Going beyond Gravity from the ground up

The Web has become a vast repository of information of all kinds, especially scientific. In astronomy, most observatories, space missions, data repositories, and other projects have websites which make a wealth of information and images freely available. There are educational websites and websites that collect information to allow you to search for what you want. You can even custom-generate digital images of any region of the sky.

In theoretical physics there are many websites that introduce subjects at various levels, from the popular to the Ph.D. level. Scientists who do simulations, such as black-hole collisions or galaxy formation, often provide extensive libraries of images and movies that can be downloaded.

The challenge today is not finding information: it is making sense of it. If you have read the book Gravity from the ground up, you will have a basis for organizing much of the astronomical the information available on the Web. The links provided in this collection generally take you one step further than the material in the book. Since many of the websites have material that is relevant to several chapters of Gravity from the ground up, the links have been organized by subject rather than chapter.

All the links below are external links. Clicking on them will open a new browser window. We will attempt to ensure that the links are up-to-date, but some may fail when websites are re-organized or projects finish or are cancelled. Many topics change rapidly, as new observations come in, so some of the links below may represent old information by the time you want to follow them. A good way of updating yourself is to use some keywords from the link title in the Google search engine. Moreover, some links may work in some browsers but not in others, so if a website does not appear to open properly, you may have more success using a different browser.

These links are provided as a way for readers to go further in the subject; they do not in any sense represent the "best" of the web for gravity, simply because there is too much out there for anyone to survey it comprehensively. Be especially careful when downloading images or software from any website: viruses can infect files and the site owners may not be aware of it. Links have been selected mainly because they follow up specific topics in the book. Inclusion of a link on this list does not mean that any opinions or views expressed on the website are endorsed by the author or publishers of Gravity from the ground up.

Contents

  • General physics and astronomy
  • Space missions and space agencies
  • Educational sites for specific subjects
  • Specific astronomical objects
  • Collections of astronomical images
  • Theoretical simulations and animations
  • History of physics and astronomy
  • Collections of links
  • People in science and astronomy
  • Other sites of interest
  • Astronomical observatories and their observing programs

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    General physics and astronomy

  • Annotated Physics Encyclopædia A collection of small articles and links, organized by subject, spanning the whole of physics.
  • Astronomer.com The astronomy magazine of WorldNews.com, full of current news stories and links.
  • Astronomy News & Links A regularly updated page of links to important recent discoveries, plus other resources.
  • Eric Weisstein's World of Science An on-line collection of encyclopedias on physics, mathematics, astronomy, and chemistry, plus a collection of biographies of scientists. Sponsored and hosted by Wolfram Research, publishers of the Mathematica symbolic computation program.
  • From Stargazers to Starships and two other web-based books on the Earth, by physicist David Stern.
  • Fundamental constants of physics The best and most recent values are tabulated by the Codata pages of the NIST website.
  • Particle Adventure An introduction to elementary particles by the Particle Data Group, which maintains up-to-date values of measurements of fundamental constants, particle masses, and other properties.
  • Phil Plait's Bad Astronomy Astronomy attracts its fair share of misunderstandings, misinformation, misinterpretations, some of them due to ignorance but some apparently deliberate. Check out this site, which explains the errors and points you in better directions.
  • Physics Central The website for the general public of the American Physical Society, containing many general and educational resources.
  • Science Odyssey The website of the 1998 television series on the American Public Broadcasting System (PBS), which contains a wealth of interesting information on various scientific discoveries, including astronomy, physics, and the Earth sciences.
  • StarDate Online is a website for general astronomy maintained by the University of Texas' MacDonald Observatory. Visit here to get current events, multimedia information, and educational background.
  • UTC-TAI Time Keeping accurate time is a serious activity, involving the running of precise atomic clocks and the monitoring of tiny variations in the Earth's rotation rate. This is the website of the coordinating institute in Paris for reconciling these different measures of time and defining what physicists and astronomers call "Coordinated Universal Time" and "International Atomic Time".
  • Zona Land is an educational website for physics and related mathematics.

