David Wiltshire: Cosmic Clocks, Cosmic Variance & Cosmic Averages

  • Thread starter Kea
  • Start date
  • Tags
In summary, the new paper by David L. Wiltshire contends that the current observational evidence does not support the controversial expansion of the universe theory known as the DE model. While the treatment of SNIa data appears to be dismissive, the paper has other interesting points that should be considered when assessing the validity of the DE model.
  • #1


People might be interested in a new paper, namely

Cosmic clocks, cosmic variance and cosmic averages
David L. Wiltshire
72 pages, 5 figures

which demolishes DE (yet again!).
Phys.org - latest science and technology news stories on Phys.org
  • #2
I like the paper, it is well written as usual [he has a way with words]. But the conclusions are not convincing. The treatment of SNIa data, for example, appears to be dismissive, IMO.
  • #3
comment from D. Wiltshire

DLW wishes to advise that the statement that the treatment of SNIa data, for example, appears to be dismissive would seem to have been made without reading all of the paper, which is understandable given it is 72 pages long. In view of the length of the paper, he has placed a summary of observational results and a faq at


In relation to the supernova data, see Figs 2 and 3, surrounding discussion and section 7.5. Apparent acceleration is now obtained, unlike in the rough approximations of earlier work. Moreover, the goodness of fit is now statistically indistinguishable from the Lambda CDM model. (Further details will be released in a paper with Leith and Ng, ref [16].) For those who wish to actually pay attention to data, the question of whether or not the "Hubble bubble" should be included (a difference between Riess04 and Riess06 gold data sets), is a serious issue for the Lambda CDM paradigm, as the supernovae data teams have pointed out (in a quiet way) in their recent eprints astro-ph/0612666, astro-ph/0701041. This feature has a natural explanation in the FB model, as discussed in section 7.5, and should ultimately be open to quantitative testing. The difference of the residuals between the Lambda CDM models and the FB model in Fig. 3 also indicate that supernovae data may prove to be a good way to distinguish the models once some thousands or tens of thousands of data points are collected, even though the present data cannot distinguish the two models.
  • #4
Point conceded. I did not fully appreciate the implications suggested in this passage during my initial reading. Will give the paper a more careful reading [I do tend to gloss at times].
Last edited:

1. What is the concept of "cosmic clocks" in David Wiltshire's work?

Cosmic clocks refer to the phenomenon of using cosmic objects such as pulsars, galaxies, and quasars to measure time on a cosmic scale. These objects have very stable and predictable behaviors that can be used to track the passage of time over billions of years.

2. How does cosmic variance affect our understanding of the universe?

Cosmic variance is the inherent randomness and uncertainty in the distribution of matter and energy in the universe. This can affect our observations and measurements of the universe, leading to variations in the data we collect. It is important to account for cosmic variance in order to accurately interpret and understand the true nature of the universe.

3. What are cosmic averages and how are they determined?

Cosmic averages are statistical quantities that represent the overall properties of the universe, such as the average density or expansion rate. These averages are determined by analyzing large-scale surveys and observations of the universe, taking into account cosmic variance and other factors that may affect the data.

4. How does David Wiltshire's research on cosmic clocks and cosmic averages contribute to our understanding of dark energy and dark matter?

Wiltshire's work on cosmic clocks and cosmic averages provides a new way of studying the distribution of matter and energy in the universe, which can help us better understand the role of dark energy and dark matter in the universe. By accurately measuring cosmic averages and accounting for cosmic variance, we can gain insights into the nature of these mysterious components of the universe.

5. What potential applications could come from studying cosmic clocks and cosmic averages?

The study of cosmic clocks and cosmic averages has the potential to improve our understanding of the fundamental laws of physics, the evolution of the universe, and the nature of dark energy and dark matter. This could also have practical applications in fields such as astronomy, cosmology, and space exploration, as well as providing a deeper understanding of our place in the universe.

Suggested for: David Wiltshire: Cosmic Clocks, Cosmic Variance & Cosmic Averages