As we mentioned in our first list about mind bending theories about the universe, the universe is a vast and mysterious place. For centuries, people have looked out into space and tried to explain why we’re here and where we came from. While it may take even more centuries before any of those questions are answered, it doesn’t mean scientists don’t have any theories.
We should also point out that these are just theories, so at times, some theories may not align with each other, or even contradict each other.
10. Why is Dark Matter so Hard to Detect?
Throughout this list, we will talk about something called dark matter. Dark matter makes up about 27 percent of the universe and about 83 percent of all matter. It is invisible because light doesn’t bounce off of it and it has a gravitational pull on regular matter, meaning it affects the movements of galaxies and galactic clusters. While it does have a gravitational effect, dark matter can pass through regular matter almost undetected. For all of these reasons, dark matter hasn’t been detected yet, but physicists are sure it exists.
One question is: why is it so hard to detect dark matter in Earth-based experiments? One possible answer comes from a group of particle physicists called Lattice Strong Dynamics Collaboration. In their simulation, they found that dark matter might have noticeable interactions with ordinary matter if they are both in conditions that are similar to the start of the universe, which is extremely high-temperature plasma. If their simulation is true, that means in the early days of the universe, dark matter might have been observable.
The good news is that these types of conditions can now be recreated in the Large Hadron Collider at CERN. Researchers are awaiting a chance to test the theory and for the first time, dark matter could be detected. If their theory is correct, it would suggest that before the universe cooled, there was a type of balancing act between matter and dark matter before they spread across the universe.
9. Dark Matter Killed the Dinosaurs
An asteroid is the most likely culprit for what killed the dinosaurs. However, what really kicked off the Cretaceous–Paleogene extinction 66 million years ago is still debated. A very far out and cosmic theory comes from physicist Lisa Randall is that it was an impact event that was caused by dark matter.
The basis of the theory goes back to the 1980s, when paleontologists David Raup and Jack Sepkoski found evidence that every 26 million years since the Great Dying of the Permian-Triassic, (which happened about 252 million years ago and 96 percent of life was wiped out), there has been a great mass extinction. Upon further research, going back a half a billion years ago, it appears that Earth suffered some type of cataclysmic event approximately every 30 million years, give or take a few million years.
However, scientists have never really sure why cataclysmic events would happen on a timetable like that. Randall’s theory is that dark matter is involved. Dark matter is believed to be scattered throughout the universe and it is used as scaffolding on which galaxies, including our home the Milky Way, are built. As our solar system rotates around the Milky Way, it “floats” and at times, it bobs like a cork in the water. And this bob happens about every 30 million years.
When we bob, our solar system may encounter a disk of dark matter. The disk would need to be one-tenth the thickness of the Milky Way’s visible disk of stars, and have a density of at least one solar mass per square light-year.
Matter and dark matter can pass through each other, but dark matter can affect regular matter through gravity. The result is that when some matter floating in space comes into contact with dark matter, it could send things flying throughout the universe, which ultimately hit Earth.
If Randall’s theory is true, dark matter could be responsible for major parts of the formation of the universe.
8. Life Spread Across the Universe Like an Epidemic
When talking about the universe, there’s one question that always pops up: is there intelligent life other than our own? Or are we just alone here? Well, scientists wonder about this too, and currently they are looking at how life, including our own, came into existence.
According to a research paper from the Harvard-Smithsonian Center for Astrophysics, the most logical answer is that life spread from star to star, like an epidemic. The concept that life spread from planet to planet and star to star is called panspermia, and of course, if you’ve seen Prometheus, that concept is a major plot point.
If life passed from star to star, that means that the Milky Way could be full of pockets of life. If the theory is correct, then it is possible that other planets in the Milky Way may host life as well.
Another interesting thing they found in their calculations is that life could be spread by microscopic organisms that hitched a ride on an asteroid, or it even could have been spread by an intelligent being or beings.
7. Why is the Universe Made of Matter?
Matter is everything that takes up space and has weight, and the opposite of matter is called anti-matter. When matter and anti-matter touch, they annihilate each other, which is exactly what happened at the start of the universe and helped drive its expansion. At the beginning of the universe, there should have been an equal amount of matter and anti-matter. However, if there was an equal amount of both matter and anti-matter, they would have canceled each other and the universe would have ceased to exist. This has led physicists to believe that there was slightly more matter than anti-matter. An amount as small as an extra particle of matter for every 10 billion antimatter particles would have been enough for matter to spread out across the universe.
The problem was that while physicists knew that there was more matter, they didn’t know why. That was until 2008, when researchers at the University of Chicago were observing subatomic particles that lived very short lives called B mesons. The researchers, who won the Nobel Prize in Physics for their discovery, found that that B mesons and anti-B mesons decay differently from one another. This means that it is possible that after the annihilations in the start of the universe, the B mesons and anti-B mesons decayed differently, leaving enough matter behind to create all the stars, planets, and even you and everything you touch, including the air you breathe.
6. Disorder Made Life Possible
Entropy essentially measures the amount of disorder in a system. If something is high in entropy that means there is more disorder, and low entropy means there is more organization. An example to visualize this is with Legos. A Lego house would have low entropy and a box of random, disconnected pieces would have high entropy.
What’s interesting is that entropy may be the reason that life exists in the first place, which doesn’t make a whole lot of sense if you take a look at the complexity of something like the human brain, which is the pinnacle of order.
