Physicists Claim Time Travel Is Impossible (This Time, They Mean It)
from the in-case-you-were-hoping... dept
Discussing the physics of time travel has come into vogue recently. Even Stephen Hawking — who admitted he used to fear being labeled a “crank,” if he discussed the physics of how time travel might be possible — has explained how time travel might work (and revealed his desire to go back in time to see Galileo… and Marilyn Monroe). However, some new research states what most of you probably already thought: time travel is a physical impossibility. While I agree that seems likely, I have to admit that I’m a bit amused that the LA Times article about this seems to assume that because it’s in a “peer-reviewed scientific journal,” that makes it the unquestioned truth. And, while I, once again, tend to agree that it’s likely that time travel is impossible, there have been plenty of other things declared impossible by scientists that later proved possible. Remember, Lord Kelvin declared “heavier-than-air flying machines are impossible,” just eight short years before he was proven wrong.
Filed Under: physics, time travel
Comments on “Physicists Claim Time Travel Is Impossible (This Time, They Mean It)”
Science of Today
All that means is a bunch of guys got together and couldn’t figure out how to do it and a bunch of other guys agreed.
Doesn’t mean a pile of dog crap for Tomorrow.
Re: Science of Today
^ this
Re: Science of Today
All that means is a bunch of guys got together and couldn’t figure out how to do it and a bunch of other guys agreed.
No – if you read the article they demonstrate some fairly obscure stuff about the speed of photons – which happens to close off one particular mechanism – no-one in the proper articles said time travel was impossible in general – just his one route.
What they are doing here is to try and get greater impact for a fairly dull and obscure research program.
If you want a respectable (sort of) physicist who thinks time travel might be possible you should try Holger Nielsen!
ps if you ever get to meet him = or attend one of his public lectures a pair of earplugs is advised!
Re: Re: Science of Today
“Fairly dull”?
I disagree. This research is fascinating — which is not to say that it’s correct or incorrect, but it’s certainly interesting.
Contrast with “trending now” on Yahoo: Kim Kardashian, Mila Kunis, Mike Tyson. Drivel and dreck, utterly worthless celebrity worship, gossip and rumor.
My point is that we live in a culture which has devalued exploration, mystery, wonder, enlightenment, learning, discovery…in favor of Jersey Shore, American Idol, and The View. No wonder the Chinese are kicking our ass.
Re: Re: Re: Science of Today
> No wonder the Chinese are kicking our ass.
Yeah, ’cause the Chinese are so well-known for their wonder and enlightenment…
Re: Re: Re: Science of Today
The chinese are copiers; not inventors…
Re: Re: Re:2 Science of Today
And the only reason they are doing so well is because our government sold us out in favor of the rich and rich corporations.
Bring back the cold war! Everyone was working then…
Re: Re: Re:2 Science of Today
of course:
if you forget things !!!
Papermaking, compass, gunpowder and printing, astronomy, argriculture, engineering, nautics,
Paper money
Fire Lance
Land Mine
Rockets
the Rudder (for steering ships)
Abacus
higher math
metal working and creation
the plow
medicine
printing and paper I guess are the biggies
Re: Re: Re:2 Science of Today
what has the US invented again ???
Re: Re: Re:3 Science of Today
if i remember rightly: condensed milk.
can’t remember if the Internet was a US thing or a joint US/other countries thing.
the US does have a long history of nicking other people’s ideas and turning them into useful things though. (you know, that thing patents are designed to stop you doing?)
Re: Re: Science of Today
When a theory of time is developed I will listen.
Mean while could some explain to me is time digital or analog.
Re: Re: Re: Science of Today
It is very hard to say whether time has discrete indivisible steps. The Plank time is lightly considered the atomic unit of time within our current theoretical framework but once you really start to dig into this question it becomes extremely difficult to answer definitively. It’s like asking whether particles are truly point-particles or waves.
http://en.wikipedia.org/wiki/Plank_time
http://en.wikipedia.org/wiki/Wave_particle_duality
Caveat: not a pshysicist
Re: Re: Re:2 Science of Today
They are both point and wave. I reality it is our limitations that are the reason that we cannot describe it properly.
Remember, matter and energy are the same thing, E=MC squared.
Since light itself exhibits both particle and wave traits there must be a matter/energy state that is in between where the photon can exhibit traits of both.
Re: Re: Re:3 Science of Today
I think it is more accurate to say that they are a “thing” that has some properties of points and some properties of waves, and that it is often useful to consider them as having properties of just points or just waves depending on the context in order to aid in mathematical understanding.
Saying they are “both” strictly implies a set of properties which includes all of the properties found in both particles and waves, which can actually be conflicting.
Re: Re: Re:4 Science of Today
It’s not conflicting at all. Consider:
Water is comprised of discreet particles, H2O molecules.
But, water exhibits wave behavior as well.
So, which is it wave or particle?
It may be that everything is comprised of particles but it is my belief that both particles and energy are merely observed states of the same thing.
Re: Re: Re:5 Science of Today
You’re making an invalid comparison
“So, which is it wave or particle?”
Water? It’s a particle. Individual water molecules do not exhibit wavelike properties, the way individual photons do. Photons have associated probability waves that describe the probability of their location at every point in the universe. The probability waves of individual photons can interfere with those of other individual photons, creating interference patterns that could not otherwise exist (wavelike property), while still existing at a specific point when directly observed (particle property).
Re: Re: Re:6 Science of Today
Water? It’s a particle. Individual water molecules do not exhibit wavelike properties, the way individual photons do.
yes they do,
and in exactly the same way, you can have a particle of water that acts like an individual molocule, or atom, and you can have many water particles acting as a wave.
You have never seen a wave in water ? you need to get out more.
It’s not only photons that have this duality of wave and particle at the same time, matter does this as well !!
exactly as light does, you can perform the double slit experiment with photons of light, electronics or individual atoms and you will see the wave effect and therefore the wave/particle duality.
The fact there is interference that occurs on the target, not in one of the two slits, means that the photon or atom passes through both slits at the same time, and interferes with itself.
so you fire a single (ONE) photon at two slits, that ONE photon travels through BOTH slits at the same time, which means two photons are passing through the two seperate slits, (when you only sent one in the first place), those two photons then interact with each other to create an interference pattern.
all matter and light have the same wave/particle duality.
as matter cannot travel at the speed of light, it is not speed that determines this duality.
