GATEWAY TO PHYSICS

by David Porthouse

It is hoped that this GATEWAY TO PHYSICS will assist newcomers in finding their way around the world of physics on the Internet. You might consider bookmarking this Gateway at once. The author is very keen on computer movies to teach physics and there is a companion page of links to relativistic flight simulators which is a prime application of Internet-based computer simulation.

TIPTOP, The Internet Pilot To Physics, aims to be the principal specialised search engine for physicists. You can do searches on various topics by clicking on TIPTOP's search page. TIPTOP is now under the wing of the Institute of Physics of London.

Another service is offered by PhysLINK. Note that PhysLINK is not a rival service to TIPTOP, because TIPTOP is a search engine like Infoseek or AltaVista, while PhysLINK is static pages of links like Yahoo or Galaxy. There is definitely room for both types of service in the world of physics.

MM-Physik has German as the base language. Many hotlink titles are in English, making this as good a guide as any to physics in the English-speaking world. There is a menu page and a page on computer software, mainly JAVA. There are mirror sites at GeoCities and CompuServe which are kept up to date.

Next we have various libraries for you to look at:

Yahoo's physics page has fully up-to-date mirror sites in Canada, Britain, Singapore and Australia.

Here is our collection of Institutes of Physics (or the equivalent) in America AIP, America APS, Australia IoP, Britain IoP, Canada CAP, Europe EPS, Finland FPS, France SFP, Germany DPG, Ireland IoP, Italy SIF, Japan JPS and Russia GPI. We will be happy to add to this rather uneven list. Please e-mail the author with suggestions.

Dr. Reza Toossi has an interesting page of links to physics software.

Software, particularly JAVA applets, may be found in TIPTOP's VLAB. PhysLINK also has a page of software links.

For something quick and easy you can see at once, click here or on the picture below. This is a sequence of frames from the author's relativistic flight simulator converted to 'plain vanilla' GIF format. You click on each frame to see the next. This does not require JAVA, MPEG or any big run-time support system.

You can get the QBasic program which produced this computer movie from the author's website. There really is free software available for anyone to download and run. If you produce free software yourself, please consider adding a short and sweet sequence of chained GIF files like this. If people have to download a massive run-time support system, you need to offer them some incentive. Even JAVA programmers should remember that many of us are still using Mosaic. Many of the JAVA contributors in TIPTOP's VLAB have been good enough to provide alternative viewing like this, and they are to be complimented on their thoughtfulness.

If you want some instant software, then download QBASIC.ZIP (about 48 K) and unzip it. You will find the source code of some Microsoft QBasic programs including the relativistic flight simulator which produced the picture above. If you don't have the QBasic interpreter available, then you can find ready-to-run EXE programs in EXE1.ZIP (about 159 K) and EXE2.ZIP (about 225 K). These EXE programs are rather longer by their nature, but work better if you have a maths co-processor (any 80x87 or 80486 DX or Pentium).

In EXE1.ZIP you will find the relativistic flight simulator, a simulation of the Kelvin-Helmholtz instability and a simulation of the Von Karman vortex street. In EXE2.ZIP you will find a Van Allen belt demonstration, a many-body gravitational simulation, a wave-particle duality demonstration, a Fitzgerald contraction and relativity of simultaneity demonstration, and another short program on the Kelvin-Helmholtz instability. All these programs appear in QBASIC.ZIP, and those which require plenty of number-crunching are grouped together in EXE1.ZIP for convenience. Even if you have QBasic available, you may wish to run compiled object code in the case of the programs in EXE1.ZIP, but if you have already downloaded and run everything in QBASIC.ZIP, then there is no need to download EXE2.ZIP since there is no worthwhile gain in performance with running the object code of programs in this second group.

In all these ZIP files there is also a README.TXT, but it is the same README.TXT in each case, so you don't have to worry about obliterating a previous README.TXT upon unzipping another ZIP file.

If you want to start collecting software, then Wade Lutgen's relativistic starflight could be your next place to go.

