Cosmic Variance was a collaborative weblog discussing physics, astrophysics, and other topics, written by JoAnne Hewett, Mark Trodden, Sean Carroll, Risa Wechsler, Julianne Dalcanton, Clifford Johnson, John Conway, and Daniel Holz. It was the successor to Carroll's earlier blog Preposterous Universe, which began in early 2004 and ran through much of 2005. The blog's name came from the cosmology concept of cosmic variance.
Cosmic Variance rapidly become "undoubtedly the most popular blog written by physicists." [1] In 2006, Nature reported that it was the fourth most popular science blog [2] and one of only five blogs by scientists in the 3500 most popular blogs. As of July 26, 2007, Cosmic Variance had a Technorati authority of 1001 and rank of 2277. In 2008, the blog became part of the Discover magazine website.
Most writing on Cosmic Variance focused on modern physics, astrophysics, and cosmology, at a level accessible to the interested non-scientist. However, topics of discussion ranged widely, including science and religion, science journalism, higher education, and politics. Several discussions on Cosmic Variance gained attention in the print media, including a discussion on women in science that compared physicist Lisa Randall to Jodie Foster [3] and a post by John Conway about his discovery of a "bump" in particle accelerator data that turned out not to be caused by the Higgs boson. [4] When the engagement of Carroll to science writer Jennifer Ouellette was first announced on his blog, the story was picked up by both the New York Times [5] and the prominent scientific journal Nature. [6]
Cosmic Variance hosted a number of guest bloggers, including string theorist Joseph Polchinski reviewing Lee Smolin's book The Trouble With Physics. [7]
Physical cosmology is a branch of cosmology concerned with the study of cosmological models. A cosmological model, or simply cosmology, provides a description of the largest-scale structures and dynamics of the universe and allows study of fundamental questions about its origin, structure, evolution, and ultimate fate. Cosmology as a science originated with the Copernican principle, which implies that celestial bodies obey identical physical laws to those on Earth, and Newtonian mechanics, which first allowed those physical laws to be understood.
In cosmology, the cosmological constant, alternatively called Einstein's cosmological constant, is a coefficient that Albert Einstein initially added to his field equations of general relativity. He later removed it; however, much later it was revived to express the energy density of space, or vacuum energy, that arises in quantum mechanics. It is closely associated with the concept of dark energy.
Brian Randolph Greene is an American physicist known for his research on string theory. He is a professor of physics and mathematics at Columbia University and the chairman of the World Science Festival, which he co-founded in 2008. Greene has worked on mirror symmetry, relating two different Calabi–Yau manifolds. He also described the flop transition, a mild form of topology change, showing that topology in string theory can change at the conifold point.
Frank Jennings Tipler is an American mathematical physicist and cosmologist, holding a joint appointment in the Departments of Mathematics and Physics at Tulane University. Tipler has written books and papers on the Omega Point based on Pierre Teilhard de Chardin's religious ideas, which he claims is a mechanism for the resurrection of the dead. He is also known for his theories on the Tipler cylinder time machine. His work has attracted criticism, most notably from Quaker and systems theorist George Ellis who has argued that his theories are largely pseudoscience.
Cumrun Vafa is an Iranian-American theoretical physicist and the Hollis Professor of Mathematics and Natural Philosophy at Harvard University.
John David Barrow was an English cosmologist, theoretical physicist, and mathematician. He served as Gresham Professor of Geometry at Gresham College from 2008 to 2011. Barrow was also a writer of popular science and an amateur playwright.
Lisa Randall is an American theoretical physicist and Frank B. Baird, Jr. Professor of Science at Harvard University. Her research includes the fundamental forces of nature and dimensions of space. She studies the Standard Model, supersymmetry, possible solutions to the hierarchy problem concerning the relative weakness of gravity, cosmology of dimensions, baryogenesis, cosmological inflation, and dark matter. She contributed to the Randall–Sundrum model, first published in 1999 with Raman Sundrum.
Cosmology is a branch of physics and metaphysics dealing with the nature of the universe, the cosmos. The term cosmology was first used in English in 1656 in Thomas Blount's Glossographia, and in 1731 taken up in Latin by German philosopher Christian Wolff in Cosmologia Generalis. Religious or mythological cosmology is a body of beliefs based on mythological, religious, and esoteric literature and traditions of creation myths and eschatology. In the science of astronomy, cosmology is concerned with the study of the chronology of the universe.
