from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An asymmetrical region surrounding the earth, extending from about one hundred to several thousand kilometers above the surface, in which charged particles are trapped and their behavior is dominated by the earth's magnetic field.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The comet-shaped region around Earth or another planet in which charged particles are trapped or deflected. Shaped by the solar wind and the planet's magnetic field.
from the GNU version of the Collaborative International Dictionary of English
- n. the magnetic field of a planet; the volume around the planet in which charged particles are subject more to the planet's magnetic field than to the solar magnetic field.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the magnetic field of a planet; the volume around the planet in which charged particles are subject more to the planet's magnetic field than to the solar magnetic field
One from Cassini, also of the interaction between the solar wind and Jupiter's magnetosphere, is here.
One from Voyager's passage through the bow shock of the solar wind against Jupiter's magnetosphere is here.
One from Galileo's studies of Ganymede's magnetosphere is here.
As for the idea that external magnetic fields cannot influence Earth because of Earth's magnetosphere, that is putting matters upside-down.
The magnetosphere is a sheath that at once protects and interacts with the Sun's solar wind.
The magnetosphere is the region of electrically charged particles that are trapped in the magnetic field of the planet.
Its so-called magnetosphere extends out 37,000 miles from Earth's sunlit side and much farther behind the planet, forming a comet-like tail.
The gas giant Saturn is surrounded by a large, protective layer of magnetic fields, called a magnetosphere, which protects its surface from the effects of solar flares and cosmic rays.
Enceladus sits deep within Saturn's magnetosphere, which is filled with electrically charged particles (plasma) originating from both the planet and its moons.
The magnetosphere is a bubble of magnetism that surrounds the Earth and protects us from solar wind.