yes only at very high speeds

The perception of time slows down, but time itself doesn't slow down. It can't. It's not a physical entity that can be affected by speed. Our bodies, on the other hand, can be affected by great speed. If we were to travel extremely close to the speed of light for 20 regular, non-space traveling years, It wouldn't feel like that long. Our bodies would have only aged a short time. It's a hard concept to grasp, but very interesting when you think about it long and hard.

Yes. The closer you approach the speed of light, the slower time passes for you. This is a basic property of Relativity.

No,time slow down is just a perception. For example,you leave the earth at a very high speed(neglect the process of accelerate). On one hand,you can observe the clock on the earth is slow down.While on the reference frame of yourself,there is no change of the time. On the other hand,people on the earth will also feel that the clock of yours has slowed down. Maybe you can take the following link as reference: http://en.wikipedia.org/wiki/Twin_paradox

Time is not slowing down when you go fast.In that case we would be doomed if another Olympic Champion runs again Oo

This is a very complex question to answer, but I'll take my best shot at it. I will start, however, not by talking about time, but by talking about distances. Imagine you are holding a ruler and looking at its shadow. You're holding it in a plane parallel to the wall, and the shadow and ruler are the same length, which is one foot. Let's choose right and left as the "x-axis" and up and down as the "y-axis". You're holding the ruler parallel to the x-axis. The shadow of the ruler is now one foot along the x-axis, and just a point on the y-axis. If you rotate the ruler 45 degrees (still in the plane parallel to the wall), now the distance of the shadow along the x- and the y-axis is about 0.7. So, when rotated, the distance the ruler "projects" along x and y changes. But it doesn't just change randomly, it changes in a way that's related to the overall length of the ruler, specifically, according to the Pythagorean theorem: x^2 + y^2 = 1 foot. We are used to thinking about all three spatial dimensions being related in this way. In all three dimensions, no matter how it's oriented in space, if you take it's projection along x, y, and z, and sum the squares, you'll get 1 foot. The ruler's length is "invariant" with regard to its rotation or position in space. Einstein's insight with relativity is that this is *not* actually the case. In fact, Einstein figured out that the ruler's overall length is actually affected by its velocity relative to the observer! So, now imagine the ruler in empty space, floating around. If you are hovering next to it, and the ruler is not moving relative to you, you will observe its length to be one foot. However, at the very same moment you make your observation, if I come whizzing past you and the ruler at a constant velocity, I'll observe the ruler as being shorter than the 1 foot long ruler I'm holding. (Actually, I'll see compression of your ruler only if it is not perpendicular to my direction of motion--if it's perpendicular, then I'll still measure it to be one foot.) So what happened to that extra distance? How can *your* ruler be squeezed by *my* motion? And furthermore, how can it appear squeezed only to me, but not to you? Even more confusingly, from *your* perspective, it's *my* ruler that's squeezed and yours is 1 foot, same as its ever been! Let's go back to the wall and the shadow. You're holding your ruler it's in the plane parallel to the wall and at 45 degrees to the x-axis (and so is the shadow on the wall). Now, if you rotate it slightly *out of plane* so that it's no longer in the plane parallel to the wall, the overall length of the shadow is no longer 1 foot, it's shorter. This is because there's now some component unaccounted for in the z direction, perpendicular to the wall. The ruler shadow on the wall is a useful analogy because you can imagine you're a 2D shadow person looking at the ruler shadow with no comprehension of the z dimension perpendicular to the wall. If you're a 2D shadow person, you've lived on the wall all your life and have no idea that there's a world off your wall. To you, forward, backward, up, and down are the only directions that exist..."out" and "in" would not be comprehensible to you. In fact, you'd have no comprehension of the actual ruler itself, you would only be able to comprehend the ruler's shadow. So, when I, from my 3D view, rotate the ruler into the z dimension, to you, the shadow appears compressed. Back into space...when I'm whizzing past you and the ruler, Einstein says that your ruler is slightly "rotated", but in not in x, y, or z. Rather, it's rotated slightly in the fourth dimension of time. It turns out that if two things are moving relative to each other, those objects appear to each other as having a small component rotated in the unseen time dimension. The amount of rotation is proportional to the relative velocity. Now consider that z-dimension. Before the rotation out of wall's plane, the ruler had no component of distance perpendicular to the wall, but after, it has a slight distance in the z dimension. This is where the analogy breaks down a little bit, but not completely. The main point is this: the distance of the ruler's projection in z changed. So, from the 3D perspective trying to understand the 4D world of space-time the ruler is rotating into this unseen fourth dimension (the "time" dimension), what affect will that have? The answer: time will have slowed down. So, now if we imagine that our rulers have a little digital clock embedded in them (I got one of these once at a trade show and though, wow! A relativity measuring device!), the ruler I zip past will tick seconds slower than mine. Just like when I rotate my ruler in front of the wall, the shadow not only compresses, but there's now distance in z, when I "rotate" the ruler in space-time (by having a velocity relative to it), it has distance in that unseen dimension that manifests as slower seconds ticking by. It's very difficult to get more in-depth than this without getting into complex math, but I hope this gives you a good overview!

