Does gravity effect immediately?
929132
Gravity was in effect before you asked the question, thats why you did not have to glue your computer to the desk.
129944
Don't worry, this will never happen. The "gravity" of the earth is actually caused by attraction between two objects of significant mass.  Were the gravitational force of the earth to vanish, that would mean that the earth itself had vanished.  It would also mean that you would be in free-fall, expereincing what might appear to be weightlessness.  not that this would matter considering that you would be in the void of space and would be dead.
47890
Imagine that the earth suddenly disappeared.  Would the moon fly off into space immediately or would it "wait" until the gravity from earth "disappeared" at some short time later?  We know that nothing goes faster than the speed of light, 3*10^8 meters per second.  So, what is the speed of gravity?\n\nThe answer, according to Einstein's General Theory of Relativity, is that gravity does not really exist.  Heavy objects warp the space-time around them.  A common analogy is to imagine that four of your friends are pulling on the corners of a sheet.  Place some tennis balls on the sheet.  Now place a bowling ball on the sheet.  The tennis balls go to the bowling ball, not because of "gravity" of the bowling ball, but because the sheet has been warped by the bowling ball.\n\nThus, according to Einstein, if the earth were to disappear, nearby space-time would cease to be warped and the moon would fly off immediately.  This is how Einstein solved the paradox that the speed of gravity appears to be faster than that of light.
989278
The effect which causes weight is actually an acceleration, and in the case of on the surface of Earth it is due to gravity.  Weight may also be caused by acceleration due to motion in a straight line, such as with astronauts during liftoff having their weight "increased".\n\nSo to answer your question depends upon if any acceleration or deceleration is happening during the journey.  If the astronauts are moving toward another planet at a constant speed, then they are completely weightless.  (Well, they will of course be pulled a very tiny amount toward any gravitational sources, but unless they are massive and nearby, the effect will be practically insignificant.)  If they are moving under acceleration, then they will feel "weight" based upon the amount of acceleration.
323244
This is conceivable, but only in a very low/no gravity environment.  Thanks for your thoughtful question.
718152
weight equals mass times acceleration due to gravity
169523
I normally refrain from answering questions that have already been answered by so many people, but in this case, so many of the answers are incorrect, and it might be useful to have a single answer that clarifies what's correct and what isn't.\n\nAn object in freefall in air is subject to two forces. Gravity, which directly proportional to the mass of the object, pulls the object down. Drag acts opposite to the object's movement, and is related to the objects size, its shape, the square of its velocity, and the density of the fluid through which it's traveling. In this case, the drag force acts upwards\n\n^  drag\n|\nO  object\n|\nv  gravity\n\nThe force due to gravity is essentially constant (it increases slightly as the object gets closer to the earth, but this increase is negligible). The force due to drag is related to the size ans shape, which is constant for rigid bodies, and to the speed, which is increasing initally.\n\nThe objects will accelerate until the forces are equal. This occurs at terminal velocity. I would estimate this to be approximately 100 mph. It would take more than 300 ft to reach this speed.\n\nIn a vacuum, there is no drag force, so the acceleration due to gravity (about 9.8m/s^2 near the earth's surface) would continue to accelerate the objects until another force acted on them (e.g. hitting the ground).\n\nSimilarly sized, shaped, and weighted objects such as an egg and an orange could be expected to fall at almost the same rate.\n\nOne final note has to do with a term I used earlier. Neither an orange, nor and egg is really a "rigid object". The egg especially might experience some degree of sloshing inside which could affect its motion. This is why tanker trucks have compartments. I'm not sure if you'd notice this effect, but if you hard boil one egg, you could perform an experiment yourself.\n\nThe bottom line is that you really shouldn't notice any difference in the way the orange or the egg falls.
546779
I think it is more accurate to say we can easily replicate the EFFECTS of gravity, rather than gravity itself.  Gravity relies on mass.  More mass, more gravity.  Any "replication" of real gravity is not replication it is the real thing.
312486
No, the apparent "phase" of the moon is relative to where you are on earth at a particular time and the moon's position in relation to the earth and the sun, it does not effect the earth's rotation.  That being said the moon has had an impact on the earth's rotation, and we can assume that it continues to exert the same gravitational forces it has through antiquity.  This isn't exactly true because the moon's orbit is actually getting larger at a rate of about 3.8 centimeters per year (negligible change)*. \n\nAs to stretching these facts to assume that it might affect the space-time continuum ever so slightly I have read several scholarly articles dealing with gravitational forces and their affect on time. Of all of these Stephen Hawking's were the easiest for me to understand and the most interesting to read.  You might want to check out his books "A Brief History of Time" and "The Universe in a Nutshell", both should be available at your local library.  Whether gravity exerted by the moon is strong enough to influence time on earth or not I’m not sure but I would assume so.  If I remember correctly the closer you are to a center of gravity the faster time passes relative to someone farther away.  The visible phases of the moon would still have nothing to do with the affect on time however.  \n\nThat was an interesting question, I hope my answer was of some use to you!\n\nRegards,\n\nArmus\n*thanks for correcting me on the orbital change Answer Guy.