    • Educational sites for specific subjects

  • Astrobiology - What Is It A NASA-sponsored site introducing astrobiology, with links to other resources in astrobiology.
  • Chris's Relpage A site that helps to visualize what objects look like when viewed by an observing moving at relativistic speeds (speeds close to the speed of light). Some images are displayed, and software to generate more can be downloaded.
  • Einstein, Albert. 1920. Relativity The Special and General Theory A complete online version of Einstein's own popular book on relativity. Hosted by the internet publisher of free books, Bartleby.com.
  • Gravitational lensing is illustrated and explained on the home page of the professional astrophysicist J Wambsganss.
  • Gravitational Wave Tutorial by the Cardiff University (UK) relativity group, one of the leading theory and data-analysis groups in the worldwide gravitational-wave community.
  • Gravitational Waves: Lectures by Kip S Thorne A pioneering experiment in web-based teaching from the California Institute of Technology: a course for graduate students has been put on the web, complete with video (several formats possible) and images of the transparencies. The lecturer is one of the leading theoretical physicists working on gravitational radiation and its detection.
  • High Altitude Observatory Education Pages Introduction to the Sun and its effects on the Earth.
  • MacTutor History of Mathematics Website An extensive collection of information on mathematics and mathematicians.
  • Math Forum - Ask Dr. Math An educational website from Drexel University in the USA, full of interesting and informative material, games, puzzles, and further links. There is also an opportunity to ask specific questions.
  • MrEclipse.com gives a huge amount of information and images of solar and lunar eclipses, by one of the world experts, Fred Espenak.
  • NASA KIDS is a special website for children under 13 who are interested in space exploration.
  • NASA Spacelink - An Aeronautics & Space Resource for Education The primary educational website and library of NASA.
  • Ned Wright's Cosmology Tutorial A readable introduction to cosmology and a news page of the latest observational results and their interpretation. Also links to an Italian translation.
  • Nine Planets A superb summary of what is known about the planets and their moons, kept up to date with the latest observations  (including images) from the Earth and from space missions. Created by Bill Arnett, this is part of the SEDS website.
  • Numerical relativity is the research field that simulates solutions to Einstein's equations of general relativity using supercomputers. This website, by one of the largest groups of professionals working on this subject, contains a wealth of images, simulations, and educational material.
  • Origins Education Outreach A website devoted to explaining NASA's Origins program of exploration of the Universe.
  • Periodic table (WebElements) A website with in-depth data associated with all the elements.
  • Physics of Microwave Background Anisotropies A website by a research physicist that contains information and explanations of the importance and the meaning of the tiny irregularities observed in the temperature of the cosmic microwave background radiation. Some of the material is accessible to non-physicists, some is meant for professionals.
  • Powersof10.com The movie "Powers of Ten" is one of the most popular and effective educational science films ever produced. This website has still images from the film and much more.
  • QuarkNet is an experiment in teaching: it is a network of schools joined to major high-energy physics accelerator institutions (CERN, Fermilab, SLAC, and others), in which students and their teachers can make contact with professional physicists.
  • Stanford SOLAR Center is an educational site about the Sun, using data from satellites to illustrate the properties of the Sun and its oscillations. The site also maintains an "Other Resources" page with an extensive collection of links to educational and research websites for the Sun.
  • Stephen Hawking's Universe The website of the American Public Broadcasting System (PBS) television series about the famous physicist's perspective on cosmology, wormholes, and new physics.
  • Werner Benger - General Relativity Images by one of the leading scientists working in the computer visualization of relativistic effects and space-times. Among the goodies are ray-raced simulations of what objects look like when they are near black holes. Also many useful links.

