Planetary and Asteroid Studies
Jet Propulsion Laboratory, Pasadena, Calif.
NASA Headquarters, Washington DC
Using new data from NASA’s Cassini spacecraft, researchers believe they have solved a longstanding mystery of solar system science: the length of a day on Saturn. It’s 10 hours, 33 minutes and 38 seconds.
The figure has eluded planetary scientists for decades, because the gas giant has no solid surface with landmarks to track as it rotates, and it has an unusual magnetic field that hides the planet’s rotation rate.
The answer, it turned out, was hidden in the rings.
Even after decades of observations and a visit by NASA’s Voyager 2 spacecraft, Uranus held on to one critical secret — the composition of its clouds. Now, one of the key components of the planet’s clouds has finally been verified.
A global research team that includes Glenn Orton of NASA’s Jet Propulsion Laboratory in Pasadena, California, has spectroscopically dissected the infrared light from Uranus captured by the 26.25-foot (8-meter) Gemini North telescope on Hawaii’s Mauna Kea. They found hydrogen sulfide, the odiferous gas that most people avoid, in Uranus’ cloud tops. The long-sought evidence was published in the April 23rd issue of the journal Nature Astronomy.
The detection of hydrogen sulfide high in Uranus’ cloud deck (and presumably Neptune’s) is a striking difference from the gas giant planets located closer to the Sun — Jupiter and Saturn — where ammonia is observed above the clouds, but no hydrogen sulfide. These differences in atmospheric composition shed light on questions about the planets’ formation and history.
Jet Propulsion Laboratory, Pasadena, Calif.
Dwayne Brown / Laurie Cantillo
NASA Headquarters, Washington
Note from George McGinn: Yesterday I watched NASA’s briefing, and the Juno Spacecraft did something nearly impossible. The largest danger to the mission is the immense radiation. Jupiter’s version of Earth’s Van Allen belt have been catching huge amounts of solar radiation for 4.5 billion years. The gravity of Jupiter is so strong that it pulls more charged particles than would directly hit it. The Juno team estimated that the spacecraft will be exposed to radiation at LD25 (LD is Leathal Dose and 25 means 25 times, so 25 times the lethal dose to a human), or having 1 million dental X-rays all at once (in a space of 2 seconds). This is equal to 260 rads.
I applaud the Juno’s team, who worked almost 12 years to get this spacecraft safely in orbit. I am excited to see finally how deep the atmosphere goes, what gases make up Jupiter, and if there is a solid or semi-solid center, or just compressed gases. And can all that gas create the large magnetic field, or what is in the center, the speed of spin, and the chemical makeup.
This Fourth of July, NASA’s solar-powered Juno spacecraft will arrive at Jupiter after an almost five-year journey. News briefings, photo opportunities and other media events will be held at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, and air live on NASA Television and the agency’s website.
Juno was launched August 5, 2011 from Cape Canaveral in Florida on an Atlas V rocket. It was estimated to take five years for the satellite to reach Jupiter, the only other gas giant without a dedicated satellite.
In the evening of July 4, Juno will perform a suspenseful orbit insertion maneuver, a 35-minute burn of its main engine, to slow the spacecraft by about 1,212 miles per hour (542 meters per second) so it can be captured into the gas giant’s orbit. Once in Jupiter’s orbit, the spacecraft will circle the Jovian world 37 times during 20 months, skimming to within 3,100 miles (5,000 kilometers) above the cloud tops. This is the first time a spacecraft will orbit the poles of Jupiter, providing new answers to ongoing mysteries about the planet’s core, composition and magnetic fields.
Juno will improve our understanding of the solar system’s beginnings by revealing the origin and evolution of Jupiter.
Specifically, Juno will…
- Determine how much water is in Jupiter’s atmosphere, which helps determine which planet formation theory is correct (or if new theories are needed)
- Look deep into Jupiter’s atmosphere to measure composition, temperature, cloud motions and other properties
- Map Jupiter’s magnetic and gravity fields, revealing the planet’s deep structure
- Explore and study Jupiter’s magnetosphere near the planet’s poles, especially the auroras – Jupiter’s northern and southern lights – providing new insights about how the planet’s enormous magnetic force field affects its atmosphere.
Juno’s principal goal is to understand the origin and evolution of Jupiter. Underneath its dense cloud cover, Jupiter safeguards secrets to the fundamental processes and conditions that governed our solar system during its formation. As our primary example of a giant planet, Jupiter can also provide critical knowledge for understanding the planetary systems being discovered around other stars.
With its suite of science instruments, Juno will investigate the existence of a solid planetary core, map Jupiter’s intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet’s auroras.
While the events below are for the media, the public is invited to watch each of the events starting on June 16. The following are televised events are:
NASA TV Events Schedule
January 20, 2016
MEDIA ADVISORY M16-005
*** NOTE: Press release are usually published under that page “Media Releases (Information for Journalist).” These press releases are usually meetings or presentation of studies. The public will most of the time have access to view or listen to most of these, but only credentialed media can ask question.
Also, before the meeting documentation may be made available, sometimes weeks before the meeting. If the documents are embargoed, we in the press know that means the information cannot be published before the embargo date and time. We use the time to pre-write our stories and prepare questions, but the embargo must be honored by all.
– George McGinn, Examining Life (And Things of Interest), Daily Defense News and Cosmology and Space Exploration news websites.