miércoles, 19 de noviembre de 2008

Particiones en Linux (lo que hay que entender)

Página: http://www.pathname.com/fhs/2.2/index.html#TOC

Lo que contiene la página:


* 1 Introduction
o 1.1 Purpose
o 1.2 Conventions
* 2 The Filesystem
* 3 The Root Filesystem
o 3.1 Purpose
o 3.2 Requirements
o 3.3 Specific Options
o 3.4 /bin : Essential user command binaries (for use by all users)
o 3.5 /boot : Static files of the boot loader
o 3.6 /dev : Device files
o 3.7 /etc : Host-specific system configuration
o 3.8 /home : User home directories (optional)
o 3.9 /lib : Essential shared libraries and kernel modules
o 3.10 /lib
: Alternate format essential shared libraries (optional)
o 3.11 /mnt : Mount point for a temporarily mounted filesystem
o 3.12 /opt : Add-on application software packages
o 3.13 /root : Home directory for the root user (optional)
o 3.14 /sbin : System binaries
o 3.15 /tmp : Temporary files
* 4 The /usr Hierarchy
o 4.1 Purpose
o 4.2 Requirements
o 4.3 Specific Options
o 4.4 /usr/X11R6 : X Window System, Version 11 Release 6 (optional)
o 4.5 /usr/bin : Most user commands
o 4.6 /usr/include : Directory for standard include files.
o 4.7 /usr/lib : Libraries for programming and packages
o 4.8 /usr/lib
: Alternate format libraries (optional)
o 4.9 /usr/local : Local hierarchy
o 4.10 /usr/sbin : Non-essential standard system binaries
o 4.11 /usr/share : Architecture-independent data
o 4.12 /usr/src : Source code (optional)
* 5 The /var Hierarchy
o 5.1 Purpose
o 5.2 Requirements
o 5.3 Specific Options
o 5.4 /var/account : Process accounting logs (optional)
o 5.5 /var/cache : Application cache data
o 5.6 /var/crash : System crash dumps (optional)
o 5.7 /var/games : Variable game data (optional)
o 5.8 /var/lib : Variable state information
o 5.9 /var/lock : Lock files
o 5.10 /var/log : Log files and directories
o 5.11 /var/mail : User mailbox files (optional)
o 5.12 /var/opt : Variable data for /opt
o 5.13 /var/run : Run-time variable data
o 5.14 /var/spool : Application spool data
o 5.15 /var/tmp : Temporary files preserved between system reboots
o 5.16 /var/yp : Network Information Service (NIS) database files (optional)
* 6 Operating System Specific Annex
o 6.1 Linux
* 7 Appendix
o 7.1 The FHS mailing list
o 7.2 Background of the FHS
o 7.3 General Guidelines
o 7.4 Scope
o 7.5 Acknowledgments
o 7.6 Contributors

viernes, 7 de noviembre de 2008

Teoría cuántica de campos presenta a Colleman

http://www.physics.harvard.edu/about/video.html

Estas son las clases de Colleman grabadas en video en los 70's. en Harvard

Quantum Field Theory on the Web

Web Tutorials on Relativity

These are some good places to begin your study of relativity. (Some readers may prefer the Popular Science sites listed at the bottom of this page.)

Visualizing Relativity

There are a large number of sites which offer computer simulations of what you would experience during relativistic space travel, falling into a black hole, etc. I think these are some of the best.
  • Relativistic Starflight, by Steve VanDevender is a C program which in effect draws a movie on your computer screen, showing the view out the front window of a relativistic starship. I was able to download, compile, and run this program without trouble. Try running it with the command

  • xrel -accel 100 -bounce -viewangle 150 -limit 0.75 -max

    This will display constant acceleration at 10g with a wide angle view, at one real time second = one day of spaceship time; at v = 0.75, deceleration at 10g is initiated, and so forth. You should be able to see very clearly how boosting effects a hyperbolic linear fractional transformation on the celestial sphere. Such an LFT has two fixed points (opposite points on the celestial sphere) and as you boost with positive acceleration toward the North star, stars flow from South Pole along longitude lines toward the North star. Since LFT's are conformal transformations, even though the night sky becomes rather "distorted" overall, small shapes (e.g. constellations) are preserved.

    If the starship were rotating along the axis of motion as well, you would see stars spiraling toward one fixed point and away from the other.

