The purpose of this thread is to introduce some concepts in physics to those people who have had little or no experience in physics such as myself. If you have taken many courses in physics, this thread will be of little interest to you unless you want to share your knowledge then even better.

There is no particular order on what we can talk about concerning Physics. Perhaps we can start with the Newton's Laws of Motion or if you don't care for that then about velocity or gravity.

In the end I hope we will get a few scientists together to discuss about the future of physics.

To start things off I will ask this question that everyone can give a answer to.

What future does Physics have and where will it take us?

It will take us to the unified field theory.

It's not how far you fall, But how high you bounce.

Thanks for the replies guys.


Question: What is Unified Field Theory?

Answer: Albert Einstein coined the term "Unified Field Theory," which describes any attempt to unify the fundamental forces of physics between elementary particles into a single theoretical framework. Einstein spent the latter part of his life searching for such a unified field theory, but was unsuccessful.

In the past, seemingly different interaction fields (or "forces," in less precise terms) have been unified together. James Clerk Maxwell successfully unified electricity and magnetism into electromagnetism in the 1800s. The field of quantum electrodynamics, in the 1940s, successfully translated Maxwell's electromagnetism into the terms and mathematics of quantum mechanics.

Here are some interesting facts to digest if you didn't already know:

If you yelled for 8 years, 7 months and 6 days, you would produce enough sound energy to heat up one cup of coffee.

The average ice berg weighs 20,000,000 tons. That's 450 Titanics!

The speed of light never changes. Blue light is actually hotter than red light.

If something moves at a velocity close to the speed of light, its time will slow down and it will shrink.

The pull of gravity inside a black hole is so strong that not even light can escape.

You seem to be on a roll. LOL

Maybe you should look up M theory too!

I am right on it

M-Theory


In J.R.R. Tolkien’s Hobbit trilogy, a series of magical rings were forged from gold, each holding incredible power for the one who wore it. To keep the powers balanced, there was one ring that ruled them all, more powerful than the others because it unified them.

M-Theory is the unifying theory of superstrings that explained multiple superstring theories to actually be different ways of looking at the same theory.

In that sense, M-Theory is “the one theory that binds them all,” and did so by revealing an 11th dimension to the beautifully elegant theory of superstrings.

Superstring theory holds that particles, previously thought of as tiny balls of energy, are actually minute wiggling strings. Although strings are smaller than any subatomic particle we are able to detect or measure, they make up all matter in the universe.

The unique vibration of strings determines what kind of particle is created, each having a different vibratory signature.

String theory is particularly important because it unites the quantum world of the infinitesimally small with the world we know through our senses. Superstrings also unites all four forces in the universe: the strong and weak nuclear forces, electromagnetism and gravity. Einstein spent his entire life seeking a unifying field theory, or “The Theory of Everything.” M-theory is the first mathematically sound theory to do this.

Before M-Theory, superstring theory held that there were ten dimensions. The three we know about, and six more dimensions forming extremely small “curled up” points existing everywhere within space/time. The strings of superstring theory exist within these six-dimensional shapes. Time made a total of ten dimensions. But soon several conflicting theories arose that all seemed to prove string theory. This was a conundrum, because it the theory was correct there should not be conflicting theories, but one definitive theory. M-Theory turned out to be that single theory that united all the others.

M-Theory proposed an 11th dimension that mathematically rid the theory of any further anomalies. In this 11th dimension a string could acquire enough energy to expand infinitely into what scientists call a floating membrane. According to the theory, our universe exists on a floating membrane, along with infinite parallel universes on their own membranes.

From this foundation, it was further found that (mathematically) gravity might “leak” into our membrane from another nearby membrane, accounting for its relatively weak force in comparison to the other forces. M-Theory and superstrings succeeded where The Standard Model did not, unifying all forces in the universe with one, elegant theory.

By introducing the 11th dimension, M-Theory successfully united the “competing” theories of string theory. Scientists saw the different theories were actually multiple ways of approaching the same theory, akin to the old proverb about the blind men each touching a different part of an elephant offering seemingly conflicting observations.