Yes because the total speed of an object through the dimension of space and the dimension of time equals the speed of light. An object moving through space must subtract from its movement through time for the sum to remain at lightspeed. So an object at the speed of light has all its movement through space and its movement through time must equal zero. Inversly a stationary object has all its movement through time and none through space. Making the quickest way to travel into the future is to stop moving.

I somehow dont believe this theory; If I am on a spaceship, travlling at light speed , then is my heart beat going to slowdown ? My heartbeat can be my clock. I can close my eyes while on the spaceship to avoid any perception related illusions. I suppose My heart must keep beating for me to be alive.

I’m not a physicist but my understanding is that time slows down for an object travelling at speed relative to other objects that are not moving or objects that are travelling slower. The passage of time is relative to the observer; this is difficult for me to explain with out using maths but basically it mean that if you were travelling on a super fast train approaching the speed of light, from your perspective time would be passing normally. You would not be able to tell that time was running slower because it is only running slower relative to an observer i.e. a man standing at the side of the rail tack watching you passing by. In principle this means time is passing faster for the man at the side of the railway track than for you travelling on the train, therefore the longer you stay on the train travelling at such high speed the greater time difference will occur between you and the observer. Theoretically you could get on the train in the year 2007 and travel at high speed before getting off the train in the year 2057. From you perspective only a short period of time will have past whereas relatively the world around you will have aged many years. I believe this theory has actually been proven and documented on a smaller scale by flying and aeroplane around the world at high speed with an atomic clock onboard. The atomic clock was perfectly in sync with another atomic clock on the ground; the experiment showed that the clock on the aeroplane had lost time by a few fractions of a second relative to the clock on the ground. Unfortunately it is currently thought to be impossible to travel even close to light speed due to many factors for example the energy requirement necessary for constant acceleration increases exponentially the closer to light speed you travel another factor connected to this is the fact the mass increases as speed increased (which means more weight) and more gravity, so any manmade craft travelling at such high speed would be implode under its own mass. I think the rate of acceleration necessary to reach light speed within the pilot’s lifetime without crushing the pilot under g-force is probably a consideration also along with other factor that I wont go into. M Eves

thats a bit mind blowing.

