"We are all in orbit around the center of the Milky Way galaxy. How big is this collection of stars? Somewhere between 200 and 400 billion suns in the Milky Way galaxy, about 100,000 light years across."

### **Key Takeaways**

1. **Human Scales Are Arbitrary** – Meters and feet are based on biology, not universal truths. Aliens wouldn’t use them.

2. **Nature’s Fundamental Constants** – Physics reveals deeper rulers:

- **Speed of light** (cosmic speed limit).

- **Planck’s constant** (quantum uncertainty).

- **Gravity’s strength** (shapes spacetime).

3. **Planck Length: The Smallest Possible** – At **10⁻³⁵ meters**, probing further creates black holes. A proton vs. This is like the solar system vs. A virus.

4. **Cosmic Scales Defy Intuition** – From our Sun (flying around it takes a year) to galaxies (Andromeda’s light is 2.5M years old), the universe is **inconceivably vast**—possibly infinite.

5. **Life’s Potential Cosmic Role** – If intelligence persists, it could someday manipulate galaxies, making life *more* than a "speck."

### **Mind-Blowing Fact**

The edge of the *observable* universe is **46B light-years away**—but the *actual* universe may be infinite.

*(Host: Brian Cox | Particle Physicist)*

**Want more?** Follow Big Think for cosmic insights. 🌌

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