"announced the detection of gravitational waves generated by colliding black holes billions of lightyears away, confirming Einstein's theory."

We can't confirm 100% a theory, at best the theory has passed other test. This is important cause that means we actually don't know if we can travel in time. We can only know that when we travel in time, beside a lot of paradox in time travel make us see something is amiss in the nature of time.

When you think of a time machine don't just imagine a person travelling back in time. I'd be really happy if a single photon could.

I think you can move forward in time, but not backwards. I think that if you could find a way to get a human up to a very fast speed (10% the speed of light), then they would experience time at a different pace than a twin back on Earth. Of course there is no easy way to get fat sacks of meat up to even 1% of the speed of light, so I don't think we will have any realistic reason to expect or hope for time travel to become real (for humans). I think if you had a twin on earth and you were the pilot of a fast 600 MPH Jet and could fly for 100 years, the time dilation difference would be less than 1 second. Of course 100 years of flying would expose you to higher doses of radiation, so you would be dead long before your twin on Earth, so hard to think of that as making any new time... LOL/Grin.

Most time travel conjecture assumes that position and momentum relative to the non-time-traveling matter around you are somehow conserved. But I can't see why that should be. It seems to me that if you were to go back in time one second, you would reappear about eight miles from your starting point. And that's just relative to our movement around the sun. But the sun is moving much faster. And the galaxy is moving much, much faster. Go back one second; where you you be? Your math has some work to do, I think.

Obviously, any time travel would entail space travel as well, so as to be in the proper place at the right time so that you showed up ON the surface of the planet you were wanting to study the past of, that or above it somewhat: One certainly would not want to pop out of a time-locus in a space occupied by other matter, it would get very messy very fast.

Einstein's space-time is only a 2D universe, not 4D. But there is a real 4D continuum called MIST Dimensions, where M=Matter, I=Idea, S=Space and T=Time.

The exact present moment, NOW Moment Reality NMR, is a dynamic and flexible grid system moving forward on the Reality Dominion Axis RDA.

From MIST, NMR and RDA it is possible to construct the Traversable Acausal Retrograde Domain in Space-time (TARDIS) -model, and find its inaccuracies and shortcomings.

When the MIST NOW moment travels curved and spiral RDA routes we can iterate different universes. The MIST NOW moment "flexible grid/net" can be effected by several forces, when the grid/net gets discontinuities in forms of appendages, 'planets', 'siblings', 'daughters' etc.

The MIST Dimensions model is based on topology and its part of a "structuring the reality project" SRP.

- JDa

Einstein's space-time is only a 2D universe, not 4D.

Erm...no? Spacetime is 4D for Einstein.

The rest of your post is...'interesting' (and by 'interesting' I mean: total garbage)

I think traveling backward in time to points already realized might be possible. However, I think that traveling into the future is highly problematic at best, nearly impossible at worst.

Why? Well... Which future? As we look forward from our current point in time, the probability that this or that event will occur becomes increasingly fuzzier. More precisely, the probability that the *effect* of this or that event will be X becomes increasingly fuzzier.

Eventually, we can't know which future is likely (or even possible) to any reasonable degree of accuracy that is useful to any destination targeting in our time machine. I think that, given the numbers of particles that make up the matter of the universe (as well as the properties involved with each), targeting any time machine to a point forward in time beyond the next instant would be impossible from a calculation standpoint.

However, I think that traveling into the future is highly problematic at best, nearly impossible at worst.

How so? We do it all the time (we can't NOT do it).

But if you mean some arbitrary far flung future then that is also doable - just travel very fast and relativistic slowdown will get you there. If you manage to travel at the speed of light then this will seem like instant time travel to you.

I think gravity would still be pulling on you as time traveled.From where you made the whole in time.Unless
it closed.But i don't see how the hole in time would close.

In my inconsiderate opinion. Time and Gravity are Forces that share intrinsic similarities.

Time & Gravity are constants, (maybe indivisible?) uni-directional attractors. Dependent on local and universal mass.

What differentiates T&G from Electro-Magnetism, is that E-M is an accelerating energy. i.e. T&G pulls, E-M pushes.

I opinionate that there is no past to return to and the future has not occurred yet.

Robert Heinlein did an amusing invention of this viewpoint in his book "Tunnel In The Sky'.

Traveling at Relativistic speeds will not move you into the future any sooner than the mundane plodding through life of us planet-bound dullards.

As you approach the speed of light, you will still be experiencing one dreary hour after another within your vehicle. Though it will appear as if the Universe outside your vehicle is occurring a sped-up clock. That POV is only real too you and only as long as your vehicle can carry you.

TARDIS? Seriously? I hope he came up with this "research" on his own time and not UBC's.

It's just academics doing a bit of nudge-nudge, wink-wink, leg-pullery.

TARDIS? Seriously? I hope he came up with this "research" on his own time and not UBC's.

Do you object to the name 'quark', or flavors 'charm', 'beauty', etc.?

When you think of a time machine don't just imagine a person travelling back in time. I'd be really happy if a single photon could.