Its not “science of today” its science, it’s the same science today as it was yesterday and will be tomorrow.
Re: Re: Re:7 Science of Today
Still not quite. You’ve got the basic concept down, but you’re off on the details. In the double slit experiment, it’s incorrect to say that a single photon passes through both slits at the same time. Its probability wave function does, but the photon itself doesn’t have a discrete location, much less two discrete locations.
Yes, I’ve seen waves in water. Those happen because trillions of molecules are acting together; it’s a fundamentally different discussion than the behavior of individual particles, atoms, etc. As for testing molecules in the double slit experiment, give it a try, see what happens. You’re correct that it’s theoretically possible, but a molecule, or even a single atom, is a vastly complex system, with numerous probability waves to account for, compared to the simplicity of a single particle.
Re: Re: Re:8 Science of Today
but the photon itself doesn’t have a discrete location, much less two discrete locations.
I tend to agree with you, but what is a ‘probability wave function’? to me its just a name, the effect observed is that the photon appears to pass through both slits.
If the photon does not have a descrete location, then by definition it must be in many locations (as shown in double slit), so if it does not have a descrete location then it’s location is more than one, as you probably know quantum theory shows that the same photon of light travels ALL possible paths, but the first one to arrive destroys the rest of them.
And it can be shown to be a physical reality that this occures and that nature uses this multiple path’s thing.
Photosynthesis, is a highly efficient process, over 95% using classical physics it is not possible to achieve this efficiency. But if quantum tunneling is included it matches perfectly.
Plants have learnt to use the particle/wave and no specifc known path of travel to acheive the very high efficienies that are measured.
but thanks for your input, you have a clear picture of what is happening, (with the appropriate degree of uncertainty).
Re: Re: Re:5 Science of Today
“particles and energy are merely observed states of the same thing“
This is fairly well proven as part of the theoretical basis for quantum physics.
Re: Re: Re:6 Science of Today
its not quantum physics its classical physics, Einstein stated E = mc^2, that is the relationship between matter and energy. E = mc2 is not really a part of quantum physics (the physics of the very very small).
Einstein was not that big on quantum theory stating something like “god does not play dice”.
Re: Re: Re:7 Science of Today
i’ve encountered two responses to this:
“Stop telling God what to do!”
and
“Not only does God play dice, but the dice are loaded.” (admittedly, the latter is from Alpha Centauri :D)
Re: Re: Re: Science of Today
what do you think the ‘theory of relativity’ is ?
is there a ‘theory of weight ?”
or a theory of length ?
or a ‘theory of cheese’
because Newtons laws does not say “theory of gravity” does that make it any less valid ?
Re: Re: Re: Science of Today
“When a [proven] theory of time is developed I will listen.“
^THIS!
Re: Re: Re:2 Science of Today
you will be waiting forever, there is no such thing as a “proven” theory.
There are testable theories, and repeatable theories, and theories that work within specific limits. But there is no such thing nor will there ever be a ‘proven’ theory.
Re: Science of Today
I love it when those who are confined to this speck of dust in the Cosmos claim to know the truth about said Cosmos. They are ignorant and unbelievably arrogant, just as those that have come before claiming to know the Truth.
Re: Re: Science of Today
A friend of mine, who has a degree in philosophy, usually has a fit when I’m foolish enough to use the word “truth” when discussing topics in science. I think a comment I read on Slashdot nailed it – science is about facts, truth is in the realm of philosophy.
What I can never get him to accept is that science is a process. What is thought to be known currently is always subject to revision. Scientists are continually trying to be less ignorant.
And I don’t believe it is arrogant to make statements claiming this is how this thing works. That’s just the process. A claim is made and others test it’s validity.
No one can say for a fact whether or not we can ever figure out how the universe works. Maybe we can. And I don’t consider that thought to be arrogant (although it is most definitely ignorant). I’m just trying to limit my assumptions.
Re: Science of Today
watching a bird fly should have gave Kelvin an idea.
Re: Science of Today
No, that’s not really true. Science advances, but it doesn’t periodically replace all it’s knowledge with new knowledge – instead, it adds to existing knowledge, while occasionally, but infrequently discarding something. The physics behind time travel is well known. And it is almost certainly impossible.
Once upon a time
Headlines from the past! (paraphrased from my memory)
Humans will never travel over 50 miles per hour. (in 1700 or so)
Head of Patent Office declares everything possible has been invented. (in 1830-something +- 30 years)
…and so on. I need more coffee before I can begin a good research-fueled rant. Anyhow, generally anytime a bloke claims something is impossible later some other bloke comes along and says “no, it’s easy, see?” and that settles it.
Consistently, humans have declared all their forebears idiots and claimed to have the only correct view upon the universe. In a century or so, our descendants will declare us to be idiots and claim they have the correct view of the universe. Odds are, we’re wrong in both statements–our ancestors weren’t idiots and our view of the universe is FAR from complete. The same will likely be true in a century and in a millennium.
Nothing is impossible; it’s all just a matter of time.
Re: Once upon a time
…and so on. I need more coffee before I can begin a good research-fueled rant. Anyhow, generally anytime a bloke claims something is impossible later some other bloke comes along and says “no, it’s easy, see?” and that settles it.
That of course includes the statement that you just made (the one that said you can’t predict that something will be impossible).
More seriously – we forget the predictions that turned out right – we make a big thing of the failures. The problem is that from here it is impossible to tell which is which and in general the ones that lots of people want to be wrong turn out to be right whilst the ones that everyone thought were obviously right are the ones that turn out to be wrong.
Re: Re: Once upon a time = "in the begining"
Time travel back in time is possible, and happens all the time, but it is relative.
If you are on the ISS or the space shuttle (if you had one) you time would go faster compared to someone on earth.
Therefore we see the people in the space station going forward in time FASTER, therefore they see out passage through time as going slower.
To them, he have traveled back in time, to us they have traveled forward in time.
Time travel backwards is possible.
Re: Re: Re: Once upon a time = "in the begining"
If you are on the ISS or the space shuttle (if you had one) you time would go faster compared to someone on earth.
Therefore we see the people in the space station going forward in time FASTER, therefore they see out passage through time as going slower.
You’re saying time moves slower for the people on the space shuttle. This is true, but I don’t think that’s what most people think “backwards” means.
Time can not move in a “reverse” direction. You can never go into the past, just change the rate at which you’re going into the future.
At least according to these scientists.