  • Relativistic Flight Simulator, by Wade Lutgen, a recent graduate of the University of Wisconsin. This is a delightful C program which "puts you in the pilot seat of a near light speed capable space vehicle" moving through a nicely simulated starfield. "This basically means that you have an infinite amount of fuel to accelerate your craft up to (but not including, of course) the speed of light. The relativistic effects of Doppler shift, stellar abberation, and mass increase have been taken into account. The rest of the physics should also be correct." There are versions for DOS and X windows. I was able to download, compile and run the second version in our X windows environment without any trouble.
  • Going Potty!, (i.e., "crazy", a pun on the teapot used in the illustrations) by Ronan Bonan (Computer Science, Trinity College, Dublin). Illustrates the Penrose-Terrel "rotation", an optical effect predicted in objects moving at relativistic speeds.
  • Gravitational Lensing, by Pete Newbury (Mathematica, University of British Columbia). Features mpeg movies illustrating lensing, Einstein rings, etc., and some good background information. Don't miss your opportunity to run your own computer simulation of a gravitational lens! I recommend that you star with the far star somewhat above the close star, and trying running the program several times, lowering the distant star a bit each time. Note the marked displacement of the image of the distant star away from its actual position (relative to the closer star). As the distant star gets closer to the near star, notice that its image gets smeared out in a crescent. As you line up the two stars more and more accurately, you should see a new "secondary image", also crescent shaped, forming on the other side of the near star, and perhaps even an "Einstein cross". Once the stars are almost perfectly lined up, you see a beautiful ring shaped image of the far star. Last but not least, compare with the HST photographs (see links below) of real gravitional lenses. Highly recommended!
  • Falling Into a Black Hole, by Andrew Hamilton (Astrophysical and Planetary Sciences, University of Colorado). If you've ever wondered what you'd see near a black hole, this is the site for you! A very well done "tour" illustrating would you would see approaching, orbiting and then falling into a black hole, featuring attractive animated gifs illustrating such effects as the "Schwarzschild bubble". (Don't miss the comparison of Schwarzschild, Eddington, and Kruskal coordinates). Highly recommended!
  • Black Holes with Java, by Peter Musgrave (Physics, Queensland University). Start with the related Central Force with Java page and then try the black hole orbit applet, which allows the user to explore the effect of changing various orbital parameters.
  • Solving Einstein's Equation in Three Dimensions, by Patricia Schwarz (Physics, Caltech), is a Mathematica notebook exploring Einstein's equation, curvature computations, null geodesics, etc.
  • Orbits in Strongly Curved Spacetime, a Java applet by John Walker (Fermilab), shows the effective potential and embedding profile as well as the trajectory of a test particle orbiting a nonrotating hole. (I have one quibble: for some reason Walker wrote the applet so that the ball hugs the "effective potential" curve (first introduced by Misner) whereas of course energy is conserved and the ball should move back and forth on a horizontal line--- see for instance the textbook by Misner, Thorne, & Wheeler or the applet by Musgrave.)
  • Geometry Around Black Holes, by Michael Cramer Andersen (Astronomy, University of Copenhagen). Features some good (advanced undergraduate level) background and some VRML images and mpeg/Quicktime movies. An excellent discussion of frame dragging and light paths near a rotating (Kerr) black hole.
  • Relativistic Simulations from the Physics Department at the University of Tuebingen. Features a half dozen magnificent mpeg movies of pulsars, orbiting a neutron star, orbiting a black hole, a relativistic flight to Polaris (compare with Lutgens program) , embeddings of "space" near a black hole, etc.
  • Numerical Relativity Exhibitions, from the NCSA Relativity Group. Features stills from production quality movies of black holes, gravitational waves, colliding black holes, etc. For mpeg versions of some black hole simulations, see this page. What more need be said! Go and look, you won't be disappointed!
  • Particle Trajectories Near Black Holes, by Peter Diener. Features a form enabling you to compute effective potentials and three dimensional trajectories for the motion of test particles near a rotating black hole. (Unfortunately, you can only see the trajectories if you have VRML or Inventor software.) Includes good background material at the undergraduate level.
  • Black Hole Simulations by Sam Hart (Physics, University of Arizona). Features fabulous gif images of fluid flow in an accretion disk, etc.
  • Magnetic Field Lines in a Black Hole Plasma Disc, by Boris Gudikson and Bjorn Ostman (Physics, University of Copenhagen). Features a brief introduction to black hole electrodynamics and accretion disks, with very nice pictures.
  • Relativistic Ray-Tracing Simulating the appearance of rapidly moving objects. This work arose as a result of a discussion with Dr Sandy Dance , in which the question arose: "If we happened to be flying past an object at nearly the speed of light, what would that object look like"?
  • Falling Into a Black Hole
  • Simulation of a Black Hole by Raytracing

Lecture Notes and Articles

  • Relativity and Cosmology, undergraduate course notes by Jose Wudka (Physics, UC Riverside). Topics covered include both special relativity (e.g., spacetime, Lorentz invariance, various "paradoxes") and general relativity (e.g., equivalence principle, black holes, gravitational waves, experimental tests of gtr). Apparently a survey course for non-majors, with little math but some very nice graphics.
  • Colliding Black Holes, five lectures by Jorge Pullin (Physics, Penn State). Topics covered include curvature, the Einstein equation, black holes, and gravitational waves.
  • Tensors and Relativity, by Peter Dunsby (Mathematics, University of Cape Town). This is a fabulous site featuring a complete course available for free over the web as html documents. (Registered students can also download postscript and dvi versions.) At the level of Schutz, A First Course in General Relavitity, i.e. more challenging than the previous site. Topics covered include vectors and tensors in flat spacetime, the conceptual basis of general relativity, curved spacetime, the field equation, and the Schwarzschild solution. Highly recommended!
  • A First Look at Relativity and Gravitation, by Clifford Johnson (Physics, University of Kentucky). At the level of D'Inverno, Introducing Einstein's Relativity. About half of two dozen lecture notes are currently available, in both html and postscript, including exercises! Topics include tidal forces, geodesic deviation, the matter tensor (aka stress-energy tensor) for dust, fluid, and EM fields, as well as Schwarzschild's solution, weak field theory, and methods for solving Einstein's equation. When complete, this will basically be a full course of lecture notes on gtr, including cosmology. At a level similar to or a bit above the preceding site.
  • Black Holes: The inside story, by Serge Droz (Physics, University of Guelph), Werner Israel (Physics, University of Alberta), and Sharon M Morsink (Physics, University of Wisconsin-Milwaukee). Originally appeared in Physics World. A beautifully illustrated html article focusing on the interior geometry of black holes.
  • Simulating Relativistic Orbits About a Black Hole, by Steven Bell (Lockheed Martin). Discusses a computer program which computes the paths of test particles in orbit about a rotating (Kerr-Newman) black hole. First published in Computers in Physics and recently updated by the author.
  • Differential Forms in Electromagnetic Theory, by Richard H. Selfridge, David V. Arnold and Karl F. Warnick (Electrical and Computer Engineering, Brigham Young). A very well done site, with extensive teaching materials available as dvi documents. A good introduction to an essential tool in relativity.

