The universe is vast. It might even be infinite, too, but we’re not really sure. So it’s no wonder that there are things about it that we just don’t understand. In a way, that’s half the fun of science: attempting to explain the apparently inexplicable. And of the plenty of mysteries out there in the cosmos – from the relationships between tiny particles, to the potential existence of giant space brains – these ten unsolved conundrums show just how weird and incredible the universe we live in really can be.
10. How did the universe begin?
This seems as good a place as any to start. One of the big unanswered questions in physics is just how the universe originated. The most common explanation, of course, is the Big Bang theory, but that itself is not without its problems. For starters, what happened just before the Big Bang is beyond our visible reach. In addition, the Big Bang should have resulted in the formation of both matter and antimatter in equal amounts. And, as their names may suggest, any time these two collided they would annihilate each other, releasing energy in the process. Regardless of how common such collisions might be, though, the expected result would be to see equal amounts of both still today. But, strangely, we see in our observable universe mostly matter.
So where did all the antimatter go? Or, put another way, how did we end up with so much matter? To get around this conundrum, theoretical physicists from the United States and the United Kingdom proposed, in 2001, the “ekpyrotic scenario.” The idea is that the universe runs in cycles and that massive sheet-like parts of our universe – or “branes” – collide with each other once every trillion years, leading to enormous Big Bang-style explosions. And instead of introducing an even division of material, these explosions then re-inject both matter and energy into the equation.