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Unexpected cooling effect in Saturn's upper atmosphere PPARC NEWS RELEASE Posted: January 25, 2007
A simple calculation to give the expected temperature of a planet's upper atmosphere balances the amount of sunlight absorbed by the energy lost to the lower atmosphere. But the calculated values don't tally with the actual observations of the Gas Giants: they are consistently much hotter. It has long been thought that the culprit behind the heating process was the ionosphere, being driven by the planet's magnetic field, or magnetosphere. By using numerical models of Saturn's atmosphere the researchers found that the net effects of the winds driven by polar energy inputs is not to heat the atmosphere but to actually cool it. Professor Alan Aylward, of the UCL Department of Physics & Astronomy, and an author of the study, explains: "The aurora has been studied for over a hundred years, yet our discovery takes us back to first principles. We need to re-examine our basic assumptions about planetary atmospheres and what causes the observed heating." "Studying what happens on planets such as Saturn gives us an insight into what happens closer to home. Planets can lose their atmospheres as we see with Mars. Do we completely understand how this happens? Are there mechanisms heating the gas and causing it to escape that we do not yet fully understand? By studying what happens in other atmospheres we may find clues to Earth's future." The study was funded by the UK Particle Physics and Astronomy Research Council (PPARC) and Sun Microsystems Ltd and carried out using the HiPerSPACE facility at University College London. |
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The voyage of Apollo 15 took man to the Hadley Rille area of the moon. Astronauts Dave Scott and Jim Irwin explored the region using a lunar rover, while Al Worden remained in orbit conducting observations. "Apollo 15: In the Mountains of the Moon" is a NASA film looking back at the 1971 flight.
Skylab, America's first space station, began with crippling problems created by an incident during its May 1973 launch. High temperatures and low power conditions aboard the orbital workshop forced engineers to devise corrective measures quickly. Astronauts Pete Conrad, Paul Weitz and Joe Kerwin flew to the station and implemented the repairs, rescuing the spacecraft's mission. This film tells the story of Skylab's first 40 days in space.
NASA's New Horizons space probe will fly past Jupiter in late February, using the giant planet's gravity as a sling-shot to bend the craft's trajectory and accelerate toward Pluto and the Kuiper Belt. Mission officials describe the science to be collected during the Jupiter encounter during this briefing.
The 24th Russian Progress resupply ship sent to the International Space Station successfully makes the final approach and docking to the Pirs module of the outpost while running on automated controls.
Barbara Morgan, the former Idaho school teacher who served as Christa McAuliffe's backup for the Teacher in Space program, sits down for this NASA interview. As NASA's first Educator Astronaut, Morgan will be a mission specialist and robot arm operator during shuttle Endeavour's STS-118 flight to the space station, targeted for launch in June.
On October 3, 1962, Wally Schirra became the fifth American to rocket into space. This NASA film entitled "The Flight of Sigma 7" explains the 9-hour voyage that gained important knowledge in the Mercury program.
The fourth servicing mission to the Hubble Space Telescope extended the craft's scientific potential with an advanced camera and performed a major overhaul on the orbiting observatory's power system with the installation of new solar arrays and an electrical heart. The crew of space shuttle Columbia's STS-109 mission tell the story of the March 2002 mission in this post-flight highlights film.