About the book
Cosmology is currently in the throes of several important disagreements. We value and wish to disseminate the differing opinions of field leaders of four important topics.
The first is the value of the Hubble constant, the most important empirical value for cosmology, which has been contentious for about a century. Lately, claims have been made of exacting precision for several, different values centered around 70 km/s/Mpc. Some values are based on the cosmological ""distance ladder"", another on data from the cosmic microwave background, one from a bi-neutron star collision and another value based on the brand new technique of measuring red giants.
Second, the existence, or not, of dark matter (DM). There are several reports of DM discovery from astronomical studies of distant galaxies, while earthbound laboratories have been unable to detect DM. There is also the controversy over the possible nature of DM - very heavy particles or very light relativistic entities or perhaps DM is a variety of dark energy? It is important to list the ongoing laboratory searches, techniques and report expected time-frames.
Third, the existence or not of dark energy (DE). The existence of this unseen force seemed secure a few years ago but not so lately. Several groups report the results from an independent analysis of astronomical data not supporting this concept. On the theory side, Others report serious problems on the theory side, for the simplest \LambdaCDM model for a cosmos with DE. These reports have encouraged a proliferation of new, imaginative and speculative theories. Finally, the direct detection of DE in a lab failed. We will allow as many views as possible on this important topic.
Fourth, the inflationary universe or not. Because discriminating data are difficult to find, this topic is open to many interpretations and novel inflationary theories now abound.
The goal of this book is in presenting several sides of each of these four topics. The idea is to approach very many major proponents and opponents with the opportunity to expound their viewpoint either with new data, data compilations, re-analyses or reviews, and, especially their own opinions of why their ideas and values are correct and those of others should be discounted.