Strange Physics & Cosmology Guidebook

How to Use This Guidebook

Think of this as a sandbox. Skim the intros to get the big picture, then tap a calculator card and play. Change one input at a time, watch how the outputs respond, and use the embedded tips to connect the math to physical intuition. Most cards are deliberately simple: they isolate a core idea so you can feel how a parameter matters before graduating to more complex models.

• Keep units straight. Every card states the expected units. If a number looks absurd, it probably is—check the units first.
• Favor orders of magnitude. Many results are best read as “about 10× this or that” rather than exact predictions.
• Reality check with limits. Try extreme values (zero, very large, speed of light, absolute zero) to see if the model behaves sensibly.
• Remember the map ≠ the territory. These are teaching tools and thought experiments, not engineering sign‑off documents.

Quantum Paradoxes

The quantum world resists everyday intuition. Instead of single outcomes, events unfurl as probability waves that interfere and entangle. Interpretations differ—collapse, decoherence, many‑worlds—but they agree on the numbers experiments deliver. Even toy models reveal implications that feel wild but are tightly constrained by math.

Popular thought experiments like quantum suicide highlight uncomfortable edges: an observer repeatedly faces lethal measurements and only experiences branches where they survive. It’s a cautionary premise, not a recommendation. Our calculators quantify how quickly your measure (your share of branches) dwindles and how noise ruins any fantasy of clean, repeatable trials.

Quick FAQ

• Is “many‑worlds” testable? Not directly. Competing interpretations generally match all lab results so far. What’s testable are the predictions of quantum theory itself.
• Could quantum randomness power free will? Randomness isn’t agency. It can add unpredictability, but choices still need structure and goals.

Living in a Simulation

The simulation hypothesis suggests advanced civilizations might run ancestor simulations indistinguishable from base reality. If such simulations are plentiful and cheap, the odds could favor our world being one of many virtual constructs. Even optimistic scenarios run into brutal constraints: bandwidth, memory, consistency, and the energy cost of erasing bits.

Scale is the enemy. Memory scales with volume and resolution; bandwidth scales with event rate; and consistency checks explode when many agents interact. Clever simulators could coarse‑grain unobserved regions or render only what’s needed, but physics ties their hands in subtle ways.

Quick FAQ

• Would proof change how we live? Day‑to‑day needs would still matter. Ethics doesn’t evaporate just because the stage is digital.
• Could déjà vu be a reset? Fun to imagine, but human memory is a better explanation than cosmic software patches.

Bending Space and Time

General relativity allows wild geometries—wormholes, warp bubbles, light‑forged black holes. Engineering them is another matter. The equations welcome exotic stress‑energy, often requiring negative energy densities or absurd luminosities. Still, plugging numbers into idealized models clarifies what stands in the way.

Relativity rewards patience with units. Keep c (speed of light) and G (Newton’s constant) visible and you’ll see which barriers are truly fundamental and which are merely technological.

Quick FAQ

• Can anything outrun light? Locally, no. Spacetime itself can expand faster than light, and metrics like Alcubierre’s move a bubble, not a ship blasting through space.
• Are wormholes time machines? Some solutions allow time shifts with moving mouths. Most are unstable under realistic conditions.

Cosmic Doom Scenarios

Not all astronomical phenomena are friendly. Certain models predict universe‑ending catastrophes or violations of comforting conjectures. Running the numbers helps gauge how worried we should be—and usually offers relief: many scenarios are wildly unlikely on any human timescale.

Dark energy could rip the cosmos apart; a metastable vacuum might tunnel to a lower energy state; rare astrophysical events could threaten biospheres. Thinking clearly about these possibilities also sharpens our experiments and observations.

Quick FAQ

• Could vacuum decay arrive without warning? Yes—and if it happens, no detector outruns it. The good news: current particle data suggests we are safe on timescales far beyond stellar lifetimes.
• Are GRBs an extinction‑level threat here? Probably rare in our neighborhood; the Milky Way’s structure and our position help.

Extraterrestrial Futures

If humanity avoids cosmic catastrophes, our descendants may spread beyond Earth. Self‑replicating probes, Dyson swarms, dark‑matter detectors, and planetary shields shift from fiction to engineering as technology matures. Back‑of‑the‑envelope models show what’s required.

Quick FAQ

• Where are all the aliens? The Fermi paradox remains unsolved. Expansion is fast on galactic timescales; silence is puzzling.
• Do swarms dim a star? A reflective, sparse swarm can redirect energy without making the star vanish from view. Infrared excess is the giveaway.

Fate of the Universe

What happens in the far future? Will expansion continue forever, halt, or reverse? Can intelligence manipulate cosmic evolution, or is heat death inevitable? Competing models make different predictions; simple calculators let you explore the parameter space.

Quick FAQ

• Is heat death guaranteed? If dark energy stays constant and protons don’t decay, the universe trends toward thin, cold, and quiet. Alternatives exist but require different physics.
• Could life ride black‑hole evaporation? Perhaps in theory; in practice, the timescales dwarf any engineering patience we can imagine today.

Assumptions, Units & Notation

Unless stated otherwise, calculators assume SI units, a flat ΛCDM cosmology for background numbers, and idealized toy models that isolate a single effect. Typical constants used:

• Speed of light c ≈ 299,792,458 m/s
• Gravitational constant G ≈ 6.674×10⁻¹¹ m³·kg⁻¹·s⁻²
• Planck’s constant ℎ ≈ 6.626×10⁻³⁴ J·s (and ℏ = ℎ/2π)
• Boltzmann constant k_B ≈ 1.381×10⁻²³ J/K
• Solar luminosity L_☉ ≈ 3.828×10²⁶ W

Where cosmology matters, we use a Hubble parameter around 70 km/s/Mpc and a dark‑energy equation‑of‑state parameter w ≈ −1 unless a card exposes it for you to play with.

Glossary of Weirdness

Decoherence

Loss of phase relationships between components of a quantum superposition due to interactions with the environment.

False Vacuum

A metastable state of a field that looks stable locally but could tunnel to a lower‑energy configuration.

Equation of State (w)

The ratio of pressure to energy density for a cosmic component. Dark energy with w < −1 can drive a Big Rip.

Planck Units

A natural unit system built from c, G, and ℏ that simplifies gravity and quantum equations.

Shapiro Delay

Extra time light takes to pass near a massive object because spacetime is curved.

Further Reading & Credibility Notes

These topics straddle the line between textbook physics and speculation. The calculators stick to mainstream equations, toy models, and widely taught constants. When a scenario relies on bold assumptions—like abundant negative energy—we say so explicitly in the card notes. For deeper dives, look for graduate‑level texts on quantum information, general relativity, quantum field theory in curved spacetime, and observational cosmology.

Safety, Ethics & Common‑Sense Notes

Some thought experiments, like quantum suicide, are discussed purely to understand interpretations and measures, not to encourage dangerous behavior. Treat them as philosophical puzzles. Never risk your health based on anything in this guide. Use the numbers to learn, not to rationalize harm.