Thanks to Twitter for bringing the Buchalter Cosmology Prize to my attention. Of course as an amateur I’m not qualified to enter, but no matter. What grabbed my attention was the way the challenge was written. It refers to the “fundamental gaps in our understanding of cosmology”. Unusually it also criticises the Standard Big Bang model and is damning about some of the theories - “there is a one-to-one trading of ignorance”. I reproduce some of it below. The Buchalter Cosmology Prize was conceived on the premise that there are still fundamental gaps in our understanding of cosmology and that currently-accepted paradigms such as inflation and dark energy are incomplete, and possibly even incorrect descriptions of our Universe. The Standard Big Bang model has done a remarkable job in explaining many fundamental observations, such as the microwave background (CMB) radiation, the Hubble expansion, primordial element abundances, and more. However many other, seemingly fundamental, observations are not immediately explained by the model. A few examples include dark matter (introduced to explain large-scale dynamics), inflation (introduced to explain the so-called Horizon Problem), and dark energy (re-introduced to explain the apparent cosmic acceleration). These examples share a common issue: they explain a phenomenon that is not understood in the context of an existing theory, by introducing a new idea or mechanism which itself is not understood and which has no physical motivation to exist, other than to explain the original phenomenon. In effect, there is a one-to-one trading of ignorance, so to speak. If the aim of science is to reduce the number of unknowns, to explain a multitude of phenomena from a parsimony of ideas, to create understanding from first principles, then these ideas would seem to fall short on those measures. If we expect the progress of science to follow Occam’s Razor, then we should be skeptical of any theory engineered to explain an unknown by introducing an effectively equal number of new unknowns, and we should continue to drive towards a true understanding from first principles. I couldn't agree more. Forbes's Razor - "The universe is a real place where only real things happen". This is my attempt to explain Dark Energy without the need for new particles, no new forces, no new dimensions and certainly no creative mathematics. I make only 1 assumption. An assumption which is supported by the history of centuries of astronomy. So what is Dark Energy? It's gravity - just ordinary gravity. The force that controls the structure of the cosmos. The only force which interacts with both dark matter and baryonic. There is only one assumption? It's one which is supported by hundreds if not thousands of years of astronomy. The universe has always been much bigger than we thought. Dark Energy is just gravity. The gravitational pull from beyond the observable universe. Our universe is only a small part of the greater cosmos. This obvious and simple explanation of Dark Energy is difficult to grasp because we've always been told that we cannot consider what is beyond the observable universe. "but this idea cannot be tested - there are no observables!" Only because we haven't looked. Of course we can detect it, but we won't find it unless we look. The theory of Cosmic Gravity explains and simplifies so much. We have to look for it. A Cosmos exerting gravitational pull on our galaxies explains and simplifies so much, not just Dark Energy. It also explains :- Why is our universe expanding? Space is not expanding. Gravity is pulling our galaxies away from us. Why did the expansion accelerate a few billion years ago? When the gravitational pull of the cosmos exceeded the internal gravity of our universe. Why no Dark Energy within our galaxy? Same answer. Why is the Hubble constant higher when you look out into space? It would under the force of cosmic gravity. Cosmological redshift? No such thing. It’s gravitational redshift. Those distant galaxies are not as far away as we think. Dark Flow? It is so simple. No mathematical engineering. No 'energy of the vacuum' pushing galaxies out of our universe. No need to worry why Dark Energy does not dilute as the universe expands. It's just gravity pulling. Once you get your head round cosmic gravity, vacuum energy sounds........ well, a bit silly. Evidence? Tests? Observables? It won’t be easy, but with so much going for this theory it has to be done. Time to go looking. 1, More and better data on the Hubble value at the extremes of the universe. 2, There will be evidence from gravitational waves. If there is baryonic matter in other parts of the cosmos, then there will be electromagnetic radiation. My bet is there is nothing near us so gravitational waves is the best bet.
3, Catherine Heymans, The Dark Universe, “Interestingly, assuming a flat ΛCDM cosmology, they find fewer clusters today than they would expect given the cosmological parameters favoured by the CMB power spectrum. This could suggest that dark energy is evolving, slowing down the growth of these structures, or, perhaps more mundanely, that the cluster selection or mass calibration is still missing an important ingredient in the analysis.”
Just like Dark Matter, we can't see the source of Dark Energy but we can see the effect of its gravitational pull. Who would not want to be the first person to detect an event from beyond the observable universe? We'll not find it if we don't look for it. It's not so long ago that some highly respected scientists did not believe that black holes existed - no observables! With such a simple idea explaining so much, there is much to be gained by looking. Oh for a cosmological Magellan. So that's Dark Energy sorted. It's just gravity. The weak force which controls the structure of the universe. Dark Matter won't be so easy but I'm working on it. Lindsay Fraser Forbes.