From quark to cosmos: the ladder of scales

All steps

1. ·Quarksmaller than 10⁻¹⁸ metresOne of the smallest known building blocks. It has no measurable size; we only know it is smaller than 10⁻¹⁸ metres. It is never found alone, always grouped inside protons and neutrons.
2. ⚛️Protonabout 1.7 × 10⁻¹⁵ metresThree quarks and the gluons that bind them. A surprising fact: only about 1% of a proton's mass comes from the quarks themselves; the rest is the energy of the bond that holds them together.
3. 🔴Carbon nucleusabout 5 × 10⁻¹⁵ metresSix protons and six neutrons packed tightly together. More than 99.9% of an atom's mass is concentrated in this tiny nucleus.
4. ◎Atomabout 0.1 nanometres (10⁻¹⁰ m)An atom is about 100,000 times larger than its nucleus. If the nucleus were a pea in the middle of a football stadium, the electrons would roam around the stands. In between is mostly empty space. Ten million atoms side by side make just 1 millimetre.
5. 💧Water moleculeabout 0.28 nanometresTwo hydrogen atoms and one oxygen atom. A glass of water holds about 8 × 10²⁴ molecules: thousands of times more than the number of glasses of water in all the world's oceans.
6. 🧬DNA helixabout 2 nanometres wideLife's recipe book. Very thin but very long: the DNA in a single one of your cells would stretch about 2 metres end to end.
7. 🦠Virusabout 100 nanometresMany viruses, such as the flu virus, are about this size. A virus cannot reproduce on its own; it borrows a cell's machinery. Whether it counts as alive is still debated.
8. 🧫Bacteriumabout 2 micrometresA single-celled, independent living thing. As many bacteria live in your body as you have cells of your own, perhaps more, and most of them help you.
9. 🔵Human cellabout 10–20 micrometresYour body has about 30 trillion cells. Each is a tiny, ever-busy factory made of trillions of atoms.
10. 〰️Human hairabout 70 micrometres thickOne of the thinnest things you can see. About 700,000 atoms fit across the width of a hair.
11. 🐜Antabout 3 millimetresSmall but complex: a complete animal with a brain, eyes, legs and self-copying cells.
12. 🧍Humanabout 1.7 metresYou. You sit roughly in the middle of the ladder of scales: between the world of atoms and the world of stars.
13. 🏔️Mount Everest8,849 metresEarth's highest mountain. The rocks at its summit were once on the sea floor and contain fossils of marine creatures.
14. 🗺️Türkiye (east to west)about 1,600 kilometresFrom Edirne to Iğdır. Light crosses this distance in less than a hundredth of a second.
15. 🌍Earth12,742 kilometres acrossOur home. About a third of its mass is iron, but most of that iron is thousands of kilometres beneath our feet, in the core.
16. 🌙The Moon's orbitabout 769,000 kilometres acrossThe Moon is 384,400 km away on average. All the other planets would fit in the gap between Earth and the Moon.
17. ☀️The Sunabout 1.39 million kilometres acrossMore than a million Earths would fit inside it. Every second it turns about 600 million tonnes of hydrogen into helium.
18. ↔️Earth–Sun distanceabout 150 million kilometresSunlight reaches you in 8 minutes and 20 seconds. The Sun you see in the sky is the Sun of 8 minutes ago.
19. 🪐Solar System (out to Neptune)about 9 billion kilometres acrossEight planets, dwarf planets, countless asteroids and comets. Light takes 4 hours to reach Neptune.
20. ✨Distance to the nearest star4.24 light-yearsProxima Centauri. Even our fastest spacecraft would take thousands of years to get there.
21. 🌌The Milky Wayabout 100,000 light-years acrossMore than 100 billion stars. The Sun takes about 230 million years to circle the centre once; when it began its current lap, dinosaurs were just appearing.
22. 🔭Observable universeabout 93 billion light-years acrossAlthough the universe is 13.8 billion years old, the part we can see is about 93 billion light-years across: space kept expanding while the light was on its way. What lies beyond, we do not know.