Stuff

I have nothing too specific to put here today, but I found some things in the web these days that I think it would be interesting to share:

HTML Book from John Baez
John Baez is a well-known mathematical-physicist that usually works with Quantum Gravity (most of the time with Spin Networks I guess) and writes a lot of interesting stuff. Particularly interesting is his book Gauge Fields, Knots, and Gravity which has a lot of introductory math and physics. Well, let us come back to the main point. The text I found interesting from him is Higher-Dimensional Algebra and Planck-Scale Physics and here is the abstract:

This is a nontechnical introduction to recent work on quantum gravity using ideas from higher-dimensional algebra. We argue that reconciling general relativity with the Standard Model requires a `background-free quantum theory with local degrees of freedom propagating causally'. We describe the insights provided by work on topological quantum field theories such as quantum gravity in 3-dimensional spacetime. These are background-free quantum theories lacking local degrees of freedom, so they only display some of the features we seek. However, they suggest a deep link between the concepts of `space' and `state', and similarly those of `spacetime' and `process', which we argue is to be expected in any background-free quantum theory. We sketch how higher-dimensional algebra provides the mathematical tools to make this link precise. Finally, we comment on attempts to formulate a theory of quantum gravity in 4-dimensional spacetime using `spin networks' and `spin foams'.

Hackers
I also found this site from a guy named Eric S. Raymond. I came to his homepage clicking in the glider (from the Game of Life) image that I'm reproducing here:




and following the Eric's Home link. You will find that hackers are not exactly those evil programmers you see in movies, which are really crackers. About this, he wrote an interesting page named How to become a hacker.

There is also this news about Gravitational Lensing:
Galactic lens reveals its inner self

This Quantum Poem that I found in the same page where I took the picture in the beginning of the post:

Quantum Physics: There's a Thing
by Graham Adair

Quantum physics. There’s a thing.
I’ve heard of nothing stranger.
You fancy juggling atoms? Well
Be mindful of the danger.
For thoughts of protons, quarks and muons:
Such exotic matter,
Are apt to tie your brain in knots,
Your sleepful nights to shatter.

The Big Bang. Sheesh! Well strike a light!
Is that what really happened?
You’re telling me we all began
As matter crushed and flattened?
And then some great explosion
Thrust us all forth into being?
I think The Big Baloney’s
A better name for what we’re seeing.

Black Holes -- what? You’re kidding me!
A huge contrivance, surely.
A ruse by Stephen Hawking
(Who accepts his praise demurely.)
So if it’s true that black holes
Suck and swallow up all matter,
Why don’t they eat up physicists
And all their nonsense patter?

And what of blessed Einstein
And his General Relativity?
Accepted though it may be
It’s a triumph of complicity.
You test it by experiment,
And analyse the outcome.
And if it makes no sense
You just amend the main theorem!

Herr Heisenberg is in a quandary,
Can’t make up his mind.
He’s dreaming up a Principle,
But unsure what he’ll find.
He thinks the laws of physics
Pose a crisis he’s averting,
But ‘til his theory’s testable
We’ll all remain Uncertain.

Well hip-hooray for SuperStrings!
A unifying theory!
At last we have a model
That’ll settle every query.
But hang on -- it’s just wacky concepts
Fraught with terminology…
It makes no sense; it’s full of holes,
It’s rubbish!
All apologies.

Now here’s a laugh: you take a clock,
And send it into space.
When down it comes, you check the time.
And Lo! It’s lost its pace.
It seems that hours pass slower
As you near the speed of light.
Time-travel’s a reality! And pigs are airborne.
Quite.

There’s dark misgivings on the rise:
Dark Energy, Dark Matter.
A new theory for why
The Universe is getting fatter.
But is it really growing?
Maybe we ourselves are shrinking!
Collapsing to a speck
Beneath the weight of quantum thinking!

A Cyclic Universe
Is what they’re telling us we live in.
A Big Bang first, expand, contract;
Then Big Crunch, new beginning.
The contents of the universe
Are bound for all eternity
To grow and live, then shrink and die,
Repeating to infinity.

In which case, all the laws of physics
Won’t be here for long.
Like us, they’ll bend and buckle
When the Big Crunch comes along.
The point of Singularity
Will deconstruct all logic,
Our physics theories then will seem
Less real than Discworld magic!

In closing, here’s an observation
Likely to confuse.
The Uncertainty Principle
Declares surprising news:
“To take a thing and look at it
Will change its very state.”
So don’t read my opinions, lest you change them.
Oops. Too late

And finally, you noted that I added a column named "I support" at the side of this blog. It would be worth to click in those links, they're interesting movements that maybe you should consider support too and put a link in your site. :)

Picture: Reactor, by Carl Goodman.