Re: Re: Re:2 Once upon a time = "in the begining"
so extend the time value, and consider that when the astronaughts come back to earth, they are living seconds of time that they have allready lived.
they have gone back in time, and are re-living their past, relative to ours.
so if you started at 1pm and went fast enough to gain 1 second of time and you stopped after 1 hour (your time), you would return at 1:59pm, and you have traveled back in time 1 second.
Because your watch says 2:00pm, but the ‘real’ time is 1:59pm, you have travelled back in time. and you can ‘re-live’ that second you get to travel back in time to the past.
Just because it ‘takes more’ forward time to travel back in time does not mean travelling back in time is impossible, or even difficult, it just means it’s relative.
you cannot arrive before you leave, but you can arrive before you are supposed to arrive before (the) time.
so what you arrive at 1:59pm instead of 2:00pm, you have arrived before the time that it is possible for you to arrive, before the time, is another way of saying ‘in the past’.
therefore time travel, either forward or backwards.
Re: Once upon a time
> Humans will never travel over 50 miles per hour.
> Head of Patent Office declares everything …has been invented.
You left off one . . .
RIAA says business innovation in music is a physical impossibility. Must stick with the past.
Saying time travel is impossible is a really safe bet. If it turns out time travel is possible, they can always go back in time and change their statement.
But since they haven’t changed their statement then that means time travel is impossible.
Peer review that shit, I win.
Re: Re:
^ this
Re: Re:
Not so different from Hawking’s approach – he left an invitation to his “party for time travellers” in a place where he expected it could be found by the right people. No-one showed up!
Re: Re: Re:
Maybe it was illegal to show up?
Re: Re: Re:
But what if, in the near future if time travel has been invented, that bit of paper is destroyed ? Surely you would have to keep it somewhere safe and the message to be a bit more clearer ?
Re: Re:
I’m you, and I come from the future to tell you that time travel is possible. Change your statement.
Well OBVIOUSLY time travel is impossible.
Have you tried to order parts for a DeLorean DMC-12 lately? Space exploration would be cheaper.
Not to mention the cost of flux capacitors today…
Re: Re:
I made one when I hit my head on the toilet. Now, that parts didn’t exist until 1955, when I hit my head on the toilet and created them…but still.
Re: Re:
Yeah and that whole 1.21 gigwatts of power thing.
Apparently the REAL reason plutonium isn’t commonly sold is because people would use it for time travel. Back to trying to harness lighting I guess…
Re: Response to: keiichi969 on Jul 26th, 2011 @ 7:41am
Stay away from DeLorians and time travel, that stuff will give you Parkinson’s :S
Nothings impossible
Nothings impossible, Only improbable. And you can’t prove a negative.
Re: Nothings impossible
Nothings impossible
Are you saying that one cannot create a perfect vacuum?
Re: Re: Nothings impossible
Only in a politicians head.
Re: Nothings impossible
By that logic, you can just reformat any statement to be a negative statement, and thus we can’t prove anything:
“Acceleration on earth isn’t 9.81 m/s^2” Oh noes!
Obviously that isn’t a negative… using math you can certainly prove it. Being lazy I didn’t read the article, but I assume they did something with math…
A negative statement is more along the lines of “Bigfoot doesn’t exist” – i.e. no one’s seen him, so you make a conclusion.
Challenge Accepted
Okay the field of science is sometimes like the the world of hacking. If you say something is impossible people take it as a challenge to prove that it actually is. My point, someone out there either just started to work on proving time travel is possible or someone just redoubled their current efforts to prove time travel is possible.
Time Travel is possible, just not backwards.
Science has known for a while now that time travel is possible, but only in one direction: Forward. Traveling to the past is impossible because no time machine can travel back to before its own existence. Unless, you can circumnavigate a black hole safely, traveling back in time a significant amount is unlikely. No man-made time machine can ever travel to the past, but it can travel to the future. Things like gravity and relative speed can change the rate at which time passes, allowing us to dilate time around us. What seems like a few moments for the time traveler, results in minutes, days, years, or even decades to the outside observer.
The whole claim that time travel is flat-out impossible is complete bullshit. We are traveling through time right now, always. GPS satellites have to compensate for the fact that time passes at a different rate in orbit as it does on earth. The LA Times article doesn’t even explain why the speed of a photon even matters and how it affects the possibility of time travel. I can only conclude that the article is making a false claim based on the lack of real explanation of why it can’t work. The article doesn’t say the cited study says time travel can’t work. It only states that photons cannot exceed the speed of light. That’s not the same thing as “time travel is impossible”. If they did find that in the study, they sure don’t explain their reasoning in the Times article.
Re: Time Travel is possible, just not backwards.
Edit:
I just re-read the article. I see that their reasoning is that superluminal travel is impossible and, by extension, time travel is impossible. That completely ignores the effects of gravity and speed though.
Re: Time Travel is possible, just not backwards.
“Traveling to the past is impossible because no time machine can travel back to before its own existence”
But as everyone knows, if you go forward in time far enough, the universe starts over, identical to the previous universe. So you just need to travel to the point you want.
Then you can get home again easy enough. Just don’t overshoot or you gotta go around the horn again…
Re: Re: Time Travel is possible, just not backwards.
remember to stop and shoot hitler when you pass by
Re: Time Travel is possible, just not backwards.
Yep, and that was already a fact. The title of this article is misleading.
Re: Time Travel is possible, just not backwards.
Perfect
It is possible
Time travel is possible. I’m doing it right now.
Time is but an illusion
So they’re saying you can’t go backwards in time by going forward vary fast. That’s OK, I could never understand that anyways. We already know that traveling vary fast lets you go forward in time (or in scientific terms your time slows and time around you stays the same). The closer to light speed you get the faster you move forward in time. Why would passing light speed make you go backwards?
This does not negate the possibility of backwards time travel, nor does it negate the possibility of FTL travel. It just means we can’t do ether in that specific way.
Re: Time is but an illusion
FTL is possible if you can create a bubble of static space and propel it from one point to another. Space can move faster than light.
Gravity can affect time travel as well. That’s why black holes are considered the ultimate time machine, if you can manage to not get sucked into it. The stronger gravity is, the faster you move forward in time.
Re: Re: Time is but an illusion
ummm . . .You don’t appear to have a very good understanding of the basic physics involved here.
Neither do I, but I think I can point out some things you appear to be misunderstanding.
