Heliosphere - Wikiparency

# Heliosphere  **Microsim — three.js (Wikitube framework):** *The edge of the heliosphere in the Solar System explorer* <div class="wt-sim" data-src="https://wikitube-3d-microsims.netlify.app/solar/Solar_System.html?obj=heliosphere&embed=1" data-title="The edge of the heliosphere in the Solar System explorer"></div> *The Solar System explorer locked on this article's state (`?obj=heliosphere`); every object and population of the [[PORTAL_Solar_System|Solar System portal]] has its own state in the same scene.*  *Try: under show, choose clouds and boundaries to hide the planets and keep the three nested shells, the termination shock at 94 AU, the heliopause at 121 AU and the bow shock near 230 AU; scroll in until the planets' region shrinks to a small patch at the centre, all of it deep inside the innermost shell; then drag the view all the way round and notice that the shells look the same from every side, a simplification, since the real heliosphere is blunt on its upstream side and drawn out into a long tail behind.* The **heliosphere** is the vast region of space dominated by the [[Sun]]: the bubble that the [[Solar_wind|solar wind]] and the magnetic field it carries blow into the surrounding [[Interstellar_medium|interstellar medium]].[^owens2013][^nasa-vim] In [[Plasma_(physics)|plasma]]-physics terms it is the Sun's magnetosphere, the cavity the Sun excavates in the local gas of the [[Milky_Way|Milky Way]], and it screens the planets from a large share of galactic cosmic rays. The word was probably coined by Alexander Dessler, who used it in print in 1967.[^dessler1967] The solar wind flows outward supersonically, far past [[Pluto]], until it slows abruptly at the termination shock; beyond lies the heliosheath of slowed, heated wind, and then the heliopause, the boundary with interstellar plasma.[^nasa-vim] Upstream, in the direction of the Sun's motion through the local gas, the boundary lies roughly 120 [[Astronomical_unit|AU]] out; downstream the heliosphere is thought to trail a long tail, though its true shape is still debated.[^opher2020][^ibex-tail] [[Voyager_1|Voyager 1]] crossed the heliopause on 25 August 2012 and Voyager 2 on 5 November 2018, the only spacecraft so far to reach interstellar space.[^nasa-vim][^stone2019] The explorer at the top of this page shows the heliosphere's boundaries as three nested shells at the distances measured by Voyager 1 and an older estimate for the bow shock; the shells are ILLUSTRATIVE, and the planets' orbits sit deep inside them. ## History The heliosphere has not always had its present size. Its extent depends on the pressure of the gas the Sun happens to be passing through, and the local interstellar medium is patchy.[^frisch2011] Modelling by Merav Opher and colleagues suggests that 2–3 million years ago the Solar System may have crossed a cold, dense cloud in the Local Ribbon of Cold Clouds, compressing the heliosphere to about 0.22 AU, inside Earth's orbit, and exposing [[Earth]] directly to interstellar gas; deposits of iron-60 and plutonium-244 in geological records are consistent with such an episode.[^opher2024] The heliosphere's future is likewise tied to the clouds ahead of the Sun on its path through the [[Local_Interstellar_Cloud|Local Interstellar Cloud]] and its neighbours.[^frisch2011] ## Structure The heliosphere is not a sphere. Its shape is set by the [[Solar_wind|solar wind]], the [[Interstellar_medium|interstellar medium]] and the Sun's motion through that medium, and because both the wind and the medium are fluids, its size breathes with them.