why is the earth round. What ways can one prove that the earth is round and revolves around the sun.?

Question

without having access to space and pictures how can one prove that the earth is round and revolves around the sun?

Answer 1

The earth is not perfectly round, it is longer around the equator due to the spinning of the earth. However the acient scientists used mathematics to determine the curvature of the earth, once they found that they could calculate that its enought to completely circle around. For instance, they would observe ships off in the distant and instead of being able to keep seeing them they would slowly seem to sink into the water. This is because of the curvature of the earth.
The scientists used the stars to map out geometrical figures that would tell them angles of curvature.

Answer 2

It is round because gravity tries to pull everything toward the center, and the natural shape that results from every bit of stuff trying to get as close to the center as possible is a sphere.

The usual proof that the surface is curved is the way a ship disappears over the horizon at sea. It seems to sink lower and lower as to goes away, until at last you can only see the top of the mast before it too sinks out of site.

Another proof that the Earth is round is the position of the North star in the sky as seen from different places. It can never be seen from anywhere south of the equator. At the equator it is always on the horizon. At the north pole, it is always directly overhead. At any place between the equator and the north pole it is at an angle above the horizon that equals your latitude. Such things are only possible on a spherical Earth.

Finally, and both most obvious and most overlooked proof that Earth is round, is that nobody can find an edge. You can travel all over the place for your whole life and never find an edge to the world. No matter where you go, it looks like an endless flat place (ignoring mountains and canyons), with the only real difference being where you see (or fail to see) the north star.

Proof that Earth orbits the Sun and not the other way around is more complicated. The main one is retrograde motion of the other planets. The planets out as far as Saturn can be seen in the sky without a telescope. They look like bright stars and they move around against a sky filled with thousands of other stars that never change position. Stars make patterns in the sky, called constellations, but the planets move from constellation to constellation, never staying in one place for long. And the way they move, usually going in one direction but sometimes reversing and going backwards, is evidence that the Earth and all those planets are going around the Sun and not The Sun and Earth going around the Earth. That motion of the planets was known since ancient times and was studied intensely by astrologers, but people had a hard time accepting that the apparently solid and stable ground under their feet was really flying through space at high speed. Other, less easily observed things, like aberration of starlight and stellar parallax really proved the truth of it. Of course now days space flight really proves it, but you wanted proofs that did not use space flight.

Answer 3

The Earth is round because its mass is sufficiently large that its gravity is strong enough to overcome the strength of the materials it is made of. Gravity is a central force, equal in all directions, so it pulls the mass into a spere. In fact, the rocks of the Earth are only strong enough to support a mountain about twice the height of Everest against gravity - a larger one would collapse under its own weight.

The Earth is actually very, very round indeed - mor sperical than a billiard ball - but is technically slight wider at the equator because of its rotation.


You can demonstrate that the Earth is round(ish) from the fact that the horizon recedes when you climb a hill or the mast of a ship. This would not happen with a flat Earth. You can also observe the change in shadows of the sun - this was used thousands of years ago by the Egyptians to estimate the radius of the Earth.

You can demonstrate it goes around the sun by observation of the suns position against the fixed stars. Complex theories can be developed to explain this motion but the simplest is a sun centric system.

And the Bible, contrary to your first answer, contains absolutely none of this information. Ignorant lot.

Answer 4

The earth is round because the Earth's gravity pulls it into a round shape. It can be proven a million ways, the simplest being the many many pictures of space that show the earth is round. If you watch a lunar eclipse, the earth's shadow on the moon is round. Many, many people have flown around the earth. The list goes on.

Answer 5

"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."

There are more proofs of the earth's roundness at the first link below.

The second link is the source for the following information, offered as proof of the earth revolving around the sun.

"There was no straightforward proof for the motion of Earth until 1725 when James Bradley discovered stellar aberration. This is (apparent) yearly change in positions of all stars in the sky due to Earth's own motion. Aberration arises due to adding up of the speed of light coming from the star and Earth's own speed. This is a very complex phenomenon and its description requires some math.

Another, much simpler, consequence of Earth's motion is stellar parallax. If Earth changes its position relative to the stars, than the stars should appear to change position in the course of the year.

A common experiment illustrating parallax is just looking at a close object (a finger, a pencil etc) with one eye at the time. When you switch from one to the other eye, the object will appear to move against the background. Closer the object is to your eyes, more pronounced the effect is.

Parallax should not be confused with aberration: parallax arises from the change of Earth's position and depends on the distance to the star, while aberration is caused by Earth's great speed and does not depend on how far the star is.

Parallax of a star was first measured by Bessel in 1838. It was not measured before because this change of star's apparent position is very small (the stars are very far from us). This was a very important discovery because Aristotle himself mentioned the lack of observable stellar parallax as the proof that the Earth is not moving (he didn't have a telescope and didn't know that the stars are so distant).

A third discovery proving Earth's motion was that of Doppler effect. Wavelength of the light that we receive from objects moving relative to us becomes a little shorter (i.e. bluer) when we approach the source and becomes longer (i.e. redder) when we move away from the source. When Earth moves toward a star, the star will appear slightly bluer (only high-tech instruments can measure this) while it will appear redder when Earth is on the other side of the orbit and moves in the opposite direction. This effect proves that Earth has a velocity relative to the stars, similar to aberration.

So, aberration (slight change in stellar positions due to Earth's speed), parallax (slight change in stellar positions due to Earth's changing position) and Doppler effect (slight change in color of stars due to Earth's speed) all prove that Earth is moving around the Sun, and not the other way round."

Answer 6

You can't. The earth is technically not a perfect round shape. It is actually oblong along the poles (of course it looks round to the naked eye in space)

Answer 7

prove it is round- sail all the way around it and come back to the same spot

prove it rotates around the sun- you must be really smart and able to follow the patterns of the stars and planets.

Answer 8

You can't prove any of this. Many of us have known for years that the round earth and sun centric ideas are a major hoax fostered by the mainstream media to support the Airlines.

Answer 9

if you look down a well and there is sunlight All the way down but at the same time someones else goes north or south to another well and there isn't then that proves it.

Answer 10

If the earth was a square there will be a edge to the earth.
And we would want that.