Space ‘moves’ faster than light because we can observe two things from a 3rd viewpoint, each moving directly away from the other at near the speed of light. The space between them will grow by the addition of the speeds.
OTOH, if we observe from either one of the objects moving directly away from each other, they will always only observe themselves as moving away from the other object at near the speed of light.
This difference in observation between the ‘neutral’ observer and the two ships is achieved in lorentz transformations, namely time dilation and space contraction.
What that means, is that no matter how fast I gun the pedal, if that star is 1 light year away, I can arrive no earlier than 1 year after I set off.
BUT, I can gun the pedal REALLY hard, and arrive in what seems to me, to be a single second. Because I perceive the space between the planets as becoming much smaller the more I gun the pedal. That’s space contraction.
On the other side, all observers on either planet would observe my ship as taking a year. That’s time dilation.
The GPS satellites have to account for relativity & time dilation, yes, to be as precise as they are.
Time doesn’t pass differently; it’s just the observers disagree on how time is passing.
As it is, unless we can go past that limit that requires infinite energy to even reach, the speed of light, there is no way in the current model to use speed to travel anywhere but forwards in time.
TL;DR: We haven’t disproved time travel the same way we haven’t disproved, say, ghosts. We HAVE disproved time travel in one way that it seemed it would work within the current model, (superluminal speeds). That being said, there are physicists with other ideas of how time travel could be accomplished.
Re: Re: Re: Time is but an illusion
Even I’m wincing at the way I imply lorentz transformations are time dilation and space contraction.
That’s incorrect.
The lorentz transformation is the equivalent of the . . . are they called newtonian transformations? of ordinary relativity.
That is, I have 2 moving objects and an observer. Say, I’m on a train, walking, and I want to know how fast I’m moving relative to the earth, (an observer standing by the train station, say).
Normally, I would add my speed to the trains & voila, very simple.
But if both me and the train are moving near to the speed of light, this is wrong. So instead of adding the speeds, (newtonian), we use a crazy formula, (lorentz).
Now it’s about time for a real physicist to come along and correct me again, right?
Re: Re: Re:2 Time is but an illusion
Your final statements are more or less correct.
in special relativity you add velocities by the expression
(v+u)/(1+vu/c^2)
so no matter how big v and u are (remember the most they can be is c) the result can never exceed c.
However when you talk about “space” moving I think you must be referring to the expansion of the universe – in which case you definitely need a general realtivity formula – not a special relativity one.
(Yes I’m a proper physicist! – I even gave a seminar with Hawking in the audience once!)
Re: Re: Re:3 Time is but an illusion
The space moving comes from Greevar, I answered what I thought he was talking about.
It makes sense to me that the universe can be growing at ‘faster than the speed of light’, since the universe is more than one entity, and things at opposite sides can be moving at near the speed of light. Is that wrong?
Thanks, Richard!
Re: Re: Re:3 Time is but an illusion
Thanks!
I was going to reply to some of the earlier posts with something along the lines of: “Well, yes, some earlier pronouncements by people in science were proven wrong. But saying ‘You can’t exceed C’ is along the lines of ‘Can’t divide by zero’. Or ‘You can’t violate the Uncertainty Principle – at least without collapsing the Universe’.
Your answer has the benefit of also saying: “You need to do more reading, y’all…”
Re: Re: Re:3 Time is but an illusion
Ok, maybe this is purely science fiction, but I recall reading somewhere that it is possible to close a portion of static space off and propel it from one point to another thus transporting any matter occupying that space and space does not suffer the speed limitations of energy and matter. Is there any truth to this or was I just fed a load of hogwash?
Re: Re: Re:4 Time is but an illusion
“In their scheme, in the Journal of the British Interplanetary Society, a starship could “warp” space so that it shrinks ahead of the vessel and expands behind it.”
I believe this was what I was thinking of.
Re: Re: Re:5 Time is but an illusion
Sounds completely different to me.
That sounds more like using gravity to change aspects of space near the gravitational field, and not so much like portioning off an area of space.
But y’know, that’s well beyond my ken.
Re: Re: Re:6 Time is but an illusion
Portioning off an area of space would require a change in the topology of space – there is no known reason why this absolutely couldn’t happen but the mechanisms for actually doing it are pure conjecture AFAIK.
The problem with warping space is that it would require prodigious amounts of energy to do it – and again there is no known way of making it happen in a useful way.
Re: Re: Re:7 Time is but an illusion
there is no known reason why this absolutely couldn’t happen but the mechanisms for actually doing it are pure conjecture AFAIK.
It’s called “mass”
All matter changes time, the more of it the more it is changed you change time, you change space, as they are one and the same.
Re: Re: Re:8 Time is but an illusion
Portioning space =/= warping space, which you are addressing.
And under warping space, he does address the energy and utility of current methods.
Re: Re: Re: Time is but an illusion
Space ‘moves’ faster than light because we can observe two things from a 3rd viewpoint,
What is “space”…. Answer “NOTHING”.
Therefore nothing travells faster than light.
if space moved ‘faster than light’ then light would be travelling backwards !!!! and that could well be the case, and we would never know it..
Re: Re: Time is but an illusion
I’ve never understood “you can’t go faster than light” Say you create a ship that can go -almost- as fast as light. then walk forward.
Or a bullet train with a racecar in it moving forward, and you move from the back seat to the front seat. except bigger with more steps and in a vacuum.
Re: Re: Re: Time is but an illusion
never mind maybe answered by above lol
Re: Re: Re: Time is but an illusion
“You can’t go faster than light” is bit overly simplistic.
“You can never go faster than the speed of light away from an observer” is more correct.
“You can go never go faster than the speed of light relative to an observer” is most correct, but that involves explaining relativity correctly.
Due to time dilation, if an observer on earth was witnessing you walk on a spaceship going near the speed of light, he would observe you moving very, very slowly. The faster the ship, the slower you would be moving, and no matter how fast you are moving relative to the ship, the observer would observe your speed to be less than the speed of light.
In fact, if the ship was moving, and you are moving down the ship to the captain’s seat at exactly the speed of light, the same observer would witness your speed to be exactly the speed of light. The slow-down from witnessing you move on a moving object exactly matches the difference between the movement of the ship and the speed of light.
Re: Re: Re:2 Time is but an illusion
In fact from the traveller’s perspective faster then light travel is perfectly possible. You could get to the other side of the galaxy in a few years – but when you got there you would discover that the galaxy would have aged by hundreds of thousands of years.