[^nasa-voyager2007] The wind's pressure varies far faster than the interstellar pressure, so the boundaries move mostly with changes in the wind: Voyager 2 crossed the moving termination shock several times, and the shock was seen to re-form within hours.[^nasa-voyager2007][^stone2008] On larger scales, motion through the interstellar gas compresses the upstream side into a blunt nose and, in the classic picture, stretches the downstream side into a heliotail.[^brandt2023] How long that tail is, or whether it exists in the classic form, is uncertain. Opher and colleagues, using [[Magnetohydrodynamics|magnetohydrodynamic]] models that include the pressure of pick-up [[Ion|ions]], concluded in 2020 that the heliosphere may be small and rounded, with a crescent or "deflated croissant" shape rather than a long comet tail.[^opher2020] Data from few directions leave room for several models.[^matson2013] ### Solar wind The solar wind carries charged particles and magnetic field from the [[Sun]]'s corona outward in all directions at several hundred kilometres per second.[^msfc-sw] Because the Sun rotates about once every 25 days, the heliospheric magnetic field carried by that flow is wound into a spiral, the Parker spiral.[^owens2013] Variations in the Sun's field, carried outward by the wind, drive geomagnetic storms at Earth.[^owens2013] ### Heliospheric current sheet The heliospheric current sheet is the surface separating regions of the heliospheric magnetic field with opposite polarity. It extends throughout the heliosphere, rippling as the Sun rotates into a shape likened to a ballerina's skirt, and it is arguably the largest single structure in the Solar System. Observations show it is often shifted slightly south of the solar equator, the "bashful ballerina".[^mursula2003] ## Edge structure Near [[Earth]] the solar wind moves at several hundred kilometres per second, far faster than the [[Speed_of_sound|speed of sound]] in the plasma, and it keeps that speed well beyond [[Neptune]]. Its pressure falls with the square of distance while the interstellar pressure stays nearly constant, so at some distance the wind can no longer hold its supersonic flow, and it must slow down in stages: first at a standing shock, then through a turbulent sheath, until the two pressures balance at the boundary.[^nasa-vim][^apod2002] A familiar analogue is the hydraulic jump in a kitchen sink, where a thin, fast sheet of water spreading from the tap ends at a ring-shaped wall beyond which the water flows slowly. ### Termination shock At the termination shock the wind drops abruptly from supersonic to subsonic speed, compressing and heating the plasma and strengthening the magnetic field.[^nasa-vim] Before the Voyagers reached it, estimates put it at about 75–90 AU.[^apod2002] [[Voyager_1|Voyager 1]] crossed it on 16 December 2004 at 94.01 [[Astronomical_unit|AU]], and Voyager 2 in August 2007 at 83.7 AU, some 10 AU closer to the Sun in the southern hemisphere, showing that the shock is asymmetric, perhaps pushed in by the interstellar magnetic field.[^stone2005][^stone2008] Voyager 2 crossed it several times as the shock moved back and forth.[^nasa-voyager2007] ### Heliosheath Beyond the shock lies the heliosheath, where the slowed wind is compressed and turned aside to flow down the tail. Its thickness on the upstream side was estimated at 10–100 AU.[^brandt2007] The Voyagers found it anything but smooth: it seems to be a froth of magnetic bubbles about 1 AU across, formed by reconnection of the folded solar magnetic field.[^nasa2011-bubbles][^nasa2013-surprise] From about 113 AU Voyager 1 entered a stagnation region in which the wind's outward speed fell to zero, the magnetic field doubled in strength and galactic electrons increased a hundredfold.