We can’t see the heliosphere. We know where it starts but not really where it ends. And we are pretty certain that most stars, and therefore most planetary systems, are bounded by heliospheres, or “astropheres,” as well.
It has a measurable physical presence, but it is always changing. And although it is hardly well known, it plays a substantial role in the dynamics of our solar system and our lives.
As it is studied further and deeper, it has become apparent that the heliosphere might be important — maybe even essential – for the existence of life on Earth and anywhere else it may exist. Often likened to an enormous bubble or cocoon, it is the protected space in which our solar system and more exists.
Despite the fact that it is the largest physical system in the entire solar system, the heliosphere was only discovered at the dawn of the space age in the late 1950’s, when it was theorized by University of Chicago physicist Eugene Parker as being the result of what he termed the solar wind.
It took another decade for satellite measurements to confirm its existence and to determine some of its properties — that it is made up of an endless supply of charged particles that are shot off the sun — too hot to form into atoms. Together these particles, which are superimposed with the interplanetary magnetic field, constitute the ingredients of he heliosphere.
Just as the Earth’s magnetic fields protect us from some of the effects of the Sun’s hazardous emanations, the heliosphere protects everything inside its bubble from many, though not all, of the incoming and more hazardous high-energy cosmic rays headed our way.
As measurable proof that the heliosphere does offer significant protection, when the Voyager 1 spacecraft left the heliosphere in 2012 and entered the intersellar medium, instruments onboard detected a tripling of amount of cosmic radiation suddenly hitting the spacecraft.… Read more