What, no Big Bang?!

[bojan]

We need to move on from our current patterns of thinking in order to achieve the next level of insight. Doing that on a rational base without sliding into metaphysics is the challenge, not arguing over old-fashioned stereotypes.

Cheers
Steffen.

It is a challenge.. but we know how to do it - it is by using mathematics as a tool.. because our mind inevitably and automatically tends to sink into metaphysics when confronted with un-graspable situations, simply because it evolved in that direction - it could have happened somehow else, but the things -as they are now- were still good enough to bring us where we (as a species) are now - at (or near) the top of the food chain (or so it seems..).
On the other hand, it is good that we have a mind capable of abstract thinking.. and mathematics is one way of disciplining that capability.
Unfortunately, not all of us have the capabilities to use that tool properly and/or effectively.
It is hard, and it requires a lot of work.

Personally, I always thought that my own background in math and physics was adequate for most applications .. after all, my education in that area was well above the average level (Mathematical Gymnasia, 5 years of uni specialising in RF electronics and communications)
And yes, all that was and still is quite sufficient for my current profession (RF electronics engineering)... but I always knew this would not be enough to properly grasp the bits and pieces of the current achievements of the theoretical physics .. the gaps exists not only in properly understood mathematical concepts of fields, vector spaces.. and most of other abstract constructions and modern terminology were also missing from my tool set. Also, the skills related to manipulation of equations were also forgotten ('if you don't use it, you loose it"..)

So, in order to be able to even ask a proper questions (not to mention offering my humble opinion on subject to others), I realised I have to go back to the school first (Suskind, of course..)!
After that, maybe.. I will post here more often (BTW, this thread really deserves to be moved from general chat into science section.. moderators?)

A good read on gauges, here:
http://terrytao.wordpress.com/2008/0...at-is-a-gauge/

[sjastro]

Originally Posted by Steffen

Are you conflating the alleged difficulty of grasping infinity with the very real difficulty of (intuitively) grasping more than three dimensions?

What I'm trying to show is that space can be finite without the need of worrying about boundaries, surrounding space etc.
By showing that space can be finite, a finite Universe is an understandable concept. A finite Universe doesn't have to be embedded in infinite space which the difficult point to grasp.
This is where the term dimension comes into play.

In the example given you as 3-D person perceives the Earth as being an object embedded in 3-D space.
Your shadow however being 2-D is constrained to the surface. The shadow is constrained by the dimension. The surface of the Earth is the space to your shadow. There is no surrounding space in the world of your shadow.

By analogy a finite Universe is like the surface of the Earth.

Regards

Steven

[sjastro]

Originally Posted by Steffen

Why does it matter what "shape" the universe has – flat, cubical, spherical, prismatic, or otherwise? Surely, this is not at the heart of the matter?

Kepler wasted his life (much of it anyway) trying to squeeze his, and other people's, observations into a system of simple geometric bodies.

We need to move on from our current patterns of thinking in order to achieve the next level of insight. Doing that on a rational base without sliding into metaphysics is the challenge, not arguing over old-fashioned stereotypes.

Cheers
Steffen.

The "shape" is confined to three possibilities Closed, Flat and Open.
Closed, Flat and Open Universes are based on Spherical, Euclidean and Hyperbolic geometry respectively.

What shape the Universe has depends on the amount of matter.
So rather than having some esoteric or metaphysical significance, the shape is based on physical considerations.

Just to throw a spanner into the works in an already difficult subject, it should be noted the Cosmologists and Mathematicians definition of flat is not the same as the layman.
For example all would agree a sheet of paper as being flat, but the surface of a cylinder or a torus are also "flat" to the Cosmologist and Mathematician.

Regards

Steven

[bojan]

Originally Posted by sjastro

...
For example all would agree a sheet of paper as being flat, but the surface of a cylinder or a torus are also "flat" to the Cosmologist and Mathematician.

Regards

Steven

Yep..
because mathematical definition of curvature of space (surface) (and type of curvature) depends on the sum of angles in a triangle in that space (we have to define what triangle is first.. )
If this sum is bigger than 180°, the space is mathematically curved, and closed.
If it is exactly 180° the space is flat.. Less than 180° and we have curved and open space.

[bobson (Bob)]

I am coming from somewhat different background when it comes to debates like this. Also completed Classic Gymnasia and then university for Physical Education. I for one don't believe maths can prove everything but is a great tool. Like mathematical modeling of Universe.
For me Philosophy was and still is ahead when it comes to subjects like this.

One smart man once said: "Ones Universe is as big as his imagination"

Immanuel Kant is best known for his work in the philosophy of ethics and metaphysics, but he made significant contributions to other disciplines. He made an important astronomical discovery, namely a discovery about the nature of the Earth's rotation, for which he won the Berlin Academy Prize in 1754.[citation needed]
According to Lord Kelvin:

"Kant pointed out in the middle of last century, what had not previously been discovered by mathematicians or physical astronomers, that the frictional resistance against tidal currents on the earth's surface must cause a diminution of the earth's rotational speed. This immense discovery in Natural Philosophy seems to have attracted little attention,--indeed to have passed quite unnoticed,--among mathematicians, and astronomers, and naturalists, until about 1840, when the doctrine of energy began to be taken to heart."

