Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Spacecraft rendezvous at Jupiter

28.02.2002


Currents between Jupiter’s poles and three of its moons mark its auroras.
© NSAS/JPL


Cassini’s image of the looping magnetic fields that surround Jupiter.
© NSAS/JPL


Two space probes lift the lid on Jupiter’s magnetosphere.
Even Stanley Kubrick couldn’t have directed it better. In the first days of 2001, two spacecraft, Cassini and Galileo, met at Jupiter 400 million kilometres from Earth, to study the mysterious forces emanating from the giant planet.

The first analysis of the data they sent back has now been unveiled1-7. It paints a dramatic picture of the planet’s invisible magnetosphere - looping magnetic fields, crackling radio emissions and intense belts of radiation surround Jupiter and interact with the solar wind and the planet itself.


Consisting only of charged particles and magnetic field lines, magnetospheres are best studied close up. "You really need to be in it to measure what’s going on," says Linda Spilker, deputy project scientist for the Cassini mission.

Cassini approached Jupiter from the direction of the incoming solar wind - the continuous blast of charged particles that stream out of the Sun. For the first time, the spacecraft recorded shifts in the wind while Galileo measured the responses of Jupiter’s magnetosphere.

Apparently, gusts of solar wind cause Jupiter’s magnetosphere to expand and contract like a giant balloon3. Simultaneous observations from the Hubble and Chandra space telescopes show that these compressions brighten the planet’s giant aurora. The aurora, which is like Earth’s northern and southern lights, dims as the pressure lessens1.

The probes also spotted electrons propelled by the planet’s magnetic field, whipping through Jupiter’s radiation belts at close to the speed of light2. Only a Jupiter-sized planet can generate magnetic fields strong enough to do this.

Astronomers will be reassured by the findings, for they agree with observations of Earth’s well-studied magnetosphere, which is routinely used to predict the behaviour of more distant planets.

Perhaps the most beautiful finding was of bright arcs of light traced through Jupiter’s aurora. The circling sprites arise when Jupiter’s moons, Io, Ganymede and Europa, emit giant tubes of charged particles. Jupiter’s magnetic fields suck these particles from the moons’ atmospheres down to the planet’s poles where they interact with one another, emitting an ethereal glow5.



Chance meeting

The cosmic conjunction wasn’t planned. Cassini was waltzing past Jupiter, using the giant’s gravitational energy to send it on to its final destination, Saturn. Galileo, an ageing probe that had been closely orbiting Jupiter and was thought to have stopped working, was found to be still going strong.

Planetary scientists "seized the opportunity offered by this first-ever conjunction of two spacecraft at an outer planet", says Thomas Hill, of Rice University in Houston, Texas.

"There will be people looking at the data for many years," says Spilker. Which is just as well. Another such rendezvous "would not be repeated for the foreseeable future", says Cassini project scientist Dennis Matson.

The chance meeting was short-lived. Cassini has since flown on towards Saturn, due to arrive there in 2004. Galileo will make the ultimate sacrifice and descend into Jupiter’s atmosphere late next year.

References

  1. Gurnett, D. A. et al Control of Jupiter’s radio emission and aurorae by the solar wind. Nature, 415, 985 - 987, (2002).
  2. Bolton, S. J. et al Ultra-relativistic electrons in Jupiter’s radiation belts. Nature, 415, 987 - 991, (2002).
  3. Kurth, W. S. et al The dusk flank of Jupiter’s magnetosphere. Nature, 415, 991 - 994, (2002).
  4. Krimigis, S. M. et al A nebula of gases from Io surrounding Jupiter. Nature, 415, 994 - 996, (2002).
  5. Clarke, J. T. et al. Ultraviolet emissions from the magnetic footprints of Io, Ganymede and Europa on Jupiter. Nature, 415, 997 - 1000, (2002).
  6. Gladstone, G. R. et al.A pulsating auroral X-ray hot spot on Jupiter. Nature, 415, 1000 - 1003, (2002).
  7. Mauk, B. H. et al. Transient aurora on Jupiter from injections of magnetospheric electrons. Nature, 415, 1003 - 1005, (2002).


TOM CLARKE | © Nature News Service

More articles from Physics and Astronomy:

nachricht Innovative LED High Power Light Source for UV
22.06.2017 | Omicron - Laserage Laserprodukte GmbH

nachricht Spin liquids − back to the roots
22.06.2017 | Universität Augsburg

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: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

Im Focus: Optoelectronic Inline Measurement – Accurate to the Nanometer

Germany counts high-precision manufacturing processes among its advantages as a location. It’s not just the aerospace and automotive industries that require almost waste-free, high-precision manufacturing to provide an efficient way of testing the shape and orientation tolerances of products. Since current inline measurement technology not yet provides the required accuracy, the Fraunhofer Institute for Laser Technology ILT is collaborating with four renowned industry partners in the INSPIRE project to develop inline sensors with a new accuracy class. Funded by the German Federal Ministry of Education and Research (BMBF), the project is scheduled to run until the end of 2019.

New Manufacturing Technologies for New Products

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

A new technique isolates neuronal activity during memory consolidation

22.06.2017 | Life Sciences

Plant inspiration could lead to flexible electronics

22.06.2017 | Materials Sciences

A rhodium-based catalyst for making organosilicon using less precious metal

22.06.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>