What is the Universe expanding into..

Do you think there was anything before the big bang?

  • I don't think there was anything before the Big Bang

    Votes: 56 12.5%
  • I think something existed before the Big Bang

    Votes: 200 44.7%
  • I don't think the big bang happened

    Votes: 54 12.1%
  • I think the universe is part of a mutiverse

    Votes: 201 45.0%

  • Total voters
    447
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What cynical nonsense! The whole enterprise of Science seeks Truth!

If you dozed off in Mathematics class, you can still learn a lot from general reading:

Higgs Boson.jpg


The Sean Carroll book is superb. And Prof. H.C. Verma is a true enthusiast if you want the Maths:


He has the ability to pick out what is important. Half the greatest Physicists and Mathematicians who ever lived are alive right now.

This is a Golden Age. It has moved on so much since the 1970's when I first encountered Quarks.

The trick is to really focus on what you are reading or watching. It takes attention span. I can usually do about half an hour before needing a break to assimilate what I have learned.

Good teachers must be trusted. It's a gift they have. H.C. Verma starts off with the easy stuff. But points out what is important.

I relearnt Newton's 3 laws from him in a whole new way. Conservation Laws! He is actually a nuclear Physicist but knows his basics.
 

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Some people think the World is held up on the back of an Elephant. Which is held up on the back of a Tortoise....

But what holds the Tortoise up? Well, it's Turtles all the way down. 😀

If you want to make progress, start with little Baby steps:


Not quite Field Theory, but getting close. What's hard about it? A Child of Ten can follow this.
 
Define "familiar"! 😀

The Hamiltonian is associated with orbits in central force fields.

I read that the Hamiltonian description is especially useful for finding conserved quantities, which play an important role in describing orbits.

I also read that Hamiltonian mechanics is a reformulation of Lagrangian mechanics.

However, it's all Greek to me! 😵 https://en.wikipedia.org/wiki/Hamiltonian_mechanics
There’s a great write up on Lagranians in Motion Mountain book 1. Can’t get to it right now - maybe I’ll find it later today And post the reference up.
 
I relearnt Newton's 3 laws from him in a whole new way. Conservation Laws!

Even schoolboy physicists are aware that Newton's laws are "conservation laws".

Newton focusses on the conservation of motion i.e. the conservation of momentum.

e.g. In the absence of a resultant force, the momentum of an object will not change - Newton 1.

Your linked video in post #8,504 doesn't get into Newton's laws till around 10:30, when the lecturer makes clear the need for a frame of reference.

As we know, Newton's laws only apply to non-accelerating (inertial) frames of reference - they are not universal laws.

I must say there is nothing that I discovered, or "relearnt", from this rather plodding video.
 
There’s a great write up on Lagranians in Motion Mountain book 1.

I do hope it's simple as the mathematics can be daunting!

Basically, while Newtonian mechanics looks at motion in terms of momentum, Lagrangian mechanics looks at motion in terms of energy.

Newtonian mechanics says which way objects will accelerate in terms of forces, whereas Lagrangian Mechanics says objects move between two points in such a way as to minimise a quantity called the action.

The Lagrangian function is defined as the difference between the kinetic energy of a system and its potential energy. The integral of the Lagrangian function over time is called the action of the system. In simple terms, movement will involve least action!

Because Lagrangian mechanics requires a potential energy function, it cannot deal with the likes of friction forces - whereas Newtonian mechanics can.

Hamiltonian and Lagrangian mechanics are equivalent, and both are useful in different situations.
 
He gives some examples of how much easier the Lagranian is to work with compared to other systems.

I can't work with either the Langrangian or the Hamiltonian!

I'm simply trying to put some flesh on the bones of the alternative mechanics Steve introduced without explanation.

He must think we are all boffins on this thread! 🤓
 
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Granted, but why would you deny me my "audience"? After all, competition is what drives scientific endeavor.

I participate in this thread because I am interested in understanding, interpreting and sharing scientific ideas and the mysteries of the universe.

If I come across as being negative, superior or dismissive of the submissions of others, then I promise to work on my social skills.
 
social skills
Highly overrated. In my experience people that claim to have superior social skills have either no understanding whatsoever of what the people around them go through, or they have a tendency to make big drama over some minor nuisance.
The HR people I've met also frequently adopt a very top-down view, it's like their job to disambiguate and separate those two words in their job description so that Human has nothing to do with Relations.

I'd rather stay grumpy in solitude, no need for more drama in this world.
 
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Granted, but why would you deny me my "audience"? After all, competition is what drives scientific endeavor.

I participate in this thread because I am interested in understanding, interpreting and sharing scientific ideas and the mysteries of the universe.

If I come across as being negative, superior or dismissive of the submissions of others, then I promise to work on my social skills.
Why not take a poll? That way you'd be sure, no?
 
Highly overrated. In my experience people that claim to have superior social skills have either no understanding whatsoever of what the people around them go through, or they have a tendency to make big drama over some minor nuisance.
The HR people I've met also frequently adopt a very top-down view, it's like their job to disambiguate and separate those two words in their job description so that Human has nothing to do with Relations.

I'd rather stay grumpy in solitude, no need for more drama in this world.
Life's too short to be grumpy while logged in here! 🙂
 
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