Download - The Big Bang Theory (Part I) How the Universe began. Mike Stuckey Warren East High School
The Big Bang Theory (Part I)
How the Universe began.
Mike StuckeyWarren East High School
Assumptions Made
Assumption 1 :
The universality of physical laws
-> The laws of physics are the same everywhere
FG =GM1M2
d2
FG
=GM
1
M
2
d2
and
Assumptions Made
Assumption 1 :
The universality of physical laws
Assumption 2 :
The cosmos is homogeneous
-> Matter and radiation are spread out uniformly w/ no large gaps or bunches.
Assumptions Made
Assumption 1 :
The universality of physical laws
Assumption 2 :
The cosmos is homogeneous
Assumption 3:
The universe is isotropic
-> same properties in all directions
-> no center and no direction
Assumptions MadeAssumption 1 :
The universality of physical laws
Assumption 2 :
The cosmos is homogeneous
Assumption 3:
The universe is isotropic
CosmologyThe study of the
nature and evolution of the
universe.Not the study of Bill
CosbyNot the study of
cosmetics and beauty supplies.
Imagine
NOTHINGNothing to see !
Nothing to hear !
Nothing to feel !
Nothing to think !
No Matter !
No Energy !
No Time !
No Pizza !!!!!!!!!
Let’s Create
The Universe !!
NOTHINGThen, about 13.7 billion years ago, something
happened …..
A large “explosion”.
A big bang.This is where and when the
universe began.
Energy and time are created, but no matter !!!
The Primeval FireballThe Beginning
Primeval Fireball(The Beginning)
The universe is in an extremely high state of energy, with
temperatures estimated to be greater than 1032 K.
It is just #$?! hot !!!!
But this ball of energy quickly expands and cools, decreasing
the temperature of the universe.
Energy & TemperatureThere is a close relationship between
energy and temperature.
The more concentrated energy there is in a substance the higher that substance’s temperature will be.
The higher a substance’s temperature is the more concentrated energy it
has.
Since the universe is expanding the energy of the universe spreads out decreasing the temperature of the
universe.
This is a key thing to remember!!!!!!!!!!!!
The Heavy Particle EraLets Make Some Protons
Heavy Particle Era
The temperature is greater than 1012 K
Less than 0.000001 seconds after the Big Bang
At these high temperatures (energy), photons collide to produce massive particles and
antiparticles
The most important particles formed are protons and
antiprotons.
Matter & Energy ConversionA matter-antimatter pair is two subatomic particles which are
identical in every way except they have opposite charges.
The antimatter equivalent to a proton is an antiproton.
An antiproton has the same properties as a proton but it has a negative charge.
The antimatter equivalent to an electron is a positron.
A positron has the same properties as an electron except it is positively charged.
Matter & Energy ConversionAt these high temperatures
(energy), photons collide to produce massive particles and antiparticles like protons and
antiprotons.
Antiproton (-)Proton (+)
The amount of matter, m, produced in this collision of photons is determined by the amount of energy, E, of the photons.
E = mc2
If there is more energy available, then more massive particles can be
produced !!!
Heavy Particle Era
The temperature is greater than 1012 K
Less than 0.000001 seconds after the Big Bang
At the end of this era, the universe is a thick soup of
heavy particles, antiparticles and energy.
The most important particles present are the protons.
The Light Particle EraLets Make Some Neutrons & Electrons
Light Particle EraThe temperature is greater than
6x109 K
Less than 6 seconds after the Big Bang
Because of the lower temperatures during this era,
the photons present can’t produce anymore heavy particles. These photons can collide to produce light particles and
antiparticles, like electrons and positrons.
Proton (+)
Electron (-)
Neutron
During this era protons and electrons interact to form neutrons. Antiprotons and
positrons interact in the same way.
At the end of this era the temperature of the universe is below the point where there is
enough energy for matter & antimatter to form from
colliding photons.
The universe consists of heavy and light particles (protons &
electrons) and neutrons.
Just what is needed to start to make atoms!!!
Some of the neutrons decay back into protons and electrons.
The neutrons which survive are very important for the next
era.
Nucleosynthesis Era (Part I)Lets Make Some Nuclei
Nucleosynthesis Era (Part I)
The temperature is around 109 K
Less than 300 seconds after the Big Bang
The neutrons which remain react with the protons to form an isotope of Hydrogen called Deuterium. (1 proton and 1
neutron)The neutrons that don’t form deuterium decay back into an
electron & a proton.
Deuterium fuses to form Helium. At this point the total mass of the Helium formed is about
25% the total mass of the universe.Some Tritium (Hydrogen with 2
neutrons), Lithium and Berylium also form.
In the first 5 minutes after the Big Bang, the protons & neutrons
that formed earlier have formed the first stable nuclei of small atoms.
These atoms still have not captured the electrons because the
temperature is too high at this time.
Nucleosynthesis Era (Part II)Lets Make Some Neutral Atoms
Nucleosynthesis Era (Part II)The temperature is around 3000 K
About 329,000 years after the Big Bang
At these low temperatures the nuclei which have formed can now
capture electrons and become neutral.
This allows light and radiation to pass through the neutral
atoms and expand throughout the universe cooling to around 2.7
K
Matter EraLets Make Some Planets, Stars
& Galaxies
Matter EraThe temperature is less than
3000 K
Over 1 million years after the Big Bang
With the radiation and matter freed from each other, the
pressures which kept the matter from clumping together is now
greatly reduced.
Matter is able to clump together forming galaxies, stars, and the
Earth.
We are still in this era.