What makes the earth return to its lowest motional energy?
152168
If I understand your question, Earth's velocity around the Sun changes as its distance from the Sun changes; we are farthest from the Sun during summer (northern hemisphere "summer")and our orbital velocity is at its lowest. When our orbit takes us in closer to the Sun in winter, our velocity increases. Kepler determined the principles behind this relationship hundreds of years ago.
1075284
The centre of the earth is called CORE. Earth is like a big magnet as close u go to the magnet the magnetic power increases. So at the centre of the earth the gravity is maximum.\n\nSimple if we go up the gravity decreases and it inreases as we go down.\n\n\nNeo
94632
Assuming (1) the Earth isn't torn apart by the impact of such a meteor and (2) the Earth wasn't molten rock in the center, you could safely expect this ball to go through the hole toward the center of the Earth, pass through the center and start moving towards the opposite end of the Earth.\n\nBecause the ball won't have gained enough kinetic energy to then break away from Earth's gravity (in the same way a pendulum always comes back and finally, to rest), the ball will then slow to a stop and return back towards the center.  Just as a pendulum will, the ball will oscillate back and forth for a while until its potential energy evens out to zero and it stops, motionless, at the exact center of the Earth.\n\nGive it a try and let us know how it all works out, okay?
1096009
At this point, the question is not what moves the sun or the earth, but what if anything is stopping it.\n\nThey were set in motion long ago. (nobody knows precisely how and why but most of the astronomy theories have to do with motion and energies imparted in a big bang or the like)\n\nOnce in motion, an object will stay in motion until something stops it.  So, nothing is moving the earth now, it is just still moving.  It will continue rotating and orbiting and winging along through space until something interferes.
576401
From what i understand the earth will eventually leave the earth system altogether in a few hundred thousand years, this process is not however do to tidal drag. That force is responsible for slowing the rotation of the earth (and other planets) What most people don't understand is that the moon acts as a stabilizer for the earth. they degree of axial tilt would vary wildly. the equator may wind up as the north pole and go back again. planets without moons all experience this extreme wobble effect.
651719
Mass.\n\nStuff which weighs a lot sucks other stuff towards it.\n\nIt's the sun's mass which keeps the Earth from flying off in a straight line into space.\n\nAnd it's the Earth's mass which pulls us towards its centre.
1182139
If you're talking about some magical reversal without physical consequences, you already have several answers. But if you're talking about physical reality... the earth's mass is about 6.6 sextillion tons and its tangential velocity due to rotation is over 800mph at the equator. You can't just stop an object that massive, moving that fast without equally huge effects. The biggest effect would be friction. Energy is conserved and stopping the rotation of earth would convert the planet's entire momentum into heat. If the reverse happened quickly enough, the heat generated would probably boil the atmosphere and the oceans off into space. Everything on the surface would burn or melt. All life on the surface would end - everything would go up in smoke. \n\nIf the reverse happened slowly, we would lose the angular momentum of our orbit around the sun. Earth would leave its orbit and either fly off into interstellar space or plunge into the sun - either way would be pretty final.
1104955
due to a transfer of Earth's rotational momentum to the Moon's orbital momentum as tidal friction slows the Earth's rotation. That increase in the Moon's speed is causing it to slowly recede from Earth (about 4 cm per year), increasing its orbital period and the length of a month as well. \nTo picture what is happening, imagine yourself riding a bicycle on a track built around a Merry-go-Round. You are riding in the same direction that it is turning. If you have a lasso and rope one of the horses, you would gain speed and the Merry-Go-Round would lose some. In this analogy, you and your bike represent the Moon, the Merry-Go-Round is the rotating Earth, and your lasso is gravity. In orbital mechanics, a gain in speed results in a higher orbit. \n\nThe slowing rotation of the Earth results in a longer day as well as a longer month. Once the length of a day equals the length of a month, the tidal friction mechanism will cease. (ie. Once your speed on the track matches the speed of the horses, you can't gain any more speed with your lasso trick.) That's been projected to happen once the day and month both equal about 47 (current) days, billions of years in the future. If the Earth and Moon still exist, the Moon's distance will have increased to about 135% of its current value. \n\nThe tides, chiefly caused by the Moon's gravitational attraction and the orbiting of Earth and Moon about a common point, act as a brake to slow down the earth's rotation. The nearer tidal bulge, which carries the greater effect, runs slightly out of alignment of the Moon overhead; the gravitational interaction between it and the Moon serves to speed up the Moon in its orbit even as it slows down the earth's rotation. As it speeds up, the Moon moves to a higher orbit. \n\nThe effectiveness of this tidal brake on the earth's rotation strongly depends on the configuration of the oceans. Thus, we should inquire as to whether the current arrangement is an average value or not. \n\nThe present rate of tidal dissipation is anomalously high because the tidal force is close to a resonance in the response function of the oceans; a more realistic calculation shows that dissipation must have been much smaller in the past and that 4.5 billion years ago the moon was well outside the Roche limit, at a distance of at least thirtyeight earth radii
373975
The Earth is not a perfect sphere so you are at different distances from the centre at different places.\nThe density of the Earth is not constant so above dense rocks you appear slightly heavier.\nThe Earth spins so at the equator you are lifted slightly by the Eotovos effect.
