The heliopause is the boundary between the heliosphere and the interstellar medium outside the solar system. As the solar wind approaches the heliopause, it slows suddenly, forming a shock wave called the termination shock of the solar wind.

In astronomy, the heliopause is the boundary where the Sun's solar wind is stopped by the interstellar medium. Source: http://helios. ... Source: http://helios. ... The heliosphere is a bubble in space produced by the solar wind. ... The distribution of ionized hydrogen (known by astronomers as H II (aitch two) from old spectroscopic terminology) in the parts of the Galactic interstellar medium visible from the Earths northern hemisphere (from the Wisconsin H-Alpha Mapper Survey) In astronomy, the interstellar medium (or ISM) is the matter (interstellar... Major features of the solar system (not to scale) The solar system comprises the Sun and the retinue of celestial objects gravitationally bound to it: nine planets and their 158 currently known moons, as well as asteroids, meteoroids, planetoids, comets, and interplanetary dust. ... Introduction The shock wave is one of several different ways in which a gas in a supersonic flow can be compressed. ... The locations of Voyagers 1 and 2 as of 2005 In space physics, the termination shock is the boundary marking one of the outer limits of the suns influence. ... Radio telescopes are among many different tools used by astronomers Astronomy (Greek: αστρονομία = άστρον + νόμος, astronomia = astron + nomos, literally, law of the stars) is the science of celestial objects (such as stars, planets, comets, and galaxies) and phenomena that originate outside the Earths atmosphere (such as auroras and cosmic background radiation). ... The Sun is the star at the center of our solar system. ... The plasma in the solar wind meeting the heliopause For the British comic, see Solar Wind (comic). ... The distribution of ionized hydrogen (known by astronomers as H II (aitch two) from old spectroscopic terminology) in the parts of the Galactic interstellar medium visible from the Earths northern hemisphere (from the Wisconsin H-Alpha Mapper Survey) In astronomy, the interstellar medium (or ISM) is the matter (interstellar...

The solar wind blows a "bubble" known as the heliosphere in the interstellar medium (the rarefied hydrogen and helium gas that permeates the galaxy). The outer border of this "bubble" is where the solar wind's strength is no longer great enough to push back the interstellar medium. This is known as the heliopause, and is often considered to be the outer border of the solar system. The plasma in the solar wind meeting the heliopause For the British comic, see Solar Wind (comic). ... The heliosphere is a bubble in space produced by the solar wind. ... The distribution of ionized hydrogen (known by astronomers as H II (aitch two) from old spectroscopic terminology) in the parts of the Galactic interstellar medium visible from the Earths northern hemisphere (from the Wisconsin H-Alpha Mapper Survey) In astronomy, the interstellar medium (or ISM) is the matter (interstellar... NGC 4414, a typical spiral galaxy in the constellation Coma Berenices, is about 56,000 light years in diameter and approximately 60 million light years distant. ... Major features of the solar system (not to scale) The solar system comprises the Sun and the retinue of celestial objects gravitationally bound to it: nine planets and their 158 currently known moons, as well as asteroids, meteoroids, planetoids, comets, and interplanetary dust. ...

Inside the heliopause is a boundary called the "termination shock" where supersonic solar wind particles are slowed to subsonic speeds by the interstellar medium. The layer between the termination shock and the heliopause is known as the heliosheath. The locations of Voyagers 1 and 2 as of 2005 In space physics, the termination shock is the boundary marking one of the outer limits of the suns influence. ... It has been suggested that this article or section be merged with Sound barrier. ... The locations of Voyagers 1 and 2 as of 2005 The heliosheath is the zone between the termination shock and the heliopause at the outer border of the solar system. ...

Outside the heliopause, the interaction between the interstellar medium and the heliopause produces the bow shock, a turbulent region in front of the Sun's progress through the interstellar medium. In a planetary magnetosphere, the bow shock is the boundary at which the solar wind abruptly drops as a result of its approach to the magnetopause. ...