Warped Passages: Unraveling the Mysteries of the Universe's Hidden Dimensions is the debut non-fiction book by Lisa Randall, published in 2005, about particle physics in general and additional dimensions of space in particular. The book has made it to top 50 at amazon.com, making it the world's first successful book on theoretical physics by a female author. She herself characterizes the book as being about physics and the multi-dimensional universe. The book describes, at a non-technical level, theoretical models Professor Randall developed with the physicist Raman Sundrum, in which various aspects of particle physics are explained in a higher-dimensional braneworld scenario. These models have since generated thousands of citations.
Sean Michael Carroll is an American theoretical physicist and philosopher who specializes in quantum mechanics, cosmology, and the philosophy of science. He is the Homewood Professor of Natural Philosophy at Johns Hopkins University. He was formerly a research professor at the Walter Burke Institute for Theoretical Physics at the California Institute of Technology (Caltech) department of physics,. He also is currently an external professor at the Santa Fe Institute, and he has been a contributor to the physics blog Cosmic Variance, and has published in scientific journals such as Nature as well as other publications, including The New York Times, Sky & Telescope and New Scientist. He is known for his atheism, his vocal critique of theism and defense of naturalism. He is considered a prolific public speaker and science populariser. In 2007, Carroll was named NSF Distinguished Lecturer by the National Science Foundation.
The Trouble with Physics: The Rise of String Theory, the Fall of a Science, and What Comes Next is a 2006 book by the theoretical physicist Lee Smolin about the problems with string theory. The book strongly criticizes string theory and its prominence in contemporary theoretical physics, on the grounds that string theory has yet to come up with a single prediction that can be verified using any technology that is likely to be feasible within our lifetimes. Smolin also focuses on the difficulties faced by research in quantum gravity, and by current efforts to come up with a theory explaining all four fundamental interactions. The book is broadly concerned with the role of controversy and diversity of approaches in scientific processes and ethics.
The Boltzmann brain thought experiment suggests that it might be more likely for a single brain to spontaneously form in space, complete with a memory of having existed in our universe, rather than for the entire universe to come about in the manner cosmologists think it actually did. Physicists use the Boltzmann brain thought experiment as a reductio ad absurdum argument for evaluating competing scientific theories.
Dennis Overbye is a science writer specializing in physics and cosmology and is the cosmic affairs correspondent for The New York Times.
Andrew E. Lange was an astrophysicist and Goldberger Professor of Physics at the California Institute of Technology in Pasadena, California. Lange came to Caltech in 1993 and was most recently the chair of the Division of Physics, Mathematics and Astronomy. Caltech's president Jean-Lou Chameau called him "a truly great physicist and astronomer who had made seminal discoveries in observational cosmology".
Bruce Winstein was an experimental physicist and cosmologist noted for his early work in elementary particle physics, particularly work toward demonstrating a serious asymmetry between particles and their anti-particles. Later in his career, he worked in experimental cosmology, measuring polarization in the microwave background radiation whose properties date back to the early universe.
Raphael Bousso is a theoretical physicist and cosmologist. He is a professor at the Berkeley Center for Theoretical Physics in the Department of Physics, UC Berkeley. He is known for the Bousso bound on the information content of the universe. With Joseph Polchinski, Bousso proposed the string theory landscape as a solution to the cosmological constant problem.
A Universe from Nothing: Why There Is Something Rather than Nothing is a non-fiction book by the physicist Lawrence M. Krauss, initially published on January 10, 2012, by Free Press. It discusses modern cosmogony and its implications for the debate about the existence of God. The main theme of the book is the claim that "we have discovered that all signs suggest a universe that could and plausibly did arise from a deeper nothing—involving the absence of space itself and—which may one day return to nothing via processes that may not only be comprehensible but also processes that do not require any external control or direction."
John Michael Kovac is an American physicist and astronomer. His cosmology research, conducted at the Center for Astrophysics | Harvard & Smithsonian in Cambridge, Massachusetts, focuses on observations of the Cosmic Microwave Background (CMB) to reveal signatures of the physics that drove the birth of the universe, the creation of its structure, and its present-day expansion. Currently, Kovac is Professor of Astronomy and Physics at Harvard University.
Chanda Prescod-Weinstein is an American theoretical cosmologist and particle physicist at the University of New Hampshire. She is also an advocate of increasing diversity in science.
Daniel Wayne Hooper is an American cosmologist and particle physicist specializing in the areas of dark matter, cosmic rays, and neutrino astrophysics. He is a senior scientist at Fermi National Accelerator Laboratory and a professor of astronomy and astrophysics at the University of Chicago.