How to build a time machine

February 24, 2016 by Steve Humble, Newcastle University, The Conversation
Is there a Dr in the house? Credit: James Bowe/flickr, CC BY

Every now and again, we all indulge in dreams about travelling in time. Wouldn't it be wonderful to return to that specific point in the past to change a bad decision or relive an experience – those halcyon days of childhood, that night you won an Oscar – or to zip ahead to see how things turn out in the far future.

The mystery of time travel is full of excitement and wonder – "But it's not science," I hear you say. You may also think that it is definitely not like any mathematics you learned at school. Well, you will be surprised to hear that it is.

At present there is a great deal of news around the discovery of . It is suggested that this experiment and future research could unlock the secrets of the universe. One of the reasons why physicists believe this to be true is linked to other monumental scientific discoveries in the past – and the fact that we may have reached another unification moment and taken another step closer to a theory of everything.

Towards a theory of everything

We have known since Isaac Newton's day that mass is inextricably linked to gravity. His unification moment was first conjectured famously while he was sitting having afternoon tea under an apple tree in Woolsthorpe, when out of the blue an apple fell on his head.

This incident made Newton think that the same force could be responsible for both the apple dropping to the ground and the moon falling towards the Earth in its orbit. He went on to show that it was true for all mass and that all bodies attract each other due to gravity. In the tabloid newspapers of the , it was announced: "We are just bodies forced to be attracted to each other by Newton's " and that "Love is a gravitational law".

Batteries and a cylinder with the mass of the sun not included. Credit: NASA/SDO, CC BY

Cue: Einstein

In the early 20th century, Einstein went further with his general theory of relativity and showed that mass and gravity are linked to time; yet another unification moment.

Einstein was born in 1879, and by 1905 had published a paper that would change the way we look at the world. This paper makes a fundamental change to the way we look at light. Until then, no one had thought too much about the speed of light – it was just another universal constant that experimental physicists attempted to calculate with ever greater accuracy. There was little appreciation of how radically different light waves were from sound and water waves.

But by using mathematics you learned at school – Pythagoras' theorem – and with a little help from Einstein's time dilation formula you can show that time will slow for someone who is moving.

Einstein's theory says that if you want to slow time down – essentially, to – you need to move fast, very fast! Imagine setting off on a mission from Earth in the year 2000, for example. You are scheduled to be away until 2032, but will be travelling at 95% the speed of light (around 285,000km a second). The amazing thing is that, on your return, your watch would tell you that it is 2010, despite it being 2032 on Earth, and you'd be 22 years younger than anyone you left behind. That's time dilation and it works at slower speeds, too, albeit to a much less profound degree.

So let's go

But there's a catch – 285,000km a second is very, very fast. The fastest land vehicle cannot even get to 1km a second and even a spaceship when escaping Earth's atmosphere is travelling at a relatively pitiful 10km a second. Even if we could reach these speeds, it is questionable whether we could survive the stress on our bodies. So time travel into the future is possible, but a bit too difficult – for now. But what about the past?

I don't know about you but I always feel a bit cheated when I read articles on time travel. I'm told all these facts but no one tells me how to build a time machine. So as not to cheat you, here follows a design for just such a thing, with great thanks to Professor Frank Tipler. Tipler published a paper on how to build a time machine, a Tipler Cylinder, back in 1974. This machine would enable you to travel back in time.

First, you need a lot of money to buy a large cylinder. When I say large, I mean very large, perhaps a 100km long. The cylinder also needs to be at least the mass of the sun, but very densely packed together. You then need to start it rotating, faster and faster, until it's rotating so fast that it starts to disturb the fabric of both space and time – and you would be able to detect a wash of gravity waves coming from this structure.

I also need to add a health warning, as coming close to such a dense structure would cause issues. The mass of the Earth pulls us down to its surface, but getting too close to an object this massive would be hugely dangerous – it would drag you towards it and squash you flat.

If you can get round this squashing problem, however, approach the rotating cylinder and start following its spin – as you get closer, strange things will start to happen. Your path, which normally inextricably moves you forward in time, changes, since moving around the cylinder in the direction of rotation will shift you back in time. The machine makes the direction of time collapse into the past, so the longer you follow the machine's spin, the further back in time you will go. To reset the movement to normal, simply move away from the cylinder, go back to Earth and you will be returned to the present – albeit a present in the past.

But be careful what you do there. Fiddle around with the past too much and – like Marty McFly in Back To The Future – you may just break up your parent's first date or even ruin your chances of being born. Time can be funny like that.

Explore further: How Einstein could help unlock the mysteries of space travel

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yoatmon
1 / 5 (3) Feb 24, 2016
"We have known since Isaac Newton's day that mass is inextricably linked to gravity."

