Time, Space and the Universe as we know it – Part 1 Early Understanding

With all it’s vastness and complexity it’s taken a long time for humans to reach the understanding that we have of the universe that we have. This is the story of evolving understanding and how simplicity gives way to incredible truth’s that seems to sit at odds with how we think life should be… and we’ve only just begun our journey of understanding.

Aristotle and the Ancient Cosmos

The Solar System

It’s been accepted for hundreds of years now that the Sun is at the centre of the solar system and our home the Earth orbits around the Sun once every 365 days and spins on it’s axis once a day. This motion creates the days and years and generally this is accepted as fact.

This wasn’t always the case though, in ancient times the universe was seen as 2 distinct separate parts, the things on Earth and the perfect heavenly realm. On the Earth there was us and the land and sea and plants and animals, while the cosmic realm was the stars and planets, they didn’t know what they were but they knew they were there.

There were 2 laws of nature or physics that applied to these 2 realms differently. These laws centered around motion and how motion was different in these 2 realms and these laws were really a mixture of science and philosophy. The natural state of motion on Earth was that objects wanted to be as close as possible to the centre of the Earth. In experimentation this seems to follow, but it’s also a philosophical answer for what we know as gravity.

The heavenly ream was seen as the spiritual realm and consisted of stars and planets and all things beyond the Earth. The natural laws of motion in the heavenly realm was that things moved in perfect circles. There was no beginning and no end.

back in the days of ancient Greece at around 300BC the philosopher Aristotle postulated the geocentric model of the universe where the Earth was at the centre of not only the solar system, but the universe and everything outside it rotated around it. The issue with this model is that it doesn’t line up with what happens in reality – the planets move across the sky in non-perfect circles and as you watch night after night they move backwards. So this model doesn’t work and this was addressed at least in part in the 2nd century AD when the Ptolemaic systems asserted that the planets move in epicycles which were circles within their circles. The basic notion was that the cosmos moved in perfect circles.

This idea wouldn’t be challenged for well over a thousand years.

Copernicus, Kepler and the Imperfect Cosmos

Copernicus was a Polish mathematician, astronomer spent his life observing the cosmos and how the planets all moved. He made what is described as his heretical version of the universe where the Earth was not the centre of the universe the Sun was. He still held to the notion that the planets moved in perfect circles but now the Sun was the centre of all things and not the Earth. This was the first step towards getting rid of the notion that Earth was somehow a ‘special’ place.

The next step was made by Kepler in the 1600’s where he worked with data gathered over years by Tycho Brahe and Kepler asserted that the planets don’t move in perfect circles and instead they move about the Sun in ellipses. These ellipses would be hard to see if drawn these ellipses differ from perfect circles by only a few percent.

It’s taken mankind nearly 2 thousand years to be able to move away from the Earth centered universe, where everything in the heavens moves in perfect circles to a universe where the Earth is not in the centre but the Sun. These notions alone would have rocked understanding and social, philosophical and religious thinking but this merely set the stage for the next big step in understating motion in the universe.

Copyright 2013-2024

Simon’s Space

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