Magnetosphere

Farther out, field lines can be significantly distorted by the flow of electrically conducting plasma, as emitted from the Sun (i.e., the solar wind) or a nearby star.

Through the use of magnetometers, scientists were able to study the variations in Earth's magnetic field as functions of both time and latitude and longitude.

The later mission of Explorer 12 in 1961 led by the Cahill and Amazeen observation in 1963 of a sudden decrease in magnetic field strength near the noon-time meridian, later was named the magnetopause.

Mercury, Earth, Jupiter, Ganymede, Saturn, Uranus, and Neptune, for example, exhibit intrinsic magnetospheres.

[8] It is an area exhibiting high particle energy flux, where the direction and magnitude of the magnetic field varies erratically.

It acts as a cushion that transmits the pressure from the flow of the solar wind and the barrier of the magnetic field from the object.

[3] It is the convergence of the shocked solar wind from the magnetosheath with the magnetic field of the object and plasma from the magnetosphere.

The structure of the magnetopause depends upon the Mach number and beta ratio of the plasma, as well as the magnetic field.

[10] Opposite the compressed magnetic field is the magnetotail, where the magnetosphere extends far beyond the astronomical object.

The tail lobes are almost empty, with few charged particles opposing the flow of the solar wind.

The two lobes are separated by a plasma sheet, an area where the magnetic field is weaker, and the density of charged particles is higher.

[11] Over Earth's equator, the magnetic field lines become almost horizontal, then return to reconnect at high latitudes.

On the dayside of Earth, the magnetic field is significantly compressed by the solar wind to a distance of approximately 65,000 kilometers (40,000 mi).

[14] On Earth's nightside, the magnetic field extends in the magnetotail, which lengthwise exceeds 6,300,000 kilometers (3,900,000 mi).

In the Solar System this includes the Sun, Mercury, Earth, Jupiter, Saturn, Uranus, Neptune,[16] and Ganymede.

[17] Jupiter's magnetosphere is stronger than Earth's by an order of magnitude, and its magnetic moment is approximately 18,000 times larger.

It is hypothesized that Venus and Mars may have lost their primordial water to photodissociation and the solar wind.

[26] The first unconfirmed detection of a magnetic field generated by a terrestrial exoplanet was found in 2023 on YZ Ceti b.