De Morgan's transformation

Administrator — Mon, 30 Nov 2009 20:46:34 +0100

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Nucleosynthesis

Administrator — Mon, 23 Nov 2009 23:19:57 +0100

The Universe is now 1 minute old, and all the anti-matter has been
destroyed by annihilation with matter. The leftover matter is in the
form of electrons, protons and neutrons. As the temperature continues
to drop, protons and neutrons can undergo fusion to form heavier atomic
nuclei. This process is called nucleosynthesis.

to build higher mass nuclei requires time, buRead More...

CP Violation

Administrator — Mon, 23 Nov 2009 23:18:08 +0100

As the Universe expands and cools and the process of creation and
annihilation of matter/anti-matter pairs slows down. Soon matter and
anti-matter has time to undergo other nuclear processes, such as nuclear
decay. Many exotic particles, massive bosons or mesons, can undergo
decay into smaller particles. If the Universe is out of equilibrium,
then the decay process, fixed by the emergent laws of Nature, can
become out of balance if there exists some asymmetry in the rules of
particlRead More...

Matter versus Anti-Matter

Administrator — Mon, 23 Nov 2009 23:15:09 +0100

Soon after the second symmetry breaking (the GUT era), there is still
lots of energy available to produce matter by pair production,
rather than quark confinement. However, the densities are so high
that every matter and anti-matter particle produced is soon destroyed
by collisions with other particles, in a cycle of
equilibrium.

symmetry means that at the end of tRead More...

Baryongenesis

Administrator — Mon, 23 Nov 2009 23:11:17 +0100

As the Universe cools a weak asymmetry in the direction towards
matter becomes evident. Matter that is massive is unstable,
particularly at the high temperature in the early Universe. Low mass
matter is stable, but susceptible to destruction by high energy
radiation (photons).

as the Universe expands and cools, matter begins to dominate over radiation

As the volumeRead More...

Quarks and Leptons

Administrator — Mon, 23 Nov 2009 23:09:56 +0100

After GUT matter forms, the next phase is for GUT matter to decay
into lepton and quark matter. Lepton matter will become our oldfriends the electron and neutrino
(and their anti-particles). But quark matter is unusual because of the
property of quark confinement.

Quarks can never be found in isolation because the strong force
becomes stronger with distance. Any attempt to separate pairs or
triplets of quarks requires large amounts of energy, which are used
to produce new groRead More...

GUT matter

Administrator — Mon, 23 Nov 2009 23:06:02 +0100

Spacetime arrives when supergravity separates into the combined
nuclear forces (strong, weak, electromagnetic) and gravitation.
Matter makes its first appearance during this era as a composite form
called Grand Unified Theory or GUT matter. GUT matter is a
combination of what will become leptons, quarks and photons. In
other words, it contains all the superpositions of future normal
matter. But, during the GUT era, it is too hot and violent for
matter to survive in the form of leptoRead More...

Inflation

Administrator — Mon, 23 Nov 2009 23:03:09 +0100

The flatness problem relates to the density parameter of the Universe, W. Values for W can take on any
number between 0.01 and 5 (lower than 0.01 and galaxies can't form, more than
5 and the Universe is younger than the oldest rocks). The measured value is
near 0.2. This is close to an W of 1, which is
strange because W of 1 is an unstable point for the
geometry of the Universe.

Symmetry Breaking

Administrator — Mon, 23 Nov 2009 23:01:04 +0100

In the early Universe, pressures and temperature prevented the permanent
establishment of elementary particles. Even quarks and leptons were
unable to form stable objects until the Universe had cooled beyond the
supergravity phase. If the fundamental building blocks of Nature
(elementary particles) or spacetime itself were not permanent then what
remained the same? The answer is symmetry.

Often symmetry is thought of as a relationship, but in fact it has its
own identical thaRead More...

Spacetime Foam

Administrator — Mon, 23 Nov 2009 22:58:16 +0100

The first moments after the Planck era are dominated by conditions
were spacetime itself is twisted and distorted by the pressures of
the extremely small and dense Universe into a mass of black holes and wormholes.

Most of these black holes and wormholes are leftover from the Planck
era, remnants of the event horizon that protected the cosmic
singularity. These conditions are hostile to any organization or
structure not protected by an event horizon. Thus, at this early
time, Read More...

Planck Era

Administrator — Mon, 23 Nov 2009 22:56:11 +0100

The earliest moments of Creation are where our modern physics
breakdown, where `breakdown' means that our theories and laws have no
ability to describe or predict the behavior of the early Universe.
Our everyday notions of space and time cease to be valid.

Although we have little knowledge of the Universe before the Planck
time, only speculation, we can calculate when this era ends and when
our physics begins. The hot Big Bang model, together with the iRead More...

