Editing Outer space (section)

=== Interplanetary space ===
{{main|Interplanetary medium}}
[[File:Comet Hale-Bopp 1995O1.jpg|right|thumb|The sparse plasma (blue) and dust (white) in the tail of [[comet Hale–Bopp]] are being shaped by pressure from [[Sunlight|solar radiation]] and the solar wind, respectively.|alt=At lower left, a white coma stands out against a black background. Nebulous material streams away to the top and left, slowly fading with distance.]]

Interplanetary space within the [[Solar System]] is dominated by the gravitation of the Sun, outside the gravitational spheres of influence of the planets.<ref name="j999"/> Interplanetary space extends well beyond the orbit of the outermost planet [[Neptune]], all the way out to where the influence of the galactic environment starts to dominate over the Sun and its solar wind producing the [[Heliopause (astronomy)|heliopause]] at 110 to 160 AU.<ref name=universetoday_interplanetaryspace /> The heliopause deflects away low-energy galactic cosmic rays, and its distance and strength varies depending on the activity level of the solar wind.<ref name=Kohler2017/><ref name=phillips2009/> The solar wind is a continuous stream of charged particles emanating from the Sun which creates a very tenuous atmosphere (the [[heliosphere]]) for billions of kilometers into space. This wind has a particle density of 5–10 [[proton]]s/cm<sup>3</sup> and is moving at a velocity of {{Convert|350|-|400|km/s|mph|abbr=on}}.{{sfn|Papagiannis|1972|pp=12–149}}

The region of interplanetary space is a nearly total vacuum, with a mean free path of about one [[astronomical unit]] at the orbital distance of the Earth. This space is not completely empty, but is sparsely filled with cosmic rays, which include [[ion]]ized [[atomic nucleus|atomic nuclei]] and various subatomic particles. There is gas, plasma and dust,<ref name="EA-20190312"/> small [[meteor]]s, and several dozen types of [[organic chemistry|organic]] molecules discovered to date by [[rotational spectroscopy|microwave spectroscopy]].<ref name=asp2003/> Collectively, this matter is termed the [[interplanetary medium]].<ref name=universetoday_interplanetaryspace /> A cloud of interplanetary dust is visible at night as a faint band called the [[zodiacal light]].<ref name="leinert_grun_1990"/>

Interplanetary space contains the magnetic field generated by the Sun.{{sfn|Papagiannis|1972|pp=12–149}} There are magnetospheres generated by planets such as Jupiter, Saturn, [[Mercury (planet)|Mercury]] and the Earth that have their own magnetic fields. These are shaped by the influence of the solar wind into the approximation of a teardrop shape, with the long tail extending outward behind the planet. These magnetic fields can trap particles from the solar wind and other sources, creating belts of charged particles such as the Van Allen radiation belts. Planets without magnetic fields, such as Mars, have their atmospheres gradually eroded by the solar wind.<ref name=ssr69_3_215/>