Graduate Level Lecture Notes and Articles

To really appreciate the beauty and subtleties of general relativity, you must grapple with the mathematics, which lies, unfortunately, just beyond the undergraduate level. Here are some fine graduate level courses, and also some expository articles on topics of particular interest.
  • A Short Course on GR, by William L. Burke, (Physics, UC Santa Cruz). Topics include weak field theory, gravitational waves, radiation damping, cosmology, the Friedmann and Lemaitre dusts, singularities, black holes, the Schwarzschild metric and Kruskal's extension of it. There is an appendix on mathematical notation. This is a single postscript document (about 75 pages).
  • General Relativity, by Petr Hadrava, (Astronomical Institute, Academy of Sciences of the Czech Republic). Lecture notes (in English) on str and gtr. Topics include the Equivalence Principle, the field equations, weak-field theory, the Schwarzschild exterior (vacuum) and interior (stellar "fluid") solutions, the Friedmann cosmological solutions. Two mathematical appendices sketch the mathematics of tensor algebra, exterior algebra, connection, Lie derivatives, Killing vectors, and variational principles. This is a single postscript document (50 pages).
  • Lecture Notes on General Relativity, by Sean M. Carroll (Institute for Theoretical Physics, University of California Santa Barbara). From a course taught at MIT. Topics covered include str, manifolds, covariant derivatives, connections, curvature, Lie derivatives, pullbacks, Killing vectors, the Equivalence Principle, the matter tensor, the field equation of gtr (Einstein's equation), the initial value and variational principle formulations of the field equation, weak field theory, gravitational waves, a complete discussion of the Schwarzschild solution, cosmology and the Friedmann solutions. Carroll's careful discussion of the geometry of the Kerr solution is particularly noteworthy. The lectures are available as either html or postscript documents (about 200 pages total).
  • Black Holes, by Paul Townsend (Applied Mechanics and Theoretical Physics, Cambridge). A very thorough introduction, studies the Schwarzschild, Reissner-Nordstrom, and Kerr solutions using a variety of coordinate systems. Additional topics include gravitational collapse, horizons, singularities, Carter-Penrose diagrams (aka conformal compactification), Hawking radiation and black hole thermodynamics. This is a 145 page postscript document.
  • A Description of the Initial Value Formulation of Vacuum General Relativity for the Non-Specialist, by Mark Miller (Syracuse University). Available either as html pages or as a 15 page postscript document.
  • Differential Geometry, by Sergei Yakovenko (Weizmann Institute). A complete set of lecture notes. Topics include manifolds, diffeomorphisms, partitions of unity, the Whitney embedding theorem, tangent bundle, algebra of vector fields, Lie derivatives, commutators, points as maximal ideals, derivations, local rings, differentiable forms, etc.
  • Riemannian Geometry and General Relativity, the problem sets (with solutions) from a course taught by Michael Shubin (Mathematics, Northeastern).

Research Frontiers

  • Living Reviews in Relativity is a fabulous resource for students. "Living Reviews in Relativity is a solely WWW-based, peer reviewed journal for physics. The journal publishes invited reviews of research in all areas of relativity. The journal is offered as a free service to the scientific community. Articles are invited pieces from specialists in their fields and are directed toward physicists at the graduate student level and beyond. Articles appearing in Living Reviews provide peer-refereed, carefully edited, current and insightful overviews of what is happening in the fields they cover." Presently, this site features very high quality review articles on Loop Quantum Gravity, Local and Global Existence Theorems, Stationary Black Holes, Rotating Stars, and more. The list of forthcoming articles is even more mouth watering!
  • The Los Alamos Preprint Server is the place to look for the very latest current research in all areas of physics, including general relativity and quantum gravity. Note that this site features a search tool.

Symbolic Tensor Manipulation Software

Anyone who studies some of the courses in the previous section will probably appreciate the desirability of software capable of computing connections and curvatures.
  • GRTensorII, a freeware symbolic tensor manipulation package available for both Maple V and Mathematica, developed by the Physics Department, Queen's University at Kingston, Ontario, and the Faculty of Mathematical Studies at the University of Southampton. Note in particular the demonstration page devoted to general relativity!

  • Which version should you use? For what it is worth, I have found that the Mathematica version is much better at trig manipulations, but is thoroughly outclassed by the Maple version whenever constraint equations appear. The Maple version also has somewhat better documentation. I use both versions.

  • Ricci, a freeware Mathematica package for doing symbolic tensor computations that arise in differential geometry. Developed by Jack Lee (Mathematics, University of Washington). Complete with a 90 page manual.
  • Information on a number of commericial tensor manipulation packages is available at CAIN (Computer Algebra Information Network), a consortium of eight European organizations.

