Imagine a world where time travel isn't just a concept of science fiction, but a reality. The key? Parallel timelines coexisting. Let's delve into the intriguing possibility of time travel, exploring the role of parallel universes and their potential to make it feasible.
Is time travel real?
Our modern understanding of time and causality comes from general relativity
- Albert Einstein’s theory combines space and time into a single entity – “spacetime”
- This theory has existed for more than 100 years, and has been experimentally verified to extremely high precision, so physicists are fairly certain it provides an accurate description of the causal structure of our universe
- For decades, physicists have been trying to use general relativity to figure out if time travel is possible
Introducing multiple histories
Recent work by Barak Shoshany, Jacob Hauser and Jared Wogan shows that there are time travel paradoxes that Novikov’s conjecture cannot resolve.
- This suggests that allowing for multiple histories (or in more familiar terms, parallel timelines) can resolve any paradox you throw at it.
Arguments against time travel
Building a time machine seems to require exotic matter, which is matter with negative energy.
- From quantum mechanics, we know that such matter can theoretically be created, but in too small quantities and for too short times.
- There is no proof that it is impossible to create exotic matter in sufficient quantities.
- Furthermore, other equations may be discovered that allow time travel without requiring exotic matter.
Eliminating the paradoxes
In physics, a paradox is a purely theoretical concept that points towards an inconsistency in the theory itself.
- One attempt at resolving time travel paradoxes is theoretical physicist Igor Dmitriyevich Novikov’s self-consistency conjecture, which essentially states that you can travel to the past, but you cannot change it.
