time dilation?

Question

as you approach the speed of light time slows down, and at light speed time stops. so wouldn't that meant that light travels instantaneously.

Answer 1

True, but only from the photon's point of view.

Answer 2

That was Newton's Folly >>> light travels instantaneously
>> meaning v = infinity or Delta (t) = 0 >> time is absolute and not relative.
in other words >> if a new mass enters the gravotational field of a planet >> then the grav. force will set in on it with v = infinity

this is wrong.

instead when v >>> approaches nearly c then rest mass, proper length, proper time interval >>>> etc etc will lose significance
>>> it is just like >>> when you are about fall into a well, then assume as if you never ventured out to the well.>>>

Answer 3

Hello cbirch -

I believe you are being confused by some of the intuitive problems that come along with the nature of light as Einstein described it over 100 years ago. The speed of light in a vacuum is constant - it has been measured and demonstrated thousands of times. This is regardless of the speed of the source or the observer - so if you are traveling toward a star or away from a star at .99 x the speed of light, then the light from that star will still pass you at exactly the same speed, which is about 186,000 miles / sec relative to you. There is no question that this occurs - it's been understood for decades. It is this part - the "relative to you" part, that Einstein turned into his theory of special relativity. As you approach the speed of light, time slows down for you, but only relative to someone else who is not traveling that fast. So if you pass someone at nearly the speed of light, then to him, your clocks will run slower, your length will be compressed in the direction of motion, and your mass will be increased - all relative to him. To you, he will be passing you at nearly the speed of light in the other direction, so you will make the same observations when describing him - his clocks will run slower, etc. This is how the dilemma of the observed constant speed of light is resolved when it comes down to the equations of motion. (note: this does not affect the Twin Paradox - that's another issue entirely, due to the "turnaround and return" part of the journey). This happens all the time in cyclotrons and high energy particles entering the earth's atmosphere.

But part of your question involved what happens to time at the speed of light. Well, that's kind of a moot question, because it's like asking what happens if I make time go backward or sideways? Our universe just doesn't work that way. As far as we know, the speed of light cannot be attained by something that has mass, like you and I. I think of time at the speed of light as having no meaning - it's like defining infinity, or the nature of the inside of a black hole singularity. The nature of the universe is just not that simple, unfortunately.

Answer 4

I only know the answer from a high school physics point of reference.

You can't actually reach speed of light, but theoretically the closer you get the slower time passes relative to a stationary observer and the more massive the object gets.

I believe these effects have been observed using particle accelerators.

Answer 5

Relativity says that time stops at the speed of light, however this does not mean that light has no speed limit, it does. I don't agree with the idea of time dilation. If you are curious as to my views on this e mail me at [e-mail] And type, "What is Tim?" in the subject box.