    • Collections of astronomical images

  • AAO Images Access to the public images taken at the Anglo-Australian Observatory. Included are photos by David Malin, one of the best professional astronomical photographers.
  • António Cidadão's collection of lunar and planetary imaging, by a superb amateur astronomical photographer.
  • Astronomical Image Library A search engine for astronomical images. Just type in the name of the object you are looking for, and it will return links to locations on the Web where you can find images of it.
  • Astronomy Picture of the Day Every day a new image from astronomy, with an explanation and links to more information. All past images going back to the start of the website in 1995 are collected at Astronomy Picture of the Day Archive.
  • Galaxy Cluster Mug Shots A collection of images of clusters of galaxies maintained by Raymond White of the University of Alabama.
  • Gravitational Lens Data Base A collection of images, data, and links pertaining to the most important gravitational lenses, plus software that will allow you to simulate the optical effect of a gravitational lens.
  • Hawaiian Astronomical Society - Deepsky Atlas A collection of images and information about the constellations, including mythological origins.
  • Messier Catalog This website maintained by SEDS provides images of the objects in the first-ever list of nebulae. Some are in our Galaxy and others are external galaxies. A selection of Messier objects seen in different wavebands can be found in The Multiwavelength Messier Museum.
  • NASA - Johnson Space Center Digital Image Collection Collection of over 9000 photographs of the American manned space program.
  • NASA's Planetary Photojournal is another site with plenty of images about the planets and their moons.
  • National Space Science Data Center photo gallery, containing images of planets and astronomical objects taken by missions of the Goddard Space Flight Center.
  • NOAO Image Gallery Emission Nebulae A collection of images of emission nebulae around hot stars in the Galaxy.
  • Planetary Data System (PDS) is NASA's archive of images of the planets.
  • SkyView allows you to generate an image of any part of the sky, using the latest digitized data from space observatories and ground-based telescopes.
  • Troubled by systems of units? See the sites suggested by the Internet Public Library's science and technology pages, or Units -- from Eric Weisstein's Treasure Trove of Physics.
  • Two collections of images of NGC objects are the SEDS interactive catalog and the GCO NGC Archive maintained by the Grove Creek Observatory in Austalia. Many of these objects are popular observing targets for amateur astronomers.
  • Web Nebulae maintained by SEDS provides images of many beautiful nebulae

    • History of physics and astronomy

  • A Brief History of High-Energy Astrophysics A NASA-sponsored web site tracing not only the modern era of space-based X-ray astronomy but also going back to early work, such as that of Michell and Laplace on black holes in Newtonian gravity, a subject treated in Chapter 4 of Gravity from the ground up.
  • A Century of Physics A survey of the development of physics in the 20th century presented by the American Physical Society.
  • Astronomiae Historia - History of Astronomy Web site maintained by the International Astronomical Union, still under development. It contains thousands of pages of documentation and links to thousands of external documents.
  •  Center for History of Physics A website of the American Institute of Physics, with general information, exhibits on specific people (like Einstein and Heisenberg), archives, and links. It hosts the Emilio Segre Visual Archives, a primary source of images of physicists.
  • Galileo Project A resource on Galileo and his contemporaries, at Rice University in the USA.
  • Mathematicians of the Seventeenth and Eighteenth Centuries A collection of biographies.

    • People in science and astronomy

  • Albert Einstein Archives Official archive of Einstein's papers at the Hebrew University of Jerusalem.
  • Albert Einstein Pictures Informal collection of images of Einstein.
  • Albert Einstein-Image and Impact A scientific biography and assessment of Einstein's work, on the AIP website for the history of physics.
  • Contributions of 20th century women to physics Collection of biographical material
  • Catalog of the Scientific Community in the16th and 17th Centuries A collection of 631 detailed biographies on members of the scientific community during the 16th and 17th centuries. Part of the Galileo Project. Based on work by the late Professor Richard Westfall of Indiana University, author of one of the most respected biographies of Isaac Newton.
  • Eric Weisstein's Treasure Trove of Scientific Biography A wonderful collection of short biographies of scientists of all eras. Part of Eric Weisstein's World of Science.
  • Fred Hoyle A biographys of one of the 20th century's most creative astrophysicists, with links to other resources.
  • Fritz Zwicky Stiftung The (German-language) website of the Foundation named after the Swiss-American astronomer and astrophysicist Fritz Zwicky, but more concerned with his "morphological method" than his astronomical work.
  • Heisenberg - Uncertainty Principle - Werner Heisenberg and the Uncertainty Principle The American Institute of Physics historical and educational website about Heisenberg and the foundations of quantum theory.
  • Jocelyn Bell  A biography of the graduate student who discovered pulsars, part of the Science Oddysey website.
  • Newton, Isaac (1642-1727) -- from Eric Weisstein's Treasure Trove of Scientific Biography An online biography of Isaac Newton. See also a different take on Newton on the Galileo Project website.
  • People and Discoveries_ People List of scientists whose biographies appear on the Science Oddysey website.