I have a few problems as well with this "theory", as for the physical proof of this test, the satellite or the air plane or whatever, the clock on the flying object was stated as to have moved slower than the clock on the ground. However we don't even know which clock was actualy traveling faster through space. I don't think that you can actually negate the fact that even the clock on the earth is moving at some speed through space that we cant really measure because there is no fixed point in space that we can say that speed is excactly at zero because everything is moving, even our whole galaxy is moving through space at some unknown speed, to my understanding we can only measure the speed of our galaxy through space relative to other celestial objects in space that are also in motion. So my point being how do we know that if we load a clock in a space ship and fly it directly away from a clock on earth, that the one on the space ship is acctually traveling faster than the one on earth? What if they are actually traveling through space at the same exact speed but in opposite directions? Or what if the space ship is actually traveling slower than the one on the earth? and further more, if the space ship travels away from the object at high speed and then turns around and comes back to the object at the same speed then the "time dialation" effect would cancel it self out and both clocks would once again read the same exact time. Another thing that I see flawed with this argument is that supposedly this experiment was performed with two atomic clocks. We don't know enough about the relationship between relativity and quantum mechanics to know that there is not some other effect in play that alters the half life of the atomic element used in the atomic clock. So my next arguement is with the way we measure the speed of light. So we take a laser and bounce it off a mirror on the moon and measure how much time it takes to come back and then calculate it using the distance that the light traveled. Very good, however if the "theory" is actually true, i have some problems with this. It has been explained that if a train passes by you traveling at the speed of light then you standing on the train platform will see the people on the train moving in slow motion because time on the train is moving slower than time is moving for you. The problem though, is if that was the case, not only is time moving slower for the people on the train, but also for the train it self, therfore to the observer on the platform the train itself would appear to be going slower than the speed of light right? So in that case we should be able to see light distortions emited by say a flash light or the sun moving lazily around right? However that doesn't happen, so that means that the train will in reality go by you at the speed of light. So if the train itself apears to be moving at the speed of light, then why is it the objects in the train appear to be moving in slow motion relative to you? How is it that two objects (the people inside the train, and the train itself) both moving at the same speed, can apear to both be traveling at different speeds? in reality the train as well as everything on the train is moving by at the same speed. Furthermore, a light year is the distance that light travels in one year based on the speed of light in a vaccum, so if you travel away from here on a rocket ship at the speed of light and travel exactly the distance of one light year, then the people on the earth tracking you would see that you traveled that distance in one year because you were traveling at the speed of light. Now you are in your shiny space suit on the rocket ship traveling at the speed of light. You stop at the predetermined point in space that is exactly the distance of one light year away from earth, now the "theory" would state that for you on the spaceship time actualy moves slower relative to observers on earth, so that means that you would actually have traveled that distance in less than a year??? (scratches head) in which case according to you on the space ship, you actually traveled faster than the speed of light!!! So therefore, if this "theory" is true, then that would mean that the speed of light actually changes based on how fast you are going and therfore, the distance of one light year isn't a constant either, it would actualy also change as your speed is faster or slower. Or you could look at the previous example from another view, the perception to you on the space ship is that it took you exactly one year to travel that distance, now to the people on earth it took you 100 years to travel that same distance, so that would meant that from the viewpoint of the people on earth you were traveling significantly slower than the speed of light? Anybody?

I teach a philosophy class in college, and I had a student ask: If time slows down as we approach the speed of light, then would it speed up if we sat motionless in outer space? Can anyone help me with this? Further, if time does speed up, would it be only a negligible amount in comparison to however fast we are going here on earth?

i want to believe this because so many brilliant minds have stated it as true. but my inner logic cannot percieve it. unless it is all relative. then it just seems less significant and plain obvious. if were talking about speed and distance, a definite time must exhaust when traveling the distance at any definite speed. why would travelling faster have any effect on the amount of time it takes for a measurement of time to expire. the time it takes to get there may change but the time itself would keep ticking at a constant rate. for both the person remaining at rest, and the person moving. it shouldnt change because of motion. the speed of light seems irrelevant to time, but it helps me make my point. if you travel faster than light, light would not exist to your perception the same as others. maybe it would be dimmer to you, or maybe you wouldnt be able to percieve it at all. or maybe you might see the expansion from its source. but this is impossible even though it is physically travelling, and it is still considered strictly constant. it travels a definite distance given a definite time. it seems more likely able to be affected by speed and distance than time expiration. time is a conscious(?) measurement of the progression of moment to moment. it seems that it constantly ticks at a steady rate and i dont see how anything could actually jump or compress the ticks when there is no physicality to it. even so i imagine the ticks get small enough to account for the speed of light to exist at each moment in its entirety. in other words the speed, or ticks of time are fast and small enough that light can operate at its speed and energy without disturbing the nature of either. so how could an object or person compress, exist more than once in, or skip, frames of time, while light, an obvious, physical, moving entity is constant. i would find it easier to believe the speed of light is capable of slight alterations. but i have no idea really. i guess further education in physics and mathematics is required to see the proof.

Your question is incomplete, does time slow down for whom? Your question asks if "you" travel fast enough..., for "you" time will always appear to elapse at the same rate, however to an observer, say, standing on the surface of the Earth observing you, time would appear to be elapsing more slowly for you than for the observer.

If Flash and Neo are any indication, yes.