3 HN users recommended this explainer4 months2020–2025score 5
Years with an HN recommendation, 2007–2026
HN returns to it whenever moving the solar system, Kardashev civilizations or generation ships come up, with some calling it their favorite Kurzgesagt video.
Kurzgesagt explains stellar engines such as the Shkadov thruster and Caplan thruster, which could move the Sun and solar system across the galaxy over millions of years to avoid hazards and reach new regions.
“Out of every video Kurzgesagt has ever produced, my favorite is this one” (HN, 2021)
Out of every video Kurzgesagt has ever produced, my favorite is this one, which talks about a stellar engine that a type Ⅱ civilization could be using: [this video]
Stellar engine a type II civilization could use to move a star.
In case anyone is interested in how grabby aliens (or we!) could travel the galaxy, Kurzgesagt has an excellent video on building a stellar engine to move our solar system at up to 50 light years per million years. Setting aside considerations of whether we'll survive the next few decades as a technological civilization, let alone the next few millions of years, the Caplan engine would let us colonize a significant fraction of the galaxy within a billion years or so. [this video]
Stellar engine moving the solar system up to 50 light years per million years.
You might enjoy Kurzgesagt's video on moving the Sun (and with it the whole solar system) they propose a method that would theoretically let us colonize the galaxy in a reasonable (but not trivial) time frame. To your exact point though, since we're moving the whole solar system, everyone would be living their whole lives on the/a ship. [this video]
Method to move the Sun and colonize the galaxy in reasonable time.
Extracts: The machine would use a Dyson sphere to collect mass, separate out helium to push the sun, and fire hydrogen at the sun to avoid crashing into the sun. It could push the Sun at a speed of about 50 light years per one million years. Matthew Caplan from Illinois State University designed the machine at the behest of Munich-based YouTube channel Kurzgesagt. The channel then created a stunning video to illustrate the device, which it dubbed the Caplan Thruster, and a paper Caplan wrote describing the machine has also been published in the journal Acta Astronautica. Video links: Kaplan thruster: [this video] Dyson sphere: [link]
Illustrates the Caplan Thruster stellar engine for moving the Sun.
I wouldn't expect an exhaust plume passing through a wormhole to move the wormhole itself (or the heavily curved "portals" at its ends) any more than a plume would move "flat"/"normal" spacetime. Separately, Kurzgesagt did a video on stellar engines (which can be much less exotic than wormholes); sounds like what you're describing: [this video]
Saying there is "no evidence" is factually absurd. There are a whole host of possibilities for practical long distance space travel. At very least for small light-weight robots. And it even seems possible that we can viably transport our entire solarsystem: [this video] . No evidence indeed... only if you lack imagination.
Evidence that moving our whole solar system might be viable.
Here's the Kurzgesagt video on moving the solar system through the galaxy: [this video] I've seen at least one "physicist reacts" video to this that tl;dw's to: "seems reasonable, would obviously require a lot of technological advancement and work"
Moving the solar system through the galaxy with a stellar engine.
It depends on what time scale you're talking about. Here's a Kurzgesagt video that describes how to do it over the course of millions of years: [this video] That's a loooong time, obviously, but it's not "theoretically impossible"
How to move the solar system over millions of years.
The "time it takes for the passengers of a generation ship to start a new civilization and gather the resources to launch another generation ship" is minuscule compared to the time to make the journey in the first place. Here's a Kurzgesagt video that essentially proposes using our solar system itself as our "generation ship" and getting from one star to the next would take on the order of a hundred thousand years, while the time to set up to travel that way seems reasonable to create in tens of thousands, or even thousands, of years. [this video]
Using the solar system itself as a generation ship.
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