Nevertheless, according to a theory by assistant MIT professor Jeremy England, higher entropy may be responsible for life in the universe. England says that, under ideal conditions, a random group of molecules can self-organize themselves to efficiently use more energy in their environment. How entropy plays into this is when energy is added to a system. The molecules jump and bounce off each other. If a few were to clump together, and energy was used more efficiently, it would continue to hold together, collecting more molecules, until eventually enough molecules clump together to become a life form. However, if there wasn’t a high entropy state, the molecules would have never been bouncing off each other. Therefore they would have never clumped together and brought about life.
5. The Universe Has No Beginning
The prevailing theory of the start of our universe is that over 13.8 billion years ago, from a point of singularity, the Big Bang gave birth to the universe and it has been expanding ever since.
The Big Bang was first theorized in 1927 and the model is based on Albert Einstein’s theory of general relativity. The problem is that there are some holes in Einstein’s theory; mainly that the laws of physics break before reaching singularity. Another big problem is that the other dominant theory in physics, quantum mechanics, doesn’t reconcile with general relativity. Also, neither relativity nor quantum mechanics explain or account for dark matter. This means that although the Big Bang is one of the best theories about how the universe started, it may not be correct.
An alternative theory is that the universe was never at the point of singularity and there was no Big Bang. Instead, the universe is infinite and doesn’t have a beginning or an end. The researchers arrived at this theory by applying quantum correction terms to Einstein’s theory of general relativity using an older model of interpreting quantum mechanics called Bohmian Mechanics. And no, we’re not exactly sure what that means, but good for them.
Their method of testing the theory will also help account for dark matter. If their theory is correct that the universe is infinite, it would mean that the universe has pockets of a superfluid filled with theoretical particles, like gravitons and axioms. If the superfluid matches the distribution of dark matter, then it’s possible that the universe is infinite.
4. The Universe Should Have Never Existed
Science fiction writer Ray Bradbury once wrote, “We are an impossibility in an impossible universe.” And according to a model based on the Higgs boson particle from King’s College London suggests he couldn’t have been more right, because the universe shouldn’t exist.
The problem is that 10-36 seconds after the Big Bang to sometime between 10-33 and 10-32 seconds, the universe underwent something called cosmic inflation, which was a rapid expansion of the universe. If that is true, the inflation would have caused quantum fluctuations, or jolts, in the energy field. These jolts would have been so strong that they would have pushed the universe out of the Higgs field, which is responsible for giving particles its mass, and the universe would cease to exist. Of course, since you’re reading this, you know that this model isn’t correct. So why does the universe exist when it shouldn’t?
One possibility is that the findings are wrong. Another is that there may be some new physics or particles that have yet to be discovered. However, until we figure it out, we should just feel lucky to be here when we theoretically shouldn’t.
3. The Universe Started Off One Dimensional
A commonly held belief about the universe is that the Big Bang was an exploding sphere, but another theory posits that for the first thousand-trillionth of a second of the Big Bang, it was actually a one dimensional line. Energy would race back and forth before creating a fabric, which is the second dimension. Then it morphed into three dimensions, which is the world we see.
If the model is correct, it would help address a few problems with the standard model of particle physics, such as the incompatibility between quantum mechanics and general relativity, and cosmic inflation. However, if this theory is true, it would only lead to more mysteries, like what mechanisms were used to make the universe morph into the different dimensions?
2. How Many Dimensions Are There?
In the last entry, we talked about how the universe may have evolved into three-dimensions; however there are many more dimensions than that. According to Superstring Theory, there are at least 10.
Here is how it works: the first dimension is just a single line, the second dimension is height, the third is depth, and fourth is duration. Where it starts to get a little bit weird is dimension five. That is where the multiverse theory comes into play. In the fifth dimension there is a universe that is very much like our own and we would be able to measure similarities and differences. The sixth dimension is a plane where there are parallel universes with all the same starting conditions, so if our universe started with the Big Bang, so did theirs. The seventh dimension is a plane full of worlds with different starting conditions.
Now, if all that wasn’t confusing enough, the eighth dimension is where things start to get really complicated and humans have problems understanding it. Basically, the eighth dimension is all possible worlds, all with different starting conditions, and they branch out infinitely. Of course, things only get more brain melting from there. In the ninth dimension, there are all possible universes that start with different initial conditions and the laws of physics of these universes can be completely different. In the 10th and final dimension anything is possible, and that is just something humans cannot even fathom.
1. We’re Living in the Distant Past of a Parallel Universe
The term “time’s arrow” was first introduced in 1927 and it aptly describes the flow of time. Humans perceive it as always going forward and it also obeys the second law of thermodynamics so entropy always increases; eggs are cracked and scrambled and they never unscramble and reform inside the shell.
The problem is that if time only goes forward, many of the best equations about how the universe works, like James Clerk Maxwell’s theory of electrodynamics, Isaac Newton’s law of universal gravitation, Einstein’s special and general relativity or quantum mechanics, would be incorrect. However, if time ran forwards and backwards, then they would all work perfectly. One way that this is possible is that at the Big Bang, two parallel universes were started. One where time moves forward, and a parallel one where time flows backwards.
The reasoning is that, if entropy increases in our universe, then when the universe started, it would have begun in a low-entropy and highly ordered state. That could be the end of another universe. That universe would start at the end and time would flow backwards, while ours flows forward.
If we could see the other universe, we would see time going backwards and we would probably see into the future of our universe (presuming that we’re not past the middle age of the universe) and we’d be living in the parallel universe’s distant past. That is, of course, if we’re not the reality that is living in reverse and don’t realize it.