Gravity, Branes And Hidden Dimensions
Ανέβηκε στις 1 Αυγ 2009
http://www.facebook.com/ScienceReason ... Physics (Chapter 3): Gravity, Branes And Hidden Dimensions (The Fourth Dimension / 4D Tesseract)
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Why
is gravity so weak? Why can a small magnet pull or push something away
from the entire earth? There is an idea that may explain it, but before
we go there, lets explore some preliminary ideas. The most popular
quantum gravity theory of today describes all fundamental particles as
vibrating strings of energy. And the theory is constructed in a whopping
nine or ten spatial dimensions instead of the three that we experience
in our everyday lives.
But what is a dimension? A line is a
familiar geometric figure. It can be completely described by giving its
length. It is a one-dimensional object. It can be imagined that the
dimensionality of an object can be created by taking an object of one
less dimensions and moving it at a right angle to that dimension. You
can create a line in your imagination by thinking of taking a point and
moving it.
Next consider a surface: A surface is also quite
familiar. A surface has both length and width and requires two
measurements to define it and therefore is a two-dimensional object.
Similar to the generation of a line from a point, we can generate a
two-dimensional surface by taking a line and moving it in a direction
other than the direction of its length.
And a solid figure is the
stuff of everyday life. It has length and width and depth and requires
three measurements to describe it, and is a threedimensional object. And
like the generation of a surface from a line above, we can generate a
three-dimensional object like a cube by taking a square and moving it in
a direction other than the directions of its length and width.
Cylinders, cubes, and spheres are three-dimensional objects.
And
now the hard part the higher dimensions are created by moving a
threedimensional solid in a direction other than its length, width or
height. And while that is easy to do mathematically, it is impossible
for us to picture it.
Now back to strings If this membrane
represents the three dimensions that we live in, then particles like
quarks and electrons are strings that have their endpoints forever
attached to those three dimensions. But the particle that is the force
carrier for gravity, the graviton, is a closed loop.
It has no
ends that are constrained to our three dimensions. So if there are other
dimensions, gravity will propagate freely there as well as in our
familiar three. And that might explain why gravity seems so weak to us.
We experience only a tiny fraction of gravitys true strength because so
much of it is leaking out into the other dimensions!
But where are these dimensions hiding? One possibility (but not the only one) is that they are all around us but are
incredibly tiny.
If
you look at a wire or a string from far enough away, it looks like a
line a onedimensional figure. But if you get closer or if you were a
lot smaller than the thickness of the wire, then you would easily see
that it has other dimensions. On the tiniest of scales, space has extra
dimensions at every point. It might look something like this if we were
small enough to see it.
---
LHC (Large Hadron Collider):
Accelerators like the LHC at CERN smash protons against anti-protons at
enormous energies perhaps enormous enough to produce gravitons. And if
they do, then perhaps we might just be able to see them form in our
limited threedimensional world and slip quickly and quietly away into
those hidden dimensions!
---
The tesseract: In geometry,
the tesseract, also called an 8-cell or regular octachoron, is the
four-dimensional analog of the cube. The tesseract is to the cube as the
cube is to the square. Just as the surface of the cube consists of 6
square faces, the hypersurface of the tesseract consists of 8 cubical
cells. The tesseract is one of the six convex regular 4-polytopes.
A
generalization of the cube to dimensions greater than three is called a
hypercube, n-cube or measure polytope. The tesseract is the
four-dimensional hypercube, or 4-cube.
---
The Cassiopeia Project - making science simple!
The
Cassiopeia Project is an effort to make high quality science videos
available to everyone. If you can visualize it, then understanding is
not far behind.
• http://www.cassiopeiaproject.com
.
---
Please SUBSCRIBE to Science & Reason:
• http://www.youtube.com/Best0fScience
• http://www.youtube.com/ScienceTV
• http://www.youtube.com/FFreeThinker
---
Why
is gravity so weak? Why can a small magnet pull or push something away
from the entire earth? There is an idea that may explain it, but before
we go there, lets explore some preliminary ideas. The most popular
quantum gravity theory of today describes all fundamental particles as
vibrating strings of energy. And the theory is constructed in a whopping
nine or ten spatial dimensions instead of the three that we experience
in our everyday lives.
But what is a dimension? A line is a
familiar geometric figure. It can be completely described by giving its
length. It is a one-dimensional object. It can be imagined that the
dimensionality of an object can be created by taking an object of one
less dimensions and moving it at a right angle to that dimension. You
can create a line in your imagination by thinking of taking a point and
moving it.
Next consider a surface: A surface is also quite
familiar. A surface has both length and width and requires two
measurements to define it and therefore is a two-dimensional object.
Similar to the generation of a line from a point, we can generate a
two-dimensional surface by taking a line and moving it in a direction
other than the direction of its length.
And a solid figure is the
stuff of everyday life. It has length and width and depth and requires
three measurements to describe it, and is a threedimensional object. And
like the generation of a surface from a line above, we can generate a
three-dimensional object like a cube by taking a square and moving it in
a direction other than the directions of its length and width.
Cylinders, cubes, and spheres are three-dimensional objects.
And
now the hard part the higher dimensions are created by moving a
threedimensional solid in a direction other than its length, width or
height. And while that is easy to do mathematically, it is impossible
for us to picture it.
Now back to strings If this membrane
represents the three dimensions that we live in, then particles like
quarks and electrons are strings that have their endpoints forever
attached to those three dimensions. But the particle that is the force
carrier for gravity, the graviton, is a closed loop.
It has no
ends that are constrained to our three dimensions. So if there are other
dimensions, gravity will propagate freely there as well as in our
familiar three. And that might explain why gravity seems so weak to us.
We experience only a tiny fraction of gravitys true strength because so
much of it is leaking out into the other dimensions!
But where are these dimensions hiding? One possibility (but not the only one) is that they are all around us but are
incredibly tiny.
If
you look at a wire or a string from far enough away, it looks like a
line a onedimensional figure. But if you get closer or if you were a
lot smaller than the thickness of the wire, then you would easily see
that it has other dimensions. On the tiniest of scales, space has extra
dimensions at every point. It might look something like this if we were
small enough to see it.
---
LHC (Large Hadron Collider):
Accelerators like the LHC at CERN smash protons against anti-protons at
enormous energies perhaps enormous enough to produce gravitons. And if
they do, then perhaps we might just be able to see them form in our
limited threedimensional world and slip quickly and quietly away into
those hidden dimensions!
---
The tesseract: In geometry,
the tesseract, also called an 8-cell or regular octachoron, is the
four-dimensional analog of the cube. The tesseract is to the cube as the
cube is to the square. Just as the surface of the cube consists of 6
square faces, the hypersurface of the tesseract consists of 8 cubical
cells. The tesseract is one of the six convex regular 4-polytopes.
A
generalization of the cube to dimensions greater than three is called a
hypercube, n-cube or measure polytope. The tesseract is the
four-dimensional hypercube, or 4-cube.
---
The Cassiopeia Project - making science simple!
The
Cassiopeia Project is an effort to make high quality science videos
available to everyone. If you can visualize it, then understanding is
not far behind.
• http://www.cassiopeiaproject.com
.
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