A strange theory claims that there exists a our universe has a twin, which has been running backwards in time since the Big Bang event.
Imagine a universe, just like our own, filled with stars and galaxies. Inside it is a solar system which has its own planet Earth, but with a big difference. Time travels in reverse there! If this sounds like science fiction plot to you (and reminds you of the movies Tenet and Mr. Nobody), then you’re not alone. However, a strange new theory suggests that a twin-universe which has been running backwards ever since the Big Bang can finally reveal the secrets of dark matter to us. Stranger still, once you understand the theory, it does make some sense. Read on to find out about this anti-universe and how it can explain the existence of dark matter. This Live Science article explains it.
What is Dark Matter
Dark matter refers to a hypothetical form of matter which is believed to account for around 85% of the matter in the universe. What is interesting about dark matter is that it does not interact with electromagnetic radiation, which means it does not absorb, reflect or emit any radiation including light. Hence, it is impossible to observe conventionally. Then, how do we even know Dark Matter even exists? We do know something exists because of all the anomalies in astrophysical observations including gravitational effect, which cannot be explained unless there is more matter present than what can be observed. And this matter is called dark matter.
The tricky thing with dark matter is that experts have not been able to prove its existence, let alone understand what it is or what it does. But, if we are to believe this twin-universe theory which imagines a universe running backwards in time since the Big Bang, we may not have to prove its existence anymore.
What is this time-reversal twin-universe theory
The theory works on the premise that before the big bang theory, the early universe was so small, dense and uniform that time appeared the same going backwards or forward. And once the Big Bang took place, the universe was effectively sliced in two, with one moving forward and another moving backwards in time. This twin-universe or anti-universe still continues to stay in the state before the Big Bang, as it never moves forward in time and is extremely dense, hot and uniform and thus cannot be observed.
If it is a little difficult to imagine a universe running backwards in time, then don’t worry. We will simplify it for you. Time is nothing but a measure of an event taking place. For instance, the Sun rises up for you to know the night has passed and morning has come. Similarly, the Earth revolving around the Sun gives us a sense of time in terms of days, weeks, and seasons. But, what if an object was stationary in the universe? What would time mean for it?
If you do not look at it from our relative position, time may just mean a constant zero for that space rock. And, what if it has stayed in that state for millions or billion of years? It would be difficult to tell whether it was moving forward or backward in time. Now, if it did not emit, reflect or absorb any light, you could say that the object was moving backwards in time as light never reached it.
So, as cool as it is to use words like twin-universe and anti-universe, it is just a way for scientists to explain the complex notions of left handed neutrinos which violate charge and parity symmetry. We can never prove this theory as by definition, it is impossible to interact with an entire universe moving backwards in time since the Big Bang. But it does give us a fresh perspective to look at the dark matter problem.