Tag Archives: magnetism

Magnetism helps shape Jupiter’s colorful jet stream bands

The uncertainty of science: New computer models, combined with new data from Juno, suggest that magnetism explains why Jupiter’s colored jet stream bands go as deep below the visible cloud-tops as they do.

Dr Navid Constantinou from the ANU Research School of Earth Sciences, one of the researchers on the study, said that until recently little was known about what happened below Jupiter’s clouds. “We know a lot about the jet streams in Earth’s atmosphere and the key role they play in the weather and climate, but we still have a lot to learn about Jupiter’s atmosphere,” he said. “Scientists have long debated how deep the jet streams reach beneath the surfaces of Jupiter and other gas giants, and why they do not appear in the sun’s interior.”

Recent evidence from NASA’s spacecraft Juno indicates these jet streams reach as deep as 3,000 kilometres below Jupiter’s clouds.

Co-researcher Dr Jeffrey Parker from Livermore National Laboratory in the United States said their theory showed that jet streams were suppressed by a strong magnetic field. “The gas in the interior of Jupiter is magnetised, so we think our new theory explains why the jet streams go as deep as they do under the gas giant’s surface but don’t go any deeper,” said Dr Parker.

This theory is intriguing, but very tentative, to put it mildly.

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Scientists claim Earth’s magnetic field not about to flip

The uncertainty of science: Using computer models and data from the past two changes in the Earth’s magnetic field, some scientists now claim that the weakening of the magnetic field in the past two centuries does not herald an upcoming flip in polarity.

To calculate the likelihood of a full field switch, Holme and his colleagues looked at the magnetic alignment of rock particles deposited in and before the two most recent excursions – the Laschamp event, approximately 41,000 years ago, and the Lake Mono event, which occurred 34,000 years ago.

The scientists found that the strength of the Earth’s magnetic field several thousand years before the two wobbles – at 49,000 and 46,000 years ago – were pretty much the same as they are now. However, they were accompanied by SAA-style weak areas of much greater magnitude.

This, suggests Holme’s teams, considerably reduces the chances of anything drastic happening now. “There has been speculation that we are about to experience a magnetic polar reversal or excursion,” says Holmes. “However, by studying the two most recent excursion events, we show that neither bear resemblance to current changes in the geomagnetic field and therefore it is probably unlikely that such an event is about to happen.

“Our research suggests instead that the current weakened field will recover without such an extreme event, and therefore is unlikely to reverse.”

Can I express my skepticism? This research is interesting, but there is no way it could provide enough data for anyone to trust such a prediction. We have zero knowledge of the behavior of the magnetic field during a polarity switch, and to claim that this data gives us enough information to say that we do understand that behavior is an overstatement of stupendous proportions.

Just as we don’t really understand the mechanics of the Sun’s magnetic field, causing it to flip polarity every 11 years, we certainly don’t understand the Earth’s either. The Earth’s magnetic field is going to do what it is going to do, and when it does, we will then maybe get an inkling as to why it does it.

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