Two Additional NASA Space Spectaculars

NASA has even more solid info to pass along… the agency’s Cassini spacecraft has discovered evidence that points to the existence of an underground ocean of water and ammonia on Saturn’s moon, Titan. These findings will appear in the March 21st issue of Science journal. Cassini‘s Synthetic Aperture Radar was used by the mission’s science team to collect imaging data during 19 separate passes over Titan between October 2005 and May 2007. The radar can “see” through Titan’s dense, methane-rich atmospheric haze. This allows for detailing of the never-before-seen surface and establishes features on the moon’s surface. Using the radar data, 50 unique landmarks on Titan’s surface were established, which were then searched for the same lakes, canyons and mountains in the reams of data returned by Cassini in its later flybys of Titan. The found prominent surface features had shifted from their expected positions by as much as 19 miles. Such a systematic displacement of surface features would be quite difficult to explain unless the moon’s icy crust was decoupled form its core by an internal ocean, which would make it easier for the crust to move. A full video presentation is available at https://saturn.jpl.nasa.gov/multimedia/videos/video-details.cfm?videoID=174. A powerful stellar explosion detected March 19 by NASA’s Swift satellite has shattered the record for the most distant object that could be seen with the naked eye. The explosion was a gamma ray burst. Most gamma ray bursts occur when massive stars run out of nuclear fuel. Their cores collapse to form black holes or neutron stars. This releases an intense burst of high-energy gamma rays and ejecting particle jets that rip through space at nearly the speed of light like turbocharged cosmic blowtorches. When the jets plow into surrounding interstellar clouds, they heat the gas, often generating bright afterglows. Gamma ray bursts are the most luminous explosions in the universe since the big bang. “This burst was a whopper,” said Swift principal investigator Neil Gehrels of NASA‘s Goddard Space Flight Center in Greenbelt, Md. “It blows away every gamma ray burst we’ve seen so far.” Swift‘s Burst Alert Telescope picked up the burst at 2:12 a.m. EDT, March 19, and pinpointed the coordinates in the constellation Bootes. Telescopes in space and on the ground quickly moved to observe the afterglow. The burst is named GRB 080319B, because it was the second gamma ray burst detected that day. Swift’s other two instruments, the X-ray Telescope and the Ultraviolet/Optical Telescope, also observed brilliant afterglows. Several ground-based telescopes saw the afterglow brighten to visual magnitudes between 5 and 6 in the logarithmic magnitude scale used by astronomers. The brighter an object is, the lower its magnitude number. From a dark location in the countryside, people with normal vision can see stars slightly fainter than magnitude 6. That means the afterglow would have been dim, but visible to the naked eye.