    • Astronomical observatories and their observing programs

  • AAO Homepage The Anglo-Australian Observatory
  • BiSON home page The website of a ground-based observing program to study oscillations of the Sun.
  • Digitized Sky Survey A project to produce digital images of all parts of the sky. Images of any part of the sky can be downloaded from this website.
  • European Southern Observatory is the major professional observatory for European countries, and has the most ambitious goals of any of the ground-based observatories. It has built four large telescopes in Chile and will link them together so that they effectively form a single large telescope.
  • Global Oscillation Network Group GONG is a major network of ground-based solar observatories that study the oscillations of the Sun. One of the member observatories has a good website on helioseismology.
  • Gravitational-wave observatories are being built and operated in various countries: LIGO in the USA, GEO in Germany with UK partnership, VIRGO/EGOin Italy with French partnership, TAMA in Japan. Many of these have educational pages as well as descriptions of their projects.
  • Isaac Newton Group of Telescopes on La Palma, in the Canary Islands. This is the public outreach site of one of the leading astronomical research observatories in the world. It gives access to many high-quality images of astronomical objects.
  • Jodrell Bank is the principal radio observatory in the UK and the discoverer of gravitational lensing.
  • National Solar Observatory Digital Library contains a large collection of solar images.
  • NOAO The website of the principal national optical observatory of the USA.
  • Pierre Auger Observatory is the largest cosmic-ray observatory ever built, and is designed to solve the problem of the ultra-high energy cosmic rays.
  • SETI is the Search for Extraterrestrial Intelligence, a research project that has captured the imagination and cooperation of millions of people around the world with its famous screen-saver, which searches for signals from intelligent beings when you are not using your computer.
  • SNO Homepage The Sudbury Neutrino Observatory is the most powerful observatory for solar neutrinos.
  • Spacewatch Project monitors the sky to track asteroids and comets, providing data on objects that may be hazardous to the Earth or that may be interesting for research.
  • Two collaborations searching for high-redshift supernovae in order to measure the acceleration of the Universe are the Supernova Cosmology Project and the High-Z Supernova Search.
  • UKIDSS Home Page A very sensitive survey with the infrared telescope UKIRT, which hopes to find both the nearest and the furthest objects in the Universe.
  • W M Keck Observatory operates a pair of very large telescopes in Hawaii, doing leading-edge research astronomy.

