Episode 46/47 — The History of Cosmology — Part I & II — are now Live!
This latest installment is a bit of a double-whammy. When the first installment aired, I foolish forgot to post about it! Lucky for me, such negligence allowed me to announce both parts of the episode together. And it is only together that they can be appreciated fully. Long story short, in this and last week’s episode, I delved into how human perceptions of the cosmos (aka. cosmology) and our place within it have changed over time.
To say these changes have been drastic would be an understatement of cosmic (sorry!) proportions. If anything, they have been seismic, mind-shattering, and exponential. With every new revolution in our understanding, the Universe as we know it has grown by orders of magnitude. The way we perceive the sum total of everything and how that’s changed goes a little something like this:
- Ancient World: our locale, the Sun, the Moon, the “moving stars,” and the celestial sphere
- Classical Antiquity: Earth orbited by the five planets, the Sun, and the Moon
- Scientific Revolution: Earth and the five planets (and Moon) orbiting the Sun
- 18th/19th Century: Our Solar System adrift in the galaxy
- 20th Century: Our galaxy is one among millions (or more)
- Mid-to-late 20th Century: Our galaxy is one among billions in the “Cosmic Web”
- 21st Century: Our galaxy is one of trillions, maybe one of countless Universes as well
As for sizes and scales, that has also been an exponential adjustment. In the past century alone, the expanse of the Universe (in space and time) has grown by several orders of magnitude. Check this out:
- 1919: 300,000 light-years (infinite)
- 1929: 280 million light-years (2 billion years)
- 1955: 4 billion light-years (6 billion years)
- 1965: 25 billion light-years (10–25 billion years)
- 1993: 30 billion light-years (12–20 billion years)
- 2006: 94 billion light-years (13.7 billion years)
Get it? And at every juncture, our understanding of cosmic forces has also taken great leaps. Between the ancient world and the Renaissance, people went from believing that nature was composed of four or five elements (wood, water, fire, air, metal) to reconsidering atomic theory. By the 19th century, scientists had a pretty good idea of what atoms looked like and had a unified system of determining motion, velocity, and gravity (Newtonian Physics).
Then came the 20th century, with Einstein’s Relativity, Quantum Mechanics, Dark Matter, Dark Energy, Hawking Radiation, the Higgs Boson, String Theory, Supersymmetry, and the Theory of Everything. As my history of science teacher once said, “science is like an onion, constantly shedding its skin.” But when it comes to cosmology, it’s more like a creature that molts in order to accommodate its insane growth. Check out the episode by following the links below:
Where to Listen:
Originally published at http://storiesbywilliams.com on July 22, 2023.