Experimental and Observational Evidence

The evidence in favor of gtr is overwhelming; nonetheless some important predictions still await confirmation (in particular, gravitational waves have yet to be directly detected, although there is already very strong indirect evidence for their existence).
  • Seeing is Believing! In recent years the Hubble Space Telescope (HST) has made spectacular observations of many phenomena predicted by gtr, including:
    • The actual accretion disks of supermassive black holes at the center of the galaxies NGC 6251 (300 million ly distant, in the constellation Ursa minor) and NGC 4261 (in the constellation Virgo) have been photographed by the HST. The first of these is, remarkably, warped like the brim of a Stetson hat: it is about 1000 ly wide, and a 3 million ly long double jet of hot gas is being flung out orthogonally to the disk. Supermassive black holes turn out to be very common; HST has found evidence of one at the center of most galaxies so far examined. In particular, one has just been found at the center of the galaxy M84 and twin jets have been tracked in real time near a suspected supermassive black hole at the center of the galaxy NGC 4151. See also Observational Evidence for Black Holes (by the Cambridge Relativity Group).
    • A dozen or so gravitational lenses have been photographed by the HST. You can see several crescent shaped images of distant galaxies lying behind a cluster of much closer galaxies called Abell 2218; this crescent shape is the unmistakable sign of a gravitational lens. As it happens, the most distant galaxy known is also seen by HST through a gravitational lens. HST has also photographed a spectacular example of an Einstein cross, consisting of four images of a single distant galaxy lying behind the closer galaxy 2237+0305
    • The fate of the universe is eternal expansion, according to recent observations of distant supernovae by the HST. Two teams of astronomers have independently concluded that their observations of distant supernovas show that our universe is modeled locally be a Friedmann model with spacelike slices having constant negative curvature. Stories in the popular press entirely overlooked the possibility (widely appreciated by specialists) that these spacelike slices need not be a hyperbolic plane but might be a quotient space with finite volume. Confusingly, press reports of this remarkable convergence of results were followed within days by apparently contradictory reports that in fact the very same observations show that the Hubble expansion is actually increasing with time, rather than decreasing as all the Friedmann models predict. Such behavior is consistent with cosmological solutions to the field equation with the so-called "cosmological constant" included, which led to a spate of news stories announcing the discovery of "antigravity". See Ned Wright's Cosmology Tutorial for more information.
    • Early protogalaxies, some 11 billion ly distant (and ll billion years old) much smaller than the modern kind, have been photographed by the HST. In fact, the HST has shown a whole sequence whereby closer galaxies look more and more like the modern variety.
    • An isolated neutron star (400 million ly distant, in the southern Constellation Coronae) has been photographed by the HST. We know what it is because it is so small (16 miles in diameter), so hot (one million degrees) and so dim that it cannot be any other kind of star.
    • A bit off topic, but while you're at it, don't miss these gorgeous pictures of exploding stars.
  • You can read about various astronomical observations of black holes in my compilation of miscellaneous press releases. See also a recent study of gas plunging violently onto the surface of a neutron star.
  • Recently, a team of astronomers led by Dr. Ignazio Ciufolini (coauthor with Wheeler of the recent book, Graviation and Inertia) were able to confirm the prediction of frame dragging by a careful examination of two low earth orbiting satellites.
  • General Relativity in the Global Positioning System, by Neil Ashby (Physics, University of Colorado) describes how the 24 GPS satellites were designed to take account of the gravitational red shift predicted by gtr; this system simply wouldn't work if gtr were not extremely accurate, since the red shift turns out to be quite significant.
  • The cosmic background radiation has been mapped in great detail by the COBE (Cosmic Background Explorer) satellite.
  • Experiments in General Relativity, (STEP, Stanford University) Describes current attempts to directly confirm frame dragging and other effects using an earth orbiting satellite--- this will be one of the most sensitive physical experiments ever performed! Features considerable background information.
  • Tests of General Relativity at Jodrell Bank radio observatory use astronomical observations of binary pulsars.
  • LIGO Home Page. "The Laser Interferometer Gravitational-Wave Observatory (LIGO) project is a pioneering effort to design and construct a novel scientific facility - a gravitational-wave observatory - that will open a new observational window on the universe." Links to other gravitational wave sites, explanatory pages,etc.

Popular Science Sites

These are good places to go to if you just want to get some idea of what relativity is all about.

For More Information

  • RELATIVITY bookmarks from Syracuse University. A comprehensive list of links to sites on the history of str and gtr, popular science type relativity sites, visualization sites, lecture notes, research journals, academic departments, relevant software sites, etc. Scroll down, the best stuff is at the bottom!
PIRATEADO VULGARMENTE POR MÍ DE LA PÁGINA

http://webplaza.pt.lu/public/fklaess/html/relativity_on_www.html

Mi crédito es haberla encontrado y con eso me basta.

Recursos en la web

Tensor de energía-momento:
Relatividad General y Geometría Diferencial: De la página anterior pero el sitio principal

miércoles, 5 de noviembre de 2008

Fechas y nombres de personajes de la ciencia

Aristóteles Estagira 384 – 322
Arquímedes Siracusa- Sicilia 287-212
Bequerel, Henri París 1852 – 1908
Boyle, Robert Lismore Castle, Irlanda 1627 – 1691
Celsius, Anders Uppsala, Suecia 1701 – 1744
Chadwick, James Chesire, Inglaterra 1891 – 1974
Copérnico Torún, Prusia, Polonia 1473 – 1543
Curie, Marie Varsovia, Polonia 1867 – 1934
Curie, Pierre Paris 1859 – 1906
Descartes La Haye, Francia 1596 – 1650
Faraday Newington, Inglaterra 1791 – 1867
Farenheit, Daniel Gabriel Gdańsk, Alemania 1686 – 1736
Fermi, Enrico Roma 1901 – 1954
Galieo Pisa 1564 – 1642
Heráclito Efeso 544/(540) – 484/(475)
Hooke, Robert Freshwater, Inglaterra 1635 – 1703
Joliot-Curie Marie París 1897 – 1956
Joliot-Curie, Jean París 1900 – 1958
Kelvin (lord)( Thompson, William) Belfast, Irlanda 1824 – 1907
Kepler, Johannes Weil der Stadt, Alemani 1571-1630
Maxwell Edimburgo, Escocia 1831 – 1879
Mendeleiev Tobolsk, Rusia 1834 – 1907
Meyer Julius Varel, Oldenbug, Alemania 1830 -1895
Newton Woolsthorpe, Inglaterra 1642 – 1727 1643 – 1727
Parménides Elea 510/(540) – 450/(470)
Pauli, Wolfgang Viena, Austria 1900 – 1958
Rutherford, Ernest Brightwater, Nueva Zelanda 1871 – 1937
Tales Mileto 639/624 – 547/546
Thompson, J. J, Cheetham Hill, Manchester 1856 – 1940
Watt, James Greenok, Escocia 1736 – 1819

