Now, the seasons are created by the relationship between our orbit and the DIRECTION of the tilt of the rotation axis. Put simply, on a human timescale the axis always points in the same direction. If you could fly out to a star that was in just such a location that you could look straight down the rotation axis, you would be looking down the axis no matter where the Earth is in it's year-long trip around the Earth. So if you now could somehow go to the sun, and look at the Earth for a year as it goes around it's orbit, you'd see that sometimes the north pole end of the Earth's rotation axis sometimes points away from the Sun, and sometimes it points away from the Sun. When it points toward the sun, the sun will be higher in the sky at noon, the days are longer: it's summer in the northern hemisphere. Six months, and half an orbit later, the north pole is pointing away from the Sun, so the sun gets lower in the sky, the days are shorter: it's winter in the northern hemisphere. BUT, in the southern hemisphere, all this is reversed. When the north pole points toward the sun, the south pole points away, and vice versa.

Answer 2

1. The earth takes 1 year to orbit the sub
2. It roates as it goes. Each of these is a day
3. The axis of this rotation is about 20 dgrees
4. For half the year, the North is inclined towards to summer; more direct solar radiation; long days = summer
5. Gravity does not cause seaons, other than in that without gravity the earth would not orbit the sun at all. But in that case, we'd be discussing different problems.

Answer 3

As the earth moves around the sun the earth keeps the same tilt on its axis. During the summer the tilt is such that the northern hemisphere is closer to the sun than the southern hemisphere and you get more light. During the winter it is just the opposite.

There is no gravitational force involved.

Answer 4

Hold your hand vertically flat in front of you, with your thumb towards you and your little finger away. Now tilt your hand slightly to the right. Imagine thats the axis of the world. The UK is in the top half. That angle doesn't change. So......It's summer (for the UK) when the top half is tilted towards the sun, and it's winter when the bottom half is tilited away. The difference in temp is due to the distance the sun's rays have to travel.

Hope that makes sense and doesn't just sound crazy!!

Answer 5

Hi. The Earth is tilted on it's axis about 23.5 or so degrees. This means that the sun's angle changes day to day, month to month, season to season, as the Earth goes around the sun.

Answer 6

The seasons have nothing to do with gravity. It depends on the angle that the suns rays strike the earth. It is called INSOLATION.
The seasons are not dependant upon the earths distance from the sun either in fact, the UK is FURTHER from the sun in summer than in winter.

Answer 7

it is because the earth "wobbles" as it spins... like a top getting ready to fall down