    • Space missions and space agencies

  • 2001 Mars Odyssey Home Page Home page of the mission. See a huge number of images, find out where the spacecraft is now, in real time.
  • Apollo Program The NASA website that gives a complete review of all Apollo missions; these were the missions of the US program to put men on the Moon.
  • British National Space Centre (BNSC) The national space agency for Great Britain
  • Chandra X-Ray Observatory The news page for this important orbiting X-ray telescope, named after the Indian-American astrophysicist S Chandrasekhar.
  • Compton Gammar Ray Observatory Science Support Center The Compton Observatory revolutionized astronomy with its view of the gamma-ray sky. This page is an entry page for all astronomers, but amateurs can follow the link to its Education and Outreach website.
  • European Space Agency (ESA) The international space agency for the principal European countries.
  • ESA Science The science website of the European Space Agency. Links to missions, photo archives.
  • French National Space Agency (CNES) The CNES English-language information page
  • Galileo Mission The web site for the NASA mission to Jupiter, containing the latest information about Jupiter and its moons.
  • Gemini Science Center The Gemini telescopes are two identical large research telescopes, one in the northern hemisphere and one in the southern.
  • German Space Agency (DLR) The DLR English-language information page
  • Gravity Probe B The website of the NASA mission to measure gravitomagnetism. It contains educational and technical material.
  • GRIN (GReat Images in Nasa) A website collecting high-resolution scans of some of the most important photographs in the history of space exporation.
  • Hipparcos Space Astrometry Mission The website of the pioneering European mission to provide extremely accurate positions for millions of stars, enabling the nearest part of the Galaxy to be mapped in 3D for the first time.
  • Hubble Space Telescope The outreach website constructed by NASA for the HST, including the vast archive of published images.
  • Italian Space Agency (ASI) The national space agency for Italy. The website is in Italian, although an English version is under construction.
  • LISA The European Space Agency website for the planned ESA-NASA gravitational wave mission.
  • Magellan mapped the surface of Venus. The PDS maintains a collection of images and online resources from the mission.
  • NASA's Beyond Einstein A website explaining the NASA program to reveal the structure and evolution of the Universe, including the role of LISA.
  • NASA's Origins Program A website explaining the NASA program to explore the origins of life in the Universe, tracing it back to the earliest structures.
  • National Aeronautics and Space Administration (NASA) The national space agency for the USA, and the leading space agency in the world.
  • Pioneer Home Page The home page of the remarkable Pioneer spacecraft, which are leaving the Solar System after having surveyed the outer planets.
  • Russian Aviation and Space Agency (PK) The national space agency for Russia
  • SOHO_ The Solar and Heliospheric Observatory is a major orbiting solar observatory.
  • Space Science Missions in Study NASA's page of missions that might be launched.
  • Space Telescope Science Institute Astronomy Resources Link to Hubble Space Telescope image library and many other educational and professional resources
  • Swift Gamma Ray Burst Explorer Mission This is the NASA follow-on mission from the Compton satellite's gamma-ray burst observations. The website contains background and educational material on gamma-ray bursts.
  • Two main US labs for unmanned scientific exploration of space are Goddard Space Flight Center and the Jet Propulsion Laboratory. Both have extensive educational material and image libraries available on their websites. Although they normally handle separate missions, they will cooperate on the NASA part of the LISA gravitational wave mission.
  • WMAP is the latest space mission to observe the cosmic microwave background radiation, and it is returning spectacularly accurate results.

    • Specific astronomical objects

  • 2001 Mars Odyssey Mission A catalog of stunning pictures of Mars
  • Apollo 11 Lunar Surface Journal Images Collection of images of the Moon from the first lunar landing
  • Astronomers find a cool black hole in Andromeda X-ray observations of the central massive black hole in the nearest large Galaxy to our own Milky Way.
  • Chandra Links Pulsar to Historic Supernova Evidence for the association of pulsars and supernovae, from the Chandra satellite.
  • CASSINI Imaging Diary:_Jupiter Photographs and movies of Jupiter by the CICLOPS camera on the Cassini mission.
  • Constellations - Digital Images of the Sky Collection of photographs of all the constellations.
  • Crab Nebula - The Movie A ten-second movie made by time-lapse photography showing changes in the structure of the gas surrounding the Crab pulsar.
  • Crab Dramatic image showing clearly the optical pulsations of the Crab pulsar, done with stroboscopic photography.
  • Earth History Website with reconstructions of the arrangements of the continents of the Earth at different geological times.
  • Mars3D The surface of Mars rendered in 3-dimensional images.
  • Mars Global Surveyor The website of the Mars Global Surveyor mission, containing images of Mars' surface, including evidence of flows of water.
  • Max Tegmark's cosmic microwave background data analysis center experiments An excellent site with the most up-to-date observations of the cosmic microwave background plus lots of links to experiments and theoretical sites.
  • Globular Cluster Page All about glocular clusters and their evolution.
    • The Milky Way Galaxy The SEDS page introducing the huge subject of our own Galaxy. For a view of the Milky Way in many wavebands, see the Multiwavelength Milky Way.
  • The Virgo Cluster of Galaxies is the SEDS page about the nearest big cluster of galaxies, containing hundreds of galaxies, many supernovae per year, and one of the nearest supermassive black holes.
  • The Earth is an astronomical object, and a good source of current geological information and educational material is the US Geological Survey. Their Flagstaff office also has an Astrogeology website, in which geological techniques are applied to the understanding of some of the planets.
  • Images of the Earth taken by astronauts from orbit.