Or even an entangled particle as a first step.

Let's say that someone projects themselves back in time by one second, also traveling through space with perfect accuracy so that they appear right next to their previous self. What happens to all the air that occupied that volume before the time traveler arrived? Wouldn't the poor fellow explode or at least balloon up painfully? It's always been too big a leap for my sci-if sensibilities.

"a UBC researcher has come up with a mathematical model for a viable time machine"
I wouldn't call it viable. This is is a pure theoretical speculation for the time being.

Betcha when we get quantum gravity it closes this loophole, along with the one for wormholes. @EyeNStein turned us all on to a video on a recent thread that seems to indicate that generic quantum gravity pretty much has to close the wormhole loophole. The video is here: https://www.youtu...gBjQ8xIo

Studying space-time is both fascinating and problematic. And it's also a fun way to use math and physics.
spanish to english

Any physicist will tell you they can fit all the space in the universe between their ears.

The Wheeler-DeWitt equation reveals that "Time" drops out, indicating that it is merely a metric to reference relative locations of particles as quantum forces dictate changes in positions. Einstein's "spacetime" may have actually been a recognition of this relation. Others (i.e., Minkowski) have extrapolated on the concept, taking it to non-physical interpretations. Thus, as Einstein said, "Time is a persistent illusion," created by a combination of physical forces and mental organization.

Mayday=

Let's say that someone projects themselves back in time by one second, also traveling through space with perfect accuracy so that they appear right next to their previous self. What happens to all the air that occupied that volume before the time traveler arrived? Wouldn't the poor fellow explode or at least balloon up painfully? It's always been too big a leap for my sci-if sensibilities.

The time portal itself prevents that from happening because
you cannot go that fast to cause that to happen.The natural laws still apply.

@zave, wormholes overcome these objections, but apparently are ruled out by any quantum gravity theory that can reproduce relativity. I'd say your sensibilities are well-calibrated.

My upper post was just a joke, but seriously, this mathematician is essentially saying, we can travel through time theoretically/mathematically. Its just not physically possible... yet.

This is the same as saying, we can build a free energy machine mathematically, its just not physically possible... yet.

Jesus Christ.

@vacuum, there are trolls here and unfortunately sarcasm looks like trolling. Be sure to label your sarcastic posts because there are those who say the same things and are serious.

Oh, DaS, thanks for acknowledging my efforts at brightening up the day for all you too somber (too sober?) scholars.

However, several of the commentators to this article have brought up an interesting point.

For some time now, even before I started to rudely interrupt you adults solemn debates over angels dancing on the head of a pin.

I have been considering how often the blaring headlines proclaim "Alien outhouses found on Mars!". And then reading the posted article talks about a breakthrough un breeding hornytoads. Then I'd follow up tracking down the original research paper. Wading through a soporific quantity of verbiage to discover the researchers had figured out that moderate rainfall is a good thing. And if we all invest a billion dollars in their project to breed flying unicorns pooping rainbows on our heads, it would create a 'Golden Age' for all Mankind!

All too many publishers and editors go for the profitable click-bait headline.

This article was released about four weeks too late, April Fool's is on the first...

Time travel backwards would require either a time persistence mechanism, with the ability to locate past positions in space-time, or the ability to reconstruct a space-time moment given only the information available "now". Traveling forward would require the ability to create a future point in space-time based on "now", or moments in space-time persistence. Forward travel would seem to require a deterministic universe with only a single timeline, else you could not travel to "the" future, only some discontinuous point. (Unless persisted time-space extended forward to the "end of time".) Traveling backwards without persisted time would also lead to determinism, and the same problem - not moving to a point in the past, but to discontinuous and newly created point. Not "the past", but a virtual and deterministic past "now", that will always generate the same series of "nows" leading to the point of departure. I am not aware of any work on how the past (or future) are persisted.

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We are all moving into forward time at one second per second, i.e. the speed of light. It's possible to move forward faster by various means, but it's not possible to move into the past. To do so requires changing one's direction in time to an imaginary number, then infinity, then a negative imaginary number. Neither imaginary nor infinite speed in time has any physical meaning.

I'll be happy to prove this if anyone makes an argument that shows sufficient knowledge to make it meaningful to them; trollish hand-waving will be ignored.

Db, I'd be willing to take your suggestion seriously if a neutral party (i.e. not invested in a positive result) could show me an EM Drive working in a vacuum....I'm waiting....

For the rest of you, I do not see any evidence advanced that the Past or the Future have an actual physical existence.

In my opinion, the problems we are all having with communicating our hypothesis' are, that we cannot even agree on the words to use to explain these concepts.

I hold that Space/Time/Gravity are three different views of the same phenomena. Doesn't mean your POV is wrong. Doesn't mean my POV is correct. We could both be wrong, we could both be right. And THAT guy over there just advanced a supposition that leaves our arguments behind in his dust!

Well simple fact is Time travel already exists and always did, we ARE TRAVELING IN TIME as you read this even. It is a simple fact which people often overlook what we fantasize about is just time travel when the direction and speed (Velocity) of it changing.