Galileo Cronología

1560 | 1570 | 1580 | 1590 | 1600 | 1610 | 1620 | 1630 | 1640
1562 July 5 Vincenzo Galilei of Florence marries Giulia degli Ammannati of Pescia. They live in Pisa.
1564 February 15 Galileo, their first child, is born.
February 19 Galileo is baptized in the baptistry of the cathedral of Pisa.
1573 May 8 Virginia Galilei is born.
1574 Vincenzo Galilei and his family move to Florence.
1575 December 18 Michelangelo Galilei is born.
1578 October 7 Livia Galilei is born.
1579 Galileo is at the monastery of Santa Maria di Vallombrosa, where he considers joining the order.
July Galileo returns to his family in Florence.
1581 September 5 Galileo matriculates as a students of the "Arts" at the University of Pisa. His father's wish is that he study medicine.
1583 According to Vincenzo Viviani, Galileo's first biographer, during his student days at Pisa Galileo formulated the isochronism of the pendulum while watching the oscillations of a lamp in the cathedral of Pisa.
Galileo first studies Euclid's Elements--not at the university, but in Florence under the court mathematician Ostilio Ricci.
1585 He completes the fourth year of his studies and returns to Florence without a degree.
1586 Galileo begins to work on certain problems in physics, following Archimedes rather than Aristotle. He invents a hydrostatic balance(bilancetta).
1585-89 Gives private lessons in mathematics in Florence and Siena.
1587 First voyage to Rome; meets Christoph Clavius.
Applies for a lectureship of mathematics at the University of Siena.
Finds certain propositions about centers of gravity which go beyond the work of Archimedes.
1588 (?) Vincenzo Galilei performs experiments on the relationship between the tension and pitch of strings. His son, Galileo, may have helped him with these and surely was aware of them.
Galileo gives two public lectures at the Accademia Fiorentina (Florentine Academy) about the shape, location, and dimensions of hell as described in Dante's Inferno.
Tries to obtain teaching positions at the universities of Pisa, Siena, Padua, and Bologna, and a lectureship in Florence. He obtains a lectureship of mathematics at the university of Pisa.
1560 | 1570 | 1580 | 1590 | 1600 | 1610 | 1620 | 1630 | 1640
1589-92 Teaches mathematical subjects at the University of Pisa (salary 160 scudi per year). Some tracts--lecture notes--written during this period have survived. In On Motion Galileo uses the Archimedian approach to motion: the speed of falling bodies is proportional to their density, not their weight as Aristotle had maintained.
According to Vincenzo Viviani Galileo demonstrated his conclusions by dropping weights from the leaning tower of Pisa. This report has been doubted by historians.
1591 Vincenzo Galilei dies, leaving Galileo, his oldest son, as the head of the family. He was responsible to meet the terms of a large endowment bestowed by his father on Virginia, his sister, who had just been married to Luca Landucci.
1592 Galileo obtains the chair of mathematics at the university of Padua in the Venetian Republic (salary 160 ducats per year), where he remains until 1610. His initial contract is for four years, renewable for two further years. His inaugural lecture is on 7 December, and his first regular lecture on 13 December. His duties are to lecture on geometry and astronomy. He gives private lessons on Euclid, arithmetic, fortification, surveying, cosmography, optics, and the use of the sector.
1593 Puts together treatises on fortifications and mechanics for his private students.
Invents a machine for raising water, a pump driven by horses. In 1594 he receives a patent on this design from the Venetian Senate.
1595 Develops his explanation of the tides which invokes the annual and diurnal motion of the Earth. It appears that his preference for the Copernican theory dates from this year.
1597 Invents a "geometric and military compass," a sector ("a mathematical instrument consisting of two rulers connected at one end by a joint and marked with several scales"). It was used to solve practical mathematical problems. He taught its use to his private students and wrote an instruction manual, later published.
For the use of his students, he prepares a Treatise on the Sphere, or Cosmographia.
1599 Enters a relationship with Marina Gamba.
Employs a craftsman, Marc'Antonio Mazzoleni, to make scientific instruments and produce the sector of Galileo's invention, which are sold to wealthy students along with his treatise explaining its use.
He obtains a new, six-year contract, retroactive to December 1598, with a salary of 320 ducats.
1560 | 1570 | 1580 | 1590 | 1600 | 1610 | 1620 | 1630 | 1640
1600 Giordano Bruno is burned at the stake in Rome.
August 13 Marina Gamba gives birth to a daughter who is baptized Virginia, who later takes the name Maria Celeste.
1601 January Marriage of Galileo's sister, Livia, to Taddeo Galetti. Galileo has promised a dowry of 1800 ducats--800 right away and 200 per year for five years. His brother Michelangelo is to pay half. Galileo borrows 600 ducats.
August 18 Marina Gamba gives birth to a second daughter who is baptized Livia, who later takes the name Arcangela.
1602 Galileo experiments with the pendulum in connection with natural accelerated motion. His friend, the physician Santorio Santorio uses the pendulum principle to invent a pulsilogium, a hand-held pendulum with which to take the pulse.
1603 He begins employing an amanuensis to copy manuscript treatises which he sells to his private students.
1604 Visits Mantua in an effort to obtain patronage from the Duke of Mantua. The effort does not bear fruit.
Experiments for the first time with uniformly accelerated motion on a gently sloping inclined plane, judging a ball's positions after equal time intervals. These experiments lead to the law of falling bodies, although it takes Galileo three more years to arrive at a mathematical demonstration of this law.
September His machine to lift water is tried in the garden of the Contarini house in Padua.
October 10 The new star (supernova) is first observed in Padua.
December 24 Galileo observes the new star for the first time.
1605 January Delivers three lectures on the new star at the university of Padua. His argument is that parallax measurements show that the new star is beyond the Moon. It is therefore in the heavens and thus change must be admitted in the heavens.
March Publishes Dialogue of Cecco di Ronchitti da Bruzene with regard to the New Star, in Padua. A second edition was published in Verona that same summer.
July The operations of the geometric and military compass is printed. It is dedicated to Cosimo II de' Medici.
1606 Summer Galileo publishes Considerations of Alimberto Mauri on Some Places in the Discourse of Lodovico Delle Colombe about the Star which appeared in 1604.
1606/7 Invents the thermoscope, a primative thermometer.
Writes a treatise on hydrostatics.
