Language Selection

English French German Italian Portuguese Spanish

Physicist throws time-travel theories a curve

Filed under

What do you get when you join a 1981 DeLorean, a "flux capacitor" and a digital dial set to Nov. 5, 1955? If you're the character of Dr. Emmett Brown in the 1985 movie Back to the Future, you've created a time machine.

The possibility of time travel has occupied the fantasies of philosophers, authors, children and directors. But to some physicists, it's more than pure fancy.

In the July issue of Physical Review Letters, Amos Ori, professor of physics at the Technion, the Israel Institute of Technology in Haifa, argues that the laws of physics don't stand in the way of building a time machine.

Ori hasn't created, or even designed, a physical time machine. He instead constructed a situation — a mathematical model — in which the laws of physics will make one for him.

"I write (the situation) mathematically. That doesn't mean that I know how to implement it practically." However, he says, if inhabitants of some highly advanced civilization could set up the conditions he describes, they might be able to travel in time.

The time machine Ori proposes isn't quite like the phone booth in Bill & Ted's Excellent Adventure or Back to theFuture's DeLorean. Ori's solution forms a closed, timelike curve. It's a bit like a song that never ends. Think of each musical note as a point in space. As you sing the notes, you move forward in time. You can travel around the curve — sing the song — but when you get to the end, you are also at the beginning.

"If you had a closed, timelike curve, that means that something could run around it forever and ever, always going to the future but always coming back to the beginning," says Ted Jacobson, professor of physics at the University of Maryland.

Ori isn't the first physicist to create a theoretical time machine. Unlike previous models, Ori's proposal doesn't require any unknown matter or energy. The previous theories were forced to use unrealistic negative energy to warp space and time.

Ori's plan requires absolute emptiness — a vacuum. That means that, in principle, a closed, timelike curve could even happen naturally, possibly through cataclysmic astronomical collisions in the abyss of space.

It is difficult for experts to imagine the exact conditions, but extremes in the universe, such as super-dense black holes, could create the conditions necessary for the formation of a time machine.

When Einstein declared that space and time were intimately connected, time travel became a physical possibility. If you could zip around like a beam of light, you wouldn't age, but physics won't let that happen. It remains to be seen whether physics will allow time travel, but Ori's work suggests it will.

Einstein opened the door for the scientific pursuit of a time machine, and physicists are searching for solutions. Ori says maybe it's possible, but "this isn't something that we are going to construct soon."

By Michelle Lefort

More in Tux Machines

Richard Stallman says Microsoft's Linux love-in is a ploy to 'extinguish' free software

GNU OS CREATOR Richard Stallman has slammed Microsoft's Windows 10 subsystem for Linux as an attempt to "extinguish" free software. Microsoft, a company whose ex-CEO famously slammed Linux as a "cancer", has a new found "love" for open source software, having last month released its hell-over-freezing subsystem that lets Windows 10 users run various GNU/Linux distros and software. Unsurprisingly, some are sceptical about Microsoft's new-found enthusiasm for Linux and open source software, including free software advocate, and founder of GNU OS Richard Stallman. Speaking to Tech Republic, he said Microsoft's decision to build a Windows Subsystem for Linux (WSL) amounts to an attempt to extinguish free, open source software. "It certainly looks that way. But it won't be so easy to extinguish us, because our reasons for using and advancing free software are not limited to practical convenience," he said. "We want freedom. As a way to use computers in freedom, Windows is a non-starter." "The aim of the free software movement is to free users from freedom-denying proprietary programs and systems, such as Windows. Making a non-free system, such Windows or macOS or iOS or ChromeOS or Android, more convenient is a step backward in the campaign for freedom." Read more Also: Microsoft’s Linux enthusiasm may not help open source

Are These the Toughest Linux Operating Systems to Install?

It’s important to keep in mind that no matter the Linux operating system you choose to install, what matters is getting it onto your computer and using it. Sure, there may be benefits or drawbacks to whatever setup you pursue, but that’s just how Linux is: various by nature. What’s really important is choosing something that best suits you. If you want a high level of flexibility, then by all means, use something like Arch Linux. And if you want something more automated, that’s fine as well. It’s still Linux, after all. Read more

Ubuntu Touch OTA-2 Rolls Out for Ubuntu Phones, Including Nexus 4 & Nexus 7 2013

The UBports community has released this past weekend the second OTA (Over-the-Air) update to supported Ubuntu Phone devices, bringing support for some old devices that were requested by the community, as well as a set of new features. Read more

Qt 5.10 Alpha in testing for KDE neon

Qt 5.10 got an alpha release last week and rumours are there’s lots of interesting new stuff for Plasma developers and other parts of KDE. Packages are available in KDE neon but hidden away in the testing repository because there is inevitably some breakage. Random bits of QML such as the clock above and Kirigami seem to be unhappy. Please do test but expect breakage and fixes to be necessary. Read more