So your comment about “relative to an observer is very important”.
Re: Re: Re:2 Time is but an illusion
“”You can’t go faster than light” is bit overly simplistic.
“”
No, he is exactly correct, it is not overly simplistic, your following statments are overly wrong.
does not matter if you are going away from the observer or towards him, you will still never exceed the speed of light.
The speed of light is dependent on the observer, or his ‘frame of reference’
You are trying to say that if two observers are travelling towards each other at over half the speed of light the total speed would exceed that of light, it does not.
The reason why it does not is because time changes, instead.
Time is relative, not illusional,
“You can go never go faster than the speed of light relative to an observer” is most correct, but that involves explaining relativity correctly”
Then perhaps you may need someone to explain relativity correctly to you !
Relativity, is just that, it says you can never go faster than the speed of light….. period.
That is WHY time travel is possible..
Re: Re: Re: Time is but an illusion
Well in general, the faster you accelerate, the more energy it takes to go faster. By the time you reach near light speed, the energy requirements to just get up and walk inside the ship would be far beyond what your body can achieve. At least that’s how it was taught to me.
Re: Re: Re: Time is but an illusion
you are on a space ship travelling 1 MPH slower than the speed of light, you run from the back of the spaceship to the front, faster than 1MPH, you’re time will slow down relative to the other people on the ship so that you do not exceed the speed of light. The amount you slow down will not be noticable by the other travellers.
what happens when you shoot a laser pointer out the front windscreen ???? 🙂
Or look at it from another way, there is NO space, there is ONLY TIME !
When you are travelling at any speed you are travelling in time, but not necessarily space.
If you are travelling at the speed of light, your frame of reference (how you see the passage of time) is the same, you’re watch does not appear to be going faster or slower.
From from an outside observer, from a different frame of reference, you’re time is zero.
Things out of your window are not going faster, they are going at the same rate they always do, but your time is going slower, so it appears to you (the observer) that things are going faster when you look out the window.
If you are just under the speed of light a second for someone on earth could be billions of years for you on your fast spaceship.
So running from the back of the ship to the front does not make you exceed the speed of light, it makes you appear to be GOING SLOWER from an outside observer, until you are running at the speed of light, then you are STOPPED !!!.
get it ?
So the person in the spaceship is NOT travelling in time at all, but everyone else around him IS.
this is 1950’s physics, we live in a quantum world now and it is clear there are far more dimentions that the 3 space and 1 time classic TOR goes too.
Re: Time is but an illusion
I’m not a physicist but I think the idea is that as you approach the speed of light time slows down for you relative to everywhere else. That means from your point of view, time seems the same inside your ship but the outside world’s “clock” gets faster and faster, meaning Causes get closer and closer to Effects.
If you were able to exceed the speed of light it would appear (again from your POV) that Effects start to precede the Causes i.e. time in the rest of the universe would appear to be running backwards. In principle, you could then slam the brakes on and be in the past.
As you correctly point out – no-one has believed for decades that time travel using this method was possible – Special Relativity itself predicts that you would need an infinite amount of energy to accelerate to the speed of light.
What most physicists (including Stephen Hawking) are betting on as being more likely is the possibility of being able to “warp” spacetime in such a fashion that you could bring a more distant patch of space (or time) closer. You could then travel to it at a speed less that that of light and then let it “snap back” to it’s previous position. This would, in theory, allow FTL travel and in certain cases possibly time travel.
Although there are indications that this might be exceedingly difficult (AIUI you need to borrow a massive amount of “vacuum energy” to make it work), it hasn’t actually been disproved yet – and it doesn’t sound as if this paper even addresses this method of travel.
(Whew, step away from chalkboard David, step away… 😉
This new find is interesting considering the Chinese government just recently banned time travel themes in movies and TV. Apparently they don’t like the idea of themes that go back before the revolution and any idea that things might have been better back then.
Now, having said that, I think the way scientists are looking at time travel may be wrong. They’re assuming that time is linear. Now, with quantum physics, string theory and the idea of multiple universes/parallel dimensions gaining traction, it could be that time is parallel and not linear.
If these dimensions exist, perhaps it might be possible. But it wouldn’t technically be “time” travel.
Re: Re:
Now, with quantum physics, string theory and the idea of multiple universes/parallel dimensions gaining traction, it could be that time is parallel and not linear.
All of which boils down to the concept of time tavel via wormholes – problem is wormholes destroy themselves by feedback before they can get big enough to travel through.
The pseudo physicist cometh… time dilation is not time travel…
Re: Pfft
Pseudo-physics sucks; that’s why you should aim to be able to sudo physics.
;-P
Re: Re: Pfft
SUDO APT-GET TIMEMACHINE
Re: Re: Re: Pfft
Sorry, “TIMEMACHINE” has been removed.
Re: Re: Re:2 Pfft
That’s funny, the error message I get is:
“Sorry, TIMEMACHINE will have been removed”
Re: Re:
Aside from wormholes, all time travel is time dilation. Unfortunately, no wormhole can be maintained that is large enough for time travel and the moment it is opened, it would snap shut due to particles causing a feedback loop through time.
Re: Re:
No time dilation means no time, no time means no travel.
Are you trying to say there is things that exist that does exist in time ?
Everything travels in time, including time itself.
Nothing also travels in time, including time itself.
As time dilation is ether a part of the everything group or a part of the nothing group it therefore travels in time.
Try going back in space, instead of back in time ?
same thing, its a positive vector (like entropy), you cannot travel ‘back’ in space either, when you are travelling from one location to another you are always going forward, in whatever direction you are going, you are going forward.
But I guess that will too much for you to get your head around as well 🙂
When God said “let there be light” before he created the planets or the starts, then what did that light shine on ?
What would of happened when he said that (let there be light) (who too???), NOTHING WOULD OF HAPPENED !!!!
It would still be dark, and there would be no light, no source of light, and no destination for light.
It would have make more logic for him (or her) to say, let there be something that will show up if light hits it, before he created light !!!.
Where was and were is that light now ?, and where did it come from ? and where did it go ?
Even the ‘big bang’ did not create light first off.
It?s all a ploy to goad scientists into proving time travel is possible.
Before:
1 – Time travel is possible.
2 – Yeah, I guess.
Now:
1 – Time travel is impossible.
2 – Fuck that!
Seems To Me
Science is the new religion for some.
