Each step up is roughly 10× faster. Human intuition covers only the first few rows.
Snail
0.05 km/h
Human walk
5 km/h
Cycling
15–25 km/h
City car / sprint
~30–50 km/h
Motorway car
~120 km/h
High-speed train (TGV)
~300 km/h
Commercial plane
~900 km/h
Concorde (retired)
~2,170 km/h — Mach 2
SR-71 spy plane
~3,540 km/h — Mach 3.2
Speed of sound (air)
1,235 km/h — Mach 1
ISS / orbital speed
~28,000 km/h
Speed of light
1,080,000,000 km/h
Light is 1,200,000× faster than a plane. The ISS orbits Earth every 92 minutes — 16 sunrises per day.
Part B · the key speed anchors you'll use every day
Walking
5 km/h
1 km = 12 min walk. 10 min = ~800 m. The foundation of all human-scale distance sense.
Cycling
~20 km/h
4× walking. 1 km = 3 min. 10 km commute = 30 min by bike.
Motorway driving
~120 km/h
2 km per minute. 100 km = ~50 min. 1 hr = ~120 km.
Commercial flight
~900 km/h
15 km per minute. 1,000 km ≈ 1 hr. The Module 3 anchor in action.
The travel time formula — works for any journey
Time = Distance ÷ Speed. Always in the same units.
300 km by car at 100 km/h = 3 hours.
300 km by plane at 900 km/h = 20 minutes (plus airport time — realistically 3 hrs total).
300 km by TGV at 300 km/h = 1 hour — often faster door-to-door than flying.
Speed in all three units — the conversion reference
km/h × 0.278 = m/s · km/h × 0.621 = mph · mph × 1.609 = km/h
Speed context
km/h
m/s
mph
Human walking
5
1.4
3.1
Competitive sprint (100 m WR)
37.6
10.4
23.4
City speed limit
50
13.9
31
Motorway / highway
120
33.3
75
High-speed train
300
83.3
186
Commercial aircraft
900
250
560
Speed of sound (sea level)
1,235
343
767
Quick rule: to convert km/h to m/s, divide by 3.6. So 90 km/h = 25 m/s — useful for stopping-distance calculations.
Part C · interactive speed & distance calculator
How long does a journey take? Pick a speed and enter a distance.
Part D · how long does it actually take? duration anchors
Real-world task durations — most people underestimate these
Boiling water (1L)
~4 min
Cooking pasta
8–12 min
Roasting a chicken (1.5kg)
~90 min
Appendix surgery
30–60 min
Hip replacement
1–2 hours
Open-heart surgery
4–6 hours
Building a house
6–18 months
Building a skyscraper
3–5 years
Building a nuclear plant
10–20 years
Writing a PhD thesis
3–5 years
Becoming a surgeon
12–15 years
Why we consistently underestimate durations
Psychologists call it planning fallacy: we remember tasks going smoothly and forget interruptions, rework, and dependencies. The fix is to estimate by analogy — how long did the last similar thing actually take? — rather than imagining a perfect run. Projects with no prior reference (building a nuclear plant, for example) are especially prone to massive overruns: the global median nuclear build time has historically exceeded 10 years, with large cost overruns common.
Part E · human body speeds — things happening inside you right now
Nerve signal speed
~70 m/s
252 km/h. Pain signals are slower (~1 m/s). That's why you feel a stubbed toe slightly after you see it happen.
Blood circulation (full loop)
~60 seconds
One full circuit every ~1 minute. The body contains ~100,000 km of blood vessels total — enough to circle Earth twice.
Heart beats per minute
~60–100 bpm
~100,000 beats per day. ~3 billion beats in a lifetime. It never stops for a rest longer than 1 second.
Blink duration
~150–400 ms
You blink 15–20 times per minute. Total "blind time" per day: ~30 minutes. You never notice.
Sneezing speed
~150–160 km/h
Air exits your nose faster than a motorway car. A cough is slower (~80 km/h) but still powerful enough to travel several metres.
Hair growth
~15 cm/year
About 1.25 cm per month, or 0.4 mm per day — roughly the thickness of four sheets of paper. Nails grow slightly slower at ~3.5 mm/month.
Body signals: how fast does information travel through you?
From stimulus to brain — comparing your own biological "latency"
Hearing triggers the fastest reactions (~160ms) — faster than vision (~250ms). This is why starting pistols are used instead of visual flags in sprinting.
Part F · stopping distances — speed kills because physics
Interactive stopping distance calculator
Drag the slider. Stopping distance grows with the square of speed — double your speed, quadruple your stopping distance.
