(1) Expanding i.e. creating new material.
The most recent major expansion has been "The Great Magnet, the Earth", in 2000. I have also considered sites on electricity, hydrostatics (buoyancy), possibly math ("Numbercrunch"), and might yet produce them, if I ever find the time. Creating new sites requires writing skills and thorough familiarity with the subject; if anyone reading this feels he or she has a good subject to add, with an idea of how it could be presented, I am open to suggestions.
Minor expansions occur all the time. In recent years "Stargazers" has added sections on lunar librations, on nuclear weapons and on the black hole at the center of our galaxy, also 8 sections on quantum physics and three on the Doppler Effect," including dark matter and dark energy. "Secrets of the Polar Aurora" was added to "Exploration of the Earth's Magnetosphere" and a history article "A Millennium of Geomagnetism" to "The Great Magnet, the Earth." Smaller expansions included additional problems and exercises in algebra and trig.
Occasionally existing sections are expanded--e.g. a recent message, quoting Aristotle on the round Earth, resulted in an appendage to section #8 of "Stargazers" (one not listed in the index). The section in "Exploration" on the aurora of 5 November 2000 wass based on letters exchanged at that time, and a recent article on migrating birds using magnetic sense to navigate at night led to an addition in "The Great Magnet," on a page describing early uses of the magnetic compass by navigators.
The question-and-answer sections of the three sites are constantly expanded, as new material comes in; as of April 2009, in the three above web sites, they contain (419, 121, 119) items. To help users, a new linked index was added to each, with questions classified by subject (not by order of arrival).
Those sections are divided into segments of about 40-100K to speed up loading, although to the user everything appears as a single file. Most Q&A sections are also linked from the bottom of the web page to which they are most relevant, often providing users with an alternate approach to the material.
The style of the web pages is informal, stressing history, applications to space and technology, and connections to society and culture, as well as the international nature of science. All these are discussed at greater length in "Using Space to Teach Physics" which appeared in The Physics Teacher in February 1999 (the link is to a draft version), and browsing through the files provides many related examples.
The layout of the web pages is similar to the one used here. Originally, fancy graphics that slow down loading were avoided--sidebars, logos, fancy buttons, Java applets etc.--only a background color. This was changed in 2006, on the recommendation of NASA reviewers, when navigation bars were added, on top, to material in various collections (e.g. lesson plans), and on the left, to nearby files in the collection. All files have sections for the benefit of search engines, and the index can be reached from links both at the very beginning ("Site Map" in the top left corner) and the end of each page (link to the home page).
Ease of reading is essential: most readers do not stay long with solid unbroken text, no matter how interesting. Key words and phrases are therefore rendered in bold face type; like subheads in newspapers, these provide places to rest the eye. Newspapers also ease the reader's job by using narrow columns and short lines of text. All too often, computer users extend windows to the full width of their screens, making text lines uncomfortably long. Here lines are shortened by using a "table" format with invisible borders (BORDER=0), which limits them (usually) to a percentage (e.g. 65%) of the window width, or a number of width units, typically 500-600 but more when text shares space with medium-size images.
Images are usually aligned to the right, for a less abrupt transition between text and image. Other tricks also
help break monotony--words presented in red, italics, numbered lists and so forth.
How familiar should an author of such pages be with HTML the encoding language used by web documents? I am not sure, although (obviously) the more one has, the better. Nowadays programs exist (in many word processors, and more elaborately, in software such as "Dreamweaver") which eliminate that chore. You write and format regular text, and the specialized program transforms everything into HTML.
I never use such codes, but write the HTML myself--often composing the text in TEXT format (or converting to it), then embedding HTML commands. Experienced HTML programmers, I was told, prefer that way, too. One only needs basic knowledge, as can by got from Joe Burns' "HTML Goodies" which also exists on the web (though the book is handier); I do not use style sheets. Not only does this give much better control, but editing is much easier, since the automatic codes spread out the text and often leave behind non-functional code. If you ever want to get back to the file and add or change, you'll appreciate an orderly layout of your HTML code.
Translation by untrained volunteers is also easier--the translator only need translate the text of each paragraph, embed in it commands for bold letters etc., then replace the English paragraph with one in the new language. The formatting, images etc. remain as before.
Like weeds in a garden, typos and minor errors crop up all the time, in spite of all efforts. Some are only noticed after many years, others are pointed out by correspondents. A careful dated tally is kept of all changes and additions on a file "Amend 2," now extending to more than 60 pages.
