Saturday, April 21, 2007

Happy Earth Day

And why did I think the notion of an ever expanding universe was romantic? But then, there's this to worry about.

5 comments:

Apollo said...

I think someday physics will discover that there is no such thing as "empty" space. That is, a true vacuum of matter or energy. It will sort of be like rediscovering the Aether, as promulgated by scientist in the 18th and 19th centuries.

Perhaps a particle accelerator or some brilliant theorist will discover there is no limit to constituent parts that make up matter with each elementary particle being made up of yet more elementary particles and so on.

Dark energy and matter are assumed to comprise 96% of the universe but we can not test this yet.

Gravity waves have not yet been discovered (if they truly exist) but the moon still revolves around the Earth, the Earth the sun, and so on.

Einstein called these "gravity well s" and they affect radiated energy as well as matter. Anything with any mass produces one.

The question is how do you create a "well" in something that has no actual physical property (ie, empty space.)

My intuition tells me there's something really big missing here.

Chavo said...

This often puzzles me, i.e., "empty space". If one accepts the unified field theory, then the big bang occurred in what?

Empty space?

"Dark energy and matter are assumed to comprise 96% of the universe but we can not test this yet."

Is this a vote for the closed universe theory? I admit it does have a certain symmetry, but how does one explain time in reverse as the universe collapses? Would it be like Merlin, living as an old man aging to a newborn? Or would we adjust as our eyes do if we stand on our hand for an extended period of time, righting the upside down world.

"The question is how do you create a "well" in something that has no actual physical property (ie, empty space.)"

Doesn't that in itself suggest the absence of empty space? Post Big Bang anyway.

And speaking of Empty Space, what is after the edge of the universe? Past the beginning of time?

Apollo said...

I don't think time reverses at least no one has been able to do the math to show that it is possible. Notwithstanding causality issues.

Our main tool for measuring the speed of objects in the universe is by analyzing spectrographically their red shifts.

When we observe or measure any object in the universe with this technique we are seeing the object as it was at some moment in the past. Whether that be the moon a second and a half ago or some object 13 Billion light years away.

The farther the object, the further back in time we see. If further objects are receding faster, that makes sense to me because of their proximity in time to the big bang.

Perhaps these calculations on the expanding universe take this into account. I'm not sure.

It could even be that the red-shift of any object we measure is actually affected by the very medium (space itself) through which the object's light waves must traverse in order for us to take their measure. If we are to believe that the universe is filled with dark matter or energy and it is affecting objects in the universe on an intergalactic scale the we must confront the possibility that this dark stuff could affect our measurements.

As for the edge of the universe, who knows? Perhaps its not there. Maybe, if we travel far enough, we just eventually end up back at our point of departure like walking around the world except in more than 3 dimensions.

Chavo said...

Apollo said: "As for the edge of the universe, who knows? Perhaps its not there. Maybe, if we travel far enough, we just eventually end up back at our point of departure like walking around the world except in more than 3 dimensions. "

This is the ant in bowl example Einstein gave of a closed universe isn't it?

Perhaps, this is the answer:

Apollo said...

Sure.

It could also be that you could travel forever into the void and never get to an edge. You might even eventually run into another superstructure of galaxies and the like whose objects were born of a separate big bang.

As for the "stringers":

Well, call me "old fashioned" but I tend to side with the particle guys.

At least they can test their theories.

The string theory community strikes me as having a great solution in search of a problem.

It all sounded good at first but it turns out their "Theory of Everything" is now starting to look more like a "Theory of Anything".

A few years ago, it was demonstrated, ironically through mathematical reasoning, that the most current theory ("M theory" I believe) could not only account for our universe but 10 to the 500th power other universes as well.

Their biggest problem though: Completely untestable and solely mathematically based theories.

This fact, unfortunately places their ideas more in line with philosophy than science. This is not a good place for the frontiers of physics to be.

Lee Smolin's book "The Trouble with Physics" is a detailed dissertation of how the physics community had become first enamored with then later trapped by string theory.

Perhaps, physics will reach equilibrium again when post-grads don't feel compelled to focus their careers in string theory research due to the existing mantras and prejudices of the current theoretical physics theocracy now in place.

In my view, 20 years of physics research has been wasted, sacrificing empirical results for elegant mathematical structure.

String theory sounds good but if you can't test it, what good is it?