Famous Paradoxes in Science( Physics and Astronomy)

 Despite being among the best on the planet, the human brain has a lot of difficulties understanding certain challenges. Although humans have developed a fairly particular conception of reality, several paradoxes indicate reality may not operate exactly as we believe it to. It's a terrific way to acknowledge how limited our knowledge of the cosmos is to think about these paradoxes.

Fermi Paradox

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The Fermi paradox is certainly well-known to many of you. This paradox attempts to respond to the query: Where are the aliens? It is named after the Italian physicist Enrico Fermi, who achieved fame for developing the first nuclear reactor.

Given that our star and Earth belong to a relatively young planetary system about the rest of the universe and that this is a time when it is theoretically possible for a civilization to develop interstellar travel, it would seem that by now we should have been visited by some kind of extraterrestrial intelligence. Now, others argue that it isn't a true paradox because we can only assume that there is intelligent life elsewhere in the universe. But in this so-called conundrum, the number of potential interstellar civilizations is estimated using the Drake Equation. The Milky Way's observable civilization count is calculated using the Drake Equation, which takes seven variables into account. This gave us the impression that there might be a huge number of Earth-like planets with advanced civilizations. But back in 1961, only our planet and a few others were known to orbit other stars. We only lately had a solid understanding.

Using information from the Kepler Space Telescope, astronomers discovered in 2020 that the Milky Way contains more than 300 million worlds with environments similar to Earth. According to the data, about half of the sun-like stars in the galaxy is home to rocky planets in habitable regions where liquid water may exist on the surface.

Photo credit- Hubble.org

In fact, there are more planets in our galaxy than there are stars. The James Webb Space Telescope is there to search for more planets that could potentially support life. The question still stands knowing how many worlds there are and how many chances there are for advanced civilizations.

Photo credit- ESA/ATG media lab

Why is the cosmos silent?

We might soon find out thanks to technological advancements, or we might have already received a visit from a distant civilization but aren't aware of it.

Many inexplicable UFO sightings have occurred recently, and some people think extraterrestrials are already present. This dilemma would be resolved with convincing evidence of that.

The Grandfather Paradox

Another well-known paradox has to do with going back in time to "take out" your grandfather—that is, to erase his existence.

Everybody here loves our grandparents, but this is only one instance.

Once more, you travel across time and perform the act, erasing the memory of your grandfather. Returning to the present, you discover that your father was never born, your grandfather has passed away, and you were never even born. Your whole past, along with your family, friends, assets, and social network, have all been deleted.

Therefore, it would be impossible to do this because you would not have been born in the first place. Theoretically, if this were to occur, you might have even created a parallel universe or entered one, according to some scientists.

Polchinski's Paradox

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The late, great Joseph Polchinski was the eminent theoretical physicist who wrote the book on string theory. Polchinski also considered a situation that would be paradoxical, involving a pool ball pushed via a wormhole that travels back in time. In this case, the billiard ball is launched into the wormhole at an angle that, if it follows the path, will cause it to emerge from the wormhole in the past at the proper angle to collide with its earlier self, throwing it off balance and restricting it from entering the wormhole in the first place.

However, some physics students have proposed ways that avoid any inconsistencies by having the ball emerge from the future at a different angle than that which generated the paradox and strike its younger self with a glancing blow rather than knocking it entirely out of the wormhole. This strike properly alters the trajectory of the ball, causing it to return in time at the proper angle to land this glancing hit on its younger self. This will change the way you see the world, so have a look.

Observer's Paradox

While Schrödinger's famous story about a cat that is neither alive nor dead is one of quantum theory's most bizarre phenomena, the observer's paradox is a situation that is actually odd. For the record, no animals have ever been hurt during this experiment; it is just a hypothetical scenario. A cat is kept in the paradox's windowless cage together with radioactive substances, a Geiger counter, a hammer, and a vial of lethal poison. The radioactive material will probably disintegrate, with a 50% chance.

The Geiger counter will activate if it detects a radioactive particle, and the hammer will then go off, destroying a vial of poison that will kill the cat.

However, you wouldn't get to know if the cat was dead or alive until you opened the box. Thus, until the box was opened, the cat would be both alive and dead.

How is this possible, you contemplate.

This is done so that what actually matters changes legitimately just by being seen. You cannot know that something is there unless you can see it. You're probably thinking right now that it's completely strange in every way. But consider the double-slit experiment, which presents a different observer's paradox. This is the most well-known physics experiment ever.

