Space is sometimes described as a vacuum better than mankind could create in any laboratory. But it is not a vacuum, but a tenuous plasma carrying the interplanetary medium (solar wind). It is also structured, forming the [Heliospheric current sheet][1].

This means that space has the characteristics of a plasma. It is electrically conductive, carries magnetic fields, and carries energy from the sun resulting from [coronal mass ejections][2] that interact with the Earth's magnetic fields to produce the aurora, and can sometimes knock out the power to cities (eg. [The Quebec Blackout][3])


  [1]: https://en.wikipedia.org/wiki/Heliospheric_current_sheet
  [2]: https://en.wikipedia.org/wiki/Coronal_mass_ejection
  [3]: http://www.nasa.gov/topics/earth/features/sun_darkness.html