we are not sure.
earth's gravity
Comets, while visible in the sky, do not normally fall to Earth. Meteors do fall towards Earth very quickly.
comet moves slowly and appears in the sky for a longer time. meteor moves swifty and seems to fall on the ground.
Sometimes they do; that's what a "meteor shower" is. The point is that all of the rocks and dust given off by a comet, and the head of the comet too, travel the way gravity and the light pressure of the Sun force them to. The head of the comet is freely falling towards the Sun. (if a comet gets close enough to a planet, the gravity of the planet becomes significant, and sometimes the comet will collide with the planet; look at Shoemaker-Levy 9, which hit Jupiter in 1994.) As the heat of the Sun begins to melt the ices of the comet, gas and dust escape from the comet. Because the gas molecules and dust particles are very light, the pressure of the Sun's light pushes them away from the comet; this forms the "tail" of the comet. Over the course of thousands of orbits, the gas and dust spreads out to fill in much of the orbit of the comet. Where the Earth's orbit intersects the comet's orbit, we see annual meteor showers.
If a comet hit the Earth hard enough and went through the core, the whole Earth could fall apart.
The sun is the largest out of the three and then the earth and then a comet.
comet sandy
The name of the comet that will pass Earth on August 15, 2011, is the comet Honda.
We don't currently know when a comet will hit planet Earth.
There is no relationship whatsoever between Earth's moon and any comet.
Would the impact of a comet on the Earth cause earthquakes? Possibly; it would depend on where the comet hit. But depending on the size of the comet that struck the Earth, the results might vary from "merely" very terrible indeed to absolutely catastrophic; The impact, the fallout, the tsunami (if a water strike) and/or the "nuclear winter" darkening of the skies with dust and debris would dwarf most conceivable earthquakes. Let me put it this way; if a large comet strikes the Earth, the last thing people will be worrying about would be an earthquake.
No, a comet will NOT hit earth in 2012.