1607 April Balthasar Capra publishes The use and construction of the proportional compass in Padua. This is a plagiarism of Galileo's book on the sector. Galileo institues a legal process that ended with the expulsion of Capra from the university and the confiscation of all unsold copies of the book. A German mathematician named Simon Marius, Capra's tutor until 1605, was implicated in the affair.
Summer Galileo first investigates hydrostatics and the strength of materials.
1607/8 Further studies on motion. Discovery of the parabolic path of projectiles.
1608 Galileo arms a lodestone belonging to his friend, Sagredo and arranges for it to be bought by Grand Duke Ferdinand I de' Medici. The 56-ounce armed lodestone could lift 132 ounces of iron.
Summer Galileo is in Florence at the insistence of the Grand Duchess Christina. Marriage of Cosimo de' Medici. Galileo proposes the lodestone as a device, or symbol marking Cosimo's character and power.
October In The Hague, Hans Lipperhey requests a patent on a spyglass.
1560 | 1570 | 1580 | 1590 | 1600 | 1610 | 1620 | 1630 | 1640
1608/9 Galileo constructs a hydrostatic balance.
Further studies of accelerated motion.
1609 Cosimo II de' Medici becomes Grand Duke of Tuscany, following his father's death.
Johannes Kepler publishes his New Astronomy, which contains his first two laws of planetary motion.
May Galileo hears about the invention of devices for seeing faraway things as though nearby (telescope) in the Netherlands.
June Galileo duplicates the invention and makes a three-powered telescope.
August Thomas Harriot, observing near London, makes a drawing of the Moon as seen through a 6- powered telescope.
Through the connections of his friend Paolo Sarpi, Galileo presents an eight-powered telescope to the Venetian Senate. He is rewarded by a doubling of his salary and life- tenure at the University of Padua. He is disappointed by the fine print.
Fall Continues his improvement of the telescope and begins to make celestial observations with the instrument.
December Makes a series of observations of the Moon, from 30 November to 19 December.
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1610 January On 7 January Galileo observes three bright little stars near Jupiter; by 15 January he has figured out that there are four satellites of Jupiter.
February While continuing his other observations, Galileo maps some star formations.
March Sidereus Nuncius, dedicated to Cosimo II, Grand Duke of Tuscany, comes off the press in Venice. The satellites of Jupiter are here called the Medicean Stars, in honor of the house of his prospective patron.
April Johannes Kepler sends a letter in support of Galileo's discoveries. The letter is published in Prauge as Conversation with the Sidereal Messenger. It is reprinted in Florence a few months later.
Galileo travels to Pisa where he shows the satellites of Jupiter to Grand Duke Cosimo II de' Medici.
June Martin Horky publishes A very short excursion against the Sidereal Messenger.
July Following negotiations, Galileo is appointed "Chief Mathematician of the University of Pisa and Philosopher and Mathematician to the Grand Duke" of Tuscany. The appointment is for life.
Galileo first observes the strange appearances of Saturn.
September Galileo moves from Padua to Florence.
Kepler verifies the existence of the satellites of Jupiter (and publishes a tract on them the next year).
November John Wedderburn, a student of Galileo, publishes, in Padua, a reply to Martin Horky's tract.
The satellites of Jupiter are observed in England by Thomas Harriot, in Provence by Nicolas-Claude Fabri de Peiresc and Joseph Gaultier de la Valette, and in Rome by Christopher Clavius and the other Jesuit mathematicians at the Collegio Romano.
December Galileo verifies that Venus goes through phases like the Moon. The phases of Venus falsify the Ptolemaic System and prove that Venus goes around the Sun, in conformance with the Copernican System.
Thomas Harriot makes his first record of an observation of sunspots.
1610/11 Lodovico delle Colombe publishes Against the Earth's Motion against Galileo's celestial discoveries.
1611 Francesco Sizzi publishes Dianoia Astronomica, Optica, Physica against Galileo's celestial discoveries.
March Galileo arrives in Rome on 29 March.
Johannes Fabricius and his father, the astronomer David Fabricius, begin their observations of sunspots in Osteel in northwestern Germany.
March or April Christoph Scheiner, S.J. and his student Johann Baptist Cysat, S.J., see spots on the Sun but don't pursue the observation.
April Upon the request of Cardinal Bellarmine, the Jesuit mathematicians of the Collegio Romano certify Galileo's celestial discoveries, although they do not necessarily agree with Galileo's interpretation of these discoveries.
Galileo is inducted into the Lincean Academy, at a banquet given by the academy's founder and patron, Federico Cesi. At this occasion the name telescope is first used.
May The Inquisition decides to check to see if Galileo is mentioned in the proceedings against the Aristotelian philosopher Cesare Cremonini, Galileo's colleague and friendly opponent at the University of Padua.
The mathematicians at the Collegio Romano honor Galileo at a banquet. Odo van Maelcote delivers a lecture on Galileo's discoveries.
While in Rome, Galileo shows sunspots to some of his friends.
June In Germany, Johannes Fabricius publishes the first book on sunspots, Narration on spots observed on the Sun and their apparent rotation with the Sun (Wittenberg, 1611).
August Back in Florence, Galileo is drawn into a dispute concerning the behavior of bodies in water, taking the Archimedean position and arguing against the position of Aristotle.
September Kepler's Dioptrice published in Augsburg.
October At a debate during a state dinner for two visiting cardinals, Galileo repeats the Archimedean arguments abouts bodies in water. He is supported by Cardinal Maffeo Barberini (later Pope Urban VIII), who became one of Galileo's patrons at this time.
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1612 January A tract on sunspots, entitled Three letters on solar spots, written by Christoph Scheiner, is published in Augsburg under the pseudonym "Apelles hiding behind the painting."
May Galileo's first letter on sunspots.
August Galileo's second letter on sunspots.
September Christoph Scheiner's second sunspot tract, A more accurate discussion of sunspots and the stars which move around Jupiter, again under the pseudonym of Apelles.
Fall The Lincean Academy decides to publish Galileo's letters on sunspots to Marc Welser.
December Galileo's third letter on sunspots.
1613 March History and Demonstrations about Sunspots and their Properties, containing the three letters by Galileo is published by the Lincean Academy in Rome. In about half the copies the two tracts by Scheiner are reprinted.
December Benedetto Castelli, professor of Mathematics as the University of Pisa, and a student of Galileo, defends the Copernican theory to the Grand Duchess Dowager Christina of Lorraine. Upon hearing about this event, Galileo composes a long letter to Castelli on his views about the relationship between science and Scriptures.
