Why doesn't the earth and moon collide?
469016
Great question.\n\nThe reason that they don't collide is that the moon is moving to fast.\n\nCheck this out- when the space shuttle is up in space it is only about a 100-150 miles up there. Why doesn't it just fall out of the sky and crash into the planet? \n\nWell the answer to why things don't fall out the sky is because they are in orbit- duh-. The space shuttle is not only up in space it is also moving sideways at a tremedous speed. The shuttle IS falling out of the sky, but the reason it doesn't ever hit the ground is all that sideways motion. Everytime it starts falling, the earth has moved out of the way ( sideways- remember) so it changes direction and starts to fall again, well guess what the earth has moved out of the way again. This keeps repeating and repeating. in essence anything in orbit- satelites, moons, and space shuttles are always falling but they never seem to get there. That is why the moon never hits the earth. It's important to remember that just because you are in space does not mean gravity is not pullin you down. I assure you if the shuttle was somehow able to suddenly stop it would fall out the sky like a rock. The reason the people in the space shuttle are floating is because they are falling and not because they are in space.\n\nI just have to add a little more to this statement- You know that in freefall ( you jumped out of a airplane ) you can't feel gravity and there is no up or down or sideways. The same thing with being in orbit since you are always falling you can't feel gravity either. One other thing the people that wrote first on this question really need to double check their facts. The Perfect distance and gravity cancelling out stuff is wrong. The moon could and used to be much closer to earth. It also went around earth much faster, but because of tidal action the moon has slowed down and gone into a farther out orbit. The moon even today is leaving the earth at about three inches a year. It is slowing down and so is our day- our day is getting longer because of the moon
830517
The moon goes around the earth faster than we go around the sun...
189537
If the earth wasnt tilted on its axis, we probably wouldnt have any gravity.  The tilt helps with the gravitational pull of everything and the moon itself.
755454
I answered this yesterday, but...\n\nWhat makes the Earth Spin...\n\nAngular Momentum. Think of a figure skater pulling their arms closer to their body while spinning, sudennly they are spinning VERY fast, then they let their arms out, and they slow down. This is because the arms still have the same amount of rotational energy as they did when they were further from the body, but when they are pulled close, they don't have as far to go to complete one rotation... the radius and circumference are smaller but the distance covered is the same over the same amount of time. This means faster rotation.\n\nHow does that have anything to do with the Earth? Simple. When the Earth formed, it formed by collecting bits of matter from space, and these bits of matter, ranging from dust to huge asteroids and larger, were all like tiny arms, adding rotational energy to the earth as they came in closer and stuck. \n\nRight now, the moon is slowing the earth's rotation as it slowly moves away from the Earth--again, this is the same process. How can this be when the moon doesn't even touch the Earth? Gravity. Gravity makes the earth and moon behave almost as if they were touching. The short explanation is that the center of gravity of the earth-moon system lies just below the surface of the earth, causing tides. Since the moon is moving away, it requires less orbital velocity to maintain it's orbit, and so the tides slow the earth more as the moon's orbital speed slows.\n\nEventually, the earth and Moon may both be tide-locked to each other, and this will happen long before the earth is tide locked to the sun (the tides have slowed rotation of the earth to the point where it always has one side facing the moon (or sun)).\n\nWhat makes the earth not stop spinning?\n\nAs mentioned before, angular momentum. The earth's surface can be slowed, but that energy has to go somewhere--it goes to speeding up the orbital velocity of the moon, which is why the moon is moving further from the earth...\n\nThe earth is moving around the sun because of the way the sun and all the other stuff in the solar system formed--from a cloud of gas and dust that collapsed into a spinning disk. The mechanics of the whole thing is still being learned and debated. As long as the Earth keeps moving in a straight line perpendicular to a line drawn between the Earth and the Sun, the Earth will continue to fall toward the Sun (by gravity) at exactly the same speed that it is flying perpendicular, and thus, like a ball on a string, it will follow a curved path around the sun.
768438
The main reason is that there is no weather on the moon to erode the surface.  Additionally, there is no tectonic movement of the surface of the moon.  Because of both these things, the surface of the moon is stable, while the earth's surface is constantly being altered.
407247
Curious is correct. It is tidal lock, not coincidence, that causes the phenomenon you ask about. Eventually, the earth would get into tidal lock also, and always show the same face to the moon, but before that happens the sun will expand in its death throes and engulf the planetary orbits out beyond Mars.
