This image shows the magnetic field lines of a planet passing by a moon and creating a wake.
Click on image for full size
J. Linker

Wake

A moon which is inside a magnetosphere usually travels slower than the magnetic field. This means that the magnetic field lines will pass over the satellite like water going around a rock. Because the moon is made of conducting material, the magnetic field will be delayed in passing around the moon. Thus the field lines will be distorted in passing over the satellite. Eventually they straighten up. The region upstream of the satellite, in the magnetic field of the planet, is called a satellite wake.

This satellite wake is different from the satellite geometric wake. The satellite wake extends in front of the satellite, in the direction in which it is moving, while the geometric wake extends in the opposite direction from the line between the satellite and the planet, and is similar to the shadow of the satellite.

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Magnetosphere

A magnetosphere has many parts, such as the bow shock, magnetosheath, magnetotail, plasmasheet, lobes, plasmasphere, radiation belts and many electric currents. It is composed of charged particles and...more

AU

AU stands for Astronomical Units. Distances in space are too large to measure in Earth standards like miles or kilometers. For distances too large to measue in AU, we use light years. A light year is the...more

The Spiral of the IMF

The solar wind is formed as the Sun's topmost layer blows off into space carrying with it magnetic fields still attached to the Sun. Gusts and disturbances form in the solar wind associated with violent...more

Spiral Path of Material

For a planet to be affected by a blob of material being ejected by the sun, the planet must be in the path of the blob, as shown in this picture. The Earth and its magnetosphere are shown in the bottom...more

The SAR Arc

The aurora we are most familiar with is the polar aurora. This is what people are referring to when they speak of the northern or southern lights. But there are other less-known auroral activity, such...more

The Effect of Aurora on the Atmosphere

This figure shows the effect of the aurora on the atmosphere. When FAC's enter the atmosphere and create the aurora, they warm the atmosphere impulsively. This impulse travels throughout the atmosphere...more

The forming Aurora

This picture illustrates the streaming of particles into and out of the auroral zone, as Field-aligned currents (FAC's) short-circuit through the ionosphere. Some of the particles entering the auroral...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA