Tech

# Wormhole Time Travel: Cambridge Physicist Proposes Possibility Of Sending Messages Through Time

A Cambridge scientist has published a paper which might contain a theoretical method to send messages backwards in time.

But, look - before anyone gets over-excited, we're still in the realm of incredibly strange physics here. No one has built a fax machine to the sixteenth century. You can't send back last week's lottery numbers, or remind yourself to pick up milk yesterday.

But it is interesting, and mind-bending stuff.

A wormhole is a theoretical tunnel through space-time, which could create a short-cut between two distant points, enabling travel in a variety of chronologically and physically confusing forms. (Sorry to all physicists for the over-simplification there).

In science fiction, wormholes are often used as a shorthand for time travel - or travel across massive distances, which thanks to relativity is sort of the same thing. Unfortunately in reality it appears that wormholes, if they do exist, are usually assumed to be very shortlived, and so unable to transmit even a single particle through.

But in a new paper, physicist Luke Butcher from Jesus College, Cambridge, suggests that a type of wormhole could exist which could stay open long enough between two points of space to send a pulse of light from one end to the other.

The method itself relates to something called 'Casimir' or 'negative' energy, first proposed by Kip Thorne in 1988 as a method to keep a wormhole open for longer. In theory - for again complex reasons - this negative energy seems like a good way to keep wormholes open. Trouble is making that energy is currently impossible.

What Butcher points out is that if wormholes are much longer than they are wide, they might contain enough Casimir energy to stay open long enough to send something as small as a photon through.

And as Phys.org notes, if you want to send a message back in time - or across vast distances - that's really all you need.

The paper's abstract states:

"We calculate the Casimir energy-momentum tensor induced in a scalar field by a macroscopic ultrastatic spherically-symmetric long-throated traversable wormhole, and examine whether this exotic matter is sufficient to stabilise the wormhole itself."

Now, some obvious caveats: the paper is still in a pre-print stage, and as Butcher notes this is all theoretical. But it's an interesting development and one that could hint at some stunning new types of experimental physics in decades or centuries to come.