I heard a scientist say once, that because we live in a gravitational field, when we walk our heads travel a?
820061
A gravitational field is generated by the Earth. Since our heads are further away from the Earth than our feet, they experience a gravitational effect slightly less than that experienced by our feet. Einstein showed that clocks at higher gravitational potential tick slower. Therefore when you walk your feet and head travel the same distance, but our heads do it in less time. Therefore since velocity = distance / time they must be travelling at a higher velocity than your feet.
921247
well somewhere in the middle you might become weightless as you would be in the center of a spinning mass. but most likely you would get to a point that the gravity would push you back. just like on a merry go round getting to the center is actually pretty hard.
357097
i guess since ur walking ur moving and when u move theres a small space where the rocks and fall into. At least thats wat i think
934235
The scientific definiton of "theory" is not what your average person on the street would think it is.  It is NOT a hypothesis, it is NOT just a clever idea that sounds right.  It is something that has been supported over and over again, in all aspects of biology.  \nEvolution is a theory, and so it gravity.  Gee, better start arguing against that, too...
858993
I think this could be how it works.. we know all bodies exert a gravitational pull towards the centre of its mass.. Even humans exert a gravitational pull on the earth.. it juz that the force is too feesible to note due to the huge size of the other object (earth). So we dont see the earth moving towards us..\n\nBut in the case of pollen n water particles, pollen is much heavier than the water molecule.. so its gravitational pull is stronger that the pull of the particle..hence the molecules move towards pollen..\n\nThats just a thought..could be true
714564
Oz gave a pretty good answer, but a magnetic field doesn't create a gravitational attraction.  Gravity and electromagnetism are two different forces (at least under normal conditions--some scientists think they may be the same under extreme heat and pressure).
801793
and gravity does what?\n\nand why don't you fall off?
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.
559732
No, it's not true.  You can only occcupy one person-sized point in space at any given time, no matter how fast it's moving.\n\n\nAs a though experiment, though, if you were to run very much faster than light, it might be possible for you to arrive back at the starting line in time to see the IMAGE of yourself departing.  \n\n\n"There was a young man, named Bright\nWho travelled much faster than light.\nHe went out, one day, in a relative way,\nand came back the previous night."\n\nThe rumbling sound that you can hear is Einstein revolving in his grave, at near-gyroscopic speeds...
641758
A better question is why do we feel ourselves moving on a lift or bus.\n\nOnly accelerations can be felt, not motion at a constant velocity. Einstein showed that motion at a constant velocity doesn't even have any meaning unless it is measured "relative" to some "stationary" observer, and even "stationary" has no meaning. But enough of that.\n\nEinstein also showed that acceleration is the same as gravity in that they can both be felt, and cannot be distinguished from each other unless you can look out a window. If you are in a closed box with no window, you cannot tell if you in a gravitational field or are accelerating.\n\nWhen a bus is traveling at a "constant" velocity, you in it are actually being accelerated in all different directions all the time as the bus bounces around. If the bus was traveling on a perfectly smooth surface at constant velocity, and had no windows, with no accelerations of any kind, you would not know you were moving.\n\nSame with the lift. You can feel only the accelerations up or down. If the lift is traveling perfectly smoothly at constant velocity with no accelerations, you would feel nothing, except that the pressure in your ears would tell you whether you are going up or down.
725993
Our equilibrium is controlled by the semicircular canals in the inner ear. The semicircular canals are filled with fluid and together, make up something called the labyrinth. The canals are lined with tiny hairs that sense movement of the fluid in the semicircular canals. These tiny hairs then send messages to the brain that give information about the position of the head. \n\nNotice that while your spinning, you don't feel dizzy...It's only after you stop.  Once you stop spinning, the fluid flows back to the normal places and it does it quickly.  Too quickly for your brain to know exactly where your head is.  The feeling of dizziness is actually a nerve impulse from your brain to the rest of your body prompting your reflex to widen your legs and reach out for something to keep you from falling.  Just like pain is a nerve impulse prompting your reflex to pull back from the source of injury.\n\nIf you think about, all of the sensations we have are just different kinds of impulses that we are familiar with and in English we have given those impulses names: Cold, Hot, Dizzy, Pain, Tickle, Itch...All generate different messages from the brain to the body, each distinct from the others.\n\nNote- That's different from Vertigo...
