A casual glance reveals only a jumble of hills, craters and escarpments. Gradually, however, as though a veil is being lifted, the blurred scene begins to feel organized and structured - too intelligent to be the result of random natural processes. Although the scale is grander, it looks the way some archaeological sites on Earth might look if photographed from 1,000 miles up. The more closely you examine it, the more it is apparent that it really could be an ensemble of enormous ruined monuments on the surface of Mars. For a long while after the 1976 Viking photographs, NASA and other scientific authorities continued to disseminate what one researcher calls "the bogus claim that the Face is a trick of light and shadow". This notion began to be challenged seriously only when Vincent Di Pietro, a computer scientist and former NASA consultant, discovered another image of the Face on frame 70A13. This second image, which had been acquired 35 Martian days later than the first one and under different lighting conditions, made possible comparative views and detailed measurements of the Face.Complete with its distinctive Sphinx-like headdress, it is now known to be almost 1.6 miles long from crown to chin, 1.2 miles wide and just less than 2,000 ft.. high. Image analysts say the bilateral symmetry of the Face, which has a natural, almost human appearance, is most unlikely to have come about by chance. This impression is confirmed by other characteristics that have subsequently been identified under computer enhancement...

In 1976, the Viking 1 Orbiter took the first photographs of the Cydonia region of Mars, showing what appeared to be a humanoid face one mile long and 1,500 feet high. UFOlogists immediately jumped on the photos as prove of a previous or present intelligence. NASA quickly bashed these theories as simply a trick of light and shadow. The Cydonia region also contained what appeared to be several pyramid-like objects, which some researchers claim are not formed by natural occurrence. The strange loss of the Mars Observer as it made its way to the red planet in 1993 temporarily dealt a blow to any hopes of obtaining new, closer photos of this puzzling region of the planet. Some submitted that the craft was not lost, but that what it found was too controversial for public knowledge. Of course, there is no way to prove this contention. NASA was accused of knowing much more about Mars and its extraterrestrial connection than it would admit.

The subsequent refusal of NASA to land the Sojourner near the Cydonia area only furthered the contention of many that the space administration was deliberately leading its technology away from the controversial area. NASA's explanation was that there were other areas which were much more hospitable for a landing sight. With pressure from the general public being the main catalyst, NASA finally agreed to re-shoot the Cydonia area on a follow-up effort. Released on April 6, 1998, new pictures only added fuel to the fire. These "new" photos only deepened the mystery, leaving no "clear-cut" tag to stamp on the images. It seems that only a future manned mission, or closer, more accurate photography will clear the air. We must remember that here on our own planet there are many structures which are not clearly defined as natural, or man-made.

In August 1996, a group of scientists announced that they had found evidence of ancient life on Mars. This evidence included bacteria-shaped objects and organic chemical molecules in the martian meteorite ALH 84001, which was collected in Antarctica. In the next few days, NASA presented the work at a press conference, the President made a statement about it, and the TV and papers were full of reports, speculation, and jokes about life on Mars.

Most of the world was unprepared for possible traces of martian life in a meteorite. Collecting meteorites in Antarctica was novel; the idea of martian meteorites was bizarre; knowledge of Mars was sketchy; and knowledge of primitive life on Earth was limited. Much of the important information is hidden in technical journals, written by specialists for specialists.

With this slide set, we hope to make some of this information accessible. The slide set and captions are divided into sections on Mars, Antarctic meteorites, ALH 84001 and its possible traces of life, and exploration of Mars and the universe. Most slides and captions can also be used independently. Terms defined in the glossary are underlined the first time they are mentioned in this booklet. The suggested reading portion of this slide set has been updated to include research published since the time of the first edition, and some of the captions have been updated to reflect the success of recent missions.

Mars

Mars is the fourth planet from the Sun, and is the outermost of the ?terrestrial? (Earth-like, or rocky) planets. It is the second closest planet to Earth. With a diameter of 6788 kilometers, Mars is about half the size of the Earth. Its elliptical orbit, thin atmosphere, and lack of an ocean give it an extraordinarily wide range of surface temperatures. Near the equator, high temperatures can reach 22?C (72?F) in summer; at the south pole in the dead of winter, lows can be -125?C (-255?F).

The surface area of Mars is equivalent to the land area of Earth. Mars appears reddish because much of it is coated with iron oxide minerals (the material that forms rust on Earth). Its atmosphere, composed primarily of carbon dioxide, is very thin. Air pressure at the planet's surface is about one two-hundredth of the air pressure on Earth. As on Earth, clouds form and dissipate each day (one Mars day, called a ?sol,? is 24 hours and 37 minutes long), and the global atmospheric circulation is driven by seasonal changes in temperature. Occasionally, winds raise dust storms. These are usually short-lived and local, but can grow to global proportions (most frequently when Mars is closest to the Sun).