[^nasa2011-stagnation][^krimigis2011] Near 122 AU it reached a "magnetic highway" where heliospheric particles could escape and interstellar ones enter along the field.[^jpl2012-highway] ### Heliopause The [[Heliopause|heliopause]] is where the pressure of the [[Solar_wind|solar wind]] and that of the interstellar medium balance, the outer boundary of the heliosphere. Crossing it should bring a sharp fall in solar-wind particles, a jump in galactic cosmic rays and a change in the magnetic field.[^nasa2012-v1] In 2012 Voyager 1 saw those first two changes; its plasma-wave instrument later showed that the surrounding plasma was about forty times denser than inside, which fixed the crossing at 25 August 2012, at about 121–122 AU.[^nasa2013-v1][^nasa-vim][^cowen2013] Contrary to expectations, the magnetic field direction barely changed across the boundary.[^vergano2013] Voyager 2 crossed on 5 November 2018 at 119 AU and, unlike its twin, met no interstellar flux tubes inside the boundary.[^stone2019] Its plasma-wave instrument measured the density jump as about a factor of twenty.[^gurnett2019] ### Heliotail The heliotail, the heliosphere's downstream extension, trailing away from the [[Sun]]'s direction of motion, may stretch for thousands of astronomical units.[^brandt2023] It cannot be seen directly, but NASA's Interstellar Boundary Explorer (IBEX) mapped it through energetic neutral atoms produced by charge exchange and found in 2013 a four-lobed, clover-like structure, with slow wind at the sides and fast wind from the Sun's high latitudes in the middle.[^ibex-tail] Particles in the tail are gradually lost by charge exchange with interstellar atoms.[^astrobio2013] ## Outside structures The [[Heliopause|heliopause]] separates plasma from the [[Sun]] from interstellar [[Plasma_(physics)|plasma]] produced by other stars, but the change is not total at the boundary: Voyager 1 found a transitional region just outside it in which some solar material still mixes with interstellar gas.[^nasa2013-v1][^nasa-glossary] Beyond the boundary, galactic cosmic rays rise and heliospheric particles almost vanish.[^jpl2013-how] The [[Interstellar_medium|interstellar]] gas flowing into the heliosphere, measured by at least eleven spacecraft, arrives from the direction of Scorpius, and its direction seems to have shifted by several degrees since the 1970s.[^nasa2015-wind] ### Hydrogen wall Interstellar neutral [[Hydrogen|hydrogen]] piles up ahead of the heliopause, where it is slowed and heated, forming a predicted "hydrogen wall".[^wood2006][^zank2013] Pioneer and Voyager ultraviolet detectors found signs of this hydrogen in 1992, and in 2018 New Horizons measurements, made from beyond [[Pluto]], of the Lyman-alpha sky background supported the detection with greater sensitivity.[^hall1992][^gladstone2018] ### Bow shock If the interstellar gas met the heliosphere faster than its own sound and magnetic wave speeds, it would form a bow shock upstream, once estimated at about 230 AU.[^apod2002] In 2012, however, IBEX measured the Sun's speed relative to the local interstellar medium at about 23.2 km/s, slower than the 26.3 km/s derived earlier from Ulysses, and together with the interstellar magnetic field this is too slow for a shock; a gentler bow wave is more likely.[^mccomas2012][^astrobites2012][^zank2013] The explorer still draws a bow-shock shell near 230 AU as the traditional outer marker. ## Observational methods ### Detection by spacecraft Only the two [[Voyager_1|Voyagers]] have reached the boundaries in person; Pioneer 10, Pioneer 11 and New Horizons are also leaving the Solar System, but contact with the Pioneers has been lost.