1614 December Tommaso Caccini, a Dominican friar preaches a sermon in Florence against Galileo and mathematicians who subscribe to the Copernican view which, Caccini avers, is heretical.
1615 January Caccini's superior apologizes to Galileo in writing.
February A Dominican friar Niccolo Lorini, who had earlier criticized Galileo's view in private conversations, files a written complaint with the Inquisition against Galileo's Copernican views. He encloses a copy of Galileo's letter to Castelli.
March The Carmelite Friar Paolo Antonio Foscarini published Letter on the Pythagorean and Copernican Opinion of the Earth's Motion and Sun's Rest and on the New Pythagorean World System, in which are harmonized and reconciled those passages of the Holy Scripture and those theological propositions which could ever be adduced against this opinion (Naples, 1615). In this book, Foscarini argues that the Copernican theory is compatible with Scripture.
Caccini gives a deposition to the Roman Inquisition.
Galileo writes a long letter defending his views to Monsignor Piero Dini, a well connected official in the Vatican.
April Cardinal Bellarmine writes to Foscarini, cautioning him to treat the Copernican theory as a hypothesis only and includes Galileo in his comments.
Summer Galileo writes his "Letter to the Grand Duchess Christina," which is not printed but circulates widely. (A Latin version is published in the Netherlands in 1636.) This is an enlarged version of his letter to Castelli of Dec. 1613.
December Galileo goes to Rome to defend his Copernican ideas.
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1616 January Writes up his theory about the tides which, he argues, proves that the earth moves. He addresses this treatise to Cardinal Alessandro Orsini.
February A committee of consultants declares to the Inquisition that the proposition that the Sun is the center of the universe is absurd in philosophy and formally heretical and that the proposition that the Earth has an annual motion is absurd in philosophy and at least erroneous in theology.
On orders of the Pope Paul V, Cardinal Bellarmine calls Galileo to his residence and administers a warning not to hold or defend the Copernican theory. An unsigned transcript in the Inquisition file, discovered in 1633, states that Galileo is also forbidden to discuss the theory orally or in writing.
March The Congregation of the Index suspends Copernicus's On the Revolutions until corrected and bans Foscarini's book entirely, Galileo is not mentioned in the decree.
Galileo has an audience with Pope Paul V, and is assured by the Pope.
May Cardinal Bellarmine writes a letter to Galileo certifying that Galileo had not been on trial or condemned by the Inquisition.
June Galileo attacks the problem of determining longitude at sea by means of eclipses of the satellites of Jupiter.
After an oral dispute between Galileo and Francesco Ingoli, it is agreed that Ingoli will write out his argument and Galileo will then reply in writing. Ingoli's tract, Disputation on the place and stability of the Earth, against the system of Copernicus, in which he uses scriptural arguments against Copernicus, is not printed. Because of the decision by the Inquisition, Galileo does not reply at this time.
1618 In October and November three different comets appear, the third one very bright. Orazio Grassi, a professor professor of mathematics at the Collegio Romano, delivers a public lecture on comets. A manuscript copy of this lecture was sent to Galileo. The lecture itself was published early in 1619 under the title On the Three Comets of the Year MDCXVIII. An Astronomical Disputation Presented Publicly in the Collegio Romano of the Society of Jesus by one of the Fathers of that same Society. At stake is the location of these comets.
1619 January/February Galileo's views on comets are requested by many, among them Archduke Leopold of Austria. He begins drafting a critique of the lecture published by the Jesuit father at the Collegio Romano.
June Mario Guiducci, a pupil of Galileo's, delivers a lecture on the comets in which he argues against the Jesuit interpretation of these bodies. The lecture, written largely by Galileo, is published under the title Discourse on the Comets. By Mario Guiducci. Delivered at the Florentine Academy during his Term as Consul.
October Under the pseudonym Lothario Sarsi, Orazio Grassi counters with a tract entitled The Astronomical Balance, on which the Opinions of Galileo Galilei regarding Comets are weighed, as well as those presented in the Florentine Academy by Mario Guiducci and recently published.
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1620 May The Congregation of the Index issued the corrections that must be made in Copernicus's On the Revolutions before it can be read.
June Mario Guiducci publishes a letter in which he replies to Orazio Grassi's Astronomical Balance.
August Cardinal Maffeo Barberini sends Galileo a poem entitled Adulatio Perniciosa, composed by him in honor of Galileo.
1621 January Galileo is elected Consul of the Accademia Fiorentina.
Pope Paul V dies. He is succeeded by Gregory XV, who dies in July 1623.
February Death of Grand Duke Cosimo II de' Medici. He is succeeded by Ferdinand II (11 years old), who will reign under the regency of his grandmother, Christina of Lorraine, and his mother, Marie Madeleine of Austria.
1622 October Galileo sends the manuscript of The Assayer, his reply to Grassi's Astronomical Balance, to the Lincean Academy in Rome.
1623 Publication of Tommaso Campanella's Defense of Galileo in Frankfurt.
February The Roman censors give permission for The Assayer to be printed.
August Upon the death of Pope Gregory XV, Cardinal Maffeo Barberini, a friend and patron of Galileo, is elected Pope and takes the name Urban VIII.
October The Assayer, now dedicated to Pope Urban VIII, is published in Rome under the auspices of the Lincean Academy.
1624 April Galileo goes to Rome where he has six audiences with the Pope Urban VIII and also has audience with a number of cardinals. The Pope assured him that he could write about the Copernican theory as long as he treated it as a mathematical hypothesis.
In Rome, Galileo shows a compound microscope to members of the Lincean Academy. Observations of a bee made with this instrument by Francesco Stelluti were published in 1630. Galileo then presented this instrument to Cardinal Zollern for the Duke of Bavaria.
June Galileo returns to Florence.
September Galileo writes his "Letter to Ingoli," in which he refutes Ingoli's Disputation of 1616. The letter is not printed but circulates in manuscript.
Galileo begins revising his treatise on tides (see 1616), which eventually results in his Dialogue Concerning the Two Chief World Systems (1632).
1624/25 A complaint against Galileo's Assayer is lodged by a person unknown to us. The complaint charges that the atomism espoused in the book cannot be squared with the official church doctrine regarding the Eucharist, in which bread and wine are "transubstantiated" into Christ's flesh and blood. After an investigation by the Inquisition, Galileo is cleared.