305090
The Moon's orbit around the Earth is elliptical, with a substantial eccentricity (as major Solar System bodies go) of 5.49%. In addition, the tidal effect of the Sun's gravitational field increases the eccentricity when the orbit's major axis is aligned with the Sun-Earth vector or, in other words, the Moon is full or new.\n\nAt Perigee (its closest Point to earth the Distance is  359861 km from earth measured from equator to equator.\n\nAt Apogee (its farthest point from eath the Distance is 405948 km from eath measured from equator to equator.\n\nAs it revolves around the earth in this EGG shaped orbit it cycles between getting further and closer from earth.\n\nTake a Boiled egg and cut it in half. Measure how THICK the white is from the yoke at any point on the FLAT cut surface of the egg. The moon would travel around the outside of the yoke. (the yoke is the earth.\n\nSee the below link for a great explanation and good photos and graphics.
1027284
because the sun's gravitational pull is much greater than the earth's...same reason the moon goes around the earth and not the other way around
135962
Actually, the moon does have an atmosphere, and EXTEAMLY thin, tiny, very small, negligible atmosphere.\n\nThe chances of getting hit are miniscule, there is virtually no risk.  You can see the moon of covered with impact craters, but remember, these happened over the course of billions of years.  The chances are very slim, you would have to VERY unlucky to be hit.
20941
Consider that the Earth moves around the Sun because of gravity, like a ball on a rope moves around your hand when you swing it.\n\nNow, consider some of the laws of gravity (in english):\nCloser objects = more gravity to eachother\nBIGGER objects = more gravity to them\n\nThe Earth is 1/100000(lots of 0's, maybe more) the size of the Sun, so we really don't affect it much, but it keeps us going around it like nuts! (once a year, right?)\n\nThe Moon, however, is not sooooo different from the size of the Earth (yes it's smaller, but not 1/10000etc(like the Earth vs. Sun thing), AND it's CLOSER to the Earth than the Sun is (WAY CLOSER)!\n\nSo because it's kindda nearer to our size, and it's kindda close, it's got 2 big check-marks for LOTS-O-Gravity!
935068
Now, I can't swear to this, because I was half asleep when I watched this, but I watched this show on the Discovery channel about a week ago.  They were talking about how the earth has a molten core that is constantly moving around, so therefore we have earthquakes.  The moon is solid, so therefore, no earthquakes.  That's also why we don't see many of the craters from asteroids that hit us over the millions of years because our earth's surface is continually changing from these earthquakes.
534376
all of them have different orbits...and each satellite is bound to its orbit by means of gravitational force...so they dont collide....however if they loose their stability of the orbit they may collide.
484339
Because it's to far away.  And it's still in orbit with the Earth.  When an object moves it doesn't want to stop.  Therefore the Moon stays with us.
25342
Think rally hard. The moon has gravity just like the earth. Have you ever seen a flag on earth stand that straight? They had a metal pole across the top and the grainy video make it look as if it is fluttering.
1149892
The moon will not escape Earth orbit. It is currently moving away from us at only 38 mm/year, due to energy transferred by tidal forces. The energy transfer is also causing Earth's day to become longer (currently it is increasing by 15 microseconds each year).\n\nTheoretically, the moon's orbit would increase until the Earth's day slows to match the Moon's orbital period. After this point, solar tides will dominate and the Moon will start moving closer to Earth.\n\nBefore this happens, the Sun will become a red giant (5 billion years from now).
798233
The moon orbits the earth.  It does not 'rise'.  Look in any good newspaper to see what time it is visible in your area.  This information can be found in the weather section.
790097
Just look at the moon.  The moon has is made up of mantle rocks, just like the Earth's crust.  But there's no water, nor is there an atmosphere.  \n\nIt's actually not a fair question.  The Earth is in a wonderful position in that water is a liquid (too close it's a gas, too far it's ice).  Water is a very abundant substance - if a planet has an atmosphere, it has water.  The moon is too small and cannot hold an atmosphere, but there's no way the Earth would lose its atmosphere due to its size.  Therefore, there's really no way for the Earth to lose water.\n\nSo assuming the Earth COULD lose its atmosphere, you'd have a surface like the moon.