Wasn't the big bang's explosion itself faster than speed of light? how does this not violate relativity, I had read an explanation earlier but it wasn't sufficient, can someone explain to me how the explosion itself is not faster than light


1 Answer 1


Firstly, the big bang wasn't an "explosion". It just means that "at the start of the universe", if you want it to phrase like that, the spatial distance between every object was zero. It doesn't mean that the universe was shrunk to a single point. See Did the Big Bang happen at a point? for more information.

But of course you are still right that space expanded faster than the speed of light. However, this is not a contradiction with (general) relativity. You can roughly think of it like that: Every object still moves with a velocity $<c$ relative to it's local frame of reference. It is only space(time) that moves faster than light, but GR allows this1. Some more information can be found here, especially this section.

1 You may have heard of the Alcubierre (warp) drive before which would theoretically work based on this.

  • $\begingroup$ so its just the space-time which expanded and not the matter itself $\endgroup$ Nov 22, 2021 at 17:41
  • 1
    $\begingroup$ Essentially, yes (if you mean "and not the matter itself moved"). $\endgroup$
    – User123
    Nov 22, 2021 at 18:03

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