# How We’ll Get to Alpha-Centauri | Cosmic Queries #115

Free with YouTube's ads, posted by StarTalk.

If the multiverse exists, where does our universe end and another begin? Neil deGrasse Tyson and comic co-host Chuck Nice tackle a wide-ranging grab bag of fan questions covering bubble universes, the nature of now, fractals, Hoag's Object, and more.

How do we tell when our universe ends and another begins? We explore the bubble universe model, where separate universes expand without overlapping, each potentially operating under different laws of physics. How can we test for another universe impinging on ours? Next we cover Neil’s favorite and least favorite astronomical words. Could Project Starshot's laser-propelled nanocraft reach Alpha Centauri before a more advanced mission launched decades later? Neil breaks down the math and how lightsails could be our most efficient way of accessing other star systems.

Is there such a thing as a shared "now"? How does a rubber sheet visualization of gravity actually work in four dimensions? We discuss Hoag’s Object and how calculating chance alignments helped us discover binary star systems. Are fractals the key to understanding everything in the universe or are they more entertaining than useful? How does an expanding universe affect time? Did time pass differently in the past? Plus, what did the sky look like when the cosmic microwave background was visible light?

Timestamps: 00:00 - Introduction: Grab Bag 1:10 - Where Our Universe Ends and Another Begins 5:55 - Favorite & Least Favorite Science Words 17:10 - Getting to Alpha Centauri 22:11 - Is There a “Real” Now? 25:11 - Visualizing Gravity 28:40 - Hoag’s Object 34:15 - Are Fractals the Answer? 41:37 - What If Time Passed Differently in the Past? 49:10 - What Did the Cosmic Microwave Background Look Like? 57:30 - Closing Thoughts

Thanks to our Patrons Joan Kirk, Robert Roberts, Mike Holland, Manickore, Zaki Imani, Christopher Johnson, Seb, Annette Hinkle, Bruce Davis, Geoff Hansen, Matthew Binggeli, Michael Greer, steph, Jo, Laurie Rieman, Monneke King,…

- What it is: Film
- Length: 1 h
- Rights holder: [StarTalk by Neil deGrasse Tyson](http://www.startalkradio.net/) (its site links the channel: https://startalkmedia.com/)
- Channel: [StarTalk](https://www.youtube.com/channel/UCqoAEDirJPjEUFcF2FklnBA)
- Plays: Wherever YouTube plays: its rights holder sets no limit
- Who can watch here: Adult profiles and older (no rating is recorded on YouTube, so adults only)
- Made for kids: No, as YouTube designates it
- On YouTube: [Watch on YouTube](https://www.youtube.com/watch?v=BxpyAt5w54w)

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