“A scientist said it, so it must be absolute truth.”
Re: Seems To Me
A scientist said it, so it has a lot more credibility than if you or I said it.
That doesn’t guarantee it is correct. It is just that the scientists’ track record and their process gives it a lot more credibility.
Nothing is more exciting or sets off a bigger flurry of scientific activity than someone disproving a well established theory.
Re: Re: Seems To Me
You’re preaching to the choir. It wasn’t a dig at science, it was a dig at people who take everything a scientist says as absolute, unquestionable truth.
Re: Seems To Me
Spoken like a true idiot. Religion knows the truth, and you dare not question. Science proposes a truth and then spends the next millions of years repeating and comparing. Nothing is a fact in science. Everything must be repeatable, and testable. This is why there are 1,000,000 religions and only one science. Every person in every country followd the same rules to produce the same results. To call it religion shows how ignorant you are, or shows you are trying to bring science down to the level of superstitious religious nonsense.
People with at least two brain cells to rub together to produce a thought see through you.
—–
In science, ‘fact’ can only mean ‘confirmed to such a degree that it would be perverse to withhold provisional assent.’ I suppose that apples might start to rise tomorrow, but the possibility does not merit equal time in physics classrooms.
–Stephen Jay Gould
But the truth is, Gravity is only a theory. It is not fact. No one can prove an apple will not float up. We can just show that in the trillions of times and apple is let go, it always falls. This is a science fact. Very different from mathematical or logic facts.
Speaking of logic, is it even possible to prove a negative? I mean can anyone here even prove I don;t have a live mermaid in my pool? I dare ya.
Re: Re: Seems To Me
I’ll repeat myself:
“It wasn’t a dig at science, it was a dig at people who take everything a scientist says as absolute, unquestionable truth.”
Atheists can be so touchy.
Re: Re: Seems To Me
far more science than religion, not less, there is NOT ‘only one science’. Just as there are not 1,000,000 religions.
Science ‘theory’ is a much higher level of proof than a meere ‘fact’, facts in themselves have no relevance to science.
A theory carries far more weight in science than a fact will ever carry.
Re: Re: Seems To Me
Science is the pursuit of the Truth.
Jesus said “I am the Truth.”
Therefore, science is pursuing Jesus.
Re: Re: Re: Seems To Me
What if Jesus was lying when he said “I am the Truth” ?
may be what he said was “I am the Truth, but everything I say is untrue!”
Lord Kelvin
Remember, Lord Kelvin declared “heavier-than-air flying machines are impossible,” just eight short years before he was proven wrong.
Actually 50 years after he was proved wrong!
http://en.wikipedia.org/wiki/First_flying_machine
Re: Lord Kelvin
you’re both wrong, when an aircraft is flying it IS lighter than air.
It is heavier than air when it is on the ground, but once a certain speed is reached, lift is created, that means the air under the wing is heavier than the air above the wing (burnulli principle).
An aircraft wing producing ‘lift’, is the same as a ship producign ‘float’.
So an aircraft is lighter than the air below it when it is flying, and heavier than the air below it when it is not.
I guess that is a bit to complicated for you guys.
Lord Kelvin was also interested in cold, sniffing nitrus oxide, and soap bubbles. But not the physics of flight.
I am quite sure he was a long time after galeao.
Re: Re: Lord Kelvin
You do realize, of course, that weight is the measure of gravitational force, and that other forces have no bearing on weight? When I jump, I weigh the same as when I’m on the ground, it’s just that other forces are slightly greater than the combined gravitational force and barometeric pressure. I laughed when I read your assertion that aircraft are lighter than air while flying.
Time travel
It was my understanding that Time Travel with-in a given universe is impossible, but with an infinite amount of universes, you could just hop into another universe that had the exact same setup as the time destination you were aiming for.
Re: Time travel
Yes that has been suggested by David Deutsch
You can read more similar stuff here
http://www.lifesci.sussex.ac.uk/home/John_Gribbin/timetrav.htm
Star Trek fans are going to have to do more than ASSERT
that time travel is possible. Just because you’ve seen it in movies doesn’t mean that it IS possible. — And I WISH that I were being facetious, but I think that really is the level of thinking of some above.
By the way: so you think nothing’s impossible? Just try this: stand against a wall with rear and shoulders touching it. Now bend over and touch your toes without falling over. — But I bet most of you Cheetos munchers can’t even SEE your toes when standing.
Re: Star Trek fans are going to have to do more than ASSERT
project much blue?
Re: Re: @AC: Star Trek fans are going to have to do more than ASSERT
When I project, I’m aware of it, and have something to say too, not just an empty one liner. YOU HAVE NOTHING TO SAY.
Re: Star Trek fans are going to have to do more than ASSERT
Actually, it is possible for some people to bend down and touch their toes in the situation that you provide. I can’t, but I’m a runner, not a gymnast. I have seen others do it (to win at bet with a teacher who thought the same as you).
It is also possible that you are full of it when you claim that anyone here is asserting that movie style time travel is possible. Though, time dilation as I’ve described above is not only possible, but has been proven.
Re: Star Trek fans are going to have to do more than ASSERT
easy, just make a horozontal “wall”, job done, it’s all relative !!!
Or stand on a wall in space !! with no gravity ? will you fall over then ?
Do you think it is impossible for a photon to be in two places at once ? or two atoms at two places at the same time ?
It’s just Apple is covering its corporate ass – to avoid reasonable consumer complaints that their “Time Machine” does not live up to expectations.
Re: Re:
iTARDIS?
But I AM traveling through time
I am doing it right now. I’m going forward, at least, as I perceive it. In fact no matter how many times you splice it it’s impossible to stand still in time. “Now” is merely a segment.
As They Might Be Giants wrote, “You’re older than you’ve ever been and now you’re even older.”
Mike: someone else being wrong does not make you right.
“… plenty of other things declared impossible by scientists that later proved possible” is a childishly flawed argument. SHOW ME even a HINT that time travel IS possible. Or matter transports. Or bipedal aliens who all speak English. Or light sabers. Or “The Force”. Or that William Shatner can act.
Re: Mike: someone else being wrong does not make you right.
“Or bipedal aliens who all speak English.”
1. Send astronauts to moon, one female, one male.
2. Make them have a kid.
3. ???
4. profit
Re: Mike: someone else being wrong does not make you right.