M-Theory also provided another crucial aspect of the puzzle in that it explained how the Big Bang might have occurred, with two membranes colliding. The energy produced from such a collision is mathematical consistent with what we know from existing science.

Because string theory predicts phenomena we cannot presently measure such as tiny strings, extra dimensions and multiple universes, some scientists reject it outright.

Others find the mathematical elegance of the theory proof in itself that it must be correct and expect M-Theory and superstrings to eventually be validated.

I confess that I may not be at the cutting edge of things so my apologies if I'm wrong here, but I don't believe that what you've stated above is true, YET, nor may it ever become true.

You've stated that String theory has actually unified all four forces. Including Gravity.

I believe this is not yet true.

It promises to do this. But hasn't yet succeeded.

At least to the best of my knowledge as we speak.

This is another area where String Theory, (or M-Theory) may be a little premature, or overly-optimistic.

In fact, Alan Guth's Inflation Theory is looking far more plausible at this point in time as an explanation for the birth of the Big Bang. And his theory has the universe starting as a random quantum fluctuation.

Now, I supposed that one could argue that membranes colliding could potentially be the cause of quantum fluctuations. But actually there's no need for that because the laws of quantum mechanics allow for these quantum fluctuations to arise randomly.

Moreover, Alan Guth's Inflation Theory does not require a large amount of energy. The sum total energy of the universe is basically ZERO for all intents and purposes. This stems from the fact that gravity qualifies mathematically as negative energy.

So by the time we add up all the positive energy and the negative gravity of the unvierse it sums to ZERO. It took NO ENERGY to create the universe! As hard as that may be to intuitively comprehend. It works out mathematically to be the case.

In fact, Inflation Theory changes a LOT of things about the early Big Bang. It was never necessary for the entire mass of the universe to be concentrated at a single point. The mass was 'created' as the spacetime was created. And this happened over the course of the expansion.

Anyway, there are books out there on the this topic.

I'm going to bed.

String theory is untestable...

Yes and no. Currently there is no test for it. That does not mean there will never be a test for it. The test they are developing now involves measurements of how elusive high-energy particles scatter during particle collisions. Most physicists believe those collisions will be observable at the Large Hadron Collider, a subatomic particle collider.

I find the physica feild of quantum mechanics very interesting and more specifically quntum computing.

I have very good reasons for suspecting that String Theory is actually wrong.

Although, this statement is not as simple as it sounds. The reason being that String Theory is not simple. There may very well be truth in some of the notions and concepts within String Theory yet, the very foundation of the theory could still be wrong.

In fact as Zazanna pointed out, some of the things that String Theory predicts may very well be testable. However, often a lot of those phenomena are not unique to String Theory.

For example, String Theory predicts supersymmetry.

Although in a sense this isn't entirely true. Actually String Theory requires supersymmetry. Proving that supersymmetry exists doesn't prove String Theory, it merely loans it support by not ruling it out.

However, there are other theories that also embrace and can survive under supersymmetry. However, they can also survive without supersymmetry.

So while the discovery of supersymmetry won't prove String Theory, the discovery that supersymmetry doesn't exist would prove it wrong.

Lee Smolin, a physicist who was once heavily involved with String Theory has written a book called "The Trouble With Physics" and in that book he makes a case why he feels String Theory is on the wrong path. I tend to agree with all his observations and have some additions reasons why I feel that it's on the wrong track.

However, there are many thing within String Theory that can survive even if String Theory is wrong.

For example, String Theory requires many extra dimensions of space in order for it to work out. It simply needs this for the descriptions of the "strings".

However, there are many other theories that can also embrace extra dimensions. So even if String Theory were proven to be false (say by the discovery of supersymmetry), that wouldn't automatically mean that all of the things associated with String Theory are wrong (i.e. Extra Dimensions).

In truth, if String Theory turns out to be true just the way it is, that would be an extreme aberration in science.

How often do scientists get things 'just right' with their first guess?

