Search Results for: Jupiter magnetic pole

Webb images in the infrared the aurora of Neptune

9:30 am

The aurora of Neptune
Click for original image.

Astronomers using the Webb Space Telescope have captured the first infrared images of the aurora of Neptune, confirming that the gas giant produces this phenomenon.

The picture to the right combines infrared data from Webb and optical imagery from the Hubble Space Telescope. The white splotches near the bottom of the globe are clouds seen by Hubble. The additional white areas in the center and near the top are clouds detected by Webb, while the greenish regions to the right are aurora activity detected by Webb.

The auroral activity seen on Neptune is also noticeably different from what we are accustomed to seeing here on Earth, or even Jupiter or Saturn. Instead of being confined to the planet’s northern and southern poles, Neptune’s auroras are located at the planet’s geographic mid-latitudes — think where South America is located on Earth.

This is due to the strange nature of Neptune’s magnetic field, originally discovered by Voyager 2 in 1989, which is tilted by 47 degrees from the planet’s rotation axis. Since auroral activity is based where the magnetic fields converge into the planet’s atmosphere, Neptune’s auroras are far from its rotational poles.

The data also found that the temperature of Neptune’s upper atmosphere has cooled significantly since it was first measured by Voyager 2 in 1989, dropping by several hundred degrees.

12 comments

Ed Stone, who ran the Voyager missions for a half century, passes away at 88

9:54 am

Ed Stone, who was the project scientist for both Voyager missions to the outer solar system and beyond for a half century, passed away at 88 on June 9, 2024.

From 1972 until his retirement in 2022, Stone served as the project scientist from NASA’s longest-running mission, Voyager. The two Voyager probes took advantage of a celestial alignment that occurs just once every 176 years to visit Jupiter, Saturn, Uranus, and Neptune. During their journeys, the spacecraft revealed the first active volcanoes beyond Earth on Jupiter’s moon Io, and an atmosphere rich with organic molecules on Saturn’s moon Titan. Voyager 2 remains the only spacecraft to fly by Uranus and Neptune, revealing Uranus’ unusual tipped magnetic poles, and the icy geysers erupting from Neptune’s moon Triton.

Stone was also head of JPL from 1991 to 2001, during the time it built and flew the Mars Pathfinder mission, which sent the first rover to Red Planet. That mission revitalized the entire American Mars exploration program for the next three decades.

Stone was one of the giants of American space exploration during its formative years. He leaves behind a legacy that will be difficult to match, highlighted most of all by both Voyager spacecraft, which outlived him.

2 comments

Jupiter’s weird magnetic field

11:34 am

New data from Juno has revealed that Jupiter’s magnetic field acts like it has three poles, one at each pole and another near the equator.

If Earth’s magnetic field resembles that of a bar magnet, Jupiter’s field looks like someone took a bar magnet, bent it in half and splayed it at both ends. The field emerges in a broad swath across Jupiter’s northern hemisphere and re-enters the planet both around the south pole and in a concentrated spot just south of the equator, researchers report in the Sept. 6 Nature.

“We were baffled” at the finding, says study coauthor Kimberly Moore, a graduate student at Harvard University.

They think the multiple poles are a result of the complexity of Jupiter’s inner core, which likely does not have the same kind of organization as a rocky terrestrial planet.

4 comments

Jupiter’s North Pole, as seen in infrared by Juno

9:06 am

The Juno science team has released an animation that shows, in infrared and in three dimensions, the storms of Jupiter’s north pole.

The link has three videos. One shows the gas giant’s surprisingly irregular magnetic field, as found by Juno. The first and third show a low and a high fly-over of the north pole, in infrared. I have embedded both fly-overs below the fold. First watch the high fly-over, which is the first video. This will make the low fly-over more understandable as it flies over the eight smaller storms that encircle the pole’s central vortex.
» Read more

3 comments

First science results from Juno

11:48 am

The Juno science team today released their first research results since the spacecraft entered orbit around Jupiter in July 2016.

“Although many of the observations have terrestrial analogs, it appears that different processes are at work creating the auroras,” said SwRI’s Dr. Phil Valek, JADE instrument lead. “With JADE we’ve observed plasmas upwelling from the upper atmosphere to help populate Jupiter’s magnetosphere. However, the energetic particles associated with Jovian auroras are very different from those that power the most intense auroral emissions at Earth.”

Also surprising, Jupiter’s signature bands disappear near its poles. JunoCam images show a chaotic scene of swirling storms up to the size of Mars towering above a bluish backdrop. Since the first observations of these belts and zones many decades ago, scientists have wondered how far beneath the gas giant’s swirling façade these features persist. Juno’s microwave sounding instrument reveals that topical weather phenomena extend deep below the cloudtops, to pressures of 100 bars, 100 times Earth’s air pressure at sea level.

“However, there’s a north-south asymmetry. The depths of the bands are distributed unequally,” Bolton said. “We’ve observed a narrow ammonia-rich plume at the equator. It resembles a deeper, wider version of the air currents that rise from Earth’s equator and generate the trade winds.”

Juno is mapping Jupiter’s gravitational and magnetic fields to better understand the planet’s interior structure and measure the mass of the core. Scientists think a dynamo — a rotating, convecting, electrically conducting fluid in a planet’s outer core — is the mechanism for generating the planetary magnetic fields. “Juno’s gravity field measurements differ significantly from what we expected, which has implications for the distribution of heavy elements in the interior, including the existence and mass of Jupiter’s core,” Bolton said. The magnitude of the observed magnetic field was 7.766 Gauss, significantly stronger than expected. But the real surprise was the dramatic spatial variation in the field, which was significantly higher than expected in some locations, and markedly lower in others. “We characterized the field to estimate the depth of the dynamo region, suggesting that it may occur in a molecular hydrogen layer above the pressure-induced transition to the metallic state.”

What I want to see is a depth map showing where Jupiter’s atmosphere ends and its solid core begins. I expect Juno will eventually be able to give us a first glimpse.

One comment