There are several different ways to turn a wormhole into a time machine. ibid.
We run into trouble with cause and effect ... Travelling into the future is possible, but suppose you want to come back again? Isaac Asimov, Horizon: It’s About Time, BBC 1980
There’s an experienced rebel, Time,
And in his squadrons Poverty;
There’s Age that brings along with him
A terrible artillery:
And if against all these thou keep’st thy crown,
Th’usurper Death will make thee lay it down. Thomas Flatman, The Defiance, 1686
The ability to travel through Time, to change your past, to see the future, it’s been a dream ... There is evidence that Time travel is not only real but exists today controlled by an elite few in the present. Conspiracy Files Unsealed: Time Travel, H2 2014
Space and Time being flexible sounds unfamiliar. Brian Greene, Beyond the Cosmos series, National Geographic 2012
The flow of Time always seems to be in one direction, toward the future. But that may not be right. ibid. Time Warp I
He [Einstein] discovered that Time could run at different rates. ibid.
There a profound link between motion through space and the passage of Time. ibid.
Space and Time are fused together = Space/Time. ibid.
Motion slows the passage of Time. ibid.
Gravity like motion can affect Time. ibid.
Why haven’t we been overrun by tourists from the future? ibid.
Things move from Order to Disorder. ibid.
Did our universe have a beginning? Could you leaf back through the pages of the cosmic history book and arrive at page one? Horizon: It’s About Time 1980
Waiting for Time to pass – timing Time in other words – appears to slow it down. So it looks as if these variations in our awareness of Time depend on our thinking. ibid.
[John] Wheeler had been Thorne’s teacher. He was also part of the first wave of research into the nature of Space and Time. He thinks the space between atoms might be full of bubbles, and once in a while two bubbles get joined together to make a tunnel. Horizon: The Time Lords 1996
In this paper Einstein declared that the slower you move, the faster time passes. An experiment in 1991 proved him right. Four atomic clocks were flown around the world ... Time on the plane had warped by just what Einstein had predicted. ibid.
But Physics does put a limit on how far back any time tourist could travel. ibid.
And that’s why we haven’t met any time-travellers – they’ve gone to one of the many parallel universes. ibid.
This is an unlikely tale about an unlikely quest. The attempt to find a way to travel through Time ... Science has found a way to travel in Time. But there’s a catch though. They’ve discovered you may not be real. Horizon: Time Trip, BBC 2003
According to Newton Time was fixed. And its flow and pace never varied ... Newton had said there was just one Time. And there was therefore just one Now. Einstein begged to differ. He said Time was much weirder than that ... The Future and the Past are out there waiting for us ... He suggested the answer was all to do with speed. Until Einstein it was thought Time flowed at the same pace everywhere. But he showed that wasn’t so. The pace of Time can change. It differs depending on the speed you’re travelling at. Bizarre as it may seem the faster you travel, the slower Time will run for you. ibid.
It’s easy to dismiss time-travel as a fantasy. But the reason it’s taken seriously at all is because it already happens. There are fully certified time-travellers. And they use Einstein’s predictions to do it. People like the cosmonauts on the MIR space station for example. ibid.
Everyone assumed Time flowed in a straight line. But what if it didn’t? What if Time could loop round like eddies in water? [Kurt] Godel suggested if you could make Time loop round like that, then you could reach the Past. You wouldn’t need to travel faster than the speed of light. You could take a short cut. ibid.
Around five years ago a group of scientists and philosophers began arguing there might be another way to travel in Time. But it wasn’t a machine in space. And it wouldn’t involve moving galaxies around. It would be a computer. And the pioneer of this unlikely approach was that unlikely pioneer of time machines, Professor Frank Tipler. ibid.
It was this infinite computing power, Tipler said, which would allow a future civilisation to travel in Time. They would do it using virtual reality. ibid.
A super civilisation wouldn’t just make one perfect simulation of the past ... If the computer of the future is churning out billions of simulations, how do we know we’re living in the original real world and not one of the billions of copies? In fact the odds against us being real are billions to one against. ibid.
Now we’re told we may not even be real. Instead we may merely be part of a computer system. Our free will, as Newton suggested, is probably an illusion. And just to rub it in, we are being controlled by a super-intelligent superior being. ibid.
Before Einstein it was thought that the passage of time was unchanging. It ran at the same pace no matter where you were in the universe or how fast you were travelling. But Einstein discovered that Time was not unchanging. The rate at which Time passed depended on the speed of which you were travelling. Horizon: Einstein’s Unfinished Symphony, BBC 2005
What Einstein said was that the stronger the gravitational field, the slower Time ticks; the weaker it is, the faster Time ticks. Horizon: What on Earth is Wrong with Gravity? BBC 2008
One of the key elements of being a human being is that we can tell the time. It allows us to make sense of the world. Horizon: Do You Know What Time It Is? BBC 2008
The Maya had an obsession with Time working out intricate ways to track its passing ... They had interlocking cycles of Time ... The Maya took time-worship to a whole new level. ibid.
You have to look into the world of the atom to tell the time. ibid.
Einstein’s picture is that Time is a dimension like Space and you move through; and so that’s how you feel its passing ... Einstein was the first to link Space and Time in this unique way. ibid.
According to Einstein the Past, Present and Future all exist. ibid.
If you take Einstein at face value the Future is as real as the Past. ibid.
This man [Ron Mallett] has a dream. He wants to travel in Time. But he’s not just dreaming. He’s working out a practical way to break the Time barrier. He’s not crazy. He’s a highly respected professor of physics. Horizon: How to Build a Time Machine, BBC 2018
And then there’s the biggest hurdle of all: determining the nature of Time itself. ibid.
Time dilation means Time appearing to speed up or slow down depending on how fast you’re going relative to anything else. ibid.
Warping Space means altering Time. ibid.
Particles really are entangled … Entanglement means instant communication … faster than the speed of light. ibid.
When a star a hundred times heavier than our Sun switches off it goes with a bang. While we see the outward explosion as a supernova, this masks the inward implosion. The core is collapsing into the most dangerous object in the universe; the density becomes so great in the centre that Gravity sucks in Time and Space itself. Universe: Stars
At the centre of a black hole is a point called the singularity. Everything that has ever fallen into a black hole is destroyed. Crushed into a pin-point of infinite density and infinite smallness. Even Space and Time are squelched out of existence. ibid.
Of all the riddles of the universe time travel may be the most perplexing. Time travel could involve going back in time or speeding into the future. But for the moment every one of us is frozen in the present. Yet Science holds out the possibility that we might loosen the hold that Time has on us. Einstein’s Theory of Relativity in which Time plays a central role, makes time-travel an open question. The Universe s5e4: Time Travel, History 2010
Travelling into the past seems improbable because Time only goes one way – forward. Physicists call this the Arrow of Time. The Arrow makes Time a one-way-street of irreversible events. ibid.
The Arrow of Time can be bent in extreme conditions. ibid.
Space and Time are linked into something he [Einstein] called Space/Time. This means that whenever Space is warped, so is Time. ibid.
The Paradoxes when we meddle with the past ... If Time Travel is possible, Nature must have a way round the contradiction. ibid.
Nature prevents paradoxes ... It can’t be done. A different idea is the strange idea of multiple universes. A third solution to the Paradox Problem is the notion that if time travel is possible you just won’t be able to change the past when you get there. ibid.
We don’t have to worry about paradoxes when we travel into the future. ibid.
It may be that time travel is possible through wormholes that are natural. ibid.