Source: Rob Waugh's Yahoo Blog - May 6, 2016
‘If time travel is possible, where are the tourists from the future?’ Stephen Hawking asked in A Brief History Of Time.
But one scientist believes that time travel is possible - and he has the design for a working ‘time telephone’, which he believes will receive messages from the future.
Ronald Mallett, 69, is a respected theoretical physicist at the University of Connecticut, and the subject of a new documentary, ‘How To Build a Time Machine’.
He believes that a ‘tunnel’ of laser light can send messages through time - and that a time machine will be built this century.
He also thinks he has the answer to Stephen Hawking’s question about why we have never seen a time traveller.
Mallett’s quest to build a time machine has been a lifelong one - inspired by the death of his father, when he was aged 10.
The young Mallett - who read a comic book version of H.G. Wells’ The Time Machine - vowed to build a machine which would let him travel back and warn his father of the heart attack which would kill him on his 11th wedding anniversary.
Ronald Mallett says, in How To Build A Time Machine, ‘I would say it was fair to call what I was doing an obsession. I was obsessed with wanting to see my father again.
‘I was obsessed with trying to find out how one could control time.
‘Everything that I became, the whole of my personality, everything about being a physicist, was based on my love for my father, and my desire to see him again.’
‘I had a mission. My goal was to figure out how to build the time machine.’
He has designed a machine which can ‘twist’ time using lasers - allowing signals to travel into the past - and now hopes to build it.
The idea is based on Einstein’s theories - and the current prototype version of the machine is a series of stacked ring lasers, glowing green, which circle a glass tube.
Mallett’s machine is based on Einstein’s General Theory of Relativity, and the fact that light can create gravitational fields.
In a scientific paper, Mallett wrote, ‘For the strong gravitational field of a circulating cylinder of light, I have found new exact solutions of the Einstein field equations for the exterior and interior gravitational fields of the light cylinder.
‘The presence of closed timelike lines indicates the possibility of time travel into the past. This creates the foundation for a time machine based on a circulating cylinder of light.’
Mallett believes physical time travel is impossible, but he thinks that messages could be sent through time - in the form of neutrons sent through a ‘tunnel’ of light.
Mallet says, ‘By assigning a 1 to the ‘spin up’ direction and a 0 to the 'spin down’ direction then [we] could send a binary code with a stream of neutron spins.
‘For example, neutrons with 'spin up’, 'spin down’, 'spin down’ would represent a binary code100 which is the number 4.
But the one thing Mallett’s machine will not be able to do is communicate with his father - or anyone else in the past.
If the machine works as expected, it will only be able to send and receive messages from the moment it is turned on - or the future - and no earlier point.
Mallett says, ‘When the first time machine is turned on it will be possible for our descendants to contact us - but we will not be able to contact our ancestors.’
In theory, at least, this solves Stephen Hawking’s problem with time travel.
The reason we have not heard from or seen time travellers is that it only becomes possible to communicate across time once the time machine is built.
Other physicists are less sure that a time machine is possible - and even Mallett says that the process of building one may be long and expensive.
Mallett has worked for decades to get to this point, publishing multiple papers on the subject - and writing an autobiography, Time Traveler, which has been optioned as a film by Spike Lee.
Mallett says, ‘When I first got inspired to study time travel, I had to be very secretive. As a young physicist, you don’t broadcast widely that your research is fueled by your passion to go back in time to see your father.
‘Instead, I cloaked my urge to understand time travel by studying black holes. But in fact, black holes and time travel are related.
‘I knew from my studies of Einstein’s theories that the strong gravity of rotating black holes could affect time. And I wondered if the gravity of circulating light, such as that created by very strong lasers, could mimic the conditions in a rotating black hole and send information into the past and future.
‘My whole existence, who I am, is due to the death of my father, and my promise to myself to figure out how to affect time with Einstein’s work as a foundation.’
'I’m the theoretical guy. The experimental physicists will have to take on the daunting – and very expensive – role of testing my theory.’