001.【A Physical Worldview】🌌 Distance and Time
Breaking Through Å, nm, km, and Light-Years on a Single Axis
🌌 Distance × ⏳ Time
Why Physical Discussions So Often Miss Each Other
Physics is one.
But humans see different worlds every time the scale changes.
The boundary is not theory or discipline.
It is SI prefixes:
f, p, n, μ, m, k, M, G, T.
🔑 Reality Check First: SI Prefixes
| Prefix | Symbol | Value |
|---|---|---|
| femto | f | $10^{-15}$ |
| pico | p | $10^{-12}$ |
| nano | n | $10^{-9}$ |
| micro | μ | $10^{-6}$ |
| milli | m | $10^{-3}$ |
| (base) | – | $10^{0}$ |
| kilo | k | $10^{3}$ |
| mega | M | $10^{6}$ |
| giga | G | $10^{9}$ |
| tera | T | $10^{12}$ |
Each step is a switch that changes the world.
🌌 Distance: From Ångström to the Universe — All in Meters
| World | Distance |
|---|---|
| Atomic radius | 1 Å = $10^{-10}\,\mathrm{m}$ |
| Transistor | few nm = $10^{-9}\,\mathrm{m}$ |
| Cell | 10 μm = $10^{-5}\,\mathrm{m}$ |
| Human | 1 m = $10^{0}\,\mathrm{m}$ |
| Mt. Fuji | 4 km = $4\times10^{3}\,\mathrm{m}$ |
| Earth radius | 6.4 Mm = $6.4\times10^{6}\,\mathrm{m}$ |
| Earth–Sun | 1 AU = $1.5\times10^{11}\,\mathrm{m}$ |
| Solar system | $\sim10^{13}\,\mathrm{m}$ |
| Galaxy | $\sim10^{21}\,\mathrm{m}$ |
| Observable universe | $\sim10^{26}\,\mathrm{m}$ |
Å → nm → μm → m → km → AU → light-year
They are all the same thing: distance.
But what matters at the Å scale vanishes at the km scale.
Common sense at the km scale is meaningless at the galactic scale.
⏳ Time: Femtoseconds and Cosmic Age Are the Same Second
| World | Time |
|---|---|
| Electronic transition | 1 fs = $10^{-15}\,\mathrm{s}$ |
| Circuit delay | 1 ns = $10^{-9}\,\mathrm{s}$ |
| Control cycle | 1 ms = $10^{-3}\,\mathrm{s}$ |
| Human reaction | 1 s = $10^{0}\,\mathrm{s}$ |
| One day | $10^{5}\,\mathrm{s}$ |
| One year | $3\times10^{7}\,\mathrm{s}$ |
| Edo period | $\sim10^{10}\,\mathrm{s}$ |
| Jōmon period | $\sim10^{12}\,\mathrm{s}$ |
| Earth formation | $\sim10^{17}\,\mathrm{s}$ |
| Age of the universe | $\sim4\times10^{17}\,\mathrm{s}$ |
From the femtosecond world,
human history is perfectly motionless.
🧠 Why This Never Feels Intuitive
Humans can intuitively grasp only about
six orders of magnitude: roughly $10^{-3}$ to $10^{3}$.
The moment you step outside that range,
even with the same unit,
it feels like different physics.
🧭 Take-Home Summary
- Physics is continuous
- Human understanding is segmented by f, p, n, μ, m, k, M, G, T
- Misunderstanding comes not from ignorance, but from scale