    • Theoretical simulations and animations

  • NOVA Online-Einstein Revealed A website of the American Public Broadcasting System (PBS) containing animations of relativity effects.
  • SFB 382 D4 - Gallery A gallery of computer-generated images of what different objects might look like when viewed from a platform moving at nearly the speed of light.
  • Supercomputers are being used by professional physicists to solve Einstein's equations, for example to collide black holes and predict the gravitational radiation from them. This site contains some of the most extensive simulations.
  • Virgo Consortium is a collaboration of scientists doing supercomputer simulations of how galaxies formed into the clusters and chains that astronomers see in their surveys.
  • Virtual Trips to Black Holes and Neutron Stars A website with computer-generated movies of what it might be like to take a trip to a black hole, including all the visual distortions produced by special and general relativity.

    • Collections of links

  • ASTRONET A collection of current astronomical information by the science journalist Carl Koppeschaar. You can see the current image of the Sun or the auroras; learn the current state of activity in the Sun or the Earth's magnetic field, learn the current time on standard international clocks, and much more. Look on this site whenever any astronomical event happens. In addition to the links on the main page, there is another page of links to all kinds of science resources.
  • Astronomy Picture of the Day's Educational Links Links to educational sites for astronomy. Maintained by NASA.
  • Astroweb A portal into a wide variety of astronomical resources
  • Exhibits and Online Source Materials for History of Physics and Allied Fields collected by the American Institute of Physics.
  • Internet Public Library, an ambitious education website of the University of Michigan, has links to many resources, including a section on astronomy and one on physics.
  • Major search engines like Yahoo and the Open Directory Project have collections of links to resources in astronomy (Yahoo, Open Directory) and physics (Yahoo, Open Directory).
  • Physics and Astronomy Education by PhysLink is a collection of links to educational resources in physics and astronomy.
  • Pretty Pictures Astroweb's list of websites providing astronomical images
  • PSIGate - Physical Sciences Information Gateway is a collection of links to educational resources in all the physical sciences.
  • Refdesk.com is one of the standard reference sites on the Web. Check out its pages for science and for astronomy for a host of links to useful information.
  • Science and Technology Index A site run by the US Brookhaven National Laboratory that points to resources in areas of science and technology that are relevant to its research.
  • Science Reference Shelf A collection of links to reference sites for physics and chemistry. A good place to start if you are unsure where to look.

    • Other sites of interest

  • Fourmilab A collection of software by John Walker, including programs that will show current views of the astronomical sky on your computer screen, screensavers, and much more.
  • International Astronomical Union The principal international organization for professional astronomy. This regulates key areas of astronomy, such as the naming of objects, defining reference systems for locating objects on the sky, time-keeping, and so on. It also organizes meetings and coordinates cooperation in many specific subject areas.
  • Inventors Online Museum A site dedicated to inventors, famous and obscure.
  • Jean-Pierre Luminet The website of one of the most interesting popularizers of relativity and related astronomy.
  • Mark Heath The website of the cartoonist who drew the "Frank Drake" cartoon reproduced in the book.
  • Nobel e-Museum for Physics The official website for the Nobel prize in physics.
  • Paleomap project A website which allows you to see the reconstructed configuration of the continents at different geological epochs. There are even animations that allow you to watch how the continental pieces moved around the globe.
  • Royal Astronomical Society is one of the oldest societies for professional and amateur astronomers and geophysicists. Its website lists the subjects of its monthly meetings and contains many useful links to further information, including its publications.
  • Science Jokes Who said that scientists can't be funny? Some are funny on purpose, others unintentionally. Find out if your sense of humor matches that of the compiler of this site, Joachim Verhagen.
  • Sidney Harris A website containing many cartoons by the most famous science cartoonist of all.
  • Students for the Exploration and Development of Space (SEDS) maintains much useful information on its website, including the Nine Planets tour of the solar system, the Messier image catalog, their NGC browser, an image catalog of nebulae, and much more.
  • Tacoma Narrows Bridge A website with images of the disintegration of the famous galloping bridge.
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