Black Holes — Gravity's Relentless Pull is an exciting, in-depth exploration of the astronomy and physics of black holes. The site was created in a collaboration between astronomy, education and Web professionals. It offers astronomical images, animations, interactive
experiments (some with audio), and an encyclopedia of accurate, up-to-date information.
Black holes are probably the most extreme objects in the Universe. The site shows that even the most mysterious of things can be understood through scientific inquiry. It
also explains many basic concepts about physics, astronomy, and science in general, including light, gravity, and the scale of our Universe. Exploration of the site is sure to
fascinate and to instill an interest in science. No specific prior knowledge about astronomy or physics is required.
This Web site "Black Holes: Gravity's Relentless Pull" is designed to be viewed by modern Web browsers, including but not restricted to, Internet Explorer (version 5 and higher), Netscape
(version 6 and higher), Safari, Firefox, Mozilla, and Opera. It should work on a broad range of operating systems, including Windows, Mac, Linux and
Solaris. Several sections of the Web site "Black Holes: Gravity's Relentless Pull" require Flash version 6 or higher. You can
download Flash for free.
You do not need Flash to view most of the Black Hole Encyclopedia section (which contains the Web site "Black Holes: Gravity's Relentless Pull's" contents conveniently sorted by topic, but without
many interactive and multimedia features). One virtual experiment (Orbit Around a Black Hole) requires Java version 1.0.2 or higher.
Evocative background audio plays on selected parts of the site. To enjoy this, be sure to have the sound system (located in the Control Panel of your
computer) turned on.
- Introduction — Black Holes are out there. But what are they?
A narrated animation provides information on how black holes are formed. The introduction can be replayed.
- Home page — Black Holes — Gravity's Relentless Pull
Brief information about the site and two entry portals to explore its contents:
- Header Navigation Buttons
- Home — Provides quick access to the Home Page.
- Journey to a Black Hole — Provides entry to three interactive modules:
- Finding the Invisible — Learn which astronomical objects populate the Universe and which ones contain
- Drag the Viewfinder circle around the night sky to locate and identify various objects in the Universe.
- Your Findings — As each object in the night sky is found, its presence is noted in this sidebar chart. Use the "i"
(information) symbol for additional information with several graphics (Previous and Next), explanations and External Links and Further
- OBJECT, DISTANCE, BLACK HOLE? — Specific information is provided as each night sky object comes into view. Use the Learn More button
for additional information with several graphics (Previous and Next), explanations and External Links and Further Reading links.
- See the Sky in Different Ways — Click the telescopes to change wavelength regime, so that the Viewfinder shows objects in the night
sky either in X-Rays, Visible Light, or Radio Waves. Click on the "i" symbol for additional information with several graphics
(Previous and Next), explanations and External Links and Further Reading links.
- The Voyage — Learn about scales and distances in the Universe by travelling to a black hole in the
binary stellar system Cygnus X-1 or the Andromeda galaxy. A cockpit environment
provides a view into the Universe. You learn about the objects you are passing and you are told about your speed of travel and distance traveled.
Click on the "i" symbol for explanations of the concepts of lightspeed and lightyear, which are used to measure your speed and distance traveled.
The voyage conveys both the scale and many important contents of our Universe. At your destination you can mouse over the black hole to see brief annotations
about specific features.
- Up Close and Personal — Learn in depth about black holes by exploring them following two paths:
- The initial animation shows the view out your spacecraft window while orbiting a black hole. Text information is provided. Use the Learn More button
for additional information with several graphics (Previous and Next), explanations and Try an Experiment, Related Questions, and External Links
and Further Reading links.
- Show Questions and Experiments — Displays links to 10 questions and 5 interactive activities called experiments. The questions and experiments
can be accessed by clicking on the titles. Our present knowledge of the subjects is reviewed, as well as their history and any open questions that
we hope to answer in the future. Notable scientists and their work are featured as well.
- Questions: Each question link includes:
- text that answers the question and provides related information,
- several graphics (Previous and Next) with explanations,
- one or more related Try an Experiment suggestions,
- several Case Studies of Black Holes,
- links to Related Questions found within the Web site "Black Holes: Gravity's Relentless Pull", and
- External Links and Further Reading.
- Experiments: Each experiment link provides an interactive activity that starts with detailed Instructions. At the end of each experiment a
Learn More button provides access to additional information with several graphics from the experiment (Previous and Next), explanations and
Related Questions and External Links and Further Reading links.
- Black Hole Encyclopedia — Provides quick access to the didactic content in the
Journey to a Black Hole modules. The encyclopedia consists of 3 parts.
- Physics: The Nature of Black Holes — Contains links to the site's questions and experiments that relate primarily to the physical
understanding of black holes.
- Astronomy: The Formation and Existence of Black Holes — Contains links to the site's questions and experiments that relate primarily
to the astronomical investigation of black holes.
- Glossary: (see below)
- Footer Navigation Buttons
- Content Overview (this page) — An overview of the Web site "Black Holes: Gravity's Relentless Pull" and a detailed discussion of its contents.
- Credits — Includes background information regarding the creators and content of the Web site "Black Holes: Gravity's Relentless Pull".
- Contact Us — Provides a way to contact the administrators of the Web site "Black Holes: Gravity's Relentless Pull".
- Glossary — Alphabetical listing with definitions of key terms used in the Web site "Black Holes: Gravity's Relentless Pull", with Further Reading links to related information.
- How to Print — Instructions for how to print Journey to a Black Hole screens (which may not print well by the usual methods of printing from a Web browser).