2M mph = 900 kps = three one-thousandths of light speed
That's may be in the range of speed that is most unfamiliar to us. We get speeds up to orbital velocities, in the 10 km/s range, as these are the "fast" objects we know (rockets, meteorites, ...), and then we get to significant fractions of light speed, mostly in the context of communication. But what goes at 900 km/s in our day to day life? Is it a number we see anywhere besides colliding galaxies?
https://en.wikipedia.org/wiki/Orders_of_magnitude_(speed)
440 km/s—"Typical speed of the stepped leader of lightning (cf. return stroke below).[31]"
445 km/s—"Max velocity of the remaining shell (mass about 0.1 mg) of an inertial confinement fusion capsule driven by the National Ignition Facility for the 'Bigfoot' capsule campaign.[32] Current fastest macroscopic human-made system."
1,000 km/s—"Typical speed of a Moreton wave across the surface of the Sun."
Good one, I didn't think about that one. It means that galaxies are travelling lightning fast, literally.
And then it gets weirder when you consider that galaxies don't actually collide at all because they're so sparse and all that really happens is they pass through each other and maybe they permanently merge or maybe some of the matter in one galaxy joins the other one and they just keep drifting apart in slightly different directions.
It goes from 3.2 x 10^-5 to 1200 fairly gradually and then suddenly to 10^9. My partner at the time looked at this and remarked "There are some unexplored orders of magnitude" which feels like a good, dramatic phrase.