The distance to the heliopause is 76 AU, as detected by Voyager 2^[1]. It is hypothesised that the heliopause could be smaller on the side of the solar system facing the orbital motion through the galaxy. It may also vary depending on the current velocity of the solar wind and the local density of the interstellar medium. It is known to lie far outside the orbit of Pluto. The current mission of the Voyager 1 and 2 spacecraft is to find and study the termination shock, heliosheath, and heliopause. Thus far, both Voyager 1 and Voyager 2 have reached the termination shock according to NASA announcements made May 24, 2005 and May 23, 2006, respectively. It is anticipated that both missions may ultimately reach the heliopause itself. // Au may refer to: Gold, an element in the periodic table Alternative universe (fan fiction), a fan fiction term Annals of Ulster, in Irish historical writings Au is a cartwheel (Capoeira) in the Brazilian martial art of Capoeira Au (區 or 歐) is a family name in Hong Kong In science Astronomical... Voyager 2 is an unmanned interplanetary spacecraft. ... Atmospheric characteristics Atmospheric pressure 0. ... Voyager 1 lifted off with a Titan 3E Centaur The Voyager 1 spacecraft is an 815-kilogram unmanned probe of the outer solar system and beyond, launched September 5, 1977, and currently operational. ... Voyager 2 is an unmanned interplanetary spacecraft. ... NASA logo Listen to this article · (info) This audio file was created from an article revision dated 2005-09-01, and does not reflect subsequent edits to the article. ... May 24 is the 144th day of the year in the Gregorian calendar (145th in leap years). ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... May 23 is the 143rd day of the year in the Gregorian calendar (144th in leap years). ... 2006 (MMVI) is a common year starting on Sunday of the Gregorian calendar. ...

Voyager 1 & 2 and Pioneer 10 & 11 approaching the heliosheath

When particles emitted by the sun bump into the interstellar ones, they slow down while releasing energy. Many particles accumulate in and around the heliopause, highly energised by their negative acceleration, creating a shock wave. Image File history File links Download high resolution version (3000x2285, 595 KB) Diagram shows Pioneer 10s systems From http://www. ... Image File history File links Download high resolution version (3000x2285, 595 KB) Diagram shows Pioneer 10s systems From http://www. ... The locations of Voyagers 1 and 2 as of 2005 The heliosheath is the zone between the termination shock and the heliopause at the outer border of the solar system. ...

An alternative definition is that the heliopause is the magnetopause between the solar system's magnetosphere and the galaxy's plasma currents. A magnetopause flows along the boundary between a magnetic field, (see: magnetosphere) and surrounding plasma. ... Schematic of Earths magnetosphere. ...

Notes

1. ↑  NASA. May 24, 2005. Voyager Enters Solar System's Final Frontier. Retrieved May 25, 2005.

1. ^ May 25th, 2006. Voyager II detects solar system's edge. Retrieved May 26, 2005

May 24 is the 144th day of the year in the Gregorian calendar (145th in leap years). ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... May 25 is the 145th day of the year in the Gregorian calendar (146th in leap years). ... 2006 (MMVI) is a common year starting on Sunday of the Gregorian calendar. ...

See also

• Bow shock
• Termination Shock
• Solar flare
• Heliosheath
• Voyager I
• Voyager Program
• Magnetopause
• Magnetosphere

In a planetary magnetosphere, the bow shock is the boundary at which the solar wind abruptly drops as a result of its approach to the magnetopause. ... The locations of Voyagers 1 and 2 as of 2005 In space physics, the termination shock is the boundary marking one of the outer limits of the suns influence. ... A Solar Flare, courtesy NASA A solar flare is a violent explosion in the Suns atmosphere with an energy equivalent to tens of millions of hydrogen bombs. ... The locations of Voyagers 1 and 2 as of 2005 The heliosheath is the zone between the termination shock and the heliopause at the outer border of the solar system. ... Categories: Jupiter | Saturn | NASA probes | Astronomy stubs ... The Voyager spacecraft Launch of Voyager 2 Voyager is also the name of a planned series of unmanned probes to Mars, cancelled in 1968. ... A magnetopause flows along the boundary between a magnetic field, (see: magnetosphere) and surrounding plasma. ... Schematic of Earths magnetosphere. ...

External links

• NASA: http://voyager.jpl.nasa.gov/mission/interstellar.html
• Univ. of Iowa Press release -- December 8, 2003
• http://www.universetoday.com/am/publish/size_of_heliopause.html