Big Bang & Nuclear Fusion PowerPoint Presentation

1. The Big Bang
Once upon a time, around 15 billions
years ago…
There was absolutely nothing in the universe
There was not even a universe
Except for an infinitely small, extremely hot point
So small it occupied no space and was nearly
infinitely dense
Singularity – so we call it
Then it expanded (exploded) in what we call
The Big Bang
So hot - hotter than anything you can name

2. •Within a tiny fraction of a second, the universe expanded rapidly, and the first
particles were created. These particles were known as quarks, anti-quarks, and
leptons. Radiation also formed, as you can see with the yellow squiggly lines. Ever
since this period, there was a constant “warfare” between matter and anti-matter,
which released radiation in the process. By 10 -43 seconds, gravity also separated from
the other forces, and became its own separate force.
After the Big Bang, the universe formed, and it
expanded violently…

3. Inflation
•The universe continued to expand, and grow cooler. By 10 –33 seconds, the
temperature dropped to 1027 degrees Kelvin and underwent a phase transition, kind
of like the process in which water turns into ice.
•As a result from the decreased heat, the strong nuclear force split off from all of the
other forces in a process known as symmetry breaking that released a whole lot of
energy.
•Then, suddenly, the universe expanded exponentially, in which the universe
expanded by a factor of 1050 times that it originally was.
•After inflation, the universe continued to expand, but more slowly. However, it never
stopped expanding, and still expands to this date.

4. Quark Soup
•By 10 –12 seconds, the weak and electromagnetic forces separated and now there were four
uniquely known forces.
•During the Grand Unification Epoch, quarks and leptons and their corresponding anti-
matter particles were constantly colliding with each other, creating photons of radiation.
Two colliding photons could also create matter and anti-matter. Quarks could decay into
leptons, and vice-versa.
•Matter, Anti-Matter, and Radiation existed in nearly equal amounts, during this epoch.
•By the end of the Grand Unification Epoch, quarks and anti-quarks eventually decayed into
hadrons.
•Hadrons included the more stable baryons as well as the less stable mesons. Both baryons
and mesons had their corresponding anti-matter particles. Baryons are also known as
protons or neutrons, the building blocks of today’s elements.
•By 10 –4 seconds, there was no longer any energy to create baryons, and a large amount of
baryons collided with anti-baryons, leaving few survivors and creating a huge wave of
photons.
•When the universe was 1 second old, the universe even cooled to the point in which
electron and anti-electron pairs could no longer be created, and another mass annihilation
occurred, leaving behind even more photons and fewer electrons.
•Eventually, Neutrinos stopped interacting with other particles, not even anti-neutrinos. As a
result, they escaped annihilation, and still drift through the universe in large numbers, and
can be a significant factor to the dark matter of the universe.

5. Big Freeze Out
•During the Era of Nucleosynthesis, beginning 1 second after the Big Bang and ending 100 seconds
afterwards, almost all of the present day helium and deuterium was created. Some of today’s
lithium was also created, in smaller numbers (Regular hydrogen atom nuclei did not have to be
created, as they consisted of only one proton!).
•Around 100 seconds after the Big Bang, the temperature dropped far enough in which protons
could join together with neutrons without being torn apart by highly energetic photons. By this
time, positrons, the anti-matter of electrons, have been completely annihilated, although a few
electrons did survive annihilation.
•Conditions were finally now ripe enough so that protons and neutrons would form helium nuclei,
consisting for around 24% of all of the light elements. The nuclei for heavier hydrogen, and lithium
would also be created by now.
•The protons that were not joined together with neutrons were destined to become hydrogen
nuclei. There was a large amount of protons left, and hydrogen nuclei afterwards consisted of 75%
of all atomic nuclei.
•The hydrogen and helium nuclei will eventually join up with electrons to form atoms 300,000
years later, and are also the seeds of future stars, which create even heavier elements. However,
for now, there are only hydrogen, helium, and lithium elements, also known as the three lightest
elements in our universe.