[^nasa-pioneer] Remote sensing fills the gaps. Energetic neutral atoms, created when heliospheric ions steal electrons from interstellar atoms, travel in straight lines and so can be mapped from inside the heliosphere. Cassini's ion and neutral camera at [[Saturn]] produced such maps in 2009 suggesting a rounder, bubble-like heliosphere shaped by particle pressure and magnetic field rather than a long comet tail.[^krimigis2009] IBEX, launched in October 2008, found an unexpected, narrow "ribbon" of neutral-atom emission two to three times brighter than the rest of the sky, apparently ordered by the interstellar magnetic field; its structure changed within six months.[^mccomas2009][^astrobio2010] ### Locally Closer to the [[Sun]], missions such as SOHO, STEREO, Ulysses, Parker Solar Probe and Solar Orbiter sample the wind and field that fill the heliosphere; Ulysses, after a [[Jupiter]] flyby in February 1992, was the first to explore its high latitudes.[^esa-ulysses] STEREO produced the first images of energetic neutral atoms from the heliosheath.[^nasa-stereo] ## Exploration history The Pioneer and Voyager spacecraft, launched between 1972 and 1977, carried instruments into the outer heliosphere along different directions. Pioneer 10, the first spacecraft sent past [[Mars]] to [[Jupiter]], returned solar wind data to about 67 AU until 1997; Pioneer 11 did so to 44.7 AU until 1995.[^nasa-pioneer][^astronautix] Voyager 1, moving faster, overtook Pioneer 10's distance on 17 February 1998 at 69.4 AU.[^nasa-pioneer-ames] [[Voyager_1|Voyager 1]] reached the termination shock in 2004 and Voyager 2 in 2007.[^stone2005][^stone2008] Within the heliosheath the Voyagers found magnetic bubbles and a stagnation region, and from May 2012 Voyager 1 recorded steeply rising cosmic rays as it approached the heliopause.[^nasa2011-bubbles][^nasa2012-v1] NASA announced in September 2013 that the probe had been in interstellar space since 25 August 2012.[^nasa2013-v1] Voyager 2, whose plasma instrument still worked, recorded the drop in solar wind speed directly when it crossed on 5 November 2018.[^nasa2018-v2] Moving outward at about 3.6 AU per year, Voyager 1 took some 7.7 years to cross the roughly 28 AU of heliosheath between the termination shock and the heliopause (derived).[^nasa-vim] ## Timeline of exploration and detection | Date | Event | |---|---| | 1904 | Johannes Hartmann, observing the binary star Mintaka at Potsdam, finds stationary absorption [[Spectral_line|lines]], the first evidence of interstellar gas.[^kanipe2011] | | 1958 | Eugene Parker predicts the supersonic [[Solar_wind|solar wind]].[^chang2018-parker] | | January 1959 | Luna 1 makes the first direct measurement of the solar wind.[^nssdc-luna1] | | 1962 | Mariner 2 measures the solar wind on the way to [[Venus]].[^jpl-mariner2] | | 1972–1973 | Pioneer 10 passes Mars and flies by Jupiter, returning solar wind data out to 67 AU over its mission.[^astronautix] | | February 1992 | Ulysses, after its Jupiter flyby, begins exploring high heliographic latitudes.[^esa-ulysses] | | 2004 | Voyager 1 crosses the termination shock at 94 AU.[^stone2005] | | 2005 | SOHO data show the interstellar hydrogen flow deflected, implying a distorted, non-axisymmetric heliosphere.[^lallement2005] | | 2009 | IBEX discovers the ribbon; Cassini maps suggest a rounder heliosphere.[^mccomas2009][^krimigis2009] | | May 2012 | IBEX results indicate there is probably no bow shock.[^mccomas2012] | | 25 August 2012 | Voyager 1 crosses the heliopause.[^nasa2013-v1] | | August 2018 | New Horizons Lyman-alpha data support the hydrogen wall.[^gladstone2018] | | 5 November 2018 | Voyager 2 crosses the heliopause at 119 AU.