They say, “Modern problems require modern solutions.” Although this statement has a funny connotation today, I find it incredibly relatable to the evolution of physics over the years. Think about this, just 500 years ago, a list of 8 unsolved problems in physics would have looked like this:
- What force is responsible for making planets go around the Sun and the Moon around the Earth?
- How big is the universe?
- Where do the Sun and the stars get their energy?
- What is the constituent of all matter?
- What is the nature of motion? Is force necessary to keep things moving?
- What is the nature of light?
- What is the nature of magnetism?
- What is the nature of “static” electricity?
Today, thanks to the advancements in science and technology, we know all the answers to the above questions. Even more impressive is that we can make some very accurate measurements and predictions about our environment.
For example, we not only know that atoms are the building blocks of all matter, but we can also measure their size, shape, and other properties with incredible precision.
But with the advancements in science and technology came new problems – which would also require “modern solutions” to evaluate. In this article, we will discuss 8 unsolved problems in physics that continue to baffle scientists today.
Dark Matter
There is a general consensus in the scientific community that everything we know and observe in the universe (i.e. electrons, atoms, planets, galaxies, stars, black holes, etc.) accounts for only about 5%!
The other 95% of the universe is composed of stuff we don’t know. One of them is thought to be dark matter, which accounts for 27% of the universe. We don’t know what it is but we know what it’s not:
- It is not visible at all – it does not absorb, reflect, or emit electromagnetic waves in any way, making it completely invisible to light and all our fancy detectors.
- It doesn’t seem to interact with matter or itself. Effectively leaving behind a ‘zero footprint’ of its presence.
But how do we know it exists? Because without dark matter, we are pretty sure there wouldn’t be galaxies, stars, planets, and certainly life!
Dark Energy
Along with Dark Matter is Dark Energy which makes up about 68% of the universe. Perhaps the best way to explain Dark Energy is by using the infamous story of Robert (Bigi).
A long time ago, there was a guy by the name of Robert. One glance at Robert would tell you he had a serious weight problem. He was so fat, as Eddie Murphy puts it, “his belt size was the Equator”. Everyone called him, ‘Bigi’ for his sheer size.
Seeing his obesity problem could be fatal, his friends concocted a plan to help Robert cut off some weight. They prepared a diet plan for him and promised to pay for his dream vacation if Robert agreed to stick to it. The proposal pleased Robert and the plan went underway.
A few months later, Robert didn’t seem to lose any weight. In fact, he put on even more weight than before! Perhaps the diet wasn’t working or Robert’s body was unresponsive.
Eventually, his friends soon made a grueling discovery, Robert was eating in secret. He just couldn’t stick to the plan!
Our universe is very much like Robert. Scientists know that the universe is expanding at an accelerating rate. It is growing bigger and bigger every day. The prevailing theory is that our voracious universe is feeding off something in secret, we don’t know what it is, but we have a name for it, Dark Energy!
Matter-Antimatter Asymmetry
They say, “nature always balances her books”. Yet there is a glaring imbalance in the universe and we don’t know why.
Back at the very beginning, the Big Bang created equal amounts of matter and antimatter in the early universe. Yet today, everything we ‘see’, from the atoms to the galaxies is almost entirely made up of matter. Where did antimatter go?
Antimatter is the antithesis of matter. Antimatter particles have the same mass as their matter counterparts but have opposite properties such as electric charge. If these two particles come together, they annihilate one another, leaving behind energy.
At the beginning of the universe, these particles should have been created in equal pairs. But something happened at the beginning that tip the scales in favor of matter particles. Scientists are yet to know what caused this.
The Measurement problem
In the 2013 thriller film, Now You See Me, one of the main characters kicks off the movie with the killer line, “The closer you look, the less you see”. He then proceeds to fool an entire audience, including the viewers, with a brilliant magic trick right in front of their very own eyes.
Physics is very much similar. Up until the 19th Century, there had been a general understanding in the science community that if we take a closer look at matter, we’d understand its behavior better. Today, we know that is a ‘total crock’.
At the subatomic level, things are quite fuzzy. Particles seize to exist as objects in definite locations and seem to be smeared all over the place, like waves. Yet when you attempt to make a measurement, you always find a particle at only one distinct position. This is known as the collapsing of a wave function and it is one of the most persistent problems in quantum physics for nearly 100 years.
A unified theory of Quantum Physics and Relativity
This is the Cain and Abel version of physics, a sibling rivalry of theories. Quantum physics deals with the physics of the subatomic world, the smallest of particles. General Relativity, on the other hand, deals with physics at the grandest of stages, the black holes, stars, and galaxies.
Ideally, these theories should complement each other. General relativity should reduce to Quantum Physics when dialed down to the atomic level and vice versa. But that is not the case.
Despite their individual success in their separate fields of application, Quantum Physics and General Relativity are at loggerheads with each other. Each says the other one is wrong although they both describe reality.
Scientists are trying to find a way to reconcile these two theories.
Origin of the universe
What do you think is the origin of the universe?
The Big Bang!
Wrong Answer! The Big Bang is a theory of how the universe evolved from a split-second after what brought it into existence. It doesn’t tell us anything about what happened at the very beginning, time zero.
Ironically, the reason we can’t figure out what happened at the very beginning is because of the feud between Quantum Physics and General Relativity!
The arrow of time
They say, “Time and tide wait for no man”. Time is always moving – forward. Physicists would love to know why is that.
One of the most interesting features of time is irreversibility. It always flows in only one direction (forward), from the past to the future through the present. Is the asymmetry of time just an illusion and we are incapable of perceiving the reverse? Or is there something more to it? This is still an open question.
The question of consciousness
While not strictly a physics problem, the nature of consciousness is a mystery that has puzzled philosophers and scientists for centuries. Some scientists believe that consciousness may be connected to quantum mechanics, but this idea remains controversial.
Any solution to these questions is sure to guarantee you a Noble prize, several other honors, and even a cover page of the Times Magazine! If you think you have a solution, you should write a scientific paper including an abstract detailing your theory and send it to “Physical Review Letters” here is their website (Information for authors). They are very honest people, they won’t steal your discovery.
