Wisdom Builder

Three Tidbit Stories

Topic:

Relativity

Einstein-based spacetime, gravity, and motion.

MODE:

Speed: 1.00

Relativity.

3 random tidbit stories in about 3 minutes.

Idea 1.

A Relativity FAQ.

Will the night sky have stars nearly forever?.

YES! Well, nearly forever. Does that surprise you? Did you think the expanding universe would someday erase the stars from our night sky? Here’s the truth as understood by modern astrophysicists: while the universe is expanding, the stars you see at night, nearly all part of our Milky Way, are gravitationally bound—and always will be.

The constellations change shape at varying rates and the night sky is quite different every 10,000 years or so. So, the shapes we see today were quite different from just 10,000 years ago. But, a night sky full of constellations will always be a part of our future.

And, our galaxy is part of a Local Group of over 50 galaxies, all gravitationally bound together. Just as planets orbit the Sun, the stars, galaxies, and dust within our Local Group are locked together in a cosmic “island.”

How big is this island? Imagine this: both Star Wars and Star Trek take place entirely within a galaxy. Star Trek takes place in the Milky Way, and Star Wars takes place a long time ago in a galaxy far, far away. Our Local Group of galaxies is an unimaginably vast expanse of space. While trillions of distant galaxies will vanish beyond the cosmic horizon, our Local Group will remain bound together, for at least trillions of years.

Over time, some galaxies will merge. For example, the Milky Way and Andromeda are on a collision course and will one day form a massive galaxy. But this process is so slow that the night sky will change imperceptibly on human timescales. And stars are far apart, they’re unlikely to collide. Instead, their gravitational pull will reshape the stars into a new galaxy.

I wrote that Relativity FAQ,

and posted it to TST 2 years ago.

Idea 2.

A Relativity FAQ.

In TST, what is the self?.

The self is the “you” experiencing the now; what that “you” actually is remains debated.

TST takes an explorative agnostic position on defining the self. TST does not define the unknown, but because the self is rich with philosophical implications, I spend considerable time exploring it. In Chapter 17 of 30 Philosophers, I explore the experience of the “now.” Your mind continually prioritizes sensory input, emotions, memories, and both prelinguistic and linguistic thoughts. At the same time, you, whatever that entails, are choosing what to focus on.

What you focus on shapes your experience of the now and can influence your future. Your attention colors impressions, influences memories, and helps shape your worldview and identity. In neuroscience, the salience network is one of the systems helping prioritize what’s important, influenced by things like emotional weight, urgency, familiarity, and expectations. This is part of why practices like Stoicism, meditation, and modern therapy can help us live better lives. By learning to influence the now, we can influence our future.

But who exactly is this “you” making choices? Is this where the self and free will reside? Are we experiencing genuine agency, deterministic processes, or some combination? Is there a persistent self, or does the Buddhist concept of non-self offer a better explanation? How do biology, psychology, and perhaps spiritual ideas fit into the picture? TST leaves these questions open. The experience of the now is something we can investigate, but the ultimate nature of the self remains an open philosophical question.

I wrote that Relativity FAQ,

and posted it to TST 4 weeks ago.

Idea 3.

A Relativity Story.

Modern Cosmology.

1608

30 Phil, Chapter 21, Galileo, Touchstone 54: Modern Cosmology.

The story of Galileo is also the story of Copernicus, and the story of modern cosmology. To properly tell the story of Copernicus, we need to mention Aristarchus of Samos, a Greek astronomer and mathematician born around 310 BCE. Aristarchus put forth a heliocentric model, proposing that the Earth and other planets orbited the Sun. Unfortunately, his ideas did not gain widespread acceptance. Over the millennia some scholars had the idea that the universe was vast, but no proof. With the invention of the telescope in 1608, the proof was within reach. This was the time when our human-centric world expanded into the vastness of space.

I wrote that Relativity Story,