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University of Iowa News Release

Jan. 30, 2004

UI's Don Gurnett To Lecture Feb. 3 On The Search For Water At Mars

University of Iowa professor and space physicist Don Gurnett will deliver a free, public lecture on "The Search for Water at Mars" beginning at 7:30 p.m. Tuesday, Feb. 3 in Lecture Room 1, Van Allen Hall.

Using slides, Gurnett will discuss the fascinating history of the exploration of Mars as well as his current research, which involves a NASA-funded project to search for underground water on Mars. The project uses a radar instrument aboard the European Space Agency's (ESA) Mars Express spacecraft that began orbiting Mars Dec. 25, 2003.

Called MARSIS (Mars Advanced Radar for Subsurface and Ionospheric Sounding), the joint Italian-U.S. project includes scientists from the University of Rome, the Jet Propulsion Laboratory and the University of Iowa. The radar, a major part of which was designed and built at the UI, is scheduled to be turned on in April, when it will probe the Martian surface to a depth of as much as five kilometers -- about three miles. If it works as expected, scientists hope to detect liquid water deep below the surface, and then map the locations of subsurface water across the planet. The radar should also reveal boundaries between different kinds of geologic materials, such as layers of lava, sheets of sand, sediments, debris from impacts and ice-rich rock and soils.

Gurnett notes that the presence of water has important implications for the possible existence of life at Mars, past or present. Opinions about the existence of water at Mars have fluctuated wildly over the course of history. For example:

--In the late 1800s, G.V. Schiaparelli made a detailed study of Mars in which he thought he saw surface lines, an observation later called "canals."

--At the beginning of the 20th century, financier and astronomer Percival Lowell promoted the idea that the canals were developed for irrigation by an advanced civilization, and popularized the idea in his book, "Mars and Its Canals" (1907).

--In 1907, the Wall Street Journal stated that the most important event of the year was "the proof by astronomical observations that conscious, intelligent life exists on the planet Mars."

--In 1938, Orson Welles' broadcast of "War of the Worlds," by H.G. Wells, led some people to believe that a Martian spaceship had actually landed in New Jersey thereby causing widespread panic along the East Coast of the United States.

--In 1957, right at the beginning of the space age, a scientist published a study of infrared spectra comparing dark patches on the surface of Mars to vegetation on Earth, and concluded that vegetation existed on Mars.

All of that changed on July 14, 1964, when the NASA Mariner 4 spacecraft flew by Mars, showing the surface to be cratered and barren, similar to the moon, with an atmospheric pressure too low for liquid water to exist. Later, in 1976, two Viking spacecraft took pictures of different regions of Mars that showed many dry riverbeds, strongly suggesting that Mars once had substantial quantities of flowing water. Even more recently, in 1997, the Mars Global Surveyor spacecraft used a laser altimeter to make precise topographical maps of Mars. These maps provided strong evidence that a deep ocean once covered most of the northern hemisphere.

Mars is now exceedingly dry and very cold, locked in an ice age, with an average temperature of minus 67 degrees Fahrenheit. Gurnett says, "The big question is where did the water go?" One possibility is that it exists in the form of permafrost, deep below the surface. Gurnett said that the surface-penetrating radar on Mars Express would provide the first opportunity to peer below the surface and confirm or disprove the presence of permafrost, and possibly liquid water in the warmer regions deep underground. Currently, NASA's twin Mars exploration rovers are also attempting to confirm that liquid water once existed on the surface of Mars.

Gurnett, a member of the National Academy of Sciences, is a veteran of more than 30 major spacecraft projects, including the Voyager 1 and Voyager 2 flights to the outer planets, the Galileo mission to Jupiter, and the Cassini mission to Saturn. He made the first observations of plasma waves and low-frequency radio emissions in the magnetospheres of Jupiter, Saturn, Uranus and Neptune and discovered lightning in the atmospheres of Jupiter and Neptune.

STORY SOURCE: University of Iowa News Services, 300 Plaza Centre One, Suite 371, Iowa City, Iowa 52242-2500.

CONTACTS: Gary Galluzzo, 319-384-0009, gary-galluzzo@uiowa.edu.