What is the reason for the Earth to follow an elliptical orbit?
339322
if any object following a straight or whatever path was to be attracted by some other larger body and put into and orbit then thru mathematical equations the orbit will always be elliptical(considering variable decceleration and velocity) that's why there is a doubt that moon was just a passing object that earth caught up..(coz it's orbit is circular and that it perfectly covers up the sun during eclipses....search for anomalies of the moon on google) so the orbit cannot be circular unless u "put" an object specifically into that shaped path...\n\nregards...\npretty rough explaination ..sorry cud not include the equations :)\n\nvivek
288737
The ellipse is a result of the mutual gravitation of two massive bodies. The center of mass of each sun-planet system is somewhere between the center of mass of the two bodies (it's still inside the sun, though), and each body revolves around the center of mass. Since both masses are moving, they orbit around each other, resulting in elliptical orbits for both (however, since the sun is always orbiting a point within the sun, it's not as noticeable. Unless you're an astronomer.
66192
It is due to the slight orbital eccentricity of Earth rotation around the Sun. Since the orbit is not perfectly circular the distance between the two bodies varies.
699589
Kepler figured out the laws that describe planetary orbits.  This enabled much more accurate planetary positions (which Kepler published), and set the stage for Isaac Newton to explain that gravity  was the force that held the planets in their orbits.\n\nUp until Kepler, everyone was sure that planetary orbits must be some form of perfect circle. His discovery that they are actually elliptical was an important turning point in the history of science, away from the Aristotelian method of applying philosophical concepts to physical reality, and towards modern empirical science.
70887
they can't.  That would be a perpetual motion machine.  \nConservation of energy says that you can't get something for nothing.  for a terrestrial body to do work continuously it would need to be given a continuous supply of energy.\n\nIn an elliptical orbit, two boddies can take turns doing work on each other and energy is conserved.
52855
It has to do with the direction the earth rotates on its axis. It rotates once every 24 hours. So, the direction it spins is the direction the sun passes by. The earth would have to completely stop and start to rotate in the opposite direction in order for the sun to rise in the west and set in the east. Hopefully that won't happen any time soon, because it would probably mess gravity all up.
398654
In the special case where centrifugal force exactly balances gravity, the orbit IS circular.  But say you have a planet in a circular orbit.  Give it a little extra speed in the direction it's going.  Now it has too much centrifugal force, and it begins to gain distance from the star -- but that means it's gaining potential energy and so must be losing kinetic energy.  So it slows down.  The detailed math shows that by the time it's gone 180 degrees around it has lost so much speed that, even though it is farther from the star, now it doesn't have enough centrifugal force to counteract gravity, so it begins to speed up.  Again, if you do the math, you see that it will return to the exact position it was at when you gave it the extra push, and with the exact same velocity it had just after that push.  So it will just keep repeating that orbit, which is highest (and slowest) at one point and lowest (and fastest) 180 degrees around; in other words, an elliptical orbit.
52806
Pluto's elliptical orbit is unusual. It is the only planetary orbit which crosses that of another planet (Neptune), and it is tilted 17 degress with respect to the plane of the solar system.
172943
The earth moves in many ways. For example:\n\n1. The surface of the earth exhibits earth tides, just like the surface of the oceans, because of the gradient of the gravity field the earth is in, due to the moon, sun and other celestial bodies (so there are usually about 2 high earth tides per day, and 2 low earth tides; they have an amplitude of a few feet). \n\n2. The ground moves due to earthquakes and volcanoes, etc.\n\n3. The ground moves due to the slow movement of tectonic plates\n\n4. The earth rotates on its axis (takes about 24 hours; this is slowing down because of the effect of the tides)\n\n5. The earth revolves around the sun (well the center of mass of the solar system actually, and it takes about 365.25 days to make one circuit)\n\n6. The pole of the earth precesses with a period of about 26,000 years (the direction the north pole points rotates)\n\n7. The axis of the earth bobs up and down while it rotates, called nutation (18.6 year period)\n\n8. The pole of the earth wobbles, called the Chandler Wobble (earth's pole moves in irregular circle of 3-15 m diameter with period of about 435 days) because of storms and other atmospheric and ocean redistributions of mass, and conservation of angular momentum. \n\n9. The earth's orbit around the center of mass of the solar system is elliptical, and the eccentricity of the ellipse varies with a period of about 100,000 years\n\n10. The axis tilt of the earth varies from 21.5 to 24.5 degrees with a period of about 41,000 years.\n\n11. The center of mass of the solar system varies a bit due to motion of the sun and the planets.\n\n12. The solar system as a whole moves in our galaxy about the center (a period of 225 million years, and moving at about 250 km/sec)\n\n13. The solar system bobs up and down in the limb of the Milky Way galaxy with a period of tens of millions of years\n\n14. Our galaxy is moving through space very rapidly (about 300 km/sec, but this depends on what you are measuring relative to; see references)
160814
It has to be at the equator.  It is the same reason that geostationary satellites are in orbit over the equator ...they always remain in the same position over the same spot of the Earth.
221678
the earth doesnt fly towards the sun cuz there r more than one force acting upon it...theres the gravitational pull the sun has on the earth as well as the fact that the moon wants to remain in motion in the same direction.this applies to newtons 1rd law of motion(his first law is that an object will remain at rest until acted upon by another object or it will remain in motion until acted upon by an object..in other words,its inertia)...since the earth has both a side movement and the gravitational pull from the sun...those 2 forces cause the earth to orbit around the sun and not fly towards it or away from it. if u dont understand this...email me (pulga0888@yahoo.com) and ill try to explain it better..........now for ur second question...wat makes the earth spin...the earth spins because of the rotation of the magna and stuff in the earths core..well in the convection zone...im pretty sure thats the answer to the second question but im not positive...if u want me to check then email me.
464601
Earth revolves around the sun because the giant nebula out of which the solar system formed was spinning and the angular momentum is conserved, and earth spins because of the initial config. Why it revolves in an ellipse, see this\nexplanation at http://www.mathsnet.net/cabri/feynman.html
1162718
Because the sun does rise in the east and set in the west.  \n\nWe do know now that the reason is not because the sun is revolving around the earth, but because the earth spins on its axis.
337086
The planets are actually trying to move in a straight line at a high speed due to the intertia from some force long ago.  When two objects are moving by each other, their gravity interacts and pulls them toward each other, bending the path that would otherwise be a straight line.  If they are too massive and too close, the gravity pulls them so much that they collide.  If things are balanced just right, the path is bent into a complete ellipse.  It's an ellipse instead of a circle because the sun is actually also being pulled a tiny bit toward the earth, as well.\n\nYou could consider gravity to be sort of a "perpendicular inertia", and the planets would revolve around the sun FOREVER if there were no other forces involved.
195652
the earth is a oblate spheroid....we do not fall to the edges because of the gravitational pull...
433264
Objects orbit one another because they have a curved trajectory that results from the vector addition of their momentum (in the direction of travel, tangential to the orbit) and the gravitational attraction to the other object (normal to the orbit).\n\nThis vector is constantly changing in direction (but not to any significant degree in magnitude) because of the object's motion, but it always keeps the satellite's acceleration pointed towards the object is it orbiting, resulting in smooth, roughly circular motion.
954984
The Earth orbits the sun in an ellipse.\n\nEvery ellipse has two foci. It is at these two points where the orbited body is normally located.\n\nPlease see the wiki source that has further information on how to get the numerical data if you need it.