[^stone2019] | ## See also - [[Solar_wind]] - [[Interstellar_medium]] - [[Local_Interstellar_Cloud]] - [[Voyager_1]] ## References [^owens2013]: Owens, M. J.; Forsyth, R. J. (2013). "The heliospheric magnetic field". *Living Reviews in Solar Physics* 10: 5. https://doi.org/10.12942/lrsp-2013-5 [^nasa-vim]: NASA Science. "Voyager: interstellar mission" (fetched 2026-09-18). https://science.nasa.gov/mission/voyager/interstellar-mission/ [^dessler1967]: Dessler, A. J. (1967). "Solar wind and interplanetary magnetic field". *Reviews of Geophysics* 5: 1–41. https://doi.org/10.1029/RG005i001p00001 [^opher2020]: Opher, M.; Loeb, A.; Drake, J.; Toth, G. (2020). "A small and round heliosphere suggested by magnetohydrodynamic modelling of pick-up ions". *Nature Astronomy* 4: 675–683. https://doi.org/10.1038/s41550-020-1036-0 [^ibex-tail]: Cole, S. (2013). "NASA satellite provides first view of the Solar System's tail". NASA. https://www.nasa.gov/news-release/nasa-satellite-provides-first-view-of-the-solar-systems-tail/ [^stone2019]: Stone, E. C.; Cummings, A. C.; Heikkila, B. C.; Lal, N. (2019). "Cosmic ray measurements from Voyager 2 as it crossed into interstellar space". *Nature Astronomy* 3: 1013–1018. https://doi.org/10.1038/s41550-019-0928-3 [^frisch2011]: Frisch, P. C.; Redfield, S.; Slavin, J. D. (2011). "The interstellar medium surrounding the Sun". *Annual Review of Astronomy and Astrophysics* 49: 237–279. https://doi.org/10.1146/annurev-astro-081710-102613 [^opher2024]: Opher, M.; Loeb, A.; Peek, J. E. G. (2024). "A possible direct exposure of the Earth to the cold dense interstellar medium 2–3 Myr ago". *Nature Astronomy* 8: 983–990. https://doi.org/10.1038/s41550-024-02279-8 [^nasa-voyager2007]: NASA (2007). "Voyager 2 proves Solar System is squashed". http://www.nasa.gov/mission_pages/voyager/voyager-20071210.html [^brandt2023]: Brandt, P. C.; Provornikova, E.; Bale, S. D.; et al. (2023). "Future exploration of the outer heliosphere and very local interstellar medium by Interstellar Probe". *Space Science Reviews* 219: 18. https://doi.org/10.1007/s11214-022-00943-x [^matson2013]: Matson, J. (2013). "Voyager 1 returns surprising data about an unexplored region of deep space". *Scientific American* blog. https://blogs.scientificamerican.com/observations/voyager-1-returns-surprising-data-about-an-unexplored-region-of-deep-space/ [^msfc-sw]: NASA Marshall Space Flight Center. "The solar wind". https://solarscience.msfc.nasa.gov/SolarWind.shtml [^mursula2003]: Mursula, K.; Hiltula, T. (2003). "Bashful ballerina: southward shifted heliospheric current sheet". *Geophysical Research Letters* 30: 2135. https://doi.org/10.1029/2003GL018201 [^apod2002]: Nemiroff, R.; Bonnell, J. (2002). "The Sun's heliosphere & heliopause". *Astronomy Picture of the Day*, NASA, 24 June 2002. https://apod.nasa.gov/apod/ap020624.html [^stone2005]: Stone, E. C.; Cummings, A. C.; McDonald, F. B.; et al. (2005). "Voyager 1 explores the termination shock region and the heliosheath beyond". *Science* 309: 2017–2020. https://doi.org/10.1126/science.1117684 [^stone2008]: Stone, E. C.; Cummings, A. C.; McDonald, F. B.; et al. (2008). "An asymmetric solar wind termination shock". *Nature* 454: 71–74. https://doi.org/10.1038/nature07022 [^brandt2007]: Brandt, P. (2007). "Imaging of the heliospheric boundary". NASA Advisory Council workshop white paper, Lunar and Planetary Institute. https://www.lpi.usra.edu/meetings/LEA/whitepapers/Brandt_whitepaper_heliospheric_imaging.pdf [^nasa2011-bubbles]: Cook, J.