Why does time only go in one direction why don’t broken dishes unbreak why can I remember the past but not future there’s nothing explicitly written in the laws of physics that says the rules change based on whether time runs forward or backward so to explain why the arrow of time points in one direction scientists have relied on statistical arguments based on increasing entropy now though researchers believe they have demonstrated that fundamentally time cannot be turned backwards in all cases because things don’t always happen the same way in Reverse to show. Time Reversal possiblity..
This the researchers simulated the orbits of three black holes which is much more complicated than I made it sound just now two objects in orbit around a central point without outside influence move in stable and predictable ways but add a third object to the mix and things start to go haywire this is what’s known as the three-body problem outside of special cases there’s no one analytic solution to calculate what the orbits of three similar bodies look like their orbits are chaotic and I mean that in the scientific sense where small differences in initial conditions can lead to huge changes in the paths they take.
Still we can use supercomputers to simulate three objects in orbit by calculating each bodies trajectory over a very short amount of time checking how the forces on all the bodies have changed and calculating their new trajectories again the program the researchers used to simulate their three orbiting black holes was Brutus I assume because it uses brute computational force to work and not because it was involved in the murder of Julius Caesar they started the three black holes off at rest and let gravity do its thing the black hole’s hypnotically danced around each other for tens of millions of simulated years before .
One was finally ejected and the two remaining settled into stability then the researchers attempted the same thing but in Reverse they took the ending conditions and just flipped the velocities then ran it again ideally that should lead to a retracing of the same orbits all the way back to their same initial positions but that’s not what happened at least 5% of the time 5% of the time the black hole’s ended up in completely different orbits not immediately for the part they followed the paths that were in a sting guaa tional from there forward time counterparts but once the black hole’s deviated even a little it was done millions of years down the line even tiny disturbances radically changed their orbits.
how tiny literally the tiniest amount possible in quantum mechanics there’s a concept called the Planck length sexually it’s the smallest meaningful measurement it’s derived using measurements that don’t change with relativity namely Planck’s constant the gravitational constant and the speed of light practically it measures out to one point six one six times ten to the negative thirty five meters or about 20 orders of magnitude smaller than a proton even if the black hole’s running backwards in time experienced a deviation that’s small eventually the black hole’s would change their orbits and the symmetry of time would break of course this is all being run on a computer so maybe limitations in computing resulted in the altered orbits but the researchers ran the calculations with over a hundred decimal places so they say that suggests.
what they’re seeing was a fundamental product of nature and Brutus wasn’t stabbing them in the back so even though equations that describe physics make no distinction between time moving forward or backward it seems that in some as-yet-undiscovered way the universe does technically.