Just picture tossing tennis balls at a wall with two slits in it. Others will pass through the slits while others will strike the wall and bounce back. Tennis balls that make it through the first wall will occasionally strike any slit walls that are located behind it. If you note the places where the tennis balls hit the second wall, you can now expect to see two strips of markings about the same size as the slits. It seems rather easy, doesn't it? When a light is shone through the double-slit experiment's slits, something extremely unexpected happens.

The term photon refers to both a particle and a wave that make up light. An interference pattern will appear on the back wall if we beam a single photon into this double slit, as if the photon were interfering with itself. The photon appears to have traveled simultaneously through both slits.

But this is where things start to get strange. The photons behave differently just from staring at the double-slit experiment as if they are conscious of your presence.

Photo credit - T.Weitkamp

We can be positive about this because there isn't any interference pattern when the researcher tries to figure out which slit the photon is traveling through.

The possibility of altering the past by seeing a photon still exists.

How is that even imaginable? There is still no answer to the enigma; perhaps you might be the one to figure it out.

The Bootstrap Paradox

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The Bootstrap Paradox asks how something that is taken from the future and placed in the past could have ever existed in the first place.

Many science fiction scenarios, such as those in the Terminator, Doctor Who, and Bill & Ted films, are based on this recurrent theme.

So let's look at one example of this paradox.

Imagine that you had the ability to travel through time, but before you leave on your great journey, you decide to go to a bookstore and buy a copy of Shakespeare's play Hamlet. Then you go back to Elizabethan London and give Shakespeare the book. Then William S. copies the book, claiming to be the author. Through generations of printing and reprinting, Hamlet eventually finds its way back to the bookstore where you first bought it.

So, the obvious question is: Who authored Hamlet?

Also, The most extreme example of a bootstrap paradox involving a human may be found in Robert A. Heinlein's 1959 short story "All You Zombies," which was the inspiration for the 2014 movie "Predestination." This story's main character is an intersex male who was born a female and is tricked into going back in time to get pregnant with his pre-gender reassignment female self, who subsequently delivers birth to himself or herself. As a result, he turns into a self-made parent who is also his own mother. It follows that the chicken-and-egg conundrum is obviously very challenging to resolve. Yet again, it appears that there are no changes made after each loop and that the story is self-contained.

Taking Out Hitler Paradox

It is an interesting twist of the grandfather paradox to go back in time and remove Hitler in order to assist end World War II. This would have some fascinating results.

Imagine you have a time machine and you have the plan to travel back in time to put things right before the conflict worsens. The problem right now is that the action invalidates any reason for time travel and any knowledge that such a justification ever existed.

Paradoxes are the inevitable result of being a time-traveling executioner. In addition to the idea of numerous universes, going back in time might result in a new reality without der Führer, but the prior timeline would still be present. You might even create a brand-new, catastrophic timeline.

But what would happen if you tried to send something back via a wormhole? 

The Black Hole Information Paradox

Photo credit- NASA's Goddard Space Flight Center

One of the biggest puzzles in physics is the black hole information paradox, a problem that results from the unification of quantum mechanics and general relativity. Calculations predict that physical data may fully fade away into a black hole, degrading into one another as a result. This is disputed by quantum mechanics, which states that information cannot ever be destroyed. Take two separate printed letters on paper and burn them. Rebuilding them from ash would be incredibly difficult but not impossible.

The minute fluctuations in temperature, ash content, and smoke would not affect the ability to distinguish between the two unique letters.

The problem with black holes is that they absorb matter and then radiate it back out as Hawking Radiation over an incredibly, incredibly long period of time. Unlike the smoke, temperature, and ash left over from burning a letter, Hawking's radiation, sadly, hides what the black hole consumed. This is because black holes are thought to destroy cosmic data based on the uniformity of Hawking radiation. 

So, does data actually disappear when a black hole collapses or does it somehow survive?

A new group of researchers has discovered the "quantum extremal surface," an invisible surface inside a black hole's event horizon, who asserts that information does, in fact, escape a black hole by way of its radiation. This surface has altered over the course of the black hole's existence exactly as would be anticipated if information escapes, and the amount of information that has radiated away from the black hole appears to be encoded there. Black holes can undoubtedly be created by something. It's an issue that hasn't been entirely fixed yet and is still under investigation.

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