Some updates have been "global," instituted across the entire site. These included adding at the start of every section a link to a "site map" index, because too many users were directed by search engines and seemed unaware of the scope of the sites. In addition, the symbol "@" in my return address was replaced with "("at" symbol)", to foil "address harvesters" for spam lists. Even earlier, the "mail to" command was removed for that same reason. Other global updates included adding an "ALT" designation to images to help blind users (a NASA demand) and changing captions in Q&A collections to red letters.
Updates also add new information on existing web pages, e.g.:
- A trip to Seward, Alaska, provided new details about Benny Benson (Spolaris.htm);
- Casual reading added information about Persian and Ethiopian calendars (Scalend.htm);
- The long timeline in "stargazers"--with items relevant to the text embedded in others from the history of society and technology (and also linked to relevant web pages--was recently expanded from 1988 to 2005;
- The experiment on induced magnetism in "The Great Magnet" was modified; other experiments or projects are also later additions--on the interplanetary magnetic field, on Oersted, on Galileo's experiment and on the inertial balance.
Changes are also made when it seems that a clearer presentation is called for. Not long ago a German girl wrote and asked--how did the builders of Stonehenge know where north was--did they perhaps have an early version of the magnetic compass? I then realized that the first section of "Stargazers" assumed too much and split it in two, with the first one starting by defining and explaining what was meant by north, south, east and west.
Pages are cross-linked, but links to outside sites are problematic. All too often a link to some very appropriate and interesting web page disappears a few years after being cited. "Astronomy Pictures of the Day" (APODs) are a good resource, and seem more or less permanent. Copyright questions led me to draw almost all of my images; they look crude but do the job, and I feel flattered when someone asks for permission to reproduce any of them.
References are also made to journals and books. Though most of the material is relatively elementary, some references cite journals such as "Science" and "Nature", as well as fairly technical books, which allows knowledgeable readers to go to a more technical level. Non-technical readers are warned when the material becomes more complex, but such citations also help impress them that here is "serious science." Those with a good grounding in science seem to appreciate a coverage which is "open at the top."
Answering correspondence always takes time. I have become quicker at it (too quick, as typographical errors attest) but the volume has also grown to about 1-2 per day.
Short, simple questions are answered at once, and if they are trivial no paper copy is kept. Students looking for someone to do their homework, or asking for an interview for their assigned projects, get a firm "no." Questioners who seek a reference usually get it, even if I have to go on "Google" and search--one could tell them to go there themselves, but the process often teaches new things.
Some mail comes from fringe-science people, ranging from honestly mistaken to crackpot. Many describe ideas which are clearly wrong but which they regard as novel. I may be somewhat overly conscientious in sending detailed, technical and serious replies to such messages, never invoking authority but citing observations and theory. Most of these people (if not all) are sincere believers, feeling their ideas are more profound and logical than those of professionalss, and I try to show them that scientists have in fact explored an amazing variety of possibilities, also have applied math and conducted observations, much more than they realize.
The hope is that this might impel at least some correspondents to read more or to tone down their claims, and not waste their own time and attention on fruitless efforts. One sometimes wonders, though. One Moslem lady wrote about her attempt to derive fundamental science by interpreting the Quran. I wrote back cautioning her that Western culture at one time similarly believed the Bible held the key to nature, which led to the trial of Galileo, now recognized as a grave mistake. She replied--yes, she knew all about Galileo, and my point was well taken. But with the Quran, she knew the science was all there.
Some correspondents are college students or physics teachers, and I try to support their interests, sometimes suggesting contacts, often sending CD disks with my files (less in recent years, after condensed "zip archives" were made available on the web sites). Being a NASA emeritus carries mail and xerox privileges, and the "Problems" section of "Stargazers" promises to send solutions to teachers who request them on their school's letterhead. Such requests are honored, and a disk is usually also enclosed. Requests to use material or images are granted, or else are directed to the owner of the material.
The messages I enjoy the most are from people who seek new knowledge. I try to reply in detail, often consulting books or the web. Inquiries come from all continents and range from the mundane to the bizarre--e.g. who owns the Moon, and how many calories per day does a polar bear need (I guessed 60,000, probably a factor 2 overestimate, but also gave a reference). The hardest question, which led to a long correspondence with several people, was--why does the left-hand pedal of a bicycle need a left-hand thread to prevent it from becoming unscrewed? Among the many questions about space and magnetism, two seem to recur. Was the Apollo landing a hoax, since no astronaut (it was claimed) can survive passage through the radiation belt? And: can a reversal of the Earth's magnetic polarity occur soon--and if so, would it endanger life? Both these were fanned by movies and TV.
