One of the most exciting results announced in Science involves Mercury's magnetic field. Until Mariner 10 discovered Mercury's magnetic field in the 1970s, Earth was the only other terrestrial planet known to have a global magnetic field. Earth's magnetism is generated by the planet's churning hot, liquid-iron core via a mechanism called a magnetic dynamo. Researchers have been puzzled by Mercury's field because its iron core was supposed to have cooled long ago and stopped generating magnetism. Some researchers have thought that the field may have been a relic of the past, frozen in the outer crust.also,
MESSENGER data suggest otherwise: Mercury's field appears to be generated by an active dynamo in the planet's core. It is not a relic.
Another significant scientific surprise involves Mercury's magnetosphere--the bubble of magnetism surrounding the planet. Thomas Zurbuchen of the University of Michigan explains: "Mercury's magnetosphere is full of many [kinds of charged particles], both atomic and molecular. What is in some sense a 'Mercury plasma nebula' is far richer in complexity and makeup than the Io plasma torus in the Jupiter system." The composition of the nebula doesn't match that of the solar wind, leading researchers to conclude "that this material came from the planet's surface. This observation means that this flyby got the first-ever look at surface composition."And many more mercurial findings.
Does the planet Mercury need to exist? - I mean in the business sense. Does it do anything? Or is it like those souvenir shells that persist forever on the mantelpiece? They have no use, but that's not the same thing as saying that they are not there for a reason. There is a difference between use and reason.
Question: If Mercury disappeared, who would notice? Who would care?