How does the term magnetosphere apply to solar wind study, and do Ceres and Vesta have magnetospheres?
The magnetosphere is that cocoon that the Earth lives inside of; it is the boundary between where the solar wind streams regularly away from the sun, and the obstacle that the Earth’s magnetic field presents to it. You can look at it as kind of a pressure boundary between the magnetic field of the Earth, the magnetosphere which is protecting the Earth, and where it no longer has any effect. We don’t think that Ceres and Vesta have magnetospheres. But the interesting thing is that in the past, Vesta in particular may have had a magnetosphere, because some of the meteorites that come from Vesta have some magnetic material in them, indicating that the protoplanet may have had a field of its own in the past. We know that Mars had a very strong magnetic field in the past and therefore should have had a strong magnetosphere, and we know that Jupiter also has a very interesting magnetosphere. So we have a lot of planets in the solar system that have or have had magnetospheres in the past. The
