Humanity has amassed an enormous amount of information about our universe and how it works. We pride ourselves in being the most intelligent species on Earth, and so far, the most capable kind in all of the universe.
However, the information we have about the structure of our universe is derived from the mere 4 percent that we can observe, measure, and analyze—regular, ordinary matter. The remaining 96 percent is “dark” stuff. It is dark because we know nothing of it (and because physicists tend to lack creativity in the naming department).
Of that 96 percent, roughly 68 percent is dark energy. This makes it the largest component of the universe, and right now, the most mysterious. Thousands of scientists around the world are working to decipher this mysterious energy that seems to guide how our universe creates large structures.
Without dark energy, our universe would eventually end up in a “Big Crunch”—a gravity-dominated fate where the universe rapidly collapses into itself. So, although we don’t know what dark energy is, we should be thankful that it’s there.
Here are the top 10 theories of what dark energy could be and what each scenario can tell us about the fate of our universe.
It Is A Property Of Space
This theory is derived from Einstein’s theory of gravitation, specifically from the fact that “empty space” can have its own energy—dubbed “the cosmological constant.” Einstein also believed that space could come into existence from nothing, and as more space is created, more energy can consequently be held within it.
This would explain the rapid expansion of the universe we observe. This sort of universe would continue expanding forever until every object in the universe was so far away from every other object that everything would end in cold darkness.
Theory Of Everything
A lot of astronomers believe the search for dark energy is futile. Instead, they lecture that finding the elusive “theory of everything” (not the Stephen Hawking movie) would naturally solve the problem of dark energy.
This theory should be able to explain the behavior of all objects in the universe—from very big to incredibly small. For now, our theories of how the universe works are divided into large-scale theories (like the theory of gravity) and small-scale theories (like quantum mechanics).
Although solving the problem of dark energy this way is logically sound, finding this theory has proven impossible for even the brightest minds in physics. Normal laws of physics seem to “break down” when one reaches the quantum level. But alas, the search goes on.
It Creates A New Fundamental Force
The fundamental forces we know of (gravity, electromagnetism, weak force, and strong force) all act within different ranges. Some affect only atomic-sized objects, while others cause the motions of planets and instigate the formation of galaxies.
This theory of dark energy states that that there is a fundamental force we still have not found that acts on enormous scales and can only be observed when the universe reaches a certain size. It would work to oppose gravity and thus pull objects in the universe away from each other.
Scientists argue that because this force acts on such a large scale, we have not yet encountered it in our everyday lives and measurements made on Earth cannot be affected by it. No one really knows if this force would be temporary or permanent. Yet, depending on this, the universe would either expand forever and turn cold or expand and contract periodically for the rest of time.