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Pasadena - Feb. 26, 2001 A newly released pair of images taken by NASA's Galileo spacecraft has captured a dynamic eruption at Tvashtar Catena, a chain of volcanic bowls on Jupiter's moon Io. They show a change in the location of hot lava over a period of a few months in 1999 and early 2000. The image above uses data obtained on Nov. 25 2000 and July 3, 1999, at resolutions of 183 meters (600 feet) and 1.3 kilometers (0.8 miles) per pixel, respectively. The red and yellow lava flow itself is an illustration based upon imaging data. The image below is a composite using a five- color observation made on Feb. 22, 2000, at 315 meters (1030 feet) per pixel. These are among the most fortuitous observations made by Galileo because this style of volcanism is too unpredictable and short-lived to target. Short-lived bursts of volcanic activity on Io had been previously detected from Earth-based observations, but interpreting the style of volcanic activity from those lower- resolution views was highly speculative. These Galileo observations confirm hypotheses that the initial, intense thermal output comes from active lava fountains. Galileo's high-resolution observations of volcanic activity on Io have also confirmed other hypotheses based on earlier, low-resolution data. These include interpretations of slowly spreading lava flows at Prometheus and Amirani and an active lava lake at Pele. These tests of earlier hypotheses increase scientists' confidence in interpreting volcanic activity seen in low-resolution remote sensing data of Earth as well as Io. However, these data are still of insufficient resolution to adequately test the more quantitative models that have been applied to volcanic eruptions on Earth and Io. These images also show other geologic features on Io. Of particular interest are the scalloped margins of the plateau to the northeast of the active lavas. These margins appear to have formed by sapping, a process usually associated with springs of water. It is speculated that liquid sulfur dioxide might be the fluid responsible for sapping on Io. A better understanding of sapping on Io will influence how scientists interpret similar features on Mars where the viability of carbon dioxide or water as the sapping fluid remains controversial. Community Email This Article Comment On This Article Related Links More related images of Io SpaceDaily Search SpaceDaily Subscribe To SpaceDaily Express Space
![]() ![]() The successful launch Thursday of India's heaviest satellite from spaceport of Kourou in French Guyana may have boosted the country's space research efforts to yet another level, but it has also lifted the spirits of at least three Direct-To-Home televisions broadcasters, one of which has been waiting for years to launch its services in India. |
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