Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NASA investigates invisible magnetic bubbles in outer solar system

02.11.2017

Space may seem empty, but it's actually a dynamic place populated with near-invisible matter, and dominated by forces, in particular those created by magnetic fields. Magnetospheres -- the magnetic fields around most planets -- exist throughout our solar system. They deflect high-energy, charged particles called cosmic rays that are spewed out by the Sun or come from interstellar space. Along with atmospheres, they happen to protect the planets' surfaces from this harmful radiation.

But not all magnetospheres are created equal: Venus and Mars do not have magnetospheres at all, while the other planets -- and one moon -- have ones that are surprisingly different.


This is a rotating animation of the planet Mercury.

Credit: NASA's Goddard Space Flight Center/Joy Ng

NASA has launched a fleet of missions to study the planets in our solar system -- many of which have sent back crucial information about magnetospheres. The twin Voyagers measured magnetic fields as they traveled out to the far reaches of the solar system, and discovered Uranus and Neptune's magnetospheres.

Other planetary missions including Galileo, Cassini and Juno, and a number of spacecraft that orbit Earth, provide observations to create a comprehensive understanding of how planets form magnetospheres, as well as how they continue to interact with the dynamic space environment around them.

Earth

Earth's magnetosphere is created by the constantly moving molten metal inside Earth. This invisible "force field" around our planet has a general shape resembling an ice cream cone, with a rounded front and a long, trailing tail that faces away from the sun. The magnetosphere is shaped that way because of the near-constant flow of solar wind and magnetic field from the Sun-facing side.

Earth's and other magnetospheres deflect charged particles away from the planet -- but also trap energetic particles in radiation belts. Auroras are caused by particles that rain down into the atmosphere, usually not far from the magnetic poles.

It's possible that Earth's magnetosphere was essential for the development of conditions friendly to life, so learning about magnetospheres around other planets and moons is a big step toward determining if life could have evolved there.

Mercury

Mercury, with a substantial iron-rich core, has a magnetic field that is only about 1 percent as strong as Earth's. It is thought that the planet's magnetosphere is compressed by the intense solar wind, limiting its extent. The MESSENGER satellite orbited Mercury from 2011 to 2015, helping us understand our tiny terrestrial neighbor.

Jupiter

After the Sun, Jupiter has by far the strongest and biggest magnetic field in our solar system -- it stretches about 12 million miles from east to west, almost 15 times the width of the Sun. (Earth's, on the other hand, could easily fit inside the Sun -- except for its outstretched tail.) Jupiter does not have a molten metal core; instead, its magnetic field is created by a core of compressed liquid metallic hydrogen.

One of Jupiter's moons, Io, has powerful volcanic activity that spews particles into Jupiter's magnetosphere. These particles create intense radiation belts and auroras around Jupiter.

Ganymede, Jupiter's largest moon, also has its own magnetic field and magnetosphere -- making it the only moon with one. Its weak field, nestled in Jupiter's enormous shell, scarcely ruffles the planet's magnetic field.

Saturn</p>

Saturn's huge ring system transforms the shape of its magnetosphere. That's because oxygen and water molecules evaporating from the rings funnel particles into the space around the planet. Some of Saturn's moons help trap these particles, pulling them out of Saturn's magnetosphere, though those with active volcanic geysers -- like Enceladus -- spit out more material than they take in. NASA's Cassini mission followed in the Voyagers' wake, and studied Saturn's magnetic field from orbit around the ringed planet between 2004 and 2017.

Uranus

Uranus' magnetosphere wasn't discovered until 1986, when data from Voyager 2's flyby revealed weak, variable radio emissions and confirmed when Voyager 2 measured the magnetic field directly. Uranus' magnetic field and rotation axis are out of alignment by 59 degrees, unlike Earth's, whose magnetic field and rotation axis are nearly aligned. On top of that, the magnetic field does not go directly through the center of the planet, so the strength of the magnetic field varies dramatically across the surface. This misalignment also means that Uranus' magnetotail -- the part of the magnetosphere that trails behind the planet, away from the Sun -- is twisted into a long corkscrew.

Neptune

Neptune was also visited by Voyager 2, in 1989. Its magnetosphere is offset from its rotation axis, but only by 47 degrees. Similar to Uranus, Neptune's magnetic field strength varies across the planet. This means that auroras can appear across the planet -- not just close to the poles, like on Earth, Jupiter and Saturn.

And beyond

Outside of our solar system, auroras, which indicate the presence of a magnetosphere, have been spotted on brown dwarfs -- objects that are bigger than planets but smaller than stars. There's also evidence to suggest that some giant exoplanets have magnetospheres, but we have yet to see conclusive proof. As scientists learn more about the magnetospheres of planets in our solar system, it can help us one day identify magnetospheres around more distant planets as well.

Mara Johnson-Groh | EurekAlert!

More articles from Physics and Astronomy:

nachricht In vivo super-resolution photoacoustic computed tomography by localization of single dyed droplets
18.04.2019 | Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences

nachricht First astrophysical detection of the helium hydride ion
18.04.2019 | Max-Planck-Institut für Radioastronomie

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: Quantum simulation more stable than expected

A localization phenomenon boosts the accuracy of solving quantum many-body problems with quantum computers which are otherwise challenging for conventional computers. This brings such digital quantum simulation within reach on quantum devices available today.

Quantum computers promise to solve certain computational problems exponentially faster than any classical machine. “A particularly promising application is the...

Im Focus: Largest, fastest array of microscopic 'traffic cops' for optical communications

The technology could revolutionize how information travels through data centers and artificial intelligence networks

Engineers at the University of California, Berkeley have built a new photonic switch that can control the direction of light passing through optical fibers...

Im Focus: A long-distance relationship in femtoseconds

Physicists observe how electron-hole pairs drift apart at ultrafast speed, but still remain strongly bound.

Modern electronics relies on ultrafast charge motion on ever shorter length scales. Physicists from Regensburg and Gothenburg have now succeeded in resolving a...

Im Focus: Researchers 3D print metamaterials with novel optical properties

Engineers create novel optical devices, including a moth eye-inspired omnidirectional microwave antenna

A team of engineers at Tufts University has developed a series of 3D printed metamaterials with unique microwave or optical properties that go beyond what is...

Im Focus: Newly discovered mechanism of plant hormone auxin acts the opposite way

Auxin accumulation at the inner bend of seedling leads to growth inhibition rather than stimulation as in other plant tissues.

Increased levels of the hormone auxin usually promote cell growth in various plant tissues. Chinese scientists together with researchers from the Institute of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

Fraunhofer FHR at the IEEE Radar Conference 2019 in Boston, USA

09.04.2019 | Event News

 
Latest News

In vivo super-resolution photoacoustic computed tomography by localization of single dyed droplets

18.04.2019 | Physics and Astronomy

Contact lenses with medicine and sugar

18.04.2019 | Life Sciences

First astrophysical detection of the helium hydride ion

18.04.2019 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>