A Gentle Introduction to Relativity

What is space?

Leo Ariel
2 min readApr 28, 2022

An Empty Box

We think of space as an empty box. An empty bucket of nothingness. Intuitively, this makes sense. After all, space is the absence of things. We say there is space between the crab and the wall of the box.

Empty Box

Then a few people came along and added a few things.

  1. Force of Gravity. Newton saw that objects were attracted to each other by an invisible force. He called this the “force of gravity”, otherwise known as just gravity.
  2. Electromagnetic Field. Faraday and Maxwell found that positively and negatively-charged objects created a field. The field alters the trajectory of electricity ⚡️, hence an electric field. The field permeates through all of free space.
Empty Box + Electromagnetic Field

Then comes the punchline. Einstein found that space itself is a field. Space is curved. Matter is what curves it.

Gravitational Field + Electromagnetic Field

Things don’t simply fall. They follow a curve, just like a ball rolling down a hill.

Examples of things that follow a curve

  • The green crab
  • An 🍎 that falls from a 🌲
  • Light
  • Time

The last two are topics for another time 🙂

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