990337
Yes you do.  It is a very small difference, and would depend which side of the earth you were on regards it's orbital path around the sun, however you would actually make a difference.\n\nIf this is a question that has been put to you by your physics proffessor, then the answer is in the long run....no, because....when you land, you absorbe the energy you displaced upon leaving.\n\nThis is about gravity.  Look up Kepler's Law.\n\ngood luck.
145598
The Earth was formed spinning (like a top) and it just hasn't stopped spinning since then.  There is very little friction that would slow it down (space is pretty empty).\n\nThere are different theories as to why it was created spinning.  But most likely it formed from gas and dust that was swirling, and that angular momentum is still with us today.
458635
It is warmer closer to the surface of the earth b/c of gravity & air acting as an insulator. Sounds strange???\n\nLet me explain...\n\nAir holds heat. It is an insulator.\n\nMost of the air is found in the troposphere, the layer closest to the earth's surface. Why???\n\nAir has mass just as we do. All objects having mass obey the laws of gravity.\n\nSince gravity is greatest closest to the surface of the earth, the gas molecules in the air will be pulled more closely to the earth.\n\nSince the insulator (gas molecules) is closer to the surface, heat will be held at the surface.\n\nThe higher you go, the less gravity & therefore there will be less air & less heat.\n\n:)
438984
Minimally, 2.  Depending on how simplisticly we are thinking about the problem.\n\n1) the Earth rotates around it's axis\n2) the Earth revolves (orbits) around the sun\nhttp://www.ucolick.org/~bolte/AY4_00/week1/motionsC.html\n\nMaximally: ???\n3) the Earth and Moon really form a system together which revolves around the sun so there is the wobble attributable to that interaction.\nhttp://search.yahoo.com/search?ei=utf-8&fr=slv1-&p=earth%20moon%20system%20motion\n\n4) the Earth precesses about it's axis changing the tilt relative to the orbital plane\nhttp://csep10.phys.utk.edu/astr161/lect/time/precession.html\n\n5-14) Perturbations in Earth's motion due to gravitational pull from other planets (Mercury, Venus, Mars, Jupiter, Saturn, Neptune, Pluto, UB313).\n\n15) Solar system motion through the Milky Way galaxy which brings the Earth along with it\n\n16) Motion of Galaxy through the universe bringing along the solar system and earth.\n\n17) Changes in motion due to sloshing of the oceans and earthquakes.\n\n...
241909
The escape velocity is the minimum velocity an object needs to obtain in order to leave the surface of the Earth and never return, it will break free of the Earth's gravitational field forever.\nIt is not necesary to obtain escape velocity just to go into space.  While orbiting the Earth, you are most definatly still trapped within the Earth's gravitational field and you will eventually return to the surface.\n\nIf an object launched from the ground with an initial velocity lower than the escape velocity, the object will eventually (it may be take a very long time) return to the Earth and fall back down.
944360
It's coefficient of friction is 0.1, which is the lowest of any solid.\n\nPS Go to wiki
453275
Most of the atmosphere rotates with the earth, but yes, I'm sure inertial effects produce a tiny, tiny amount of friction.  More important are tidal effects of the moon's gravity, which are gradually slowing down the earth's rotation.  In a few billion years the difference in the length of the day will be noticeable.  And there's another kind of "air" resistance -- the solar wind, a continuous (but varying) stream of particles ejected by the sun.  These are mostly charged particles and are deflected by the earth's magnetic field toward the poles, where they produce the auroras (borealis and australis?), the northern and southern lights.
540447
Let's just talk about Earth. The earth's diameter is 12756 km. Its circumference is pi x 12756 = 40074 km. The earth spins 1 round in 24 hours. That's 1700 km/h, or 472 m/s. If it rotates in an OPPOSITE direction, it's like the Earth is rotating at 944 km/s and suddenly stops. What happens? You fly through the air at 944 km/s. All the houses fly through the air at 944 km/s. Whole forests fly at 944 km/s. Even whole mountain ranges and mountain tips fly at 944 km/s. The ocean's waters fly backward at 944 km/s. Talk about a uber tsunami. I don't know what the friction of air against these object would do to them. Can anyone solve that? Even the Earth's crust might become detached with its outer mantle, I think. Lava breaks out everywhere, global earthquakes... In short: All hell breaks loose. Man, that's even worse than the Death Star. Superman actually does that to Earth in one of his movies. He's a major nut!