section_path: Regions/Regions near the Earth
section_name: Regions near the Earth
paragraph_text: Regions near the Earth
  
  Space in proximity to the Earth is physically similar to the remainder of interplanetary space, but is home to a multitude of Earth–orbiting satellites and has been subject to extensive studies. For identification purposes, this volume is divided into overlapping regions of space.
  
  Near-Earth space is the region of space extending from low Earth orbits out to geostationary orbits. This region includes the major orbits for artificial satellites and is the site of most of humanity's space activity. The region has seen high levels of space debris, sometimes dubbed space pollution, threatening any space activity in this region. Some of this debris re-enters Earth's atmosphere periodically. Although it meets the definition of outer space, the atmospheric density inside low-Earth orbital space, the first few hundred kilometers above the Kármán line, is still sufficient to produce significant drag on satellites.
  
  Geospace is a region of space that includes Earth's upper atmosphere and magnetosphere. The Van Allen radiation belts lie within the geospace. The outer boundary of geospace is the magnetopause, which forms an interface between the Earth's magnetosphere and the solar wind. The inner boundary is the ionosphere.
  
  The variable space-weather conditions of geospace are affected by the behavior of the Sun and the solar wind; the subject of geospace is interlinked with heliophysics —the study of the Sun and its impact on the planets of the Solar System. The day-side magnetopause is compressed by solar-wind pressure—the subsolar distance from the center of the Earth is typically 10 Earth radii. On the night side, the solar wind stretches the magnetosphere to form a magnetotail that sometimes extends out to more than 100–200 Earth radii. For roughly four days of each month, the lunar surface is shielded from the solar wind as the Moon passes through the magnetotail.
  
  Geospace is populated by electrically charged particles at very low densities, the motions of which are controlled by the Earth's magnetic field. These plasmas form a medium from which storm-like disturbances powered by the solar wind can drive electrical currents into the Earth's upper atmosphere. Geomagnetic storms can disturb two regions of geospace, the radiation belts and the ionosphere. These storms increase fluxes of energetic electrons that can permanently damage satellite electronics, interfering with shortwave radio communication and GPS location and timing. Magnetic storms can be a hazard to astronauts, even in low Earth orbit. They create aurorae seen at high latitudes in an oval surrounding the geomagnetic poles.
  
  xGeo space is a concept used by the US to refer to space of high Earth orbits, ranging from beyond geosynchronous orbit (GEO) at approximately 35,786 km (22,236 mi), out to the L2 Earth-Moon Lagrange point at 448,900 km (278,934 mi). This is located beyond the orbit of the Moon and therefore includes cislunar space. Translunar space is the region of lunar transfer orbits, between the Moon and Earth. Cislunar space is a region outside of Earth that includes lunar orbits, the Moon's orbital space around Earth and the Lagrange points.
  
  The region where a body's gravitational potential remains dominant against gravitational potentials from other bodies, is the body's sphere of influence or gravity well, mostly described with the Hill sphere model. In the case of Earth this includes all space from the Earth to a distance of roughly 1% of the mean distance from Earth to the Sun, or 1.5 million km (0.93 million mi). Beyond Earth's Hill sphere extends along Earth's orbital path its orbital and co-orbital space. This space is co-populated by groups of co-orbital Near-Earth Objects (NEOs), such as horseshoe librators and Earth trojans, with some NEOs at times becoming temporary satellites and quasi-moons to Earth.
  
  Deep space is defined by the United States government as all of outer space which lies further from Earth than a typical low-Earth-orbit, thus assigning the moon to deep-space. Other definitions vary the starting point of deep-space from, "That which lies beyond the orbit of the moon," to "That which lies beyond the farthest reaches of the Solar System itself." The International Telecommunication Union responsible for radio communication, including with satellites, defines deep-space as, "distances from the Earth equal to, or greater than, 2 million km (1.2 million mi)," which is about five times the Moon's orbital distance, but which distance is also far less than the distance between Earth and any adjacent planet.