No it isn't; it's exactly the other way around. Or does indeed, the tail wag with the dog?
sergpush36
not rated yet Feb 24, 2016
i would like to have this machine if it were exist.
Thirteenth Doctor
3 / 5 (2) Feb 24, 2016
I would do everything in my power to make it look like a TARDIS. Also its ALWAYS "Doctor" not "Dr" when referring to Doctor Who.

Trust me, I would know.
Jeffhans1
1.7 / 5 (3) Feb 24, 2016
Sending data back in time should be much easier than physically travelling through it. The first person to be able to communicate through time has already been born and based on what she shared, this becomes possible in the year 2040. So any governments or companies trying to hide dirty secrets had better be prepared for full disclosure by that year. A world without secrets seems impossible to us today, but someday it will be nearly impossible to imagine it any other way.
betterexists
not rated yet Feb 24, 2016
Is this possible? "JUST Dispatch an Atomic or other Clock to Very Distant Galaxy & Watch The Date on it after a month using some kind of Radio or Other waves!"
Nope, Right?
indio007
5 / 5 (7) Feb 24, 2016
SO If I go back into time 50 years am I also magically transported to the Earth's spatial position 50 years ago?

Time travel = nonsense of the highest order.
betterexists
2 / 5 (1) Feb 24, 2016
How are Time Travel & Quantum Entanglement Related?
baudrunner
1 / 5 (3) Feb 24, 2016
I think this professor Tipler character just wants his name attached to something for posterity. There is no reason to assume that this rapidly rotating cylinder is traveling backward in time. If anything, it might slow time down, like the traveler in the first example. As long as you're moving that fast, it doesn't matter that you're not going anywhere.

You know what they say, "Those who can, do. Those who can't, teach."
big_hairy_jimbo
5 / 5 (1) Feb 24, 2016
Hmmm, once you get the cylinder up to a speed where time starts to flow backward, would the machine disappear? Wouldn't the machine itself also be affected and travel backward in time?

OR if it stays in the NORMAL present, then as soon as your spacecraft travels back in time, surely it could only go back as far as to when the machine REACHED the backward time travel rotation rate. Surely you cant't travel backwards in time beyond the machine being operational.

@indio007, I don't think you need to worry about the position of the Earth. Such a cylinder won't be near Earth, and keep in mind you are in a space craft. So you leave Earth, fly to the Cylinder, do your stuff, then fly back to Earth. The cylinder would be placed in an orbit around the Sun, so wherever the Sun (and Earth) goes, the Cylinder would follow. So your location should always remain relative to the Sun.
Urgelt
4 / 5 (2) Feb 25, 2016
Careless article.

Newton never said an apple fell on his head. He reported to his friend William Stukeley that he wondered why apples always fell perpendicularly to the ground. Stukeley, an archeologist, became one of Newton's biographers, and he did not say Newton was beaned by an apple.

The author presents these time travel scenarios as solid science. But they are not. What they are is conjecture, and they rely heavily on Einstein's decision to rule out simultaneity. Lorentz didn't agree; using the exact same equations but different conjectures, he described a universe in which simultaneity is possible. Quantum mechanics experiments demonstrate simultaneity in entanglement experiments - change one particle and its entangled buddy changes instantaneously.

I'm not going to pretend I know which conjecture is correct. But I do think we should demand experimental evidence for Einstein's interpretation before we rush off to declare these time travel scenarios to be true.
Mimath224
4 / 5 (1) Feb 25, 2016
Maybe I'm missing something here but wouldn't a cylinder so dense start to collapse so that it wouldn't be a cylinder?
Let's just suppose that TT was possible what we wouldn't know is if Time has its laws at that level. There might be equivalent 'conservation laws' which might prevent us performing certain deeds or worse one might have an allergic reaction for being in the wrong time and poof, nothing left to return. Well, I mean, we are only dreaming here, aren't we?
Nanook
2 / 5 (1) Feb 25, 2016
A world without secrets seems impossible to us today, but someday it will be nearly impossible to imagine it any other way.

I hope I live that long.
Burnerjack
2 / 5 (1) Feb 25, 2016
Seems to me that time dilation is a change in the perception of the rate of time. This, to me, is far different than "time travel", where one may jump forward or backward in the 'time stream'.
My only question is why does a supposedly science oriented site put forth such a deceptive article? IMNSHO, it does a disservice to both the site and the audience. I expect more from a site like this.
Burnerjack
2 / 5 (1) Feb 25, 2016
I think this professor Tipler character just wants his name attached to something for posterity. There is no reason to assume that this rapidly rotating cylinder is traveling backward in time. If anything, it might slow time down, like the traveler in the first example. As long as you're moving that fast, it doesn't matter that you're not going anywhere.

You know what they say, "Those who can, do. Those who can't, teach."

