Spacetime

It is generally assumed that fundamental constants such as c have the same value throughout spacetime, meaning that they do not depend on location and do not vary with time.

Einstein discovered that space and time are just two different aspects of spacetime.

He worked as a young person in the aerospace industry; subsequently he joined the spacetime corps.

Block time is the entirety of time, including the past, present and future, coexisting in a four-dimensional spacetime block called a "block universe." If one inhabits a block universe, one's view of time as only ever moving forward steadily is merely an illusion, a physical artefact that is mathematical.

Quantum correlation transcends spacetime.

Would faster-than-light travel be possible in the future? We know that in current science, it seems impossible. There are possible workarounds like folding spacetime itself. The Japanese-American physicist Michio Kaku advocates teleportation.

But perception isn’t reality. A key distinction lies in intent and origin. If these extraterrestrials present themselves as deities (like the Goa’uld in Stargate SG-1), they might exploit our awe for control. Alternatively, they could be benevolent, indifferent, or just curious—none of which inherently makes them gods. Philosophically, a god often implies worship-worthiness tied to ultimate power or moral perfection. An alien species might outclass us in tech—say, building Dyson Spheres or warping spacetime—but still be fallible, selfish, or mortal. Would we call a super-smart, super-strong human a god? Probably not, unless they transcend the natural order entirely.

A transcendent God, like Allah or the Christian Trinity, exists outside spacetime, crafting it from nothing (ex nihilo). Extraterrestrials, no matter how godlike, likely evolved within the universe’s 13.8-billion-year history. Even if they predate humanity by eons or live in higher dimensions (a sci-fi staple), they’re bound by physicality or some form of existence tied to the cosmos. Could they fake transcendence? Maybe—imagine them projecting a voice from the sky or rewriting physics locally. But true transcendence implies being uncaused, eternal, and limitless, beyond even the wildest alien capabilities.

In a spacetime, the Riemann curvature tensor has 256 components, but fortunately they don't all have to be directly calculated thanks to some symmetries.

An event is a point in spacetime, specified by the coordinates x, y, z, and t.