And String Theory truly is String Guess, as this point in time.

Much of the motivation behind it is the promise of melding together Quantum Mechanics and General Relativity.

However, to date, it has not yet fulfilled that promise.

That could be an illusion that will forever remain just out of reach of String Theory. Thus far it has been very elusive.

In fact, this is one of the things that Smolin points out in his book. Everyone keeps saying that String Theory melds Quantum Mechanics together with General Relativity. But it hasn't done that yet! Thus far this has just been an empty claim.

Yet it is this claim that many people use to promote String Theory. And they often make it sound like it has already achieved this goal, when in fact, it hasn't.

Here's the problem...

Someone will invent a new mathematical description which connects quantum electrodynamics and general relativity based upon the foundation of both...

Maxwell's equations.

They are wrong.

What's wrong?

Maxwell's equations?

I think you'd have a hard time supporting that idea, especially if you don't have equations to offer to replace them that suggest something different yet still fit the observed behavior of electromagnetism.

I don't think anyone questions the validity of Maxwell's equations. In fact, they aren't even truly Maxwell's equations, they are a collection of previous equations that Maxwell simply unified in a very remarkable way.

I think it would be a very hard sell to dismiss Maxwell's equations without, at the very least, offering something to replace them.

I'm dismissing Cantor's Set Theory, but I'm fully prepared to offer a replacement Set Theory that works at least as good, and arguably far better.

Oh, I know... trust me!

I cannot offer a better explanation other than that seems to be the the point at which all discreprency in science begins.

For us beginners that are learning from scratch I post this and salute you with a glass of cognac from the finest brand

Newton's Laws of Motion

First Law of Motion

An object that is at rest will remain at rest unless a nonzero net (or total) force is exerted on it.

This one is fairly easy to believe and sounds intuitive enough.

However, the next part of the first law might sound less plausible.

Simply stated, an object moving at a constant velocity will continue to move at a constant velocity (moving at a constant speed and in a straight line) unless a nonzero net (or total) force acts upon the object.

Recall that constant velocity means that the object is moving at a constant speed and in a constant direction.

At this point, you might be thinking to yourself about something you saw in the world that contradicts the statement I just made.

For instance, think of a car rolling in a straight line while in neutral.

If what I stated above were true, then the car should be able to roll in a straight line at a constant speed forever.

This is obviously not true in real life because everyone knows the car eventually comes to a stop.

This certainly seems to prove that Newton's first law of motion is false. Or does it?

I assert that the above observation is consistent with Newton's first law which states that an object moving at a constant velocity will continue moving in that fashion unless a nonzero net force acts upon that object.

You might already know the answer.

It is true that the car would continue to move in a straight line at a constant speed if there was no net force acting on the car.

However, is there really no net force acting on the car? In fact, there is a nonzero net force acting on the car, causing it to slow down.

And, you probably already know what that force is.

The force responsible for slowing down the car is friction.

Therefore, the above observation about a car slowing down while in neutral is not inconsistent with Newton's first law of motion. It just seems to contradict it at first.

If this is confusing, pause for a moment and think about it for awhile.

This is a pretty surprising fact to most people when they first hear it.

If we were able to remove all the friction between the ground and a ball, once you start the ball rolling, it would roll on forever in a straight line.

This is a perfect tie-in to Newton's second law.

We just discovered that objects like to move in straight lines and at constant speeds unless a force acts upon them.

In fact, when a force acts on an object, the force causes the object to change its velocity. In other words, forces cause objects to accelerate.

Regarding electromagnetism...

If this is a premise for both quantum mechanics/electrodynamics and general relativity, which it is... then why are there different conclusions?

A true premise with true axioms leads to true conclusions...

Why does there exist the descreprencies between the quantum conclusions?

Are we to believe that all of the conclusions are true?

Maxwell's equations are fine. They will always work.



F still equals ma. Even though we may develop a deeper
insight, useful equations are always still valid ways
of describing our world even as our deeper understanding
develops.

F can also be dp/dt...it's ok if you understand it.