Is time travel possible if we design a vehicle that travels in the speed of light?
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Let us look at TIME from the point of view of an ordinary person like me - without the equations and the maths. First, let's nail this TIME TRAVEL. Let's use an example of traveling from point A to point B - a distance of 1000 kilometers.
If I drive the car non-stop at an average speed of 100 km per hour, I will reach point B in 10 hours. If I drive at 200 km per hour, I will reach the destination in 5 hours. Right?
I can therefore say that either the time of travel has reduced by 50% or the distance has reduced by 50%. The result is the same. We know that the "distance" cannot really be reduced because it is something physical, so we conclude that we have utilized lesser time to reach the destination because we increased the speed. Quite true, too.
If I drive the car (I have a super-duper car) at 500 km per hour, I will reach the destination in just 2 hours.
Already, I can tell my friends that I have traveled in time! How? Well, if I had driven sanely like other people, I would have taken 10 hours to reach point B, but I increased my speed to 500 km per hour, therefore I have traveled to the "future" - 8 hours in the future, precisely. The others who followed me at 100 km per hour will reach the destination only 8 hours after I reached there - therefore as far as they are concerned, I am already in a point that would be reached by the others 8 hours later.
"No object can travel at a speed greater then speed of light. But if you are able to achieve 99.99% the speed of light .Then as you will increase the speed of your object time will start to slow down for you.Where as rest of the world will be moving at the normal speed. Which means you will have a one way trip to future by approaching the speed of light."
Sounds familiar, no? If you go fast, your time will slow down for you. (Instead of 10 hours, you will be in Point B in 5 hours - time slowed down?) Rest of the world will be moving at normal speed (the other guys in the car at 100 km per hour?) Which means you will have a one way trip to future by approaching speed of light.(by driving at 500 km per hour am I going 8 hours in future?)
Do you see how silly it is? People are so confused with this "time travel" crap (thanks to Einstein and Hawking et al) they don't seem to realize it is only "relative" and not real. It is Just "imaginary" to say the least.
As far as the people in the 100 km per hour car are concerned, I zipped past them to "their future" - 8 hours ahead of them. As far as I am concerned, they are in the past - 8 hours in the past - right? Wrong. In actual fact, I am in my "present" and they are in their "present".
Same way, to get to "Proxima" I need to travel fast. Like - theoretically if I travel at 90% of light speed, I will reach there in just over four years. So according to everyone, if I put up a super good telescope and point it towards the Earth, I am looking at the past - some 32 years - because I have worked out that 28 years would have passed on my home planet, and light takes 4 years to reach Proxima.
In the same way, on reaching Point-B 8 hours earlier, if I put up a super good telescope and look at the route coming in from Point-A, I will see the others coming along at 100 km per hour - am I really looking at 8 hours in the past?
Don't laugh at this example: It is just like the Indian who goes to the U.S. for the first time - unless the Dollar is converted to Indian Rupees he is not able to figure out the cost of materials over there. Similarly wherever we are in the Universe, we know only our "time".
Sure, I know that time dilation shows up only with relativistic speeds, but I gave the above examples to show that it is not "time travel". I can go further and ask, after reaching Point-B, if I look at Point-A through a powerful telescope, am I seeing the "past"?. You will say "No - because both point A and point B are on Earth. OK, then - in a broader sense - though Proxima's light takes four years to reach Earth, aren't we both in the same Galaxy? For argument's sake, if we can have an UNIVERSAL TIME for the entire Earth, can we not have a GALACTIC TIME for the entire galaxy? When humans begin interstellar travel, it may be necessary too.
You see, my point is - time has no independent existence - it may just be a common unit of measurement making it easier for us to describe the various motions that we see around us in our daily life. Have you ever considered - the "present" is not measurable whereas the "past" and "future" are measurable - like "ten minutes ago" or "last month" etc and "ten minutes later" or "next month" etc. for past and future, respectively.
Every instant we are experiencing the present, it is turning into the past. This shows that the past and the present are purely a concept in our minds. First, we develop the concept of "time" as we grow up from childhood to adulthood. We are constantly experiencing the "present" - parts of which are retained in memory as the "past". And because of this memory of the "past" events, we are able to imagine a "future". [Rainfall this year was much more than last year; I hope next year will be normal]. However, even our thinking of the past or the future is only in the "present". It can never be anything else!
Let us not mistake time-dilation for time-travel!
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