GeoLog

General Assembly 2018

NASA’s Juno mission reveals Jupiter’s magnetic field greatly differs from Earth’s

NASA’s Juno mission reveals Jupiter’s magnetic field greatly differs from Earth’s

NASA scientists have revealed surprising new information about Jupiter’s magnetic field from data gathered by their space probe, Juno.

Unlike earth’s magnetic field, which is symmetrical in the North and South Poles, Jupiter’s magnetic field has startlingly different magnetic signatures at the two poles.

The information has been collected as part of the Juno program, NASA’s latest mission to unravel the mysteries of the biggest planet in our solar system. The solar-powered spacecraft is made of three 8.5 metre-long solar panels angled around a central body. The probe (pictured above) cartwheels through space, travelling at speeds up to 250,000 kilometres per hour.

Measurements taken by a magnetometer mounted on the spacecraft have allowed a stunning new insight into the planet’s gigantic magnetic field. They reveal the field lines’ pathways vary greatly from the traditional ‘bar magnet’ magnetic field produced by earth.

Jupiter’s magnetic field is enormous. if magnetic radiation were visible to the naked eye, from earth, Jupiter’s magnetic field would appear bigger than the moon. Credit: NASA/JPL/SwRI

The Earth’s magnetic field is generated by the movement of fluid in its inner core called a dynamo. The dynamo produces a positive radiomagnetic field that comes out of one hemisphere and a symmetrical negative field that goes into the other.

The interior of Jupiter on the other hand, is quite different from Earth’s. The planet is made up almost entirely of hydrogen gas, meaning the whole planet is essentially a ball of moving fluid. The result is a totally unique magnetic picture. While the south pole has a negative magnetic field similar to Earth’s, the northern hemisphere is bizarrely irregular, comprised of a series of positive magnetic anomalies that look nothing like any magnetic field seen before.

“The northern hemisphere has a lot of positive flux in the northern mid latitude. It’s also the site of a lot of anomalies,” explains Juno Deputy Principal Investigator, Jack Connerney, who spoke at a press conference at the EGU General Assembly in April. “There is an extraordinary hemisphere asymmetry to the magnetic field [which] was totally unexpected.”

NASA have produced a video that illustrates the unusual magnetism, with the red spots indicating a positive magnetic field and the blue a negative field:

Before its launch in 2016, Juno was programmed to conduct 34 elliptical ‘science’ orbits, passing 4,200 kilometres above Jupiter’s atmosphere at its closest point. When all the orbits are complete, the spacecraft will undertake a final deorbit phase before impacting into Jupiter in February 2020.

So far Juno has achieved eleven science orbits, and the team analysing the data hope to learn more as it completes more passes. “In the remaining orbits we will get a finer resolution of the magnetic field, which will help us understand the dynamo and how deep the magnetic field forms” explains Scott Bolton, Principal Investigator of the mission.

The researchers’ next steps are to examine the probe’s data after its 16th and 34th passes meaning it will be a few more months before they are able to learn more of Jupiter’s mysterious magnetosphere.

By Keri McNamara, EGU 2018 General Assembly Press Assistant

Further reading

Connerney, J. E. P., Kotsiaros, S., Oliversen, R. J., Espley, J. R., Joergensen, J. L., Joergensen, P. S., et al. A new model of Jupiter’s magnetic field from Juno’s first nine orbits. Geophysical Research Letters, 45, 2590–2596. 2018

Bolton, S. J. et al. Jupiter’s interior and deep atmosphere: The initial pole-to-pole passes with the Juno spacecraft, Science, 356(6340), p. 821 LP-825. 2017

Guillot, T. et al. A suppression of differential rotation in Jupiter’s deep interior, Nature. Macmillan Publishers Limited, part of Springer Nature. All rights reserved., 555, p. 227. 2018

Wildfires in the wake of climate change

Wildfires in the wake of climate change

Last year saw some of the biggest blazes in history, and may be a sign of things to come.

2017 was a record year for wildfires. California and neighboring western states saw the most destructive fire in US history, with an estimated 18 billion dollars worth of damage over the season. In central Portugal, fires caused 115 deaths over the same period. Researchers presenting at a press conference at the European Geosciences Union General Assembly in Vienna, Austria, suggest this may be a sign of things to come.

With climate change, wildfires are expected to be on the rise, as fire-prone regions become hotter and drier. But how did weather and climate contribute to this disastrous season? Strong winds and warm temperatures are thought to be responsible for last year’s fires in California, but it remains unclear how much climate change contributed to these conditions. Etienne Tourigny, of the Barcelona Supercomputing Centre, has been on the case.

“Would this event have been possible with or without climate change?” Tourigny asks. “It’s hard to say. What we can say is that there is a high chance that these kinds of events will be more present and more frequent in the future, especially if we see temperatures increasing as they have”

Central Portugal is already very susceptible to wildfires. It’s hot, it’s dry and it’s forested: a recipe for the perfect storm. The 2017 season was particularly tragic due to an unusual set of circumstances: a tropical cyclone passed as the Portuguese Centro Region was ablaze. The nation hoped that the hurricane would bring rain to put out the fires, but, instead, the storm passed the area by, bringing strong winds and spreading the flames.

200 thousand hectares were burned in two days. Even if this was spread throughout an entire season, it would be a very bad year. Speaking at the conference, António Ferreira, a scientific coordinator at the Research Centre for Natural Resources, Environment and Society in Coimbra, Portugal, puts it frankly: “that’s hell as it was taught in Sunday School.”

The region is also vulnerable to climate change, and an increased risk of wildfires is expected by the end of the century. New strategies are needed to prevent such losses in future. Ferreira emphasised that there is no quick fix and, to reduce the risk, policies, plans, habits and investment have to change.

