Observatory is Wet and Broken 

SpaceRef.com; Nov. 19, 2001; News: "Super-Kamiokande Neutrino telescope Heavily Damaged by Accident" 

NYTimes.com; Nov. 13, 2001; Science: "Accident Curbs Japan Research Into Cosmos's Ghostly Particles"

Photomultiplier tube exhibit at Super-K

The Super-Kamiokande (Super-K) Observatory is a marvel of engineering. Located about 300-km northwest of Tokyo, this $100-million facility was completed in 1996 as an international collaboration between Japanese, U.S., and other researchers. Like many facilities that do astrophysics research, Super-K can generate observations that tell us about the internal state of the Sun, detect supernovas, and add to our understanding of cosmology. But unlike many facilities that contain the title "Observatory" this one is 2.7-km deep in an old zinc mine -- forever shielded from the light of any celestial object.

So how does this underground observatory generate observations? While a general discussion of Super-K's operation is easy to understand, the scale is mind-boggling. Super-K's instrumentation is almost 50-million liters of super-pure water in a cylindrical tank 40-m wide and the same measure high -- the height of a 13-story building. 11,000 photomultiplier tubes line all sides of the tank to detect light flashes in the water. These half-meter long detectors cost $3,000 each and can detect light from a single photon. Data processing equipment logs the intensity of light and arrival time.

Marvelous indeed, but what light does Super-K expect to detect deep inside a mine? Cerenkov radiation. These are light photons emitted when an electrically charged particle enters a medium at a speed faster than that of light in the medium. The light is emitted in the shape of a cone that intersects the wall of photomultipliers as a ring. Cerenkov radiation is generated by some neutrinos -- particles produced in nuclear reactions -- from such sources as the Sun, far-off supernovas, and cosmic ray interactions with the atmosphere. The whole telescope must be deep underground to shield it from other types of particles that could setoff the detectors.

A series of breakthrough experiments at Super- K determined that at least one type of neutrino must have at least some mass. Because of the abundance of neutrinos in the Universe, their total mass would now have to be accounted for in theories of galaxy formation and cosmology.

But this breakthrough research came to a sudden end on November 12, 2001 when a photomultiplier tube in the tank imploded and caused a chain reaction of implosions that destroyed 7,000 of the expensive detectors. The accident happened as the tank was being filled with water after being drained for maintenance. Yoji Totsuka, director of the Super-K has pledged to rebuild the detector. Repairs are estimated to take a year at an estimated at $20 to $30-million.

IO's Thunder God

Space.com; Dec. 11, 2001; Solar System: "New Images of Jupiter's Moon Io Reveal Volcanic Action"

Tupan Patera caldera.  NASA/JPL

A known "hot spot" on Jupiter's sulfurous, volcanic moon IO was imaged in great detail this past October, by the Galileo spacecraft in orbit around the Jupiter system. The stunning image of volcanic crater "Tupan Patera" (a Brazilian thunder god) reveals a volcanic crater 75-km across with walls 900-m tall.

Warm lava shows as black, sulfurous compounds yellow, red deposits may be condensed sulfur, and the green is where condensed sulfur interacts with lavas. The near-color image differs slightly from the human eye perception of the scene by including a small amount of infrared frequency light in the red component. Image resolution is 135-m per pixel.

Scientists are not completely sure on how to interpret the image. The yellow sulfur may be flowing down the sides of the crater and on top of the lava. Hot lava boils away parts of sulfur to form the dark patches. 

Europa Subrosa

Discovery.com; Dec. 12, 2001; Discovery News: "Case Made for Life on Jupiter Moon"

What looks like tie-dye is actually a Galileo Orbiter, near-infrared, false-color image of Europa superimposed on a black-and-white surface image of the moon. Blue indicates fresh water ice; splotches of other colors represent non-ice material -- including the enigmatic reddish areas.  NASA/JPL

Jupiter's Europa moon has a frozen surface of water ice kilometers thick that may conceal a liquid ocean. Long fractures crisscross the white surface of the moon that contains material of various reddish, brown, and yellow hues. Infrared spectra of some of these colored areas indicate they are formed from hydrated salts. Scientists had thought that a future probe could penetrate the ice and search for life in the ocean. Data from the Galileo spacecraft indicates they perhaps needn't look so deep for life. A new -- very speculative -- explanation has emerged for the reddish patches on Europa's surface: sulfur eating bacteria.

A NASA/Ames researcher compared infrared spectra of frozen samples of various E-coli bacteria to the infrared spectra of the reddish patches on Europa: they were surprisingly congruent. Species of the pinkish-brown bacteria used in the study include radiation resistant and sulfur "eating" types that could probably survive the conditions inside the putative subsurface ocean. 

 NASA/JPL

 NASA/JPL