Cosmic Singularity

Administrator — Mon, 23 Nov 2009 22:50:17 +0100

One thing is clear in our framing of questions such as `How did the
Universe get started?' is that the Universe was self-creating. This
is not a statement on a `cause' behind the origin of the Universe,
nor is it a statement on a lack of purpose or destiny. It is simply
a statement that the Universe was emergent, that the actual of the
Universe probably derived from a indeterminate sea of potentiality
that we call the quantum vacuum, whose properties may always remain
beyond our undeRead More...

Unification

Administrator — Mon, 23 Nov 2009 22:48:30 +0100

One of the reasons our physics is incomplete during the Planck era is a lack
of understanding of the unification of the forces of Nature during this time.
At high energies and temperatures, the forces of Nature become symmetric.
This means the forces resemble each other and become similar in strength,
i.e. they unify. When the forces break from unification (as the Universe
expands and cools) interesting things happen.

Birth of the Universe

Administrator — Mon, 23 Nov 2009 22:47:03 +0100

Physics of the early Universe is at the boundary of astronomy and
philosophy since we do not currently have a complete theory that
unifies all the fundamental forces of Nature at the moment of
Creation. In addition, there is no possibility of linking
observation or experimentation of early Universe physics to our
theories (i.e. its not possible to `build' another Universe). Our
theories are rejected or accepted based on simplicity and aesthetic
grounds, plus there power of prediction Read More...

Dark Energy

Administrator — Mon, 23 Nov 2009 22:45:58 +0100

The current observations and estimates of dark matter is that 20% of dark
matter is probably in the form of massive neutrinos, even though that mass
is uncertain. The another 5% to 10% is in the form of stellar remnants
and low mass, brown dwarfs. The rest of dark matter is called CDM (cold
dark matter) of unknown origin, but probably cold and heavy. The
combination of all these mixtures only makes 20 to 30% the amount mass
necessary to close the Universe. Thus, the Universe appearsRead More...

Dark Matter

Administrator — Mon, 23 Nov 2009 22:18:46 +0100

From comparing the mass estimates to the observed amount of light from
galaxies, and from the abundance of light elements, that there is a
problem with the fraction of the mass of the Universe that is in
normal matter or baryons. The fraction of light elements indicates
that the density of the Universe in baryons is only 2 to 4% what we
measure as the observed density. The rest of the mass appears to be
`missing', meaning unobserved or dark.

Exactly how much of the Universe is Read More...

Cosmological Models:

Administrator — Thu, 19 Nov 2009 22:01:36 +0100

In modern cosmology, the different classes of Universes (open, flat or closed)
are known as Friedmann universes and described by a simple equation:

In this equation, `R' represents the scale factor of the Universe (think of
it as the radius of the Universe in 4D spacetime), and H is Hubble's constant,
how fast the Universe is expanding. Everything in this equation is a constant,
i.e. to be deterRead More...

Density of the Universe

Administrator — Thu, 19 Nov 2009 22:00:40 +0100

There are two possible futures for our Universe, continual expansion (open
and flat), or turn-around and collapse (closed). Note that flat is the
specific case of expansion to ever slowly speeds aproaching zero velocity.

One of the key factors that determines which history is correct is the amount of
mass/gravity for the Universe as a whole. If there is sufficient mass,
then the expansion of the Universe will be slowed to the point of
stopping, then retraction to collapse. If Read More...

Measuring Curvature

Administrator — Thu, 19 Nov 2009 08:13:46 +0100

Measuring the curvature of the Universe is doable because of ability to see great distances
with our new technology. On the Earth, it is difficult to see that we live on a sphere. One
stands on a tall mountain, but the world still looks flat. One can see a ship come over the
horizon, but that was thought to be atmospheric refraction for a long time.

Our current technology allows us to see over 80% of the size of the Universe, sufficient to
measure curRead More...

Geometry of the Universe

Administrator — Thu, 19 Nov 2009 08:10:29 +0100

general relativity allows for spacetime to be curved, thus the whole Universe may have a non-flat geometry
three possible shapes are allowed, flat, positive or negative curvature

Can the Universe be finite in size? If so, what is ``outside'' the Universe?
The answer to both these questions involves a discussion of the intrinsic
geometry of the Universe.

There are basically three possible shapes to the Universe; a flat
Universe (Euclidean or zero curvature), a spRead More...

Blog entries

De Morgan's transformation

Nucleosynthesis

CP Violation

Matter versus Anti-Matter

Baryongenesis

Quarks and Leptons

GUT matter

Inflation

Symmetry Breaking

Spacetime Foam

Planck Era

Cosmic Singularity

Unification

Birth of the Universe

Dark Energy

Dark Matter

Cosmological Models:

Density of the Universe

Measuring Curvature

Geometry of the Universe