A Beginner's Guide To The World-WideWeb

During the past year, a lot of excitement has been generated about the Internet in general and the World-Wide Web (WWW) in particular. I would venture to say that a certain portion of the readers of LPIB are already familiar with "surfing the net," but if you are one of those who have not had a chance to experience the Web yet, I would like to give you a quick tour. In less than the time you might spend reading one of the LPSC abstracts, I am going to describe some of the basics about accessing information on the Web.

What is the World-Wide Web?

Even though the Internet has been around for a while, it had always required users to learn a lot of arcane Unix commands before becoming proficient at getting around on the Internet. In 1989, the European Laboratory for Particle Physics CERN in Switzerland initiated the World-Wide Web project, and later the National Center for Supercomputing Applications (NCSA) at the University of Illinois developed a program (called a browser) named Mosaic that made navigating the net as simple as pointing and clicking a few buttons with your mouse. This has greatly simplified the process of information gathering and, as a result, the popularity of the Web exploded.

The World-Wide Web is a global hypermedia system that delivers text, graphics, sound, and video over the Internet. The best way is to think of it as a global virtual library where, with the click of a few buttons, images and text are automatically and transparently retrieved from sources around the world and displayed on your computer screen. All this is done without your having to know where the documents are stored or how they are accessed.

Why do I want to get on the Web?

With its newfound popularity, the WWW is fast becoming the tool of choice for universities, government agencies (e.g., NASA and NSF), organizers of scientific conferences and workshops (e.g., LPSC, DPS of AAS), and commercial companies to deliver information to their users and potential customers. It is also a fast and efficient way for users to find and access information online. Thus it is both a means to disseminate timely information, such as providing conference programs and abstracts to potential attendees, as well as a tool to search archival databases, such as the electronic abstracts at the Astrophysics Data System (ADS) or the images from a particular planetary mission from the Planetary Data System (PDS). And the subjects need not be confined to scientific research, since you can browse the collection at the Louvre just as easily as you can take an electronic tour of the White House or the Library of Congress.

How do I access the Web?

To get on the Web, you need two things. First, you need a program called an information browser such as Mosaic from NCSA. It runs on PCs , Macs, and X-windows displays. If you do not have one on your machine, talk to your computer systems manager and it can easily be set up on your computer*. It is expected that when Microsoft ships its Windows 95 product later this year, a web browser will be automatically installed in the Windows package. Second, you need to know the Uniform Resource Locator (URL) of the Home Page of the place you want to get the information from. The URL is like an electronic address on the Internet and the Home Page is like the entrance to your house. You may remember that not long ago, you added your fax number and e-mail address to your business card. Well, the URL of one's Home Page is fast becoming another line you find people scribbling onto pieces of paper when they exchange information. With these, you are ready.

An Example

I will use accessing the LPI Home Page via Mosaic as an example. The URL for the LPI Home Page is:

http://www.lpi.usra.edu/lpi.html. After you have Mosaic opened on your screen, usually by typing the word mosaic or clicking on the mosaic icon in your Windows, you click on the "file" button and select the "open URL" option. Type in the URL (http://www.lpi.usra.edu/lpi.html) and hit return. The LPI Home Page should appear on your screen after a few seconds. It is a large image map with icons embedded in it. You can click on any of the four icons on the right side of the image, i.e., Description, Hot Topics, 26th LPSC, and Online Services to access information contained within the Home Page. Each click will launch you to the next level of information. If you are not using a browser that can display images, you can use the text index, which is highlighted and underlined.

Suppose you click on the Hot Topics icon: It will bring up another page of topics on your screen. If you click on Clementine Images, yet another screen appears with thumbnail images from the Clementine mission listed on the screen. Clicking on each image will bring the full image to the screen. Clicking on the word "caption" will display the image description. If you place the mouse arrow on the image and then click the right button, you will bring up a menu. With this menu, you can double the size of the image, save the image to your local disk, or rotate the image, just to name a few operations.

If you click on the 26th LPSC icon instead, the page for LPSC information will appear. Click on "Conference Announcements" to get the first, second, or third announcements. Click on "Program and Abstracts" to get the time and room number of talks. You can search for authors, speakers, and topics, and have the information displayed with or without the abstract. If you click on the "Print" button, you can have the information onscreen printed to your local printer, or you can e-mail the information to yourself by clicking on the "Mail to" option. Clicking on the "Back" button will bring up the previous page on the screen; repeating "Back" allows you to retrace your path through the Web.

Using the hypertext features of the Web, most home pages point to other home pages with related information. For example, from the LPI Home Page you can click on the highlighted text "PDS" (Planetary Data System) and the PDS Home Page will appear on your screen after a few seconds. Using this technique, you can roam the globe from continent to continent. A feature known as the "Hotlist" allows you to record the URL of places you have visited for return visits at a later date. This is equivalent to a list of frequently dialed numbers on your phone and is a handy way to get around without having to type in URLs all the time.

Some Observations

Someone once wrote that surfing the net is like going to college for the first time and discovering pizza parties. Some will like them so much that they'll skip classes and have all-night bull sessions with anchovies, pepperoni, and beer. Some will taste the pizza once and swear off pizzas completely. Some will partake in moderation and find the experience a refreshing break from their homework. Pizza, anyone??

* NCSA Mosaic can be downloaded free for noncommercial use by anonymous ftp at ftp.ncsa.uiuc.edu. A character mode browser called Lynx is available to run on Unix, VMS, and PCs from the University of Kansas. The program can be downloaded by anonymous ftp at ftp2.cc.ukans.edu. Also, commercial services like Prodigy have an option to connect to the WWW for an hourly rate. Other commercial services like America Online and Compuserve are also planning such options later this year.

--Kin Leung

(Mr. Leung is the LPI Computer Systems Manager and the Project Manager of LPI Online.)

Useful Planetary Science World-Wide Web Addresses

There is a wide array of planetary-science related information available using Mosaic and the World-Wide Web. Many of the locations listed here remain "under construction," so you may wish to revisit interesting sites from time to time.

We'll start our survey with the LPI Home Page, where you will currently find announcements of upcoming conferences and of the Undergraduate Summer intern program, a collection of databases and images, and on-line versions of recent LPI Bulletins.


The NASA Home Page (includes connections to home pages for the various field centers)


Guide to NASA Online Resources


NASA Public Affairs


Recent News from JPL


Hubble Space Telescope Images


The Planetary Data System Home Page (includes connections to the various PDS nodes)


PDS Geoscience Node


PDS Imaging Node


The National Space Science Data Center


The National Geophysical Data Center


The National Center for Atmospheric Research


Shuttle Imaging Radar (SIR-C)


Johnson Space Center Digital Image Collection (Earth Observations and Manned Space Flight Press Release Images)


Many recent and upcoming NASA planetary missions have Web home pages, including the Magellan Project


Magellan Image Browser


Clementine Project



Clementine Image Browser


Project Galileo


Mars Global Surveyor Mission


Mars Pathfinder Project


Near Earth Asteroid Rendezvous Mission


A number of sites provide access to imagery from the Comet Shoemaker-Levy 9 impacts with Jupiter. These include



Hyperlinks to these addresses are available on the LPI Home Page in the "Online Services" section under the heading "Useful Planetary Science WWW Sites." This survey has undoubtedly omitted other sites of interest to the planetary science community. If you know of other Web sites that should be brought to the attention of LPI Bulletin readers, send the http address to thompson@lpi.usra.edu for inclusion in a future issue of the Bulletin. Happy Webbing!

--Walter S. Kiefer, LPI