I think this is awesome? but also hot nonsense.
- Here, we have chosen ship parameters at the very conservative end of the range that allows for a transition to Type iii: ships from the home system and all settlements are launched no more frequently than every 0.1 Myr, technology persists in a settled system for 100 Myr before dying out, and the ship range is ~3 pc (scaled up in a manner that preserves the qualitative and quantitative behavior of settlement given the small number of stars, chosen to keep the computation time manageable). This represents settlement ship speeds of order 10 km s−1 (i.e., similar to our own interstellar probes and consistent with acceleration via gravitational slingshots from giant planets) and journey times of up to 0.3 Myr, but the dynamics are set by the ship range and so are unchanged with faster ships.
So - civilizations don't die out for a hundred million years (a civilization of velociraptors - got it), ships are launched no more often than every 100,000 years (the cave paintings at Lascaux plus 83,000 years), and ships are expected to travel for up to 300,000 years.
In this model, seed cultures are expected to last at least twice as long as placental mammals have so far.
This came to me via the Wall Street Journal. I think it's important to note how much precedence is given to cool videos, even when they're based on Spinlaunch garbage.