Human Scale Reference Point

• Humans ~1.7m tall positioned in middle of universe scale
• 3-story building ~10m tall = 6x bigger than human
• Squirrel ~27cm = 6x smaller than human
• Building-to-human ratio = human-to-squirrel ratio

Transportation and Migration Scale

• A320 aircraft: 37m long = 23x bigger than human
• Rufous hummingbird: 7cm = 23x smaller than human
• Both fly intercontinental distances
• Hummingbird migrates Alaska-Mexico
• If hummingbird same size as jet, would circle Earth 85x/year

Insect and Ant Scale

• Dinoponera ant: 55x smaller than human
• Colonies ~100 individuals, no queens
• Nests reach 1.2m deep
• Human equivalent: 25-story towers with status competition
• Mosquito: 235x smaller than human
• Empire State Building: 235x larger than human

Perception Boundaries

• Coarse sand grains: 3mm, 550x smaller than human
• Can feel shape/roughness, see individually
• Used in concrete for tallest towers
• Burj Khalifa: 828m tall, 500x larger than human
• If human that tall, people would appear as sand grains

Urban Networks vs Biological Systems

• Lisbon city: 6,000x larger than human
• Human small arteries: 6,000x smaller than human
• City-human ratio = human-blood vessel ratio
• Small alley to city = 0.1mm arterial to human
• Capillaries to human = water pipes to Lisbon

Cellular Scale

• Skin cell: 30 micrometers diameter, 100,000x smaller than human
• Neutrophil: half skin cell size
• Red blood cell: 7 micrometers
• Cell-to-human ratio = human-to-Tokyo metropolitan area
• Tokyo spans 160km, largest urban area globally

Agricultural Dependencies

• Germany: 875km north-south, 4th biggest agricultural exporter
• Rhizobia bacteria: 3 micrometers long, nitrogen-fixing
• Agricultural production impossible without bacteria
• Both Germany and bacteria ~550,000x larger/smaller than human

Planetary Scale

• Earth diameter: 12,700km, 7.7 billion times larger than human
• Corynebacterium: 0.3 micrometers, lives on skin/eyes
• 100 billion bacteria on human body
• 10x more bacteria than humans on Earth

Solar System Scale

• Neptune: 49,500km wide, 4x wider than Earth
• Jupiter: 140,000km diameter, could swallow Earth
• West Nile virus: 50nm diameter
• Coronavirus spike proteins even smaller
• Virus-to-human = human-to-Jupiter ratio
• Virus kills cells 500x larger using tiny proteins

Stellar Scale

• Sun: 10x bigger than Jupiter, billion times larger than human
• Controls all planets, source of all life energy
• DNA strand: billion times smaller than human
• Contains all life information

Galactic Scale

• Sagittarius A* black hole: 14.5 billion times bigger than human
• Hydrogen atom: 15.5 billion times smaller than human
• Solar system: 22 trillion times larger than human
• Low-energy neutrinos: 100 trillion times smaller than human
• 100 trillion neutrinos pass through human every second

Subatomic Scale

• Single proton: 1 quadrillion times smaller than human
• If proton human-sized, hydrogen atom would be 12 Everests tall
• Alpha Centauri distance: 24 quadrillion times larger than proton
• Quarks: quintillion times smaller than human
• Quarks constantly pop into existence with antiparticles
• Annihilate each other instantly

Cosmic Scale Extremes

• 174 light-year sphere with 16,000 stars = human-to-quark ratio
• Milky Way: close to 1 sextillion times larger than human
• High-energy neutrinos: sextillion times smaller than human
• Observable universe: 93 billion light-years diameter
• Billion billion billion human lengths
• Only 465,000 Milky Ways side by side

Theoretical Limits

• Smallest detected particle: proton at near light-speed
• Squished into pancake shape
• Planck length: theoretical smallest distance
• 100 million times smaller than pancake proton
• Universe could be considerably larger than observable
• Human positioned exactly in middle of scale

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