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1626 Horatio Grassi publishes his reply to The Assayer, a book entitled Ratio Ponderum Librae ac Simbellae, in Paris.
1627 March Urban VIII bestows a pension of 60 scudi per year on Vincenzio, the son of Galileo.
1629 November Galileo once again takes up contact with Spanish authorities about the determination of longitude at sea by means of the satellites of Jupiter.
December Galileo becomes a grandfather, when Sestilia Bocchineri, his son Vincenzio's wife since the previous year, gives birth to a boy who is given the name Galileo.
1630 Publication of Christoph Scheiner's Rosa Ursina, the definitive work on sunspots for over a century.
Death of Johannes Kepler.
February Urban VIII bestows a pension of 40 scudi per year on Galileo.
April Galileo finishes his Dialogue Concerning the Two Chief World Systems.
May/June Galileo is in Rome to clear his Dialogue with the censors and make arrangements to have it printed by the Lincean Academy. He obtains conditional permission from the Secretary of the Vatican
Summer An outbreak of the plague begins to disrupt commerce and travel between cities.
August Federico Cesi, the founder and patron of the Lincean Academy, dies. This is the end of his academy.
Fall Galileo sends the preface and ending of his Dialogue to the Secretary of the Vatican for corrections. He has now decided to print the book in Florence.
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1631 Spring Through Grand Duke Ferdinand II and his ambassador in Rome, Galileo negotiates with the Secretary of the Vatican about the printing of the Dialogue. The final result is that the preface and ending would be approved in Rome while the remainder of the book would be checked and approved by the Inquisition in Florence.
1632 February Printing of the Dialogue is completed.
Summer Further distribution of the Dialogo is prohibited by Pope Urban VIII and a special commission is appointed to examine the book.
September Based on the report by the special commission, Urban VIII refers the case to the Inquisition. The Pope himself presides over a meeting of the Inquisition in which the decision is made to summon Galileo to Rome.
October Galileo is notified of the summons by the Inquisitor in Florence. He promises to obey but requests that the trial be moved to Florence.
November At a meeting of the Inquisition presided over by Urban VIII, Galileo's request is refused. If necessary he will be forced to obey the Inquisition's order.
December The Florentine Inquisitor notifies Rome that he had visited Galileo, who was ill in bed, and that three physicians had signed a statement that Galileo was too ill to undertake the journey to Rome.
At a meeting again presided over by Urban VIII himself, the Inquisition rejects Galileo's excuse as a subterfuge and sends him notification that if he does not come to Rome voluntarily he will be arrested and brought to Rome in chains.
1633 January Galileo leaves Florence on 20 January and, after two weeks quarantine (because of the plague) just outside Rome, he arrives there on 13 February. As a special favor to Grand Duke Ferdinand II de' Medici, the Pope allowes Galileo to stay at the residence of the Tuscan ambassador. Galileo is forbidden social contacts.
April Galileo is formally interrogated by the Inquisition. From 12 to 30 April he is detained in the building of the Inquisition but in a comfortable apartment.
The consultants called in to examine Galileo's Dialogue, file their reports.
A plea bargain is arranged whereby Galileo will be allowed to plead guilty to lesser charges and will receive a lenient sentence.
On 30 April Galileo confesses that he may have made the Copernican case in the Dialogue too strong and offers to refute it in his next book.
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June Urban VIII decides that Galileo will be imprisoned for an indefinte period.
With a formal threat of torture, Galileo is examined by the Inquisition. The next day he is sentenced to prison at the pleasure of the Inqusition and to religious penances. The sentence is signed by only seven of the ten cardinal-inquisitors.
In a formal ceremony at a the church of Santa Maria Sopra Minerva, Galileo abjures his errors.
First Galileo is allowed to be under house arrest at the residence of the Tuscan ambassador, and then at the residence of the archbishop of Siena in that Tuscan city.
July Galileo arrives in Siena. Here he begins putting together his Discourse on Two New Sciences.
December He is allowed to return to his villa in Arcetri, near Florence, where he is under house arrest for the remainder of his life.
1634 Winter Suffers from a painful hernia. He requests permission from Rome to consult physicians in Florence. The request is denied, and he is given to know that further requests such as this will result in imprisonment.
April Galileo's daughter, Maria Celeste, who has lived in a convent near Arcetri for many years, dies.
Summer A treatise on machines, entitled Mechanics, completed by Galileo in 1602, has been translated into French and is published in France by Marin Mersenne.
1635 A Latin translation of the Dialogue is published in Strassburg by Matthias Bernegger.
1636 Publication of Letter to the Grand Duchess Christina in both Italian and Latin.
May Louis Elsevier, a Dutch publisher, visits Galileo in Arcetri and agrees to publish the Discourse on Two New Sciences in Leiden.
August Galileo sends a proposal to the States General of the Netherlands for determining longitude at sea using eclipses of the satellites of Jupiter.
November The States General appoint a committee to examine Galileo's proposal.
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1637 April The States General award Galileo a gold chain worth 500 florins in recognition of his longitude effort. His proposal was deemed not to be practical.
July Galileo writes to Elia Diodati that he has lost all vision in his right eye.
November Announces he has discovered a new libration of the Moon, different from the optical libration.
1638 January Has lost vision in his left eye and is now totally blind. He petitions the Inquisition to be freed. The petition is denied. He is, however, allowed to transfer to his house in Florence in order to be closer to his physicians. In March he obtains permission to attend church on religious holidays, provided that he have no contact with others.
July The Discourse on Two New Sciences comes off the press in Leiden in the Netherlands.
August When the gold chain from the Dutch States General is presented to Galileo, he refuses it. For this he is commended by Pope Urban VIII.
During a serious illness, Galileo prepares his last will and testament.
September John Milton visits Galileo in Arcetri.
1641 Galileo conceives of the application of the pendulum to clocks.
1642 January Galileo dies in Arcetri on 8 January.
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