Many physics departments in colleges will have a single computer linked to the Internet run by a member of staff, and many unlinked computers available for student use. This arrangement is likely to be a permanent one. In SHELL.ZIP (about 27K) you will find some rudimentary Intranet support software. There is a simple SHELL program to run the software from, a TRANSFER utility to enable you to shift everything from computer to computer, and a READTHIS.TXT to tell you what is going on. At this stage we are simply establishing the idea of Intranet utilities. More should come later.

ISPEC, the International Space Physics Educational Consortium, deals with space physics.

Astroweb, the principal service for astronomers, has a subsidiary page on physics-related resources. There is also a page entitled 'Pretty Pictures'. A mirror site for AstroWeb is incorporated into the World Wide Web Virtual Library.

The connection to physics may be tenuous, but we'll give NASA, the U.S. National Aeronautics and Space Administration, a mention.

Scientific American is a well-known U.S. monthly science magazine published in several languages and normally available anywhere in Great Britain, for example.

New Scientist is a British science weekly. There is also New Scientist Hotspots.

The author's favourite general-purpose search engine is Infoseek, and AltaVista also warrants a mention. If you are setting up a website, publicise it first in Infoseek, AltaVista and TIPTOP in that order. Read the author's views on Link Syndication and consider an exchange of hotlinks as recommended.

Other well-known search engines are Excite, HotBot, Lycos and WebCrawler.

MetaCrawler is a search engine which does not maintain a database itself, but instead passes your enquiry to other search engines and collates the results. It does a good job of collation and eliminates rubbish. Note that Yahoo can also offer a tour of the major search engines, but you have to push the buttons yourself.

Advertisement: Click here to read about the author's recommended best practice on search engines.

You can find out about Internet news groups in DejaNews. You can find software in SoftSeek.

If you have a website which you want to promote, then read what advice this author is giving.

Some advice about graphics may be found by clicking here. This tells you about GIF and JPG, and how the picture which appears above was derived from a QBasic program.

Suppose you are looking for something on the Internet. Often you need to know some key phrase such as quantum mechanics measurement problem in order to find it. A preliminary list of such 'magic words' may be found by clicking here. The idea is to get us all speaking the same standard jargon as quickly as possible.

The Dewey Decimal Classification number for physics is 530. Click here for more information. BUBL uses Dewey numbers.

You may be pleasantly surprised by what your local library can now offer. Recently the author went to his nearest library, a very ordinary branch library, to order a paper from a physics journal. He filled out a card and paid 60p (about one U.S. dollar), and the paper arrived from the British Library about two weeks later.

Times are hard and jobs for physicists may be not all that easy to come by. We advise you to learn C++ and JAVA if you do computational physics, in order to have some knowledge that could get you a job elsewhere. This is no reflection on the intrinsic merits of other languages: some Pascal-like language would have been a better choice, but C++ it is.

Learn HTML. The 'ML' bit is also a decent typesetting language, so your curriculum vitae could be turned into a file such as CV.HTM, and printed out using any web browser (the author still uses Mosaic) and a bubblejet or laser printer. Here is the 21st Century literacy test: you fail if you cannot do a simple task like this.

The author's website has a subsidiary page of QBasic programs including programs on quantum mechanics, relativity, the numerical gravitational many-body problem and the Van Allen belt. There is a second page on fluid dynamics with computer simulations of the Kelvin-Helmholtz instability and the Von Karman vortex street. These last two simulations must of course incorporate a random number generator to get the necessary symmetry-breaking. The author would like to work out how to incorporate a random number generator into computer simulations of quantum mechanics, and that is the main theme of his website.

Any good textbook on quantum mechanics will tell you that the Dirac wave packet has a superluminal wave velocity but a subluminal group velocity. There is a computer simulation to show this on the author's website. The author, being a realist, regards the Dirac wave packet as something more than just a calculational device, and proposes that the wave packet can go all-superluminal any time we need a collapse of the wave function. Since phenomena involving the collapse of the wave function have a nonlinear interaction between matter and radiation, we must turn to computer simulation in an effort to see what is happening. That is why this page and this website exist.