-R. (2011). "NASA probes suggest magnetic bubbles reside at Solar System edge". NASA/JPL. http://www.nasa.gov/home/hqnews/2011/jun/HQ_11-174_Voyager_Update.html [^nasa2013-surprise]: Zell, H. (2013). "A big surprise from the edge of the Solar System". NASA. http://www.nasa.gov/mission_pages/voyager/heliosphere-surprise.html [^nasa2011-stagnation]: Zell, H. (2011). "NASA's Voyager hits new region at Solar System edge". NASA. http://www.nasa.gov/mission_pages/voyager/voyager20111205.html [^krimigis2011]: Krimigis, S. M.; Roelof, E. C.; Decker, R. B.; Hill, M. E. (2011). "Zero outward flow velocity for plasma in a heliosheath transition layer". *Nature* 474: 359–361. https://doi.org/10.1038/nature10115 [^jpl2012-highway]: NASA Jet Propulsion Laboratory (2012). "NASA Voyager 1 encounters new region in deep space". Release 2012-381. http://www.jpl.nasa.gov/news/news.php?release=2012-381 [^nasa2012-v1]: NASA (2012). "Data from NASA's Voyager 1 point to interstellar future". https://www.nasa.gov/mission_pages/voyager/voyager20120614.html [^nasa2013-v1]: NASA (2013). "NASA spacecraft embarks on historic journey into interstellar space". https://www.nasa.gov/news-release/nasa-spacecraft-embarks-on-historic-journey-into-interstellar-space/ [^cowen2013]: Cowen, R. (2013). "Voyager 1 has reached interstellar space". *Nature* news. https://doi.org/10.1038/nature.2013.13735 [^vergano2013]: Vergano, D. (2013). "Voyager 1 leaves Solar System, NASA confirms". *National Geographic*. http://news.nationalgeographic.com/news/2013/13/130911-voyager-interstellar-solar-system-nasa-science-space/ [^gurnett2019]: Gurnett, D. A.; Kurth, W. S. (2019). "Plasma densities near and beyond the heliopause from the Voyager 1 and 2 plasma wave instruments". *Nature Astronomy* 3: 1024–1028. https://doi.org/10.1038/s41550-019-0918-5 [^astrobio2013]: *Astrobiology Magazine* (2013). "The unexpected structure of the heliotail". http://www.astrobio.net/pressrelease/5553/the-unexpected-structure-of-the-heliotail [^nasa-glossary]: Greicius, T. (2013). "Voyager glossary". NASA. http://www.nasa.gov/mission_pages/voyager/glossary.html [^jpl2013-how]: NASA Jet Propulsion Laboratory (2013). "How do we know when Voyager reaches interstellar space?". Release 2013-278. http://www.jpl.nasa.gov/news/news.php?release=2013-278 [^nasa2015-wind]: Zell, H. (2015). "Interstellar wind changed direction over 40 years". NASA. http://www.nasa.gov/content/goddard/interstellar-wind-changed-direction-over-40-years/ [^wood2006]: Wood, B. E.; Alexander, W. R.; Linsky, J. L. (1995). "The properties of the local interstellar medium and the interaction of the stellar winds of ε Indi and λ Andromedae with the interstellar environment". *Bulletin of the American Astronomical Society* 27(4). http://www.aas.org/publications/baas/v27n4/aas187/S045002.html [^zank2013]: Zank, G. P.; Heerikhuisen, J.; Wood, B. E.; et al. (2013). "Heliospheric structure: the bow wave and the hydrogen wall". *The Astrophysical Journal* 763: 20. https://doi.org/10.1088/0004-637X/763/1/20 [^hall1992]: Hall, D. T. (1992). *Ultraviolet Resonance Radiation and the Structure of the Heliosphere*. PhD thesis, University of Arizona. https://repository.arizona.edu/handle/10150/186043 [^gladstone2018]: Gladstone, G. R.; Pryor, W. R.; Stern, S. A.; et al. (2018). "The Lyman-α sky background as observed by New Horizons". *Geophysical Research Letters* 45: 8022–8028. https://doi.org/10.1029/2018GL078808 [^mccomas2012]: McComas, D. J.; Alexashov, D.; Bzowski, M.; et al. (2012). "The heliosphere's interstellar interaction: no bow shock". *Science* 336: 1291–1293. https://doi.org/10.1126/science.1221054 [^astrobites2012]: *Astrobites* (2012). "No shocks for this bow: IBEX says we're wrong". http://astrobites.com/2012/05/14/no-shocks-for-this-bow-ibex-says-were-wrong/ [^nasa-pioneer]: NASA