As my mother used to say:
"Those that can, do.
Those that can't, teach.
Those that can't teach, teach 'gym'.
compose
Feb 25, 2016
This comment has been removed by a moderator.
Lynorg
4.5 / 5 (2) Feb 25, 2016
Wouldn't orbiting a pulsar acomplish the same thing as this cylinder machine?
RobertKarlStonjek
4 / 5 (1) Feb 25, 2016
From my evaluation of the nature of time, time breaks down into its components parts at the extremes of nature (Black Holes, light speed, the quantum scale etc).

On the quantum scale, for instance, entropy loses its meaning just as pressure and temperature do. Time loses its direction except in a very few examples of non-reversible processes.

Causation, for photon emission, is no longer from what we perceive as emitter to what we perceive as absorber. Entanglement implies bidirectional causation.

We still imagine being able to place a clock anywhere in nature, but this may, in itself, be a human *imposition* on nature. In other words, just as we imagine being able to 'see' electrons, for instance (photons are far to big relative to electrons for light to image electrons) and even quarks and other particles, we expect to be able to locate and 'time' particles.

A break up of time into its components would help to explain much
betterexists
not rated yet Feb 26, 2016
What Time Travel?
Prof. Lubin says ½ hr. enough to go to MARS.
viko_mx
1 / 5 (1) Feb 27, 2016
Before the cause, can not manifest the consequence of it. So the idea for the time machine is silly from the scientific point of view.
anonieme_x
5 / 5 (1) Feb 27, 2016
Astronaut Sergei Avdeyev has traveled 1/50sec into the future. If you move your hand away from your body, it travels in time relative to your body. To NOT travel in time is a challenge.
SkyLy
not rated yet Feb 27, 2016
Before the cause, can not manifest the consequence of it. So the idea for the time machine is silly from the scientific point of view.


Well, there's something, and not nothing. This is the proof that consequence can come before the cause, if "before" has any meaning here.
Whydening Gyre
5 / 5 (1) Feb 27, 2016
SO If I go back into time 50 years am I also magically transported to the Earth's spatial position 50 years ago?

Nope, and I'll bet it would take you at least 50 years to catch up...
KBK
5 / 5 (1) Feb 28, 2016
here is no reason to assume that this rapidly rotating cylinder is traveling backward in time
This effect is very subtle, but the reasons for it are well substantiated.


It's all about angular differentials.

This is why when you hear about dimension shifting, or time differential devices, or anti-gravity devices....they all involve some form of gaseous, ionic, or fluid motion, possibly in rotation or resonant oscillation.

Thus, angular differential in the true quantum particle-to-particle sense. Solids, lattice, ie macroscopic elemental considerations--simply won't work for this 'effect' (if it is to be localized and created).

Gravity is multi-axis vector spin polarized...so.....cancellation or nullification, must be similarly enacted.

This also explains mass, time, inertia, and so on.
Whydening Gyre
5 / 5 (1) Feb 28, 2016
If you move your hand away from your body, it travels in time relative to your body. To NOT travel in time is a challenge.

LOL ! An interesting truism...:-)
baudrunner
1 / 5 (1) Mar 01, 2016
here is no reason to assume that this rapidly rotating cylinder is traveling backward in time

This effect is very subtle, but the reasons for it are well substantiated.
Yah, nice try. In the imagination, maybe. Next, though, you'll be telling me that it is impossible to travel faster than light, but isn't that what that thing would have to do to travel backwards in time? Doesn't the article suggest that the light-speed barrier is also the time barrier?

It ain't possible to travel back in time because of things like the idiomatic paradox of it being impossible to go back and kill yourself because you wouldn't exist in the present to do that because you would be dead if you had. No rational thought experiment to test the idea works in principle. Math might lead you to believe that time travel is possible, but math can be very misleading.
Whydening Gyre
not rated yet Mar 02, 2016
Here's another thought...
If you could instantaneously transfer to a coordinate in space (where you HAD been), what time would it be when you arrived?
Zzzzzzzz
not rated yet Mar 02, 2016
Seems to me that time dilation is a change in the perception of the rate of time. This, to me, is far different than "time travel", where one may jump forward or backward in the 'time stream'.
My only question is why does a supposedly science oriented site put forth such a deceptive article? IMNSHO, it does a disservice to both the site and the audience. I expect more from a site like this.

Burnerjack, just keep reading the articles on this site..... If you think THIS one disappoints, just you wait.......
Zzzzzzzz
not rated yet Mar 02, 2016
Astronaut Sergei Avdeyev has traveled 1/50sec into the future. If you move your hand away from your body, it travels in time relative to your body. To NOT travel in time is a challenge.

Indeed - we are ALL time travelers. We cannot stop being time travelers, without the dense cylinder or some other construction to slow our travel through time to a stop. Light speed forever I suppose would accomplish the same thing. I doubt I would enjoy either existence.....
I wouldn't get too wrapped up in being disappointed by the article though - it has stimulated some actual thought. There are enough other examples on this site of articles that actually pretend to present science that simply do not, in any sense.

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