yee@trident.arc.nasa.gov (Peter E. Yee) (04/07/91)
Archive-name: astro/magellan/magellan-images/1991-04-03 Archive-directory: ames.arc.nasa.gov:/pub/SPACE/VICAR/ [128.102.18.3] Original-posting-by: yee@trident.arc.nasa.gov (Peter E. Yee) Original-subject: Hot spot, volcanic-like features identified on Venus (Forwarded) Reposted-by: emv@msen.com (Edward Vielmetti, MSEN) [Ron seems to off-line due to a system change, so I'm taking the liberty of posting this for him. We will be making the Magellan CD-ROM available for anonymous ftp from the SPACE archives on ames.arc.nasa.gov (just as soon as we get it!) -PEY] Paula Cleggett-Haleim Headquarters, Washington, D.C. March 29, 1991 (Phone: 202/453-1547) Jim Doyle Jet Propulsion Laboratory, Pasadena, Calif. (Phone: 818/354-5011) RELEASE: 91-48 HOT SPOT, VOLCANIC-LIKE FEATURES IDENTIFIED ON VENUS The planet Venus may be venting interior heat through giant hot spots called coronae, a form of volcanism, a Magellan scientist said at NASA's Jet Propulsion Laboratory, Pasadena, Calif.. "Coronae may be hot spots, the surface expression of hot material rising from the interior of the planet," said Dr. Ellen Stofan, a geologist on the Magellan project. She said coronae are among the several types of circular features associated with volcanism that have been identified on Venus. Others include large volcanoes and spider web-shaped features called arachnoids. Coronae are circular or oval features as much as a mile or more high surrounded by a ring of ridges and troughs. They range in size from about 100 miles to more than 600 miles in diameter and are seen in many low-lying plains regions on Venus. Arachnoids are circular volcanic structures surrounded by complex fractures. They may form by volcanism in a region where the surface is pulling apart or extending, Stofan said. "Coronae, arachnoids and volcanoes are ways in which Venus transfers heat from its interior out to the surface," she said. "On Earth, this loss or transfer of heat is dominated by plate tectonics. It is too early to determine if Venus also has plate tectonics, but hot spots do seem to be important to Venus' heat loss." "High-resolution Magellan data have revealed many exciting new aspects of coronae," she said. The Magellan spacecraft has mapped with imaging radar more than 67 percent of Venus since last Sept. 15. The first 243-day mapping cycle ends May 15. Project management also announced that the first CD-ROM, or compact disc read- only-memory, containing Magellan mosaics of radar images was released to the National Space Science Data Center (NSSDC) for public distribution. One CD-ROM can hold about 600 megabytes of information or about 270,000 pages of text. The information can be easily accessed with a computer using a CD-ROM reader similar to audio CD-players. Magellan CD-ROMs containing 10 Magellan mosaics each, or 560 individual images, are produced by JPL and Dr. Raymond Arvidson of Washington University, St. Louis. "Distribution of data to the public by CD-ROM will revolutionize the way science is done," said Project Scientist Dr. Steve Saunders. "CD-ROM technology provides an excellent way to store, distribute and access large volumes of data. "I can see a time in the near future when students all over the country can be using this kind of data in classwork and projects," he said. The first Magellan CD-ROM may be obtained through the NSSDC, Goddard Space Flight Center, Code 601.4, Greenbelt, Md. 20771. Several more CD-ROMs will be delivered to the NSSDC in the coming months, Saunders said. All Magellan mosaics will eventually be placed on CD-ROMs and delivered to the NSSDC for distribution to the public. Black and White photographs to illustrate this story are available to media representatives by calling NASA Headquarters Audio/Visual Branch at 202/453-8373. Photo numbers are 91-H-181 to -184.