Moving out to the Cosmic Scale.

If we change our perspective and look at what happens on the Cosmic scale, we find things are not so intuitive. Although we can usually still find explanations for what we see and measure, they are not what we would naively expect and are often very alien to us.

For example:

• The Earth is hurtling around the Sun at ~30 km/s, yet we feel stationary.
• Time runs at different rates depending on the speed the observer is travelling and strength of the gravity in their environment.
• Space can be curved.
• A straight line in curved spacetime can look bent to us.

The theory of General Relativity, which predicts some of the weirder of these effects has been highly successful in predicting all manner of Cosmic events including Black Holes and the evolution of stars. Using the mathematical models gives very good predictions of how the universe behaves but the meaning of the models are not ones which can be easily visualised. What does it even mean to say that space can be curved?

Our brains are optimised to be good at throwing rocks, catching prey, and navigating landscapes or other activities which would aid our survival in the environment we evolved in. There was no survival advantage in understanding how stars are formed or the concept of space and time being “curved”.

As we look at situations which are further from the environment we were designed to function in, the “weirder” reality seems to become.