Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Storms on Uranus, Neptune Confined to Upper Atmosphere

21.05.2013
Shedding light on a long-standing mystery surrounding the cloudy worlds of Uranus and Neptune, scientists at the UA’s Lunar and Planetary Lab have discovered that the massive jet streams and weather phenomena associated with them appear to be ripples on the surface rather than extending deep into the planets' interior.
Similar to the giant gas planets Jupiter and Saturn, their smaller cousins, Uranus and Neptune, have long been known to harbor swirling clouds and violent winds churning up their atmospheres. Massive bands of jet streams encircling the entire planet have been observed in both cases.

But given that Uranus' atmosphere is believed to be thick enough to swallow the entire Earth, it was not known just how far the weather perturbations reach into the planet's interior.

Now a team of planetary scientists with the University of Arizona's Lunar and Planetary Laboratory, including William Hubbard and Adam Showman, has published the results of new analyses that put an upper limit to the weather zone on Uranus and Neptune.

According to their data, reported in the journal Nature, the atmosphere on both planets goes from screaming winds of infernal violence to dead-quiet at a much shallower depth than previously thought.

"Our analyses show that the dynamics are confined to a thin weather layer no more than about 680 miles deep," said Hubbard. "This number is an upper limit, so in reality, it is possible that the atmosphere quiets down even shallower than that."

For the study, which was led by Yohai Kaspi, a planetary researcher at the Weizmann Institute of Science in Rehovot, Israel, the team applied computer simulations and numerical analyses to data collected by the spacecraft Voyager 2 during a fly-by in 1989.

Without a means to probe the atmosphere of gas giants directly, the researchers had to rely on indirect measurements to gather clues about weather patterns on the two planets.

"For Neptune and Uranus, the only spacecraft data we have were taken with Voyager 2's equipment more than 20 years ago, and we won't be able to get anything that lives up to today's standards anytime soon," explained Hubbard, whose research focuses on studies of the structure and evolution of Jupiter, Saturn and extra solar giant planets.

Instead, the team used deep circulation theories developed by Showman and Kaspi to predict what the gravitational fields of Neptune and Uranus should look like. This method takes advantage of the fact that large weather perturbations in the atmospheres of giant planets modify their gravitational fields in a way that allows researchers to draw conclusions about the nature and extent of those weather phenomena.

"Basically, by applying these newly developed theories, we are able to tease out new information from old data," Hubbard said. "The reason we can constrain the weather to the upper 680 miles or so is that we would see a much stronger distortion of the gravitational field if the weather extended much deeper."

Hubbard said he made calculations back in 1989, at the time of Voyager 2's encounter with Neptune, "but today of course we have much better methods than two decades ago, so we can put a more accurate constraint on these phenomena than I was able to at the time."

As a co-investigator on NASA's Juno mission currently en route to Jupiter, Hubbard develops tools for analyzing the gravity signal from the giant gas planet with the famous Red Spot. Hubbard showed how high-precision gravity data from a close-range orbiter of Jupiter can be used to determine the depths to which Jupiter's extraordinary zonal wind patterns penetrate.

Juno's goal is to study the interior composition of the largest planet in our system, which is thought to have formed before the other planets and hold answers to many unsolved questions about the formation of our solar system.

"We are going to get similar data for Jupiter and Saturn, but in much higher quality than what we have from Voyager 2," he said, and also with higher precision than anything that has been done on Jupiter so far."

Using two radio receivers, one on the spacecraft and one on Earth, locked in synchrony, Juno will be able to measure gravity with unprecedented accuracy, Hubbard explained.

Unlike the jet streams on Uranus and Neptune, Hubbard said the winds are much more subtle on Jupiter and Saturn.

"When we start getting detailed data from Juno, we are going to use those methods to apply to what we see on Jupiter and Saturn," he said. "We want to see how deep these weather phenomena go on those planets."

Hubbard explained that researchers believe the atmospheric disturbances are more numerous on Jupiter and Saturn but less strong compared to Uranus and Neptune, for reasons that may have to do with the planets' different compositions and their angles between the magnetic fields and rotational axis.

"In the case of Earth, our atmosphere is very thin and almost negligible from the point of view of gravity," Hubbard explained. "One would need extremely sensitive measurements to see the effects of the atmosphere on the Earth's gravitational field."

"In the case of giant gas planets, we are talking about deep, hydrogen-dominated atmospheres that are much denser, more like an ocean than an atmosphere. There is so much mass involved that it leaves a much more visible signature on the gravity."

In this artist's impression of Voyager 2's 1989 encounter with Neptune, the gas giant's Great Dark Spot is visible in the distance. Thought to be a hole in the giant planet's cloud cover, winds in that area have been clocked at 1,500 miles per hour, the fastest in the solar system (not the subject of this study). (Photo: NASA)

Extra Info

UA planetary researcher Erich Karkoschka assembled observational data into this animated video showing the swirling features in Neptune's atmosphere.

In another video, he combined images of Uranus taken with the Hubble Space Telescope into a stunning animation revealing the planet's seasonal changes, wobbling rings and circling moons.

Contacts

Researcher Contact:
William Hubbard
Lunar and Planetary Laboratory
520-621-6942
hubbard@lpl.arizona.edu

Media Contact:
Daniel Stolte
University Communications
520-626-4402
stolte@email.arizona.edu

Daniel Stolte | University of Arizona
Further information:
http://www.arizona.edu

More articles from Physics and Astronomy:

nachricht DGIST develops 20 times faster biosensor
24.04.2017 | DGIST (Daegu Gyeongbuk Institute of Science and Technology)

nachricht New quantum liquid crystals may play role in future of computers
21.04.2017 | California Institute of Technology

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

DGIST develops 20 times faster biosensor

24.04.2017 | Physics and Astronomy

Nanoimprinted hyperlens array: Paving the way for practical super-resolution imaging

24.04.2017 | Materials Sciences

Atomic-level motion may drive bacteria's ability to evade immune system defenses

24.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>