“SHOW ME even a HINT that time travel IS possible”
It is. I’m travelling through time right now as I sit here and write. I only travel forward though, because apparently you can’t go backward according to some scientists. Which is a bummer because I have a deadline and this is really eating my time…oh well.
“Or matter transports”
My car transports matter. So does my wheelbarrow.
“Or bipedal aliens who all speak English”
Don’t some of those cross your border (assuming you have easily crossable borders) illegally every day? Granted most of them probably don’t speak English very well, but some probably do.
“Or light sabers”
I think you can buy those. They do crazy light and sound effects. You can also get Darth Vader masks to pretend that you are as cool as Lord Dark Helmet.
“Or “The Force””
That one is easy: just multiply mass with acceleration.
“Or that William Shatner can act.”
Better then you can. Your act isn’t very convincing or funny. But I guess we can’t all be stars 🙂
Re: Mike: someone else being wrong does not make you right.
a hint ?? put two atomic clocks in 2 aircraft, fly those two aircraft in opposite direction around the world, and then compare the times displayed on the two clock, then compare those times with a third atomic clock that is on the ground, and a forth one on the sun.
Get the hint ???
If you could not travel in time, how could you travel in any other dimention ?
Look at something, and you are travelling back in time, look at something far away and you are travelling far back in time.
What the hell is your education system teaching you these days ?
In a world of knowledge and information how come most appear here, to know so very little ?
I hope they figure it out soon I got a lot of patents I need to file
Re: Re:
use one of your patents, and travel to “soon” and find out !
Re: Re: Re:
Darryl, the joke is that he’d go back in time to patent things other people invented.
For that matter, I would go back in time to make my time machine the very first patent.
Oh, wait, there’s a boardgame based around that . . .
Re: Re: Re: Re:
well im going to go forward in time and get a better time machine then go back in time and patent that, so suck it :b
All this means is that using the current model time travel appears to be impossible.
The thing to remember here is that theoretical physics is all about descriptive models, not iron-clad reality. A different view could well shine a light (sorry) on a relatively (sorry) straightforward method of time travel.
Re: Time travel impossible, watch makers revolt !!!!!
Theoretical physics is ONLY about IRON-CLAD reality, it’s just that reality seems odd and different to everyday (macro, large structures) like atoms and photons.
I am a time traveller, I travel at the rate of 1 earth second per earth second.
Put an atomic clock on a photon of light and it would travel the total length of the universe in ZERO time (by it’s clock) and about 14 billion years by our clock on earth.
Hawking was a good physists of his day, but they day ended a long time ago, and is more often shown to be wrong than right.
I guess it is therefore far more important for you guys to know how to rip off music and to find torrents and talk “the net” than it is to have a basic understanding of why you can even exist, or what reality is ?
May be you should start or “war on ignorance!!”
Re: Re: Time travel impossible, watch makers revolt !!!!!
“Hawking was a good physists of his day, but they day ended a long time ago, and is more often shown to be wrong than right.”
So now darryl knows MORE than fucking stephen hawking? Yeah right.
“I guess it is therefore far more important for you guys to know how to rip off music and to find torrents and talk “the net” than it is to have a basic understanding of why you can even exist, or what reality is ?”
Disproving Hawking and Einstein is now a “basic understanding” of the universe? Wow you just dont exist in the same reality as the rest of us, do you?
Re: Re: Re: Time travel impossible, watch makers revolt !!!!!
So now darryl knows MORE than fucking stephen hawking? Yeah right.
I know one thing !!!! that physics is not about who knows more or less than someone else.
It’s not a fucking competition.
Um who here has disproved either Hawking or Einstein, most certainly NOT ME !!! If anything, I am stating here clearly that Einstein was CORRECT, yet he did not PROVE anything.
So ‘disproving’ him is both wrong, and incorrect, Einstein has nothing to ‘disprove’.
Einstein’s TOR has been proven consistant with observational science for a very long time, If I agree with Einstein as does most other scientists, then how can you say I disproved anyone ? or even tried too ?
Huh?
Time travel is entirely possible. We’re all doing it. All the time.
They proved that traveling back in time is impossible by exceeding the speed of light by proving that you cannot exceed the speed of light.
There are plenty of other theories to achieve time travel that didn’t involve them, like flux capacitors!
Superman and Star Trek IV are fully disproven now. Why science!? Why did you do this to us!?
At least we still have Back to the Future and Hot tubs.
“just eight short years before he was proven wrong.”
yeah, im traveling into the future 8 years, where time travel is already possible.
Re: Re:
exactly, +1
Mike version 10, stating in 2525, “even Hawking said time travel was impossible” those idiots !!!
Next we will be told “there are no more scientific discoveries to be made”
Time travel...
What is time?
A day, Earth spins once
A year, Earth circles the Sun once.
Cesium clock, cesium atom vibrates back and forth generating a signal that the atomic clock can detect.
All units of time are nothing more than a measure of distance divided by velocity.
The faster you go the shorter the apparent distance.
What we are really talking about is the space time continuum that is represented as an energy structure moving like a wave through what we perceive to be the universe.
Just as you can never walk down the same path the exact same way you cannot traverse the continuum the same way so, time travel is impossible both forwards and backwards.
Also, time does not exist in a black hole. Why? Because a black hole is a point singularity with no size hence no distances. Without distances to traverse there can be no time.
Re: Time travel...
The faster you go the shorter the apparent distance.
No, the faster you go the shorter the apparent time.
Also, time does not exist in a black hole. Why? Because a black hole is a point singularity with no size hence no distances. Without distances to traverse there can be no time.
A black hole is not a point singularity, with no size.
Black holes are quite big, (and heavy).
A black hole is just a bunch of stuff that is so heavy that the escape velocity exceeds the velocity of light.
or if you like, that distance is compressed so much that light cannot ‘go the distance’ in time.
(distance = space).
Re: Re: Time travel...
Once you pass the event horizon there are no distances. Hence the name ‘point singularity’. The only thing enourmous about them is their mass. Once inside the event horizon our physics break down and the singularity concept is one of th BIG reasons it breaks down.
Now, in reality, no one knows what is inside a black hole since no one has gone into one to study it and returned to tell the tale…
It may have distances inside but strictly speaking, if you do the math then everything inside of it is crunched down into a point that has no size. Hence the name ‘point singularity.’
Re: Re: Re: Time travel...
