Is Time Travel Possible? – Part 2
There are many theories as to how Doctor Who’s TARDIS travels through time. Currently it’s outside of our technology, but it is something that captures our imagination. What would it be like to travel back and philosophise with Socrates? Or to play piano with Beethoven? Or to discuss politics with Abraham Lincoln?
One theory involves using wormholes. Somehow a wormhole is created and it is used to travel through time. One end of the wormhole could be accelerated close to the speed of light, thereby providing a tunnel back in time. However, that’s not true time travel as you could only go back in time to the point of the creation of the time machine. This would certainly explain Stephen Hawkins comment about not seeing time travelling tourists – the machine hasn’t been built yet, so they cannot visit this time.
The energy requirements for creating a wormhole are staggering though. It is theorised that to create a stable wormhole of the size needed to transport a person would take many time more energy that our Sun would produce in its lifetime. This is of course, discounting any future power sources that may be invented to be capable of this feat.
Another possibility for time travel is that instead of physically travelling through time, our consciousness is sent back to inhabit a body. Instead of becoming a time traveller, you become a body tourist! This possibility fits Stephen Hawkin’s theory about the absence of time tourists well. It may also explain why ideas that are well in advance of current technology suddenly appear.
If a heavy atomic nucleus was placed in a strong magnetic field, it would elongate into a cylinder. The density and spin of this would, theoretically, be enough to create a time machine. Projecting gamma rays at it may allow information, but not matter (people / objects) to be sent back in time. The first flaw in this theory is that the destination time must be able to receive the information sent to them. The second theory comes from Robert Forward who first proposed this idea. He states that until there is a single theory combining relativity and quantum mechanics all these speculations may well be nonsense.
Researchers are now looking at a phenomenon known as quantum entanglement. This has proved useful in cryptography, and has shown some intriguing possibilities. Quantum entanglement may well allow faster than light or FTL communication and time travel. Einstein referred to this as “spooky action at a distanceâ€; where particles instantly exchange information in order to maintain correlations between them.
Quantum entanglement is a phenomenon where the quantum states of two particles reference each other, which leads to correlations between their observed properties. This means that measurements on one particle that influence its state are instantly noticed at the other particle. This, as you can imagine, has intrigued researchers and is creating lots of discussion in the scientific community.
Physicists have also suggested that time travel may be absent due to something known as the anthropic principle. This argues that a universe which allows for time travel is one that intelligence could never evolve in. It would be impossible for any being in this universe to sort events into past or future and would be unable to comprehend the universe.
Of course time travel does assume that there is a past, present and future, i.e. that time has a direction, that it flows from past to the future. Many of the new age spiritual systems argue that time is in fact an illusion.
As you have probably noticed time goes slower when you are doing something boring and faster when you are having fun and enjoying yourself. So therefore time is a product of your perception of it.
As time is the fourth dimension, when you step into the fifth dimension, that inhabited by spiritual beings, time ceases to exist so everything appears to happen at once.
Whether we will ever experience time travel within our life times is unknown, but in the meantime Doctor Who will continue to entertain us with his adventures through time and space.
