Looking Into a Mirror

Standing in front of a full-length mirror, you can look at your whole body, viewing it as a single remarkable object – a living creature. But you can also dig into details, exploring the ways your body interacts with the world around it, or how it makes use of the energy in the food you eat to get you moving.

Number of Cells in a Body

Zoom in further and you will find somewhere between 10-100 trillion cells. Each cell is a sophisticated package of life, yet taken alone, a cell certainly isn’t you. Go further still and you will find complex chemistry abounding – you have a copy of the largest known molecule in most of your body’s cells: the DNA  in chromosome 1.

Number of Atoms in a Body

Continue to look in even greater detail and eventually you will reach the atoms that make up all matter. Here traditional numbers become clumsy – a typical adult is made up of around 7, 000, 000, 000, 000, 000, 000, 000, 000, 000 atoms. It’s much easier to use scientific notation to denote the number of atoms in a human body: 7 x 10 ²⁷ atoms, meaning 7 with 27 zeroes after it.

The Universe Inside You: The Extreme Science of the Human Body
Brian Clegg

Brian Clegg
born 1955

. Brian Clegg website
. Wikipedia

Brian Clegg is an English science writer. Clegg is the author of popular science books on topics including light, infinity, quantum entanglement, and surviving the impact of climate change.

Books Brian Clegg has written include:

• Are Numbers Real?: The Uncanny Relationships Between Maths and the Physical World
• Big Data: How the Information Revolution Is Transforming Our Lives
• Gravitational Waves: How Einstein’s spacetime ripples reveal the secrets of the universe (Hot Science)
• Professor Maxwell’s Duplicitous Demon: How James Clerk Maxwell unravelled the mysteries of electromagnetism and matter
• The God Effect: Quantum Entanglement, Science’s Strangest Phenomenon
• The Graphene Revolution: The Weird Science of the Ultra-thin (Hot Science)
• The Quantum Age: How The Physics Of The Very Small Has Transformed Our Lives
• The Reality Frame: Relativity and our place in the universe
• The Universe Inside You: The Extreme Science of the Human Body