Not quite. The event horizon and the singularity are not the same thing. The event horizon is a spherical region outside the black hole inside which the escape velocity exceeds the speed of light. The distance between the singularity and any point on the event horizon is dependent on the mass of the black hole. An event horizon contains space and can be described using the terms “size” and “distance.” Only the singularity itself has no size (or Planck size, depending whether various string theories are accurate).
Forget time, lets talk IP, patents, 'ideas' and copyright
Is Intellectual property like time ? you cannot take it ? like Mikes concept of ‘you cannot own an idea’, that somehow it is universal, therefore free for all.
Does that apply with time, after all you cannot ‘put it in a box’ or call it a physical thing, (like you’re definition of copyright) you are not taking anything physical off them so it’s ok to download their song.
How does that apply in your mind to time ? does it have value ? because it is available to everyone does it make it any more or less valuable ?
if an ‘idea’ has no value until you make something of it, does that imply that time has equally no value unless you do something with it ?
(time and/or space) its all the same.
Time travel
Of course time travel is possible. All you need is an official Dethklok Time Travel Face Bag(tm).
This article and its associated comments section are a remarkable mess. We’ve got…
…a peer-reviewed article stating something we already knew but have observed directly for the first time (which is important–observational support of theoretical predictions means we’re on the right track)…
…a press release relating that information to the public which mentions, somewhat offhand, that it means that a certain very specific phenomenon that was once considered a possible manifestation of time travel has been disproved…
…an LA Times article misreporting on that press release (“this proves that all time travel is impossible”)…
…a techdirt article that propagates the misinformation, and directs its (somewhat justified) incredulity towards science and the peer-review process in general rather than a simple case of shoddy reporting…
…and the entire blogosphere scrambling to clean it all up.
physics lessons from daryl, this just became my favorite post of the year
Dr. Brian Greene submitted an excellent metaphor for understanding relativity and time dilation. Say you’re traveling in space along an axis “x” at 100 mph, and then you alter your course by 45 degrees counterclockwise, towards axis “y,” without changing speed. How fast are you traveling? 100 mph. How fast are you traveling along axis “x”? 50 mph. How fast are you traveling along axis “y”? 50 mph. Your speed, which was originally confined to a single dimension, is now equally split between two dimensions.
For whatever reason, we are all traveling at speed “c” through the dimension of time (or slightly less than c, because of the Earth’s gravity and whatnot, but close enough). When we travel at any speed through any of the three visible dimensions of space, we’re diverting our motion through time into motion through space. Our speed relative to absolute spacetime is constant; it’s just a matter of which direction we’re going in.
Well...
The Vulcans were adamant that time travel was impossible (see: ST Enterprise). And these are some pretty smart guys, guys that had “faster than light” travel well before the human race… Clearly they got proven wrong (again, see: ST Enterprise and Temporal Cold War).
Let me get this straight… The scientists proved that a photon, which is a particle of light, cannot travel faster than light. Um, that’s like saying a boxcar cannot travel faster than a train. What the hell does that prove?
I suppose there’s more to it, but that’s my first impression from the article.
Re: Re:
Let me get this straight… The scientists proved that a photon, which is a particle of light, cannot travel faster than light. Um, that’s like saying a boxcar cannot travel faster than a train. What the hell does that prove?
How can a boxcar travel faster then the train it is connected too ??
This is right, a boxcar cannot travel faster than the train, light cannot go faster than the speed of light, nor can it go slower.
Light is not strictly a particle, it is a quantum state, a quanta of energy.
If a train cannot exceed a certain speed, then the components of that train cannot exceed that speed either.
when you put more energy into a train (turn up the throttle), you go faster, when you put more energy into a photon, it does not go faster, but had more energy.
If there was a law of physics that said a train could not travel over 100mph no matter what you did to it, if you put more energy into it, (turn up the throttle) when you were going 100MPH allready, the train (not being allowed to go any faster), would use that energy somewhere else, so the train might be going 100MPH and the wheels would be spinning at a rate to equal 200MPH, but the train cannot go faster than 100 so no matter how much extra energy you put in you cannot exceed that speed.
So you could have a train going at it’s max speed of 100MPH but it’s wheels might be spinning at a much higher rate (equivalent to 1000Mph), and the more energy you put in the more the wheels spin, the the train (and the boxcar) will not increase in speed.
Same with a photon, it travells at c no matter how much energy you put into it.
Same with a spaceship, no matter how much energy you put into it, you cannot exceed a specific speed.
Impossible is nothing.
You can time travel forward not backwards.
Music Industry and time travel
If they figure out how to make time travel work, better hope the music industry does not get a hold of it. Knowing them, they would probably kill the parents of all the people who were instrumental (no pun) in developing computer and ftp technology before they were born. lol?
time travel
Well the idea of traveling in time, is one of the most storied plot devices in fiction ever since, and it is an amazing one. However, some killjoy researchers have just found that time travel is basically extremely hard, so individuals had better just get accustomed to the present.If you wanna know more I found this here: Possibility of time travel quashed by scientists
Well, some scientists claim neutrinos can
We’ll have to wait for everyone to do their own independent studies, but if they can, it will change the idea that the speed of light is absolute.
‘Through the wormhole, the scientist can see himself as he was one minute ago. But what if our scientist uses the wormhole to shoot his earlier self? He’s now dead. So who fired the shot?
Read more: http://www.dailymail.co.uk/home/moslive/article-1269288/STEPHEN-HAWKING-How-build-tim
hi
this was not helpful at all
My vote is for time travel being impossible. Time seems to be something that many physicists discuss, but few define. Perhaps one could think of it as a rate of energy propagation or conversion. http://www.paranatours.com/
Re:
Chinese govt. ban on time travel themes? source? Themes that go back before the revolution are better how? When you white scumbags were trying to colonize China and make the Chinese 2nd class citizens in their own country? Or when you English scumbags poisoned that country with opium. Now having said what asshole? Your casual slander? You worthless POS.
What good is parallel time travel imbecile.. if you merely effected change in another dimension/universe? Do everyone a favor and shut the f-up.
Time
What if, what we refer to as “Time Travel” seen in movies isn’t what we have “rationally” thought it to be because “travelling” of any kind would be “abandoning” the very time based world itself.
Does this make sense to anyone? Time is a measurement so in essence i am referring to the pendulum motion.
Time travel
I just want to go back to when this post was posted: July 26th, 2011. That is fine. I just want to go back NOW.
best plan
someone go back in time and get rid of nigggers