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Cosmology - The Next Step
Transcript of Cosmology - The Next Step
The eight Eras of Cosmology
And, what about the whole "Birth of the Universe" thing?
Funky stuff, based on mathematics, so hard for our brains to visualize.
Notice the angles of the triangles...
The current explanation for the size of the Universe is called the Inflationary Model
Currently, the universe is very big,
But, this presents us with some problems.
Geometry of the Universe
There are 3 possible "curvatures" of the universe.
1) Positive -
Like a sphere
2) Negative -
Like a saddle
3) Flat -
Like a sheet of paper
And the straightness of the lines
To understand each of these...
It might help to visualize...
What a pair of parallel lines would do in each case.
Some possible weird implications of the different geometries...
Perhaps the universe is like a 3-D hall of mirrors
It would look like this from the inside
Which, it kind of does.
Or, maybe it's like a Mobius strip.
The 3-d version is called a Klein bottle
What if you took a flat piece of paper...
Rolled it into a tube...
And connected the ends into a torus (like a doughnut)
There is even a weird shape based on every point being the center of the "saddle" shape of a negative curve
There are two theoretical pillars of cosmology.
That means that these two things are assumed to be true before we even start to explain or experiment upon our observations.
The first is the Theory of Relativity
Basically, Big Al said that the speed of light is a constant.
The second is the Cosmological Constant
It basically states that...
All of the physical laws we observe near Earth are the same everywhere.
Light travels at 186,000 miles per second...
... and always in straight lines.
So... if the light curves...
It must really be space that is curved.
All of the experiments that have been done on Earth are governed by the same laws you would find in some galaxy far, far away.
mass X mass
Let's take a moment to review the 3 pieces of evidence that support the Big Bang.
1) The CMB
3) Olber's Paradox
Most of the ideas currently associated with the study of Cosmology started when Edwin Hubble discovered that the "spiral nebula" were actually other galaxies.
This was a real mind blower and rapidly increased the number of ideas regarding the Universe and it's fate.
What is Cosmology, Anyway?
Cosmology is the science of the origin and development of the universe.
Ideas about Cosmology are largely due to the tools and techniques of modern Astronomy.
Most scientists begin with the Big Bang, about 13.8 bya...
... and end with a quiet and dark universe in the very distant future.
You do NOT need to memorize, just get familiar
1) Planck Era (All four known forces are unified.)
2) GUT (Grand Unified Theory) Era (Gravity becomes distinct.)
3) Electroweak Era (The nuclear strong and weak forces becomes distinct.)
4) Particle Era (particles begin to form)
5) Era of Nucleosynthesis (nuclear fusion creates Helium, and tiny amounts of heavier elements)
6) Era of Nuclei (electrons are not yet bound to nuclei)
7) Era of Atoms (electrons recombine to form neutral atoms, and the first stars are born)
8) Era of Galaxies (Galaxies begin to form, leading up to the present)
Check these resources for some extra info... Just click on them and you should go there in a new window. If not, copy and paste.
...or, try some of your own.
Big Al said this was caused by extremely massive objects....
Observations proved him right.
So, on to other big, cool things...
of the universe.
That's right, the
The Universe may have an unexpected
So, the Big Bang gave birth to the Universe.
About 13.8 billion years ago.
Is there like an order to the events?
Well, of course there is.
Getting more of both.
very old and ...
There is one called the light horizon.
If we are on a ship at sea we are surrounded by the horizon in every direction.
So, another ship on that distant horizon could see us on his horizon.
But he could also see a further ship on his far horizon.
That we could not.
This same situation would seem to present itself on the horizon of the universe, the 'Light Horizon'.
In one direction we see distant, ancient galaxies
About 13 billion ly away.
In the opposite direction we see the same thing.
That means that the light left them 13 billion years ago, almost the beginning of time.
And, the same is true of the galaxies in the other direction.
How can this be?
That means these guys
Are about the same distance away as these guys
But, can they see each other?
And can those guys way over there...
See an even further set of galaxies on their far side?
And so on...
And so on...
And so on...
Who is the mommy and daddy of the universe?
What made it start?
What was there before?
If the universe is expanding, what is it expanding into?
You can probably think of even more...
So, if the universe is getting... you know.
What is going to happen?
Remember the 3 curvatures of the universe?
Current thinking is that there are also 3 possible fates of the universe.
One idea is that the expansion of the universe will slowly grind to halt and the universe will maintain equilibrium.
A precarious balance of forces and energy.
Another is that the expansion will slow...
Come to a stop...
... start to be pulled by gravity into..
A Big Crunch
But, the rate of expansion seems to be
So, the most likely scenario...
The universe will die a cold, dark death in the very distant future.
There are also some ideas about even larger scale weirdness.
If you want to blow your mind even more...
Check out some of these concepts...
This means that the Universe went through a very rapid expansion when it was very young.
Go back and look at the previous picture, the one on the left. (use the left arrow key)
See how it expands rapidly at first, then more slowly?
By the way, the movie Interstellar has some cool ways to explain some of this stuff. It is definitely worth seeing.