In all correspondence, and indeed, in anything that goes on the web, the simplest English wording is used, and all terms are defined. For instance, "magnetic force" gets preference over "magnetic field," unless the latter is defined (e.g. as "region in which magnetic forces may be observed"), and "different kinds of light" (or a similar phrase) rather than "electromagnetic spectrum." Unfamiliar acronyms are always defined, too.
Anything written--letter or web page--must be reread (best, more than once) with the thought "where can the reader possibly get a wrong impression?" If any ambiguity is found, that part is rewritten. I recall a publicity-minded professor of mine, early in the space age, who was asked what would happen to riders of an airplane in the polar stratosphere if a big solar flare went off. Dramatically, he spread his hand and said: "Pouff!" It was quoted in the press and embarrassed the university.
Publicity is a hard but essential task. Many web sites compete for attention, and the "signal to noise" ratio on the web is not encouraging. NASA and its contractors have a large, fancy web presence, with ample funding; they cite each other extensively and for that (and maybe for other considerations) they get preferential treatment from search engines, though the material is often flashy and shallow. NASA has not promoted "Stargazers" and related sites, except as marginal links. As a result, it has been my impression that most users reach my sites not through their home pages but by asking a search engine about some peripheral subject, e.g. Lagrangian points (others may hear of them by word of mouth). Judging by messages received, many such users often remain unaware of the full scope of the site and never visit the home page. That was why a "site map" link was later added at the top left of every web page.
Articles have been published in "The Physics Teacher" about these web collections: "Space Physics for Poets," by D.P. Stern and M. Peredo (The Physics Teacher, 35, 38-9, 1997), and Using Space to Teach Physics by D.P. Stern, (The Physics Teacher, 37, 102-103, 1999). The sites also contain an unpublished paper "Teaching about the Earth's Magnetism in High School," a subject further expanded in a talk given in a meeting of the Natl. Assoc. of Science teachers. Another talk describes an early version of "Exploration of the Earth's Magnetosphere," and other talks told about magnetism to NSTA members or to a teacher's workshop, or guided teachers in presenting Kepler's laws.
Over the years I have often written to webmasters, asking to be linked, and have proposed links to Google, Yahoo, and DMOZ.ORG. It takes appreciable work--even when the letters are variations on a standard format--and results are slow to show up. Some such messages go to sites visited while searching for material. One also learns a lot by typing the title of one of these pages into (say) Google and seeing what comes up: too many web sites seem aware of some of the files but not of the rest.
Such searches have also uncovered unauthorized "mirror sites" where institutions have placed copies of the material on their own servers. I do not mind such copying ("most sincere form of flattery" etc.), but when the material is years out of date, I offer the webmasters up-to-date files on a CD. Results are mixed: a site in Russia never replied, one in the US removed all files, and one in Japan gratefully posted the new files, but they then disappeared after a few years.
The web servers used here
The first site, "Exploration of the Earth's Magnetosphere," was posted in 1994 with the goal of making the general public more aware of my own field of research, by providing a clear, explicit, self-contained and non-mathematical exposition.
Its impact was much more modest than was hoped. As intended, it does enable a person with only a basic knowledge to acquire a fairly detailed understanding of its area, better than that of most NASA science administrators. But doing so requires persistence and motivation, because a lot of material is covered.
At that time I worked with Dr. Mauricio Peredo, a post-doctoral associate who was also interested in outreach, and as a favor he placed it on the web server he was supervising for the ISTP (International Solar-Terrestrial Physics) program at www-spof.gsfc.nasa.gov ; "gsfc" stands for Goddard Space Flight Center and "spof" was the acronym of his data facility. Later links also responded to istp.gsfc.nasa.gov , and when the ISTP program ended and was replaced by the PWG trio of satellites (Polar + Wind + Geotail), also to pwg.gsfc.nasa.gov . All these are just labels, linking the user to a computer at the NSSDC facility (National Space Science Data Center) at Goddard.
Most links to these collections still refer to one of those URLs, and and the sites are often described as belonging to NASA, which they are not. It has been one of my disappointments that even though time and again NASA support was sought--both in formal proposals and as informal requests--it was always turned down. Perhaps it comes from not being part of some larger institution supported by NASA.
The material underwent NASA evaluation in 2005-6, yet NASA declined to add the material to its list of resources. Its web pages give top billing to sites of organizations NASA supports, while "Stargazers" etc. are placed near the bottom or left out. Yet NASA has never created any comparable material at the high school and beginning college level, and no comparable source of such material exists anywhere else on the web. I sometimes feel like Cinderella, waiting for the fairy godmother and the glass slipper.