6. For the next 300,000 years….
•The universe continued to expand and cool
•Photons of electromagnetic radiation could not move freely, as they kept colliding with
electrons or other matter. Radiation and matter were interconnected.
•When the universe cooled down to around 3000o
K, electrons could now orbit nuclei
without being knocked off by photons.
• and electromagnetic radiation can travel throughout the universe without being
disturbed. Now the universe has become transparent.
•By the time the universe is 300,000 years old, the three lightest elements H, He, Li were
formed when electrons started to orbit around the nuclei of these atoms. The universe
back then was composed of mostly H, with a bit of He, and a trace of Li
•The vast sea of photons free to travel across space still persists to this day, in the form of
the Cosmic Microwave Background.
•This radiation has now cooled to around 2.73 degrees above absolute zero, but is still
among the strongest pieces of evidence for the Big Bang. It was also extremely smooth
•Tiny ripples have also been discovered among the radiation, which are minute
fluctuations of matter and energy. These fluctuations were amplified by gravity to form
many of the objects that now make up our universe: stars, galaxies, etc.
Parting Company

7. Timeline of the Universe

8. •gravity separated from other forces (10 -43 seconds)
•strong nuclear force separates from other forces (10-33 seconds)
•weak and electromagnetic forces separate (10-12 seconds)
•quarks combine to form particles( 10 micro seconds)
•nuclei of light atoms form (3 minutes)
Separation of Forces:
Basically, there are four main forces in the universe, as theorized by the “Standard Model” of matter. One is
the familiar gravitational force, which is a long-range force, dominating the interactions of matter across
vast distances.
There is also the electromagnetic force, which is also long range, and keeps electrons inside their nuclear
orbits. Electromagnetic force is also behind electromagnetic radiation, which can travel over infinite
distances. There are many types of electromagnetic radiation at different wavelengths, including visible
light, gamma rays, radio waves, infrared, etc.
The strong nuclear force binds the particles that make up the nuclei of atoms. This force only operates
under very short, sub-atomic distances.
The weak nuclear force is the force that underlies some types of radioactive decay. This force only operates
under very short, sub-atomic distances.
Physicists also theorize that all four forces are carried by particles called bosons, which do interact at
certain energies. At a high enough temperature, these forces to become indistinguishable as they were just
after the Big Bang when the temperatures were extremely high.
In the Grand Unification Theory, the forces start to merge when you look back far enough into time when
the temperature is much higher.

9. What Particles Really Are…
•Basically, quarks are the building blocks of protons and neutrons, which are
the building blocks of atoms.
•Leptons are the building blocks of electrons, and neutrinos.
•Anti-quarks have only been in the universe for a very short period of time.
When it meets a quark, both of them annihilate each other.

10. Why We Believe in the Big Bang
Why Scientists Believe in the Big Bang:
I. The Night Sky
II. The Expanding Universe
III. Background Radiation
IV. The Abundance of Helium
V. The Evolution of Stars and Galaxies
The following list are the 5 major reasons why most scientists believe in the
Big Bang. There are many other reasons, but these reasons are the main
reason why scientists believe in the Big Bang.

11. Misconceptions about the Big Bang
there was no explosion; there was (and continues
to be) an expansion
Rather than imagining a balloon popping and releasing
its contents, imagine a balloon expanding: an
infinitesimally small balloon expanding to the size of our
current universe
we tend to image the singularity as a little fireball
appearing somewhere in space
space began inside of the singularity. Prior to the
singularity, nothing existed, not space, time, matter, or
energy - nothing.

12. Nuclear Fusion Reaction
 A fusion reaction is a
nuclear reaction that
combines, or fuses, two
smaller nuclei into a larger
nucleus.
 It is difficult to make fusion
reactions occur because
positively charged nuclei
repel each other.

13. How can two nuclei get close enough to
combine?
 They must be moving very fast!
ै All nuclei are positively charged thus they repel
each other
ै Kinetic Energy (KE) must overcome mutual
repulsions of the various nuclei to push them
close enough to combine
ै KE increases as temperature increases
ै Temperature must be millions of °C (about 4.0
x 107K) like Sun & other stars

14. Does nuclear fusion occur naturally?
 Yes! The reaction in stars like our sun consist of
collisions among protons, deuterons, H, and
helium nuclei as follows:
2
1

15. How does the Sun produce energy?
 The Sun, made mostly
of H produces its energy
by fusion of H nuclei
 2 protons (H-1) fuse to
make H isotope (H-2);
then H-1 + H-2 form an
isotope of He-3.

16. How does the Sun produce energy?
 To complete the
process, 4 H nuclei
combine into 1 He
nucleus during which a
small amount of matter
changes into a huge
amount of energy.