The theory of the start of the universe seems to be one of the few things that astronomers can confirm with certainty when it comes to space. The Big Bang is still considered one of the most solid theories, but there had to be something before that that caused it, after all, matter does not appear out of nowhere. But there are infinite questions still related to this beginning that do not have answers, and thus figuring out exactly how the universe started and what is left from the previous iteration continues to be one of the biggest goals in physics.
Now, scientists believe that the way to do this is to try to find the “mistakes,” the leftover marks from massive events early in the universe’s history that may or may not be visible, but that could point towards what happened before the Big Bang.
The remains of the creation of the universe, what is left after the Big Bang
Billions of years ago, when the universe had just exploded into existence right after the Big Bang, everything was incredibly hot, and all the fundamental forces of nature were basically mashed together into one. As things cooled down, those forces split apart one by one in what scientists refer to as “phase transition” and created what we now know as the universe, or at least a version of it that is familiar to us today.
In this process, there would have been imperfections that would have become what are called cosmic strings, which are super-thin, ultra-dense lines stretching across the universe that link everything together. This idea of strings that hold the universe together has been around since the 1970s, but for a while, people kind of stopped talking about them, especially after new inflationary models seemed to explain the universe’s early days without needing to bring strings into it.
But now, scientists have proven that these strings do exist and that they might even give off gravitational waves we can actually try to detect. This is a huge accomplishment for the scientific community, as often when it comes to space, we tend to need to rely on what we do not see in order to know what is out there.
The renewed interest in strings started with a recent study from the Indian Institute of Astrophysics, when in a sky region called CSc-1, researchers spotted something strange, two galaxies that looked way too much alike. Since this is not common or entirely possible, there should be some difference, experts then thought that this was not two galaxies at all and that maybe it was one galaxy appearing twice, thanks to a weird trick called gravitational lensing.
Gravitational lensing happens when a really big object bends space-time and makes light from faraway objects bend or duplicate and would have been a good explanation, but this was not the case, so they had to look for alternate explanation and landed on strings.
More specifically, they posited that a tilted string might have sliced through the region and caused the duplication, which, if it turns out to be true, it would be the first time we have actually seen something that could be a cosmic string. One of the scientists even said, “If this is confirmed, it would be the first direct visual evidence of one of these structures, which could change the course of modern theoretical physics.”
Despite the excitement of this potential discovery, there is still a long way to go to prove string theory as a potential theory for the formation of the universe. It is still exciting that a theory that had almost been discarded can resurface once again and make us rethink everything we know about the universe.