Paradox-free time travel is theoretically possible, according to the
mathematical modelling of a prodigious University of Queensland
undergraduate student.
Fourth-year Bachelor of Advanced Science (Honours) student Germain Tobar has
been investigating the possibility of time travel, under the supervision of
UQ physicist Dr Fabio Costa.
“Classical dynamics says if you know the state of a system at a particular
time, this can tell us the entire history of the system,” Mr Tobar said.
“This has a wide range of applications, from allowing us to send rockets to
other planets and modelling how fluids flow.
“For example, if I know the current position and velocity of an object
falling under the force of gravity, I can calculate where it will be at any
time.
“However, Einstein's theory of general relativity predicts the existence of
time loops or time travel – where an event can be both in the past and
future of itself – theoretically turning the study of dynamics on its head.”
Mr Tobar said a unified theory that could reconcile both traditional
dynamics and Einstein’s Theory of Relativity was the holy grail of physics.
“But the current science says both theories cannot both be true,” he said.
“As physicists, we want to understand the Universe’s most basic, underlying
laws and for years I’ve puzzled on how the science of dynamics can square
with Einstein’s predictions.
“I wondered: “is time travel mathematically possible?”
Mr Tobar and Dr Costa say they have found a way to “square the numbers” and
Dr Costa said the calculations could have fascinating consequences for
science.
“The maths checks out – and the results are the stuff of science fiction,”
Dr Costa said.
“Say you travelled in time, in an attempt to stop COVID-19’s patient zero
from being exposed to the virus.
“However if you stopped that individual from becoming infected – that would
eliminate the motivation for you to go back and stop the pandemic in the
first place.
“This is a paradox – an inconsistency that often leads people to think that
time travel cannot occur in our universe.
“Some physicists say it is possible, but logically it’s hard to accept
because that would affect our freedom to make any arbitrary action.
“It would mean you can time travel, but you cannot do anything that would
cause a paradox to occur.”
However the researchers say their work shows that neither of these
conditions have to be the case, and it is possible for events to adjust
themselves to be logically consistent with any action that the time
traveller makes.
“In the coronavirus patient zero example, you might try and stop patient
zero from becoming infected, but in doing so you would catch the virus and
become patient zero, or someone else would,” Mr Tobar said.
“No matter what you did, the salient events would just recalibrate around
you.
“This would mean that – no matter your actions - the pandemic would occur,
giving your younger self the motivation to go back and stop it.
“Try as you might to create a paradox, the events will always adjust
themselves, to avoid any inconsistency.
“The range of mathematical processes we discovered show that time travel
with free will is logically possible in our universe without any paradox.”
Reference:
Germain Tobar, Fabio Costa. Reversible dynamics with closed time-like curves
and freedom of choice. Classical and Quantum Gravity, 2020; 37 (20): 205011
DOI: 10.1088/1361-6382/aba4bc
Tags:
Physics