—Lord Kelvin, physicist, 1897

According to Thomas Huxley:

"The sort of geological speculation to which I am now referring (geological aetiology, in short) was created as a science by that famous philosopher, Immanuel Kant, when, in 1775 [1755], he wrote his General Natural History and Theory of the Celestial Bodies; or, an Attempt to Account for the Constitutional and Mechanical Origin of the Universe, upon Newtonian Principles."

—Thomas H. Huxley, 1869

In the General History of Nature and Theory of the Heavens (Allgemeine Naturgeschichte und Theorie des Himmels) (1755), Kant laid out the Nebular hypothesis, in which he deduced that the Solar System formed from a large cloud of gas, a nebula. He thus attempted to explain the order of the solar system, seen previously by Newton as being imposed from the beginning by God. Kant also correctly deduced that the Milky Way was a large disk of stars, which he theorized also formed from a (much larger) spinning cloud of gas. He further suggested the possibility that other nebulae might also be similarly large and distant disks of stars. These postulations opened new horizons for astronomy: for the first time extending astronomy beyond the solar system to galactic and extragalactic realms.[19]

Yes, things changed a lot since then.


cheers

bob

[Zaps]

There are many people online who still deny the reality of the quantum world despite the fact that their online presence is a testament to the accuracy and validity of quantum theory.

Some will always struggle to accept seemingly abstract concepts, and things like quark flavors and electron transitions are judged to be "too ridiculous to be true," just like, say, the BBT.

[xelasnave]

Originally Posted by Zaps

There are many people online who still deny the reality of the quantum world despite the fact that their online presence is a testament to the accuracy and validity of quantum theory.

Some will always struggle to accept seemingly abstract concepts, and things like quark flavors and electron transitions are judged to be "too ridiculous to be true," just like, say, the BBT.

Ironically if many of the great discoveries are examined one finds them being made by one individual who judged the current popular belief to be highly improbable or even too ridiculous to be true.
If we consider the man who first proposed the BBT a priest and a phyisist must have asked the
question about the Universe presented to him by his faith..I wonder how he was viewed by fellow priests. They would have considered him as a heritic and he would have seen his view as nevertheless consistent with his faith.
May I also say wonderful posts.
alex

[2stroke (Jay)]

Think i seen that on a tv series or astro doc already, it was like 2hrs of theory I'am sure someone on here can name the episode of the series. That had a few different theory's put in the episode, don't smoke pot as it kills short term memory rofl. Something about it all so expanding and srinking over and over again ect as well.

[rustigsmed (Russell)]

Originally Posted by 2stroke

Think i seen that on a tv series or astro doc already, it was like 2hrs of theory I'am sure someone on here can name the episode of the series. That had a few different theory's put in the episode, don't smoke pot as it kills short term memory rofl. Something about it all so expanding and srinking over and over again ect as well.

Was it this one?
http://www.zappah.com/shows/sbs/what...ang-22-07-2013

[2stroke (Jay)]

Might have being but pretty sure it was part of a series though, have it here somewhere out of the 100 odd astro doc's and series epi's. Lol to much time on youtube and isohunt

[sjastro]

Originally Posted by bojan

It is a challenge.. but we know how to do it - it is by using mathematics as a tool.. because our mind inevitably and automatically tends to sink into metaphysics when confronted with un-graspable situations, simply because it evolved in that direction - it could have happened somehow else, but the things -as they are now- were still good enough to bring us where we (as a species) are now - at (or near) the top of the food chain (or so it seems..).
On the other hand, it is good that we have a mind capable of abstract thinking.. and mathematics is one way of disciplining that capability.
Unfortunately, not all of us have the capabilities to use that tool properly and/or effectively.
It is hard, and it requires a lot of work.

Personally, I always thought that my own background in math and physics was adequate for most applications .. after all, my education in that area was well above the average level (Mathematical Gymnasia, 5 years of uni specialising in RF electronics and communications)
And yes, all that was and still is quite sufficient for my current profession (RF electronics engineering)... but I always knew this would not be enough to properly grasp the bits and pieces of the current achievements of the theoretical physics .. the gaps exists not only in properly understood mathematical concepts of fields, vector spaces.. and most of other abstract constructions and modern terminology were also missing from my tool set. Also, the skills related to manipulation of equations were also forgotten ('if you don't use it, you loose it"..)

So, in order to be able to even ask a proper questions (not to mention offering my humble opinion on subject to others), I realised I have to go back to the school first (Suskind, of course..)!
After that, maybe.. I will post here more often (BTW, this thread really deserves to be moved from general chat into science section.. moderators?)

A good read on gauges, here:
http://terrytao.wordpress.com/2008/0...at-is-a-gauge/

Its good to see an engineer who is prepared to broaden his horizons.
Unfortunately some engineers seem to think the prerequisite knowledge of physics and maths in an engineering degree is good enough to overturn all of theoretical physics.

An example is the electric Sun nonsense by the electrical engineer Don Scott.
http://www.youtube.com/watch?v=RD_32D6fHSQ

Regards

Steven