How Powerful is the Sun?
PSun ~ 𝟒 × 𝟏𝟎𝟐𝟔 joules/sec
= 400,000,000,000,000,000,000,000,000 watts
(= 400 Trillion, Trillion watts!)
 And this will continue for the Sun’s ~10-Billion-Year Lifetime!
Q: What can the Sun do to us from 93,000,000 Miles away?
A: Quite a lot!
The “Solar Constant”
≈ 1400 Watts per Square Meter!
Q: What could the Sun’s Power Source be?
A?:
• Not Chemical Energy
(i.e., “Oxidation/Combustion”…
e.g., “Burning” wood, coal, etc…)
• Not Gravitational Energy from
“Kelvin-Helmholtz” Contraction…
• Only one Power Source sufficient…
=> Nuclear Fusion!
How to get energy from Nuclear processes…
Move towards a “more stable”
(more strongly bound) nucleus!
Where Nuclear Energy actually comes from…
But a Nucleus is full of Positively-Charged Protons…
(…what Fundamental Force of Physics could be Strong enough to
hold Nuclei together against the Repulsion of “Like Charges”…?)
 Yes, that’s right…
It’s the “Strong Force”!
 And YES, the particles
carrying the Strong Force
are called “Gluons” (No joke!)
Fusion in the Core of the Sun: What it takes…
No“Cold Fusion”!
The key reaction
of Solar Fusion:
The “Proton-Proton
Chain”
The 1st Step:
(…but what are these
“ingredients”?)
All the Steps…
Q1: What is “Antimatter”?
Q2: What happens when
“Matter” & “Antimatter” meet?
(Diagram below shows the Opposite Process
from the one above – Neutron Decay
into a Proton, Electron, & Anti-Neutrino –
caused by the Weak Force)
The Particles that make up our Universe… The “Standard Model of Particle Physics”
The most elusive sub-atomic particle…
the Neutrino…
 Neutrinos DON’T “feel” the Strong (Nuclear
Binding) or Electromagnetic (Charge) Forces!
 They just feel the Weak (Radioactive Decay)
Force! (…& a tiny bit of Gravity!)
Why Care about Neutrinos…?  They helped Shape the Universe that we live in!
And the tremendous penetrating power of Neutrinos helps us Study the Universe, today!
(Neutrinos!)
(Not Neutrinos)
Where do Neutrinos come from?
• The Big Bang! (the “Cosmic Neutrino Background”)
• The Sun (produced by nuclear fusion reactions)
• The Earth's atmosphere (produced by cosmic rays)
• Supernovae within our galaxy (produced by scattering reactions)
• The Earth's crust (produced by uranium and thorium decays)
• Cosmic accelerators (produced by pion and kaon decays)
• Nuclear power plants (produced by nuclear fission reactions)
• Neutrino superbeams (produced by pion and kaon decays)
• Neutrino factories (produced by muon decays)
Astrophysical and/or Nuclear Neutrino Sources
(from “Nature”, and Human-Generated)
Many Neutrinos
from the Sun’s core…
Where on Earth is best
to look for them…?
Some Neutrino Detectors…
Super-Kamiokande
Borexino
The Unusual Behaviors of Neutrinos can explain some key mysteries of our Universe!
(e.g.: The “Solar Neutrino Problem”, Baryogenesis, (Some) Dark Matter…)