834589
no...gravity always acts on one point known as your center of gravity...not on ur face\nbut since there is a pull on ur body ur joints in ur body are compressed togethere because between the joints is a lubricating fluid.....gases and fluids(to a smaller extent) can be compressed this is the cause of shortning
1120914
I believe it would be instantaneous, but it's a fascinating question.  Perhaps the speed of light, because there are those who argue that gravity is another form of energy generally, and the whole "unified field" thing that I confess I do not understand at all.  \n\nI suppose part of the question is how the sun could "suddenly vanish" in the first place.  Would it in fact vanish instantaneously, or at the speed of light?  Even if it fell into a black hole, that would be an event, and events have a place in space/time.  That we would not know it had vanished until the light stopped coming to us some minute or two later (speed of light for 93 million miles), because of the light, then would gravity be following with that light?  The light is, after all, energy and therefore -- says Einstein -- matter, and that's what responds to gravity . . . \n\nGeeze, you make my head hurt with these puzzles.  I hope some really heavy-duty physicist takes a shot at this question!
1164981
I think you have left off part of the question. The speed of a ball is a vector. When you hit the ball, the vector points upward and forward. Gravity pulls the vector downward. Small forces (air friction, etc.) retard the total speed, but assume those can be ignored.\n\nAt some point, the pull of gravity will pull the vector to point down instead of up. That's the maximum height. The horizontal component of the speed vector should not change (given our assumptions). It still goes forward at the initial velocity. However, The vertical component is instantaenously at zero. In a moment, the ball will start to accelerate vertically and the vector will continue to pull down below the horizontal line becuase of the force of gravity.\n\nIf this were not true, the ball would reach maximum height and then just drop from the sky (0 overall velocity) which you know it does not do.\n\nSo of your choices, probably equal to initial or ever so slightly les than initial would be the best.\n\nThe same thing happens if you drop, say, a ball from 10 feet and fire a bullet from a height of 10 feet. The both hit the ground at the same time.The fact that the bullet is speeding horizontally doesn't affect gravity pulling on it vertically. (yeah small effects like curvature of the Earth, wind resistance, etc. being ignored).
618210
Not due to gravitational pull?!
136380
This is actually a very deep and interesting question.\n\nIt is believed that gravity travels at the speed of light. So yes, gravity does have a speed. The postulated particles that might carry the gravitational force, gravitons, would travel at the speed of light. \n\nIf the earth were removed, the moon would not immediately fly off, because the curavature of space-time would take a finite time to get there. \n\nThis was recently measured and verified as Jupiter passed in front of a quasar, and the gravity of Jupiter bent the radio waves from the quasar. Using the equations of general relativity and the observations of this bending, it was verified that gravity does travel at roughtly the speed of light (see attached reference). \n\nHowever, there is some controversy concerning the validity of the measurement (see 2nd reference).\n\nIn Newtonian mechanics, gravity has to act instantaneously to conserve angular momentum. However in General Relativity, this extra angular momentum is carried away by gravitational radiation i.e., a gravity wave (see 3rd and 4th references)
743049
Yes, light is affected by gravity. For example, if you take light at the base of a building and make it go to the top of the building, the light at the top will be slightly redder than that at the bottom. This redshift is due to the gravitational filed of the earth. This effect has been measured, although it is small. Also, light will bend slightly around a massive object. For example, light that just grazes the limb of the sun will be bent by about 1.7 seconds of arc. This is a very small amount of bending!\n\nTo get more dramatic effects on light, you have to look at much more dense objects than the sun. It is possible for light to orbit a black hole in a circular orbit, but that orbit is unstable. The gravitational lenses that a previous poster commented on are usually from light going past a very massive galaxy rather than a black hole. These are currently being used to help investigate dark matter and dark energy.\n\nThere are differences between the way light is affected by gravity and how ordinary matter is affected, but the differences are subtle and based in the fact that light goes at the 'speed of light', which is a special speed in relativity.
806969
Hmmm change in gravity?\n\nYou need to send a free sample of hair dye to NASA so they can sent it out in space and test it for you.
949273
The land does not move beneath us.  What are you talking about - the revolution of the Earth on its axis?\n\nIf that is the case, please take note, as I have seen nobody answer this frequently asked question correctly.\n\nIf you turn round quickly on the spot, you'll soon get dizzy, even though no part of your body is moving much more than a few miles per hour.\n\nIf you drive around a traffic island at 60 mph, you will throw your passengers all over the place.\n\nIf you drive around the city loop at 60 mph, you will hardly notice any turning forces.\n\nSo, speed is not the critical factor in how turning affects you.  What affects you is the rate at which you are changing direction. \n\nWith the Earth taking 24 hours to turn once, at any point in time you are not changing direction hardly at all, and from minute to minute you are travelling in a straighter line than a draughtsperson could draw.  \n\nTravelling in a straight line at constant speed has no effect on you at all, even if it is 1 million mph.