Where did all the Elements come from?
Nucleogenesis and Fusion of Subatomic Particles
Reviewing the Beginning13.7 billion years ago
Extremely hot
Expanding “soup of particles”
Inflation: early phase rapid expansion
Cooling with steady, constant expansion
Nuclear Weak Force
Nuclear Strong Force
Cosmic Background Microwave Radiation
Baryons: Protons & Neutrons Made up of quarks
Fusion of nuclei Hydrogen (makes up 90% of the Universe today) Helium Lithium Beryllium
No electrons attached to these nuclei Too hot
The Nuclear Weak ForceThe Weak Force is responsible
for Initiating hydrogen fusion in
stars the radioactive decay of
subatomic particles
o Large nuclei are unstable
o Neutron = proton + electron
o β-decay: Neutrons fall apart to form a proton and an electron, the electron escaping
Nuclear Strong ForceProtons are all positive and would love to repel each
other
The nuclear strong force holds the nucleus together You must have energy to exert a force. Nuclear energy powers the strong force.
Affects very small space
HUGE amount of energy – released in fission…bombs
Nuclear Strong Force: Squeezing a Nerf Ball
Imagine squeezing a nerf ball The ball wants to expand
to its original shape It cannot because the force
of your hand is too great.
The nuclear strong force is like an invisible hand that holds the nucleus (Nerf ball) together.
Without it, there could only be Hydrogen in the Universe
FusionProton-Proton Chain
2 Hydrogen fuse to form Helium Helium fuse to form Carbon Carbon fuses with Hydrogen to form Nitrogen Nitrogen fuses with Hydrogen to form Oxygen…..
Requirements of FusionHeat-Heat-Heat
Gravity pulls the atoms together
Gravitational pressure heats the gases to millions of degrees
Mass - Stars: the bigger they are the hotter they are More Mass = More heat
= more fusion = more elements
IronFusion in stars can form nuclei that have up to 26
protons = IRON Too much energy is required to overcome the
electromagnetic repulsion
• Creating elements heavier that iron requires more energy
Fusion also Creates NeutronsNeutrons – captured by other atoms to form
Isotopes Isotopes are forms of standard elements with extra
neutrons
The Heavier ElementsSupernova of extremely massive stars
Cores of these stars are saturated with iron Extreme pressure and temperature
Gamma radiation breaks the iron nuclei releasing more energy
Shock-wave produces enough energy to fuse elements heavier than iron up to and including Uranium