how does earth rotates? can anybody prove this? also whats the shape of earth? prove this too?

Question

the question is: prove that whether earth rotates or not?
also prove that the shape of earth is sphere?

Answer 1

It fell to French physicist Leon Foucault to offer indisputable proof of Earth's rotation. He did so in a novel manner. Realizing that the free fall of a weight was difficult to measure accurately, he began experimenting in his cellar using a 2-meter pendulum with a 5-kilogram bob.



On February 3, 1851 he presented his experiment to his colleagues, and Prince Louis Bonaparte asked him to give a public demonstration. The scene could hardly have been more dramatic. Foucault set up a pendulum more than 60 meters long hanging from the domed ceiling of the Pantheon in Paris. The pendulum never retraced its path as each swing deviated to the right, which meant that the floor of the Pantheon was moving! Foucault had at last provided the first dynamical proof of Earth's rotation. Foucault pendulums now hold a place of honor in science museums worldwide.



The interest in falling bodies did not end with Foucault. In 1902 E. H. Hall at Harvard University conducted a careful experiment in which 948 balls were dropped 23 meters. Using Gauss's theory, he predicted an eastward deviation of 1.8 millimeters. His experimental result was 1.5 millimeters, but he also observed a southward deviation of 0.05 millimeters, which is not expected from Gauss's theory.



As late as the 1940s some authors regarded the southward deviation as a mystery, but it is explicable as part of the Coriolis force. The basic equation predicts only an eastward deviation, but inclusion of further mathematical terms reveals that a small southward deviation should occur. What is amazing is that Robert Hooke expected it more than 300 years ago. High school students seeking a challenging science fair project need look no further!

http://www.lawrencehallofscience.org/gems/rotates.html



Now that we have access to space, the easiest way to prove the Earth is spherical is to leave it and view it from a distance. Astronauts and space probes have done just that. Every picture of Earth ever taken shows only a circular shape, and the only geometric solid which looks like a circle from any direction is a sphere.



One of the oldest proofs of the Earth's shape, however, can be seen from the ground and occurs during every lunar eclipse. The geometry of a lunar eclipse has been known since ancient Greece. When a full Moon occurs in the plane of Earth's orbit, the Moon slowly moves through Earth's shadow. Every time that shadow is seen, its edge is round. Once again, the only solid that always projects a round shadow is a sphere.

http://www.physlink.com/Education/AskExperts/ae535.cfm

Answer 2

It is all about the reference frame. One can mathematically define the rotation of the solar system and even the movement of entire universe around the earth. It could even be defined mathematically assuming that your personal computer was the center of the universe.



In fact, this is exactly what some European scientists did when the church was pushing the theory that the earth was the center of the universe and mankind was the center of creation. Turns out that the math is very VERY complicated. The math describing the motion of the planets in our solar system is tremendously more straight forward if you select our sun as the center of rotation.



Regarding the shape of the earth, an ancient Egyptian scientist demonstrated that the earth was round and did a measurement that was pretty darn close to the actual diameter 2000+ years ago. Since then, we have all sorts of evidence. You can see the shape of the earth's shadow on the moon during a lunar eclipse. You can sail or fly all the way around, you can send satellites into orbit and you can go into orbit and look back at earth. Technically, the earth is an oblate spheriod.

Answer 3

If you spend an hour under the stars, you'll se that they have moved with your own eyes. Watch the Sun rise or set: you're actually seeing the Earth rotate. Point even a small telescope at a star and watch for a few minutes: the star will move out of the field of view very quickly.



The ancient Greeks figured out that te Earth was round from observing the shadows cast by objects in different locations. In fact, Eratosthanes measured the diameter of the Earth very accurately in the 2nd century BCE. The exact shape of the Earth is an oblate spheroid: a sphere slightly flattened at the poles. This was only discovered when we began to lauch Earth satellites in the 1950s and 1960s.

Answer 4

Proving that the Earth rotates... well, movement of the Sun in the sky is strong evidence, though before Galileo found the moons of Jupiter, a lot of people took that to be the Sun moving around the centred Earth. I guess you can say it was 100% 'proved' when we put satellites in space which observed the Earth rotating, but people knew much earlier.



The Earth is an oblate ellipsoid - a squashed sphere. It's around 1/300th thicker at the equator than from pole to pole. The round shape can be proved by looking at the shadow of the Earth on the Moon, and, of course, it can be seen from space.

Answer 5

Sunrise! Sunset!



We can see the sky rotating above us, indicating that the earth is rotating below the sky. The stars and other bodies can be seen to trace a route across the sky, all of which circles around two celestial poles.



We can measure objects, such as the sun or stars, at different parts of the earth simultaneously, thereby showing the curvature of the earth. For example, at midday the sun above the equator will produce no shadow, while at a different latitude there will be a shadow. The amount of shadow indicates the angle, hence curvature of the earth at those points.



Now, we can send satellites into orbit, orbiting this spheroidal earth and seeing its rotation. Geosynchronous satellites take advantage of this, by staying above one point on the equator as the earth rotates.

Answer 6

Earth rotates in an elliptical orbit. Just become an astronaut and go to moon and take pic and it will be proved.

Answer 7

Please look into any elementary geogrphy text book and you will get the answer.