You keep adding in dark matter, but this article has nothing to do with dark matter. I didn't discuss dark matter. The article is about the metric expansion

You keep adding in dark matter, but this article has nothing to do with dark matter. I didn't discuss dark matter. The article is about the metric expansion of space, or if you're really really really stubborn about that (you appear to be) the redshift-distance relation sans mechanism. That relation is an empirical fact and has been known for more than a century. Indeed, the discovery of that relation both predated the discovery of galaxy clusters and enabled the discovery that galaxies are collections of billions to hundreds of trillions of stars. > experiment You are being way too fussy about this. Sure, you can take an ultra-Popperian attitude towards cosmology, but that would make you an extremist rather than a scientist; science generally doesn't work that way. You'll be hard pressed to find any scientist who advocates ignoring observational evidence simply because local direct testing is infeasible with current technology. Heck, we still can only demonstrate the inverse square law for gravitation down to micrometer scales in laboratory settings, and there was no experimental value for the gravitational constant until the start of 19th century. Yet there Neptune is. At any rate, you do not really seem interested in learning about the theoretical underpinnings of dark energy in any way, and if you're as uninterested as you appear to be in advancing your own understanding of the standard cosmological model and the many observations and experimentally well-validated theories that it wholly captures (notably the Standard Model of Particle Physics and General Relativity), then it seems wasteful to continue this thread. I have no need or desire to "convert" you, and am uninterested in your personal beliefs or what you believe I believe or why I believe it. Honestly, I hope my withdrawing from the conversation will make you feel better.