Physics is a harsh science. It defies you and all your present knowledge, every time you try to ascertain your current knowing. “A slap on the face”, if you put it in a less sophisticated way. In 1900, the British physicist Lord Kelvin dared asserting that, “There is nothing new to be discovered in physics now. All that remains are more and more precise measurements”. Might I say, sarcastically of course, that Lord Kelvin deserves a noble prize because everything known at that time is currently partially or completely non-sense.
I would define physics as the branch of science which keeps its learners awake at night.
Let us now open “Pandora Box” for the biggest mysteries of physics. After all, Socrates would have said, I know that I know nothing.
What is Dark Energy?
No matter how astrophysics crunches the numbers, the universe simply doesn’t add up. Even though gravity is pulling inward on space – time, it keeps expanding outward faster and faster. To account for this, astrophysicists have proposed an invisible agent that counteracts gravity by pushing space – time apart. They call it “Dark Energy”. In the most widely accepted model of dark energy, it is a “cosmological constant”, an inherent property of space itself, which has “negative pressure” driving space apart. As space expands, more space is created, and with it, more dark energy. Based on the observed rate of expansion, scientists know that sum of all the dark energy must make up more than 70% of the total contents of the universe. But no one knows how to look for it.
What is Dark Matter?
Evidently, about 84% of the matter in the universe does not absorb or emit light. “Dark Matter”, as it is called, cannot be seen directly, and it hasn’t yet been detected by indirect means, either. Instead, dark matter’s existence and properties are inferred from its gravitational effects on visible matter, radiation and structure of the universe. The shadowy substance is thought to pervade the outskirts of galaxies, and may be composed of “weekly interacting massive particles”, or WIMPs. Worldwide, there are several detectors on the lookout for WIMPs, but so far, not one has been found.
Why is there an arrow of time?
Time moves forward because a property of the universe called “entropy”, roughly as the level of disorder, only increases, and so there is no way to reverse a rise in entropy after it has occurred. The fact that entropy increases is as matter of logic: there are more disorderly particles than there are ordered particles, and so as things change, they tend to fall into disarray. But the underlying question here is why entropy was so low in the beginning, when a huge amount of energy was crammed together in a small amount of space?
Are there parallel universes?
Astrophysical data suggests space time might be “flat”, rather than curved and thus it goes on forever. If so, then the region we can see (which we think of as “the universe”) is just one patch in an infinitely large “quilted multiverse”. At the same time, the laws of quantum mechanics dictate that there are only a finite number of possible particle configurations within each cosmic patch. So, within infinite cosmic patches, the particles arrangements within them are forced to repeat-infinitely many times over. This means there are infinitely many parallel universes; cosmic patches exactly the same as our (containing someone exactly like you), as well as patches that differ by just one particle’s position, patches that differ by two particle’s positions, and so on down to patches that are totally different from ours.
Bizarre …………..isn’t it!!!
Why is there more matter than antimatter?
The question of why there is so much more matter than its oppositely – charged and oppositely spinning twin, antimatter, is actually a question of why anything exists at all. One assumes the universe would treat matter and antimatter symmetrically, and thus that, at the moment of Big Bang, equal amounts of matter and antimatter should have been produced. But if that happened, there would have been a total annihilation of both. Protons would have cancelled with anti-protons, electrons with anti-electrons, neutrons with anti-neutrons, and so on, leaving behind a dull sea of photons in a matter less expanse. For some reason, there was excess matter that didn’t get annihilated, and here we are. For this, there is no accepted explanation.
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