Physics and Astronomy Glossary Technical terms of science have very specific meanings. Standard dictionaries are not always the best source of useful and correct definitions of them. This glossary is not intended to be complete. It focuses on those terms which give students particular difficulties. Some words have subtle and intricate meanings which cannot be encapsulated in a short definition. That's why textbooks exist. This document is continually under development and may never be finished. Glossary Accurate. Absolute uncertainty. Compare: relative uncertainty. Action. Avogadro's constant. One must specify whether the value of Avogadro's constant is expressed for a gram-mole or a kilogram-mole. Though it seems inconsistent, the SI base unit is the gram-mole. Is Avogadro's constant just a number? , e, 3, 100, etc. The reciprocal of Avogadro's constant is numerically equal to the unified atomic mass unit, u, that is, 1/12 the mass of the carbon 12 atom. 1 u = 1.66043 x 10-27 kg = 1/6.02252 x 1023 mole-1. Because. cgs.
Utopia or Dystopia « where past meets future Imagining the Tenth Dimension As bright as a hundred million Suns: The clusters of monster stars that lit up the early universe -- ScienceDaily The first stars in the Universe were born several hundred million years after the Big Bang, ending a period known as the cosmological 'dark ages' -- when atoms of hydrogen and helium had formed, but nothing shone in visible light. Now two Canadian researchers have calculated what these objects were like: they find that the first stars could have clustered together in phenomenally bright groups, with periods when they were as luminous as 100 million Suns. Alexander DeSouza and Shantanu Basu, both of the University of Western Ontario in Canada, publish their results in a paper in Monthly Notices of the Royal Astronomical Society. The two scientists modelled how the luminosity of the stars would have changed as they formed from the gravitational collapse of disks of gas. In a small cluster of even 10 to 20 protostars, the ongoing bursts would mean the cluster would spend large periods with enhanced brightness.
Why the Global Brain needs a Therapist « Utopia or Dystopia The idea that the world itself could be considered an overarching form of mind can trace its roots deep into the religious longings of pantheism- the idea that the universe itself is God, or the closest thing we will ever find to our conception of God. In large part, I find pantheists to be a noble group. Any club that might count as its members a philosophical giant like Spinoza, a paradigm shattering genius such as Einstein, or a songbird like Whitman I would be honored to belong to myself. But alas, I have my doubts about pantheism- at least in particular its contemporary manifestation in the form of our telecommunications and computer networks being granted the status of an embryonic “global brain”. I wish it were so, but all the evidence seems to point in the other direction. Key figures in this idea that our communications networks might constitute the neural passageways of a great collective brain predate the Internet by more than a generation. EAGLEMAN: Yeah. Like this:
Cosmology Books and Links Note: Except for the removal of dead links, this site has not really been updated since the author retired in 2009. Some Good Books The Once and Future Cosmos (Scientific American, 2002). A reprint of the Sept. 2002 issue of Scientific American . Adams, Fred & Greg Laughlin, The Five Ages of the Universe (Free Press, Simon & Schuster, 1999). Croswell, Ken, The Universe at Midnight: Observations Illuminating the Cosmos ( Free Press, 2001). Duncan, Todd & Craig Tyler, Your Cosmic Context (Pearson Addison Wesley, San Francisco, 2009). Ferris, Timothy, The Whole Shebang: A State-of-the-Universe(s) Report (Simon & Schuster, New York, 1997). Freeman, Ken & Geoff McNamara, In Search of Dark Matter (Springer/Praxis, 2006). Freedman, W.L., ed., Carnegie Observatories Astrophysics Series, Vol. 2: Measuring and Modeling the Universe (Cambridge Univ. Goldsmith, Donald, Einstein‘s Greatest Blunder? Greene, Brian, The Fabric of the Cosmos: Space, Time, and the Texture of Reality (Knopf, NY, 2004).
The Beginning of the Universe and the Limit of Knowledge “Despite its name, the big bang theory is not really a theory of a bang at all. It is really only a theory of the aftermath of a bang.” -Alan Guth So you finally understand it. Image credit: original source unknown. The farther back we go, the closer together everything was, the higher in temperature (and shorter in wavelength) all the radiation was, and — of course — the younger the Universe was. Image credit: Ned Wright (possibly Will Kinney, too), via At some point, it was hot enough that neutral atoms couldn’t even form; as soon as an electron would find an atomic nucleus, a high-enough-energy photon would come along and ionize the atom’s constituents. Image credit: Lawrence Berkeley National Laboratory. But not indefinitely; we can only go back a finite amount of time in the past, and that’s because what we consider “our Universe” didn’t begin from a singularity 13.8 billion years ago, but began when the previous stage — cosmic inflation — came to an end.
Gore Vidal Early life Vidal's father served as director of the Commerce Department's Bureau of Air Commerce (1933–1937) in the Roosevelt administration, was one of the first Army Air Corps pilots and, according to biographer Susan Butler, was the great love of Amelia Earhart's life. In the 1920s and 1930s, he was a co-founder of three American airlines: the Ludington Line, which merged with others and became Eastern Airlines, Transcontinental Air Transport (TAT), which became TWA), and Northeast Airlines, which he founded with Earhart, as well as the Boston and Maine Railroad. The elder Vidal had also been a West Point football quarterback, coach, and captain and an all-American basketball player. He also participated in the 1920 and 1924 Summer Olympics (seventh in the decathlon; U.S. pentathlon team coach). Writing career Fiction Screenplays Essays and memoirs