Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Faraday Disk Dynamo01:23

Faraday Disk Dynamo

A Faraday disk dynamo is a DC generator, producing an emf that is constant in time. It consists of a conducting disk that rotates with a constant angular velocity in the magnetic field, perpendicular to the disk's plane. The rotation of the disk causes a change in magnetic flux, which induces an emf, causing opposite charges to develop on the rim and in the center of the disk. The polarity of the induced emf can be determined by the direction of the magnetic field and the direction of the...
DC Generator01:19

DC Generator

An alternator converts mechanical energy into electrical energy that varies sinusoidally, resulting in AC current. Meanwhile, a DC generator converts mechanical energy into electrical energy, which are DC pulses with the same polarity. The construction of a DC generator is similar to that of an alternator, except that the pair of slip rings is replaced by a single split ring, also called a commutator. The commutator functions like a periodic rotary switch; it changes the contacts with the...
Potential Due to a Magnetized Object01:24

Potential Due to a Magnetized Object

Magnetic dipoles in magnetic materials are aligned when placed under an external magnetic field. For paramagnets and ferromagnets, dipole alignment occurs in the direction of the magnetic field. However, the dipoles align opposite to the field in the case of diamagnets. This state of magnetic polarization due to the external field is called magnetization. Magnetization is defined as the dipole moment per unit volume. It plays a similar role to polarization in electrostatics.
The vector...
Electric Generator: Alternator01:25

Electric Generator: Alternator

Electric generators induce an emf by rotating a coil in a magnetic field. A simple alternator is an AC generator that creates electrical energy that varies sinusoidally with time. A simple alternator consists of a conducting loop that is placed inside a uniform magnetic field. The loop is connected to split rings connected to the external circuit with the help of brushes.
The magnetic flux passing through the coil varies sinusoidally as the loop rotates inside the magnetic field. This...
Induced Electric Dipoles01:28

Induced Electric Dipoles

A permanent electric dipole orients itself along an external electric field. This rotation can be quantified by defining the potential energy because the external torque does work in rotating it. Then, the potential energy is minimum at the parallel configuration and maximum at the antiparallel configuration. While the former is a stable equilibrium, the latter is an unstable equilibrium.
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...
Nuclear Fusion02:45

Nuclear Fusion

The process of converting very light nuclei into heavier nuclei is also accompanied by the conversion of mass into large amounts of energy, a process called fusion. The principal source of energy in the sun is a net fusion reaction in which four hydrogen nuclei fuse and ultimately produce one helium nucleus and two positrons.
A helium nucleus has a mass that is 0.7% less than that of four hydrogen nuclei; this lost mass is converted into energy during the fusion. This reaction produces about...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Deuterated water and the formation of the satellites of Uranus.

Proceedings of the National Academy of Sciences of the United States of America·2026
Same author

Little to no active faulting likely at Europa's seafloor today.

Nature communications·2026
Same author

Titan's strong tidal dissipation precludes a subsurface ocean.

Nature·2025
Same author

Author Correction: Seismic detection of a 600-km solid inner core in Mars.

Nature·2025
Same author

Endogenic heat at Enceladus' north pole.

Science advances·2025
Same author

Seismic detection of a 600-km solid inner core in Mars.

Nature·2025

Related Experiment Video

Updated: May 8, 2026

A 100 KW Class Applied-field Magnetoplasmadynamic Thruster
11:47

A 100 KW Class Applied-field Magnetoplasmadynamic Thruster

Published on: December 22, 2018

Powering Ganymede's dynamo with protracted core formation.

Kevin T Trinh1, Flavio Petricca2, Douglas J Hemingway3

  • 1Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91101, USA.

Science Advances
|May 6, 2026
PubMed
Summary

Ganymede

More Related Videos

Simulation of the Planetary Interior Differentiation Processes in the Laboratory
06:04

Simulation of the Planetary Interior Differentiation Processes in the Laboratory

Published on: November 15, 2013

Related Experiment Videos

Last Updated: May 8, 2026

A 100 KW Class Applied-field Magnetoplasmadynamic Thruster
11:47

A 100 KW Class Applied-field Magnetoplasmadynamic Thruster

Published on: December 22, 2018

Simulation of the Planetary Interior Differentiation Processes in the Laboratory
06:04

Simulation of the Planetary Interior Differentiation Processes in the Laboratory

Published on: November 15, 2013

Area of Science:

  • Planetary Science
  • Geophysics
  • Astrobiology

Background:

  • Ganymede is the only moon in our solar system with an active magnetic field.
  • Previous research suggested its magnetic field originated from a metal core formed billions of years ago.

Purpose of the Study:

  • To reevaluate Ganymede's thermal evolution and core formation.
  • To explain the moon's persistent magnetic dynamo.

Main Methods:

  • Thermal evolution modeling of Ganymede's interior.
  • Analysis of core formation processes from a "cold start" accretion scenario.

Main Results:

  • Ganymede's dynamo may be sustained by ongoing core formation, a novel concept.
  • A continuously forming iron-sulfur (Fe-FeS) core can explain the dynamo.

Conclusions:

  • Ganymede's magnetic field does not require an ancient metal core.
  • Ongoing core formation provides a viable mechanism for Ganymede's long-lived dynamo.