Ames Research Center. "Pioneer 10 and Pioneer 11". https://www.nasa.gov/centers/ames/missions/archive/pioneer10-11.html [^krimigis2009]: Krimigis, S. M.; Mitchell, D. G.; Roelof, E. C.; Hsieh, K. C.; McComas, D. J. (2009). "Imaging the interaction of the heliosphere with the interstellar medium from Saturn with Cassini". *Science* 326: 971–973. https://doi.org/10.1126/science.1181079 [^mccomas2009]: McComas, D. J.; Allegrini, F.; Bochsler, P.; et al. (2009). "Global observations of the interstellar interaction from the Interstellar Boundary Explorer (IBEX)". *Science* 326: 959–962. https://doi.org/10.1126/science.1180906 [^astrobio2010]: *Astrobiology Magazine* (2010). "The ever-changing edge of the Solar System". http://www.astrobio.net/pressrelease/3634/the-ever-changing-edge-of-the-solar-system [^esa-ulysses]: European Space Agency (2013). "Ulysses fact sheet". https://sci.esa.int/ulysses/47369-fact-sheet/ [^nasa-stereo]: NASA. "STEREO creates first images of the Solar System's invisible frontier". https://www.nasa.gov/mission_pages/stereo/news/invisible_frontier.html [^astronautix]: Wade, M. "Pioneer 10–11". *Encyclopedia Astronautica*. http://www.astronautix.com/p/pioneer10-11.html [^nasa-pioneer-ames]: NASA (2015). "The Pioneer missions". https://www.nasa.gov/centers/ames/missions/archive/pioneer.html [^nasa2018-v2]: Potter, S. (2018). "NASA's Voyager 2 probe enters interstellar space". NASA. https://www.nasa.gov/press-release/nasa-s-voyager-2-probe-enters-interstellar-space [^kanipe2011]: Kanipe, J. (2011). *The Cosmic Connection: How Astronomical Events Impact Life on Earth*. Prometheus Books, pp. 154–155. ISBN 978-1-59102-882-6. [^chang2018-parker]: Chang, K. (2018). "NASA's Parker Solar Probe is named for him. 60 years ago, no one believed his ideas about the Sun". *The New York Times*, 10 August 2018. https://www.nytimes.com/2018/08/10/science/eugene-parker-solar-wind-nasa-probe.html [^nssdc-luna1]: NASA Space Science Data Coordinated Archive. "Luna 1". https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1959-012A [^jpl-mariner2]: NASA Jet Propulsion Laboratory. "50th anniversary: Mariner 2, the Venus mission". https://www.jpl.nasa.gov/mariner2/ [^lallement2005]: Lallement, R.; Quémerais, E.; Bertaux, J. L.; et al. (2005). "Deflection of the interstellar neutral hydrogen flow across the heliospheric interface". *Science* 307: 1447–1449. https://doi.org/10.1126/science.1107953 ## Sources - NASA Science, Voyager interstellar mission pages: https://science.nasa.gov/mission/voyager/interstellar-mission/ - Frisch, P. C.; Redfield, S.; Slavin, J. D. (2011). "The interstellar medium surrounding the Sun". *Annual Review of Astronomy and Astrophysics* 49: 237–279. ## Further reading - Owens, M. J.; Forsyth, R. J. (2013). "The heliospheric magnetic field". *Living Reviews in Solar Physics* 10: 5. https://doi.org/10.12942/lrsp-2013-5 - Brandt, P. C.; et al. (2023). "Future exploration of the outer heliosphere and very local interstellar medium by Interstellar Probe". *Space Science Reviews* 219: 18. ## External links - NASA IBEX mission — https://science.nasa.gov/mission/ibex/ - NASA Voyager — https://science.nasa.gov/mission/voyager/ - IBEX at Princeton — https://ibex.princeton.edu/ ## Wikipedia : Wikitube **Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/Heliosphere) : [Wikitube](https://en.wikitube.io/wiki/Heliosphere) · pinned revision [1372549208](https://en.wikipedia.org/w/index.php?oldid=1372549208) · 2026-09-18 ## Previous hub tags Hubs: `Life_Physics`. Portals: [[PORTAL_Solar_System]]. --- *Solar System portal child articles, wave 1 · 2026-09-18 · drafted · row SOL-027 · explorer state `?obj=heliosphere`.*