Speed90 km/h
Reaction distance
—
~0.75 s reaction time
Braking distance (dry)
—
grows as speed²
Total stopping distance
—
—
Part G · 0 to 100 km/h — the universal measure of a car's acceleration
0–100 km/h times across all categories
Bar length = time taken. Shorter = faster. Click a category to explore.
Why 0–100 km/h? And what does it actually feel like?
0–100 km/h (0–62 mph) is the universal benchmark because it represents the most common real-world acceleration scenario: joining a motorway or overtaking. The number is honest — it can't be gamed by gearing tricks the way top-speed figures can. Below 4 seconds feels violent; your vision narrows and you're pressed into the seat with ~0.6–0.8 g. Below 2 seconds (modern hypercars) produces a brief sensation of near-weightlessness followed by sharp chest compression — roughly equivalent to fighter-pilot g-onset. The electric advantage is real: an electric motor produces maximum torque from 0 rpm, while a petrol engine must reach its torque peak (often 3,000–5,000 rpm). This is why a modest family EV often outaccelerates sports cars from a standing start, even if it's slower at high speed.
Part H · the speed of light — putting the universe in perspective
Light travels 300,000 km per second. How far in each timeframe?
1 nanosecond
30 cm — a ruler
1 blink (200ms)
60,000 km
1 second
300,000 km
1.3 seconds
~384,000 km — Earth→Moon
1 minute
18M km
8 minutes
150M km — Earth to Sun
4.2 years
nearest star (Proxima Centauri)
When you look at the Sun, you're seeing it as it was 8 minutes ago. The night sky is a time machine — the further you look, the older the light.
Cosmic distance explorer
Select a destination to see how long a light-speed signal takes to get there.
Part I · the other end of the scale — speeds that are almost imperceptible
Incredibly slow — but not zero
All values in mm/year for comparison.
Human nail growth
~42 mm/year
Human hair growth
~150 mm/year
Stalactite growth
0.1–3 mm/year
Continental drift
~25–50 mm/year
Tree trunk widening
~5–20 mm/year
Sea-level rise (current)
~3.6 mm/year
Sahara expansion
~5,000 m/year
Continental drift moves at roughly the same speed as your fingernails grow. Africa and South America separate by about the width of your hand every year. Over 100 million years, that's the Atlantic Ocean.
Rate vs. cumulative effect — the patience of slow processes
The Grand Canyon took ~5–6 million years to form — yet the Colorado River only erodes ~0.3 mm of rock per year. Small rates, given enough time, produce colossal results.
Part J · Guinness World Records — fastest of everything
Official world speed records across categories
Click any record card to reveal the story behind it.
All records on one scale (km/h, logarithmic)
Each grid line is 10× faster.
Part K · fastest roller coasters in the world
Top-speed coasters — ranked
Click a coaster to explore its stats and story.
How do the fastest coasters achieve such speed?
The old chain-lift method tops out around 120–130 km/h. The fastest coasters use hydraulic launch or linear synchronous motor (LSM) systems. A hydraulic launch works like a giant syringe — oil is pressurised over several minutes, then released in 1–4 seconds to slam the train down the track. Formula Rossa accelerates from 0 to 240 km/h in 4.9 seconds — requiring riders to wear protective goggles against wind and insects. For comparison, a Formula 1 car reaches 0–100 km/h in about 2.6 seconds but only reaches ~370 km/h top speed — slower than the fastest coasters.
Part L · the Large Hadron Collider — the fastest thing humans have ever built
Proton speed
99.9999991% c
~1,079,251,200 km/h
Circumference
27 km
buried 50–175 m underground
Orbits per second
11,245
each proton beam
Collision energy
13.6 TeV
Run 3 (2022–present)
The LHC ring — straddling the Swiss-French border
The LHC sits in a circular tunnel straddling the border between Switzerland and France, near Geneva. CERN's main campus is in Switzerland, but about 70% of the tunnel runs under French territory. The ring has a circumference of exactly 26.659 km and was the most expensive scientific instrument ever built at the time of its first operation in 2008, costing approximately €4.4 billion for construction alone.
What 99.9999991% of light speed actually means — relativistic effects
At these speeds, Einstein's special relativity isn't a theory — it's a measurable engineering constraint.
Time dilation (Lorentz factor γ ≈ 7,461)
7,461×
A proton's internal "clock" ticks 7,461× slower than ours. If a proton were the size of a human, it would age only 4 seconds during a full day of operation in the LHC.
Length contraction
÷ 7,461
The 27 km ring appears contracted to just 3.6 metres from the proton's perspective. It "sees" the entire tunnel as shorter than a car.