Even in the high Arctic, fires present a threat. This time, it’s not a direct risk to life or infrastructure, but a threat to the environment. Nikolaos Evangeliou, from Norwegian Institute for Air Research, stated that, even in icy regions, wildfires have the capacity to alter the Earth’s climate and accelerate melting.

Thawing permafrost during the 2017 summer left Greenland’s peatlands vulnerable to wildfires and between 31 July and 21 August about 2300 hectares of peatland were burned. Seven tonnes of black carbon generated by the fires rained down on the ice sheet, making the surface darker and causing it to absorb more heat.

If the ice sheet darkens, it reduces Earth’s ability to deflect solar radiation, allowing more of the sun’s energy to warm the planet. The change in Earth’s reflectivity following last year’s wildfires was small, but it is a warning. With larger fires predicted as the climate warms, we could expect much bigger changes to the Earth’s reflectivity towards the end of the century. Such warming spells further trouble for wildfire-sensitive regions.

By Sara Mynott, EGU 2018 General Assembly Press Assistant

References

Evangeliou et al. Open Fires in Greenland: An Unusual Event and its Impact on the Albedo of the Greenland Ice Sheet. Geophysical Research Abstracts, Vol. 20, EGU2018-12383, 2018, EGU General Assembly 2018.

Leitão et al. Dealing with climate change: how to cope with wildfire threat in a climate transition region. Geophysical Research Abstracts, Vol. 20, EGU2018-16640, 2018, EGU General Assembly 2018.

Tourigny et al. An observational study of the extreme wildfire events of California in 2017: quantifying the relative importance of climate and weather. Geophysical Research Abstracts, Vol. 20, EGU2018-9545-1, 2018, EGU General Assembly 2018.

At the Assembly 2018: Thursday Highlights

At the Assembly 2018: Thursday Highlights

Welcome to the fourth day of General Assembly excitement! Once again the day is packed with great events for you to attend and here are just some of the sessions on offer. You can find out more about what’s on in EGU Today, the daily newsletter of the General Assembly – grab a copy on your way in or download it here.

Union-wide sessions

The Union-wide session of the day focuses on the Cassini mission to Saturn and future perspectives for the exploration of the outer solar system (US3). The session will feature reports on the amazing discoveries that this mission brought and the new understanding we have gained of the Saturnian system. Join the discussion from 8:30 to 12:00 in room E1.

Thursday’s Great Debate will discuss natural versus anthropogenic threats for life on Earth (GDB5 from 13:30-15:00 in room E1). The session will explore the consequences of extreme events, from magnetic field reversal to anthropogenic climate change, for life on Earth. Tune into to the sessions on Twitter using the #EGU18GDB hashtag or online by webstreaming.

The EGU Early Career Scientists’ Forum (12:15–13:15 in room N2) is the best place to find out more about the Union and how to get involved. Because the EGU is a bottom up organisation, we are keen to hear your suggestions on how to make ECS related activities even better. There will be plenty of opportunities during the forum for you to provide feedback. It’s also over lunch, so you’ll find a buffet of sandwiches and soft drinks when you arrive!

At the Early Career Scientists’ Forum you can let us know what you would like from the EGU, find out how you can get involved in the Assembly and meet other scientists in the EGU early career scientist community. (Credit: EGU)

Scientific Sessions

Some of today’s interdisciplinary highlights include sessions on…

Short Courses

Take the opportunity to expand your skills in one of today’s short courses and splinter meetings. Be sure to share what you learn on social media using the hashtag #EGU18SC:

Medal Lectures

There’s also a number of Medal Lectures on throughout the day – here’s a sample of what’s on offer:

If you need a change of pace, stop by the Imaggeo Photo Exhibition beside the EGU Booth (Hall X2, basement, Brown Level). You can vote for your favourite finalists there, but be quick because the voting deadline is today at midnight! While you’re in the area, you can also take the opportunity to meet your Division’s representatives in today’s Meet EGU appointments.

The Arts at EGU

Tonight from 19:00 to 20:00 in room E1 you can experience geoscience through music with a concert by EMusic (ElectroMagnetic Music), a collaboration between geophysicist Antonio Menghini and musician Stefano Pontani. Their new show “Sounds from the Geology of Italy”, will feature musical styling drawn from electromagnetic data collected in 4 beautiful scenarios: the Phlegrean Fields, Venice Lagoon, Selinunte Temple and Castelluccio Plain.

EGU’s poet (Sam Illingworth) and cartoonist (Matthew Partridge) in residence have been circulating the Assembly to share their conference experiences and communicate science. You can see their work posted daily here.

Have a lovely day!

The EGU General Assembly is taking place in Vienna, Austria from 8 to 13 April. Check out the full session programme on the General Assembly website and follow the Assembly’s online conversation on Twitter at #EGU18.

Head on over to the EGU Booth!

Head on over to the EGU Booth!

You can find the EGU Booth in Hall X2 on the Brown Level. This is the place to come if you’d like to meet members of EGU Council and Committees (Meet EGU) and find out more about EGU activities.

Here you can discover the EGU’s 17 open access journals, browse the EGU blogs (GeoLog, the EGU Blog Network and the EGU Division Blogs), catch up on the conference Twitter feed, and more! We will also be giving away beautiful geosciences postcards, which the EGU will post for you free of charge.

Beside the booth you’ll also find the finalists in the EGU Photo Contest, make sure you vote for your favourite images!  You’ll also find the Assembly Job Spot – be sure to check it out if you’re looking for a job in the geosciences, or someone to fill as spot in your research group.

If you have any questions about the EGU, or want to be more involved in the Union, come and ask us, we’re happy to help!