We live in an expanding space-time continuum. Those are fancy words to say that space and time are not the separate concepts we perceive them to be; but rather are aspects of the same thing.

So, for instance, we are all traveling at the speed of light right now. However our velocity is through time, not space. This is a consequence of Einstein's special theory of relativity.

As we increase our velocity through space, our velocity through time decreases. If we could travel through space at the speed of light then our velocity through time would be zero.

One way to imagine this is an x-y graph with velocity through time on the vertical y axis, and velocity through space (one dimension of space) on the horizontal x axis. Considering only the first quadrant (upper-right) of this diagram, we draw the first quarter of a circle. The radius of that circle is the velocity c -- the speed of light.

The radius that points upwards along the time axis represents an object that is not moving through space, but is moving through time at c. The radius that points horizontally to the right along the space axis represents an object (a photon say) that is traveling at c through space and is not traveling through time at all.

Every object in our universe must exist at some point on that circle. And every such object forms an angle between that point, the origin, and the x axis.

Every object in our universe has a velocity through space that is the cosine of that angle, and a velocity through time that is the sin of that angle. Therefore every object is moving through space-time at c.

Source: x.com/unclebobmartin/status/1832417821424300379