Why is time travel into the future possible, but time travel into the past is not?

well probably because you are already travelling into the future,(every second you are travelling to the future), but travelling back to the past means to reverse time, which is not possible because it is against the law of nature. the law of nature is that time always move forwards, not backwards.
every minute is passing away even as you are sitting in front of the computer, yes it is passing away and you are not realising it. that's travelling into the future. you are now travelling into the future...dip into the future. the past could remain as memories, but you cannot turn the time back.
even if you can travel back to the past, the things altered here on earth is of the future, they cannot be altered, e.g. materials, "new" buildings, infrastructure, cannot be turned back to "old" ones.
so time travel back to the past is not possible. it is against the clock time - the law of nature.
energy needs to be conserved. (the law of the conversation of energy)

L E Gant is right, the laws of entropy forbid travel into the past. There are also several other reasons. The laws of conservation also forbid it, the laws of conservation of energy of matter and of angular momentum. Travel into the future follows the arrow of time as defined by a British physicist, Arthur Stanley Eddington, who realised that entropy, which we know always increases, further defines the direction of the flow of time. Were it not so, the Universe would be a nonsense, with glasses lying shattered on the floor suddenly joining together and leaping back onto the table from which they fell. We won't see that happen if we sit and watch until the end of time!

Time travel into the future is possible because we're doing it all the time, at the superlight speed of one second per second.

Travel into the past would mean reversing entropy.

to go in past u have to exceed speed of light(which seems not possible)and to go in future you have to be near at speed of light..according to einstein's theory!!

right here is what i can declare for specific: a million. you may shuttle into the destiny at a fee of a million 2d each 2d. in case you opt to shuttle 10 years into the futue the adventure will take you 10 years and that's a one way holiday. 2. because of our understanding of the character of time, you may replace the cost at which era passes by using increasing your speed or relation to a gravitational container. as a consequence in the adventure that your speed replaced with comprehend to the Earth then there'll be a disparity between the cost at which era exceeded for the Earth and the cost at which era exceeded for you, the equation to calculate the time dialation is referred to as the Lorentz remodel. t' = t/sqrt(a million- (v^2 / c^2)) As for regardless of if prompt time shuttle into the destiny (or previous) is attainable that's greater often than not purely hypothesis.

time travel to the future is a issue of breaking the speed of light which cannot be done with any technology we have, but going backwrods in time just is not possible with any laws of physics it just does not happen

Traveling to the past is compleatly probable, light has already touched the past therfore making it a event in time, space and time are cannected.. Without light particles we would not have time so technically if ur traveling into the future u would see nothing.. U can't see what not even light has touched yet