164797
this is a vague queston. But I believe i know what you are asking. Well He already believed that Pangea had formed and broken apart. Evidence from Glacial Striations and rock formations, not to mension an almost perfect mactch of shorelines. I guess it would have more support for his theory. He concluded that the continents were moving. What he could not prove was the mechinism for the movement. it is not actually the continents moving. They are hitching a ride on the techtonic plates.
208514
Yes, anything with mass generates gravity.  Gravity will only effect things which have mass, so the fact that you are stuck down means you have mass, and thus gravity.
239506
Mr. Question's answer is baloney - a tell-tale sign is the complete lack of sources "a scientist in a northwest university"... give us names and places, please! \n\nAnyway, if you're interested in a "real-life" time machine, you need to look at General Relativity, in which time (being a dimension in space-time) can be warped in the presence of gravitational fields. However, you'd need a gigantic, massively heavy, incredibly quickly rotating object in order to warp spacetime enough to make any kind of dent in the passage of time.
801582
No, physicists have always known that gravity is the one "force" that we really still don't understand. Now it is true that at macroscopic or large distance scales, we understand gravity very well through Einstein's General Relativity Theory. But at the quantum level, the scale of sub-atomic particles, we have no idea how gravity works there. And the most interesting thing is that when we try to probe and understand gravity at the quantum level, we find that we have to abandon all our currently understanding of space and time, as well as the notion of 3-dimensional space.
938858
YES! Time travel is possible. For example, an object traveling at high speeds ages more slowly than a stationary object. This means that if you were to travel into outer space and return, moving close to light speed, you could travel thousands of years into the Earth's future.\n\nNewton's most important contribution to science was his mathematical definition of how motion changes with time. He showed that the force causing apples to fall is the same force that drives planetary motions and produces tides. However, Newton was puzzled by the fact that gravity seemed to operate instantaneously at a distance. He admitted he could only describe it without understanding how it worked. Not until Einstein's general theory of relativity was gravity changed from a "force" to the movement of matter along the shortest space in a curved spacetime. The Sun bends spacetime, and spacetime tells planets how to move. For Newton, both space and time were absolute. Space was a fixed, infinite, unmoving metric against which absolute motions could be measured. Newton also believed the universe was pervaded by a single absolute time that could be symbolized by an imaginary clock off somewhere in space. Einstein changed all this with his relativity theories, and once wrote, "Newton, forgive me."\n\nEinstein's first major contribution to the study of time occurred when he revolutionized physics with his "special theory of relativity" by showing how time changes with motion. Today, scientists do not see problems of time or motion as "absolute" with a single correct answer. Because time is relative to the speed one is traveling at, there can never be a clock at the center of the universe to which everyone can set their watches. Your entire life is the blink of an eye to an alien traveling close to the speed of light. Today, Newtonian mechanics have become a special case within Einstein's theory of relativity. Einstein's relativity will eventually become a subset of a new science more comprehensive in its description of the fabric of our universe. (The word "relativity" derives from the fact that the appearance of the world depends on our state of motion; it is "relative.")\n\nWe are a moment in astronomic time, a transient guest of the Earth. Our wet, wrinkled brains do not allow us to comprehend many mysteries of time and space. Our brains evolved to make us run from saber-toothed cats on the American savanna, to hunt deer, and to efficiently scavenge from the kills of large carnivores. Despite our mental limitations, we have come remarkably far. We have managed to pull back the cosmic curtains a crack to let in the light. Questions raised by physicists, from Newton to Kurt Gödel to Einstein to Stephen Hawking, are among the most profound we can ask.\n\nIs time real? Does it flow in one direction only? Does it have a beginning or an end? What is eternity? None of these questions can be answered to scientists' satisfaction. Yet the mere asking of these questions stretches our minds, and the continual search for answers provides useful insights along the way.
1168282
I read a book about this.  I don't remember the title, but this guy claimed he had it.  He claimed that all atoms are expanding at the same rate.  This is what causes gravity.  More massive objects expand in more space in less time than less massive objects.  \n\nI don't remember the details of the rest of the fields, but they all related to this expansion of atoms.