Antimatter

Antimatter basics

Common antiparticles

JavaScript — antimatter calculations

// Annihilation energy
const c = 3e8;
function annihilationEnergy(mass_kg) {
  return 2 * mass_kg * c * c;  // 2 because both matter and antimatter
}

// 1 g of matter + 1 g antimatter
console.log(`1g + 1g: ${(annihilationEnergy(1e-3) / 1e9).toFixed(0)} GJ`);
console.log(`= ${(annihilationEnergy(1e-3) / 4.184e9).toFixed(0)} kt TNT`);
// ~43 kt — equivalent to 4 Hiroshimas

// Electron-positron annihilation
function electronPositronPhotons() {
  // Each photon energy = m_e·c² = 0.511 MeV
  // Total in CM frame: 1.022 MeV split between 2 photons
  return 511e3;  // keV
}

console.log(`e+ + e- → 2 × ${electronPositronPhotons()} keV photons`);

// Cost of producing antimatter (rough)
function antimatterCost() {
  // Current: ~$60 trillion per gram (very rough estimate from particle physics)
  // Production rate: ~10⁻¹⁰ g/year worldwide
  // Inefficiency: many MeV input per single antiparticle
  return {
    cost_per_gram: '~$60 trillion',
    efficiency: '~10⁻⁸ (very low)',
    production: '~10⁻¹⁰ g/year worldwide'
  };
}
console.log(antimatterCost());

// Specific impulse if used for rocket
function antimatterIsp() {
  // Theoretical max: photons exit at c → Isp ~ 3 × 10⁷ s (vs ~450 s for chemical)
  return c / 9.81;  // ~30 million seconds
}

console.log(`Antimatter rocket Isp: ${(antimatterIsp() / 1e6).toFixed(1)} million seconds`);
// 30,000,000 — vastly more than any chemical rocket

Where antimatter matters

• PET scanners. Medical imaging via positron emission and annihilation gamma detection.
• Particle physics. Accelerator collisions create matter-antimatter pairs; study fundamental particles.
• Cosmology. Big mystery — why matter dominates over antimatter in observable universe.
• Nuclear physics. Beta-plus decay produces positrons.
• Cosmic rays. Some cosmic rays are antimatter (positrons, antiprotons); studied for dark matter clues.
• Future propulsion. Theoretical: highest specific impulse possible. Practical: not feasible currently.
• Foundational tests. Anti-hydrogen experiments at CERN test CPT symmetry and gravity on antimatter.

Common mistakes

• Treating antimatter as exotic. All particles have antiparticles. Some are their own antiparticles (photon, Z boson). Antimatter is integral to particle physics.
• Believing all of universe might be antimatter elsewhere. Searches show none. Boundaries between matter and antimatter regions would emit detectable gamma rays.
• Thinking annihilation always gives 2 gamma rays. e⁺e⁻ → 2γ at low energies. At higher energies, multi-photon, hadron production possible.
• Confusing antimatter with dark matter. Different things. Antimatter — known particles, opposite charge. Dark matter — unknown particles, no electromagnetic interaction.
• Believing antimatter is impossible to handle. CERN traps anti-hydrogen for ~17 minutes. Hard but not impossible.
• Dismissing antimatter as fictional. Real, observed, used in medicine. Not science fiction.