Gradually I began feeling uneasy about investing so much in a site which had no official standing and was only kept on the server as a favor. (Indeed, it later turned out that the head of NSSDC was unaware of those files, and they ran the risk of being purged during some routine clean-up. That was since fixed. Another time I was told by a NASA educator "we have no responsibility or funding to maintain your sites.") The programmers updating my files at Goddard Space Flight Center were paid by other projects which had prior call on their time, and my educational material only received attention when free time opened up. In the end I therefore bought the domain www.phy6.org ("phy6," pronounced "physics," is also my car's license plate) and my son Allon arranged with a friend to host the files. It now (9/07) gets about 60,000 hits per day (about 28,000 pages), a number still growing.
The NASA sites had 1,217,000 hits in December 2001 (219,000 pages, 7000/day), after which statistics stopped. They are now accessible again: including the new server, the use of my files has reached about 1,200,000 pages per month (early September 2007; pages--not hits), though the number drops in mid-summer.
The web is world-wide, and one easily becomes ambitious when communicating to the entire world. This is after all a unique resource on space-related science, at a level the public can understand. Indeed, messages come from all continents, and web statistics include all countries.
However, not everyone speaks English--in particular, the main first language in the Americas is Spanish, not English. I therefore issued a call for volunteer translators, with many interesting responses. Unfortunately, the project has no budget and no outside funding, and many volunteers quickly back out once they realize the magnitude of the job. With just a little funding, I could have got (for instance) a good Russian translation by a scientist. But being unable to support him, all I have is one sample translation of a key web page.
Concerning Spanish, I was fortunate to find a conscientious translator, Mr. Jesus Mendez, a naval architect working in a chemical plant near Bilbao, Spain. He gradually translated most of the files, and his work is now being updated by Felix Perez of Burgos, Spain, Thamara Quintini in Venezuela, and Marina Berti in Vermont, More recently a major expansion of Spanish sites was undertaken by Horacio Chavez, an engineer in a papr mill in Anahuac, near Chihuahua, Mexico. Horacio even started translating lesson plans. On the other hand, so far no help has materialized from UNAM, the national university of Mexico.
A French translation of "The Great Magnet" was sponsored by the Belgian space effort, two volunteers in Paris are about halfway through "Exploration", and "Stargazers" was translated by Dr. Guy Batteur, a retired French surgeon "for his own enjoyment." Almost all of his files are now on the web, each has taken about an hour of extra work.
An Italian translation of "From Stargazers to Starships" is underway, conducted by Giuliano Pinto. The initial group of pages, on astronomy, is already on the web.
In German, a research fellow in Leipzig, Dr. Sven Friedel has translated "The Great Magnet, the Earth," and an evening school teacher in Berlin has assigned his students to "Stargazers"--it is stalled now, but I hope it gets done. Jan Motyka in Chicago has started on "The Great Magnet" in Polish, and Iyemori Toshihiko with 4 colleagues in Kyoto have translated that collection to Japanese. Other attempts were promised in Chinese (All of "Stargazers"!) and Iranian.
Other efforts did not get far anough. Inquiries have come from Greece, Turkey, Iran, Ethiopia, and a few files were translated into Japanese, Chinese and Portuguese. One Japanese professor wrote he would have liked to translate "Exploration", but cannot find the time--and besides, by making his students study it in English, they learn English as well!
Of course, languages like Russian, Greek and Japanese use different alphabets, and even French, German and Spanish need special letters, which complicate the task. Coordinating translations has taken a lot of time and effort, and I started a search for a volunteer coordinator. Regrettably, some contacts have slipped for lack of time and energy,
(6) Long term goals
Where does all this lead? I view this web project as part of a widespread movement to use the web for making information openly available to anyone seeking it. There already exists a "Gutenberg Project" to place major literature resources on the web, maps are freely available, medical advice, dictionaries, etc. etc. My sites try to open areas of astronomy, space, physics and geophysics to people who want to educate themselves--not as dry technical manuals, but in an attractive format which wraps together science, technology, history and diverse aspects of culture, in as many languages as possible. Nothing else fills that niche. Although primarily aimed at self-study, they also try to cater to teachers in our public schools (and in universities) where the need for interesting science material is great.
It is an ambitious effort and may ultimately require more than one person. I would like to see it keep going--perhaps even expand it to additional areas, if I am granted the time and the strength.