As we said, the author is a realist and not, for example, a positivist. These words are being used in their technical sense and do not have any polemical significance. The fact that a realist view of quantum mechanics involves the embracement of nonlocal theories is nothing to worry about. We will soon be in the 21st century and we have to start thinking about nonlocality sometime.

Relativity is going to do well on the Internet. Here are some websites to get you started. Wade Lutgen's relativistic starflight program is written in C++, and can be downloaded as source code or object code like the author's programs.

Looking at the author's relativistic flight simulator, you may be thinking 'I can do better than that'. Just e-mail the author when you do, and a hotlink will appear here. Your publicity machine is already in existence.

A baby gravitational many-body program can be found among the author's QBasic programs.

Henley Quadling's gravitational many-body website is for grown-ups.

Here are a couple of computational fluid dynamics links to lists of CFD codes:

NCSA is the United States' National Center for Supercomputing Applications, best known for producing the Mosaic web browser. This is a big website.

To turn any Pentium-class computer into a supercomputer, run it in MS-DOS or DR-DOS (not Windows) with the minimum of device drivers. Configure the BIOS to power down the hard disk after a few minutes of non-use (beware of unwanted side effects) and then run it twenty four hours a day (pay attention to cooling and a decent mains supply) with the monitor switched off except when you want to view it. Some appropriate software are the 'virtual-time simulations' to be found on the author's fluid dynamics page, where the animation is de-coupled from the number-crunching. Otherwise write your own software.

Here are some links on the quantum mechanics measurement problem, but we warn you that by the nature of this subject, nothing changes quickly:

Will we ever see a computer simulation of the Big Bang? Would it demolish the Book of Genesis, or be just a latter-day Tower of Babel? Click here for a discussion. We may be firing the opening shots in a long war.

If you want to help, then please download KIT.ZIP (about 61 K) where you will find some useful files when you unzip it. HINTS.TXT makes some suggestions on how you can help to spread knowledge of the availability of free computer simulations to teach physics. NOTICE.TXT is intended to be printed out and placed on a notice board. LETTER.TXT contains a list of the most useful hotlinks, including this page, which you can print, photocopy or fax and pass on to your friends. RFS.EXE is the relativistic flight simulator for MS-DOS, but it also generates a hotlink back to this page from which better software may be accessed at a future date, so it is a useful program to give to your friends, beyond its intrinsic merits (if any). LINKS.HTM is a list of hotlinks to physics in HTML format which you can adopt on your own website, and you can re-edit it as much as you like.

Physics departments in universities and colleges all over the world are being mailed with a facsimile print-out of START.HTM which contains a selection of hotlinks fitted onto an A4 page. These pages are being sent by surface mail (the cheapest service) and priority is being given to 'Yahoo have-not' countries.

Guarantee: This page is guaranteed to be compatible with Mosaic and later generations of web browsers. It is also compatible with graphics systems from 640x480x4bp to 800x600x8bp. It will stay that way. Maybe only 1% of the world is still using Mosaic, but it is wrong in principle to cut them off, given the worldwide scope of this page. If we ever go over to using frames and other fancy features, we will preserve a low-tech low-bandwidth option for Mosaic users in distant countries. Our objective is to teach physics, and not to sneer at the primitive equipment which you are using. Once you have learnt some physics and increased your earning power, you can buy something up to date.

Special measures have been taken to maintain the reliability of this website, with critical files getting extra attention. You should find that everything can be downloaded. Please complain if it can't.

All the hotlinks on this page are expanded in their full form to enable you to pass it around as a Local File. This page is subject to continual revision, so if you received it as a Local File, you can get an up-to-date version by clicking here. Remember that you may have to re-bookmark the up-to-date version and delete the old bookmark.

Reciprocal Hotlinks

http://info.fuw.edu.pl/physics.html

http://sps1.phys.vt.edu/~pat-man/bookmark.html