I'm not claiming that physics has explained this, I'm claiming physics implies that it's astronomically unlikely if not impossible for us to be visited by alien spacecraft.
What part of physics specifically? The one where there are billions of planets in out galaxy alone? Or the one where FTL travel is possible with warp drives?
> The real question is therefore not whether a space-time solves Einstein’s equations, but whether the distribution of mass and energy required to make it a solution to the equations is physically reasonable.
> And for the Alcubierre drive the answer is multiple no’s. First, as I already said, it requires negative energy. Second, it requires a huge amount of that. Third, the energy is not conserved.
> [...] Bobrick and Martire explain that if you want superluminal motion, you need negative energy densities [in their new paper about slower than light, physically realizable warp drives]. If you want acceleration, you need to feed energy and momentum into the system. And the only reason the Alcubierre Drive moves faster than the speed of light is that one simply assumed it does. Suddenly it all makes sense!
Also, even if it were, the amounts of mass/energy required to achieve the motions that are being claimed would make these ships extraordinarily easy to detect (for some of the claimed accelerations, they would likely turn into black holes before actually accelerating that fast!).
Also note that the number of planets in the galaxy is irrelevant as long as we have no idea about the likelihood of abiogenesis (and we don't).
[0] http://backreaction.blogspot.com/2020/11/warp-drive-news-ser...
Not anymore. [1]
> Second, it requires a huge amount of that.
That's a matter of scientific and technological advancement. All engines gets improved over time, needing less energy. There are already some proposals that lower the energy required to that of an alkaline battery. [2]
> Third, the energy is not conserved
This escapes my knowledge.
[1] https://arxiv.org/pdf/2104.06488.pdf
[2] https://newatlas.com/physics/ftl-warp-drive-no-negative-ener...