In 1900, the British physicist Lord Kelvin said: “There is nothing new in physics to be discovered. All that remains is to make more and more accurate measurements. However, starting in 1900, over three decades, scientists developed quantum mechanics, which turned out to be incompatible with general relativity, which gave rise to one of the deepest contradictions in physics.
Today, no scientist would dare to claim that our physical knowledge of the universe is nearing completion. On the contrary, with each new discovery it seems that there are only more unresolved issues. Naked Science presents a selection of the biggest unsolved mysteries in physics.
What is dark energy?
The universe continues to expand faster and faster, despite the fact that the main force acting in it - the force of attraction, or gravity - is counteracted. Given this, astrophysicists have suggested that there is an invisible agent that counteracts this very gravity. They call it dark energy. In the generally accepted understanding, dark energy is a "cosmological constant", an inalienable property of space itself, which has "negative pressure". The more space expands, the more it (space) is created, and with it, dark energy. Based on the observed growth rates of the Universe, scientists have concluded that dark energy must account for at least 70% of the total content of the Universe. But it is still not clear what it is and where to look for it.
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What is dark matter?
Obviously, about 84% of the matter in the universe does not absorb or emit light. Dark matter cannot be directly seen. Its existence and properties are fixed due to its gravitational effect on visible matter, radiation and changes in the structure of the Universe. This dark substance permeates the outskirts of the Galaxy and consists of "weakly interacting massive particles." Until now, none of the detectors has been able to detect these particles.
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Why does the “arrow of time” exist? Time is moving forward. This conclusion can be drawn based on a property of the universe called "entropy", which is defined as the level of increasing disorder. There is no way to reverse the rise in entropy after it has already happened. The “arrow of time” is a concept that describes time as a straight line from the past to the future. "In all processes there is a dedicated direction in which the processes go by themselves from a more ordered state to a less ordered one." But the main question is this: why was entropy at a low level at the time of the birth of the Universe, when a relatively small space was filled with colossal energy?
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Are there parallel universes?
Astrophysical evidence suggests that the space-time continuum can be "flat" rather than curved, which means it continues indefinitely. If so, then our universe is just one of the infinitely large Multiverse. According to calculations carried out in 2009 by physicists Andrei Linde and Vitaly Vanchurin, after the Big Bang, ten to the tenth power to the tenth power to the seventh power (10 ^ 10 ^ 10 ^ 7) universes were formed. Lot. Lots of. If parallel universes exist, how could we ever detect their presence?
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Why is there much more matter than antimatter?
In fact, the question is not why there is more substance than oppositely charged antimatter, but why something exists at all. Some scientists speculate that after the Big Bang, matter and antimatter were symmetrical. If this were so, the world we see would be immediately destroyed - electrons would react with anti-electrons, protons - with antiprotons and so on, leaving behind only a huge number of "naked" photons. However, for some reason, there is significantly more matter than antimatter, which allows us all to exist. There is no generally accepted explanation for this.
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How to measure the collapse of quantum wave functions?
In the strange realm of photons, electrons and other elementary particles, quantum mechanics is a law. Particles do not behave like tiny balls, they act like waves that travel over huge areas. Each particle is described by a wave function, which indicates its possible location, velocity, and other properties. In fact, a particle has a range of values for all properties until it was experimentally measured. At the moment of detection, its wave function “collapses”. But how and why do measurements of particles in the reality that we perceive collapse for their wave function? The question of the measurement problem may seem esoteric, but we still have to get closer to understanding what our reality is, and whether it exists at all.
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