akemiiwaya — 2013-10-24T13:20:55-04:00 — #1
Originally published at: http://www.howtogeek.com/174486/is-time-travel-possible/
Traveling through time is a popular storyline for sci-fi movies and books, but is time travel actually possible? Colin Stuart discusses the topic, Earth’s most famous time traveler Sergei Krikalev, and more in this new TED-Ed video.
h_dang_ho — 2013-10-25T06:40:39-04:00 — #2
I was a bit disapointed with the video to be honest, I expected a bit more. All it did was explain the effects of the relativity theory. Also their definition of time travel is a bit... plain.
Since you can't freeze time it's impossible to not travel through time. Also if we ever move to Mars (or a part of the population does), like suggested in the video, people on both Earth and Mars will be time traveling with respect to eachother constantly, the same way which is already explained by them before when people use vehicles.
Also they don't even mention traveling backwards. Even if that's impossible I think they still should have mentioned it.
jivejimmy — 2013-10-25T14:38:53-04:00 — #3
While I may be a little fuzzy on relativity theory I recall that as speed increases, so does mass. And an object travelling at the speed of light would have (almost?) infinite mass. This would make travel at speeds high enough to achieve meaningful time travel impossible. An object with a large enough mass would attract planets, suns, and any other bodies capable of local annihilation. Just sayin.
h_dang_ho — 2013-10-25T16:23:51-04:00 — #4
No you're sort of correct and wrong at the same time. The whole point is that when you get close to light speed it becomes really obvious and noticable. At lower speeds the effect is also there. It's just a lot less. That's why in the video they tell you if you travel by plane around the world the time passed for you has been a little shorter than those on earth not flying around.
From what I understand, to have something with mass to reach light speed you need infinate energy.
An object with large mass does attract. That's what black holes do. But it's not like there are black holes so everything gets sucked in instantly. Black holes are actually very common. They're the things that keep systems like our milky way together.
themike — 2013-10-25T18:07:53-04:00 — #5
time travel was never possible with my ex. getting there on time was feat in itself...
nsdcars5 — 2013-10-25T22:38:23-04:00 — #6
freeman — 2013-10-28T04:04:56-04:00 — #7
don't have much faith in time travel. can a man be signals that can be transferred? No!:(
michaeltunnell — 2013-10-28T19:20:21-04:00 — #8
Is Time Travel possible?
Yes absolutely...you are doing it right now...one second at a time (ok you can go smaller with miliseconds, nanoseconds and blah blah)
Time Travel Theory
There are many theories revolving around time traveling but the one that makes the most sense in my opinion is that time travel is theoretically possible at some point with the bending of space (not exactly but that is the closest description without breaking out some calculus). The theory basically says that if a time machine were ever to be invented it would be possible to travel forward in time because the machine would be possible to exist in that time but it could never travel to the past because once you go past the point of the creation of the machine then the machine could no longer exist.
So if someone ever creates one they will only be able to go back and forth in time from the moment it was created to any time forward.
Lets say it was invented in 2023 and the person used it to travel to 3023 that would theoretically be possible, they could then go back to 2023 or anywhere in between BUT they could never go farther back than the moment they finished creating it.
The speed of light is a completely different topic because that is not relevant to time. If you travel at the speed of light to somewhere you are still in the same timeframe you are just in a different location now. Lightyears are a measure of distance, not time. For reference = 1 Lightyear is about 5.8 Trillion Miles.
Nothing with Mass could ever travel at the speed of light but it is theoretically possible to travel close to it but never as fast or faster than light. Of course there are thousands of limitations to actually doing that but the possibility of it happening at some point is there.
With all that said there are some cool things that a human can experience that makes it seem like time has stopped or sped up.
For example: if you are in a plane flying west around the earth at the equator then the Sun would appear as if it is not moving because you would be moving fast enough in the same direction for the Sun to stay in the same spot throughout the flight.
chungie — 2013-10-28T21:10:11-04:00 — #9
Are you referring to momentum?
wilsontp — 2013-10-29T10:48:58-04:00 — #10
Mass doesn't increase... not exactly. Your inertia increases, because the effects of relativity require that more energy is required to accelerate an object as it approaches the speed of light.
I'm not a physicist, but here's what I understand about Relativity:
Due to the light-speed limit, as an object approaches the speed of light, all of its internal motion has to be redirected toward the direction the object is moving. AT the speed of light, the object can have no other internal motion: electrons can't orbit their atoms. Atoms and molecules can't move around in fluids. Heat and other energy can't move between components of the object. Even the molecules themselves have to stop vibrating.
Time dilation is what you get when that effect starts to kick in: you are forcing the subatomic particles in the object to stop moving along other paths and move in the direction of the object itself. As more of the object's internal motion is wrapped up in moving along that straight line, less is available for chemical reactions and the exchange of energy - kinetic energy included.
This means that you have to exert greater and greater force, relative to the mass of the object, to accelerate the object closer to the speed of light, since you're not just accelerating the object itself, but you're decelerating all of the object's internal motion.
None of this causes the object to increase its gravitational pull against other objects; it just increases the object's inertia.
So the speed of light limit makes an object's inertial mass increase, but not its gravitational mass.
jivejimmy — 2013-10-30T16:06:04-04:00 — #11
I know way less than you but that sounds right. My mistake was
confusing gravitational mass with inertial mass. I won't let that
chungie — 2013-11-11T21:49:36-05:00 — #12
Okay, seems as if you know what you are talking about. Time travel will be possible but not in this day and age.
Good Luck Kids! ... or Kids to come!