Relativistic mass increase
7,461×
A proton at full LHC speed has an effective mass 7,461× its rest mass. This is why accelerating further gets exponentially harder — it approaches an infinite-energy wall.
Orbits per second
11,245
Each proton completes 11,245 laps of the 27 km ring every second. In 10 hours, each proton travels ~10 billion km — roughly the distance to Saturn.
How close to light speed is the LHC, really?
Even the fastest spacecraft (Parker Solar Probe) is barely visible on this scale. The remaining gap to light speed cannot be closed — it would require infinite energy.
Part M · anchor numbers to memorize
5 km/h
Human walking speed
1 km = 12 min · the foundation of all distance intuition
120 km/h
Motorway car — 2 km per minute
100 km = ~50 min driving
300 km/h
High-speed train (TGV, Shinkansen)
Often faster than flying for <500 km city-centre to city-centre
900 km/h
Commercial aircraft
1,000 km ≈ 1 hour — the module 3 rule
1,235 km/h
Speed of sound (Mach 1) at sea level
Thunder arrives ~3 sec after lightning per km of distance
300,000 km/s
Speed of light
Earth to Moon in 1.3 sec · Earth to Sun in 8 min
25–50 mm/yr
Continental drift
Same rate as your fingernails grow — yet it built the Atlantic Ocean
Part N · faster or slower? — speed intuition game
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Part O · test yourself
1. You hear thunder 6 seconds after a lightning flash. How far away is the storm?
About 2 km. Sound travels ~340 m/s. The rule of thumb: 3 seconds of delay ≈ 1 km. So 6 seconds ≈ 2 km. Light from the flash arrives almost instantly (less than a millisecond at 2 km), so the gap is purely sound travel time. At 6 seconds, the storm is close — seek shelter.
2. Paris to Lyon is about 460 km. Which is faster door-to-door: TGV or plane?
The TGV — easily. The train takes about 2 hours at ~300 km/h, city-centre to city-centre. A flight takes ~1 hour in the air, but add 45 min check-in, 30 min to/from each airport, and 20 min baggage = ~3.5–4 hours total. For any journey under ~600 km between well-connected cities, high-speed rail is almost always faster door-to-door than flying.
3. The ISS orbits at 28,000 km/h. How long does one full orbit of Earth take?
About 92 minutes. Earth's circumference at orbital altitude (~400 km up) is roughly 42,000 km. 42,000 ÷ 28,000 ≈ 1.5 hours = 90 minutes. This means ISS astronauts see 16 sunrises and sunsets every single day — one every 45 minutes.
4. A surgeon says your operation will take "about 3 to 4 hours." Is that unusual, or normal for major surgery?
Completely normal for major surgery. Appendix removal: 30–60 min (minor). Hip replacement: 1–2 hours. Knee replacement: 1–2 hours. Open-heart surgery: 4–6 hours. Liver transplant: 6–12 hours. A 3–4 hour estimate puts you in the "significant but routine" category — complex enough to require careful work, but not an unusually long procedure. Add recovery room time and you're typically looking at waking up 1–2 hours after the stated surgery duration.
5. You're driving at 90 km/h and need to stop suddenly. Roughly how far does the car travel while you react and brake?
About 55–65 metres total. At 90 km/h you're travelling 25 metres per second. Human reaction time is ~0.7–1 second, covering ~18–25 metres before you even touch the brakes. Then braking distance at 90 km/h on dry road is roughly 40 metres. Total: ~55–65 m. On wet roads, add 50%. This is why motorway tailgating is so dangerous — at 120 km/h, the total stopping distance exceeds 90 metres, longer than a football pitch.
6. Continental plates drift at about 25–50 mm per year. How far has Europe moved away from North America since the Roman Empire (~2,000 years ago)?
About 50–100 metres — roughly the length of a football pitch. At 40 mm/year × 2,000 years = 80 metres. This is imperceptible on a human timescale, which is exactly why the idea of moving continents was ridiculed when first proposed. But over 100 million years, that same rate produces ~4,000 km of separation — the width of the North Atlantic.
7. You send a radio command to a Mars rover when Mars is at its furthest point from Earth (~400 million km). How long before the rover receives your command?
About 22 minutes (one way). Radio signals travel at the speed of light: 400,000,000 km ÷ 300,000 km/s = ~1,333 seconds ≈ 22 minutes. A round-trip "conversation" would take ~44 minutes — which is why Mars rovers must be largely autonomous. You cannot drive them in real time from Earth. When Mars is at its closest (~56 million km), the delay is ~3 minutes each way.