Notes on some interesting factoids I learnt from Anders Sandberg's draft book, Grand Futures.

"Starlight is heavier than worlds" - Anders Sandberg

Looking at the energy density of stuff in the universe, we find a few surprising, and not so surprising, facts. First, the obvious: baryonic matter itself is a rounding error, contributing 4.5% of the energy of the universe. Nine tenths of those sweet, sweet baryonic numéraire are stuck in the warm plasma floating between galaxies. About half the remainder forms the stuff of stars.

Planets don't even match a thousand of the contribution of stars to the energy density of the universe. Somewhat surprisingly, supermassive black holes have a contribution. Regardless, the fact remains that planets are a rounding error to a rounding error to a rounding error of the energy of dark matter and energy. Even starlight contains more energy. So in a [...]

---

First published:
October 9th, 2025

Source:
https://www.lesswrong.com/posts/mzifm6wePKfnFTAaB/stars-are-a-rounding-error

---

Narrated by TYPE III AUDIO.

---

Images from the article:

Scientific table showing poststellar radiation types and planetary matter density measurements.

Apple Podcasts and Spotify do not show images in the episode description. Try Pocket Casts, or another podcast app.

“Stars are a rounding error” by Algon

LessWrong (30+ Karma)