Saw this as an answer to another question and can’t wrap my head around the logic. What? How? Why??
In: 56
Okay… things do not happen instantly.
If I do something here, the “reality” of that change ripples out across space and time. Until that ripple, that “bubble” of change, moves past you, you have no idea what I’ve done.
If I turn on a flashlight and point it at you, until the reality bubble of that change ripples outwards and contacts you, you still think the light is off.
Hence, what we call the “speed of light” isn’t just the speed of light. It’s the speed of reality. The speed of you causing something to happen, and that change rippling out across the universe. The speed of “causality”.
Everything that happens, from an atomic level, to gravity, to light from the sun, etc. all happen at a given point. But the fact that they happened at that point cannot affect ANYTHING else in the universe until the reality-bubble of that change has caught up with those other things. If the sun were to disappear now, we’d not know for 8 minutes – that’s how long it would take for the “reality” of the sun disappearing to ripple across space until it reached the Earth. For those 8 minutes, it would still look like the sun was there, we’re still continuing being pulled in by the gravity of it, etc.
The fact is that in everyday life, the speed of light is SO FAST that we don’t see this effect ourselves. A beam of light can circle the earth 7 times in a second, so we never really see this effect ourselves.
But the reality of any change, force, influence, energy, effect, collision, anything whatsoever… it ripples outwards from that event at the speed of light, and until it reaches you it basically “hasn’t happened yet” from your point of view.
We notice this effect in astronomy, even in our satellites (they sent us beams of light or radio waves or whatever, but it takes a little while for them to reach the Earth, it is not instantaneous). When the distances are vast, this effect is noticeable.
If you are an observer sat in the middle of space, and someone somewhere does ANYTHING, the reality of their actions, and all the actions that causes, don’t reach you for a period of time. That reality is moving outwards from that event at the speed of reality / light / causality. Until it does reach you, it literally hasn’t happened yet as far as you’re concerned, or as far as anything is concerned.
And there’s no real way to cheat it. If someone created a black hole in a nearby part of space, we literally would be unable to detect it “faster” in any way whatsoever. If we put a probe right next to it, that probe could only send us a signal to tell us what it detected at – at best – the speed of light. So that signal of “Hey, watch out! Someone built a black hole!” would only reach us at the same time as, or after, the gravitational effect of the black hole itself.
The speed of light is poorly named. It’s the speed of reality catching up across the universe.
And in real terms, absolutely nothing happens “instantly”. Not even gravity, light, etc. The best they can do is the speed limit of the universe… the speed of light. The speed of reality.
Latest Answers