Liquid water or "warm ice" may have once existed or may exist today on Europa, one of Jupiter's four largest moons, opening speculation that the moon may be able to support primitive forms of life.
    "This moon is a marvelous place," said Dr. Ronald Greeley of Arizona State University. Pointing to images of the moon which show surface ice which has been broken up and shifted, the Galileo imaging team scientist noted that "this shows the ice crust has been or still is lubricated from below by warm ice or maybe even liquid water."
    Planetary scientists have theorized for some time that liquid water could exist within the Galilean moon. Tidal heating, generated within the moon due to the orbital resonance within which it is locked, may produce enough energy to melt some of the ice.
    "A major goal of Galileo's studies of Europa is to search for signs of current or past activity to help answer the question: Is there a liquid zone on Europa?" said Greeley. "We are interested in identifying the time and places on Europa where liquid water might exist."
    "The pictures are exciting and compelling, but not conclusive," NASA Administrator Dan Goldin said in a statement. "The potential for liquid water on Europa is an intriguing possibility, and another step in our quest to explore the solar system, the stars, and the answer to the great mystery of whether life exists anywhere else in the cosmos."
    The images of Europa, as well as other results from Galileo, were released at a press conference August 13. Other results presented include an eruption of a geyser-like volcano on the moon Io and detailed images of Jupiter's Great Red Spot.

Neutron stars may be subject to powerful events that most closely resemble terrestrial earthquakes, a team of scientists announced earlier this month.
    The team, led by Richard Epstein at Los Alamos National Laboratory, studied repeated flashes of low-energy gamma rays emanating from neutron stars to earthquake activity in the American West. They found a "strong resemblance" between the two events in terms of size and frequency.
    "A neutron star is more like Earth than a gas planet like Jupiter because both have crusts that appear to behave in similar ways," Epstein told UPI. "In terrestrial and stellar quakes, strain energy builds up in the crust and is released explosively in fault regions."
    The results of the research may not only lead to a better understanding of neutron stars, but also to earthquakes. "By studying a relatively young neutron star, scientists can look at seismic evolution over one-thousandth of the star's lifetime," Epstein said. "By contrast, only a few hundred years of quake data are available for the four-billion-year-old Earth."