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Apologies for having never posted here before, likely never again... but "The probably sausage-shaped bubbles"... doesnt that sound like it was lifted from "The Third Policeman?" Has anyone checked to make sure that its true and not a joke? — Preceding unsigned comment added by (talk) 14:02, 5 September 2012 (UTC)

Pic of the day[edit]

The image Image:Voyager 1 entering heliosheath region.jpg is due up as Wikipedia:Picture of the Day on Sunday and so will also be shown on the Main Page. This picture illustrates a range of related articles, but I've decided that Heliosphere is probably the most useful primary link.

The associated caption is at Wikipedia:Picture of the day/August 21, 2005. The caption is normally based on excepts drawn from the illustrated article, but in this case I've had to take snippets from several different places. Hopefully, someone editing this page, can take a look at the caption and make sure it still makes sense. In particular it looks like the December 2004 date for Voyager 1 entering the heliosheath may not be universally accepted just yet. -- Solipsist 11:48, 19 August 2005 (UTC)


How exactly is 250,000 mph subsonic?

  • It is compared to the speed of sound in the material being discussed. In this case the subject is basically a very thin gas. You might have confused the terminology with that of the speed of sound in air at sea level. (SEWilco 04:59, 21 August 2005 (UTC))
  • I was wondering this same thing. Perhaps since the related photo is on the front page and will be prominent for a bit, it would make more sense to either a) change the adjective or b) expain how 250,000 mph is subsonic. It's not very obvious for non-astro-physicists. --JD79 13:41, 21 August 2005 (UTC)

Rotational Period[edit]

On the main Sun entry, the rotational period for the sun is shown to range between 25 and 35 days, but a full rotation is 28 (see opening paragraph of the Sun#Structure section.) I'm assuming that the 27 on this entry refers to the 28 on that entry (or vice versa.) I don't know which one is correct (if either) but I'd just like to point out the discrepancy. Tonytnnt 06:21, 5 March 2007 (UTC)

contradictory information[edit]

Firstly there should be a consensus on the spelling of Voyager 2, in this article it uses both Voyager 2 and Voyager II, I believe the correct usage is the numeric (Voyager 2).

Also exactly when Voyager I passed through the termination shock is contradicted within the article. The worst paragraph is the one below which contradicts the article and is badly written therefore I'm suggesting removing it completely but leaving the old version here.

In May 2005, it was announced that Voyager 1 had crossed the termination shock and entered the heliosheath in December 2004, at a distance of 85 AU. In contrast, Voyager II began detecting returning particles suggesting it was entering the termination shock when it was only 76 AU from the sun, in May 2006. This implies that the heliosphere may be irregularly shaped, bulging outwards in the sun's northern hemisphere and pushed inward in the south.[5] Master z0b 05:33, 5 September 2007 (UTC)

This contradicts the previous statement "In May 2005, NASA announced that Voyager 1 had crossed the termination shock and entered the heliosheath in December 2004, at a distance of 94 AU. An earlier report that this had occurred in August 2002 (at 85 AU) is now generally believed to have been premature." now I'm no scientist so I don't know what the general consensus is. Master z0b 05:37, 5 September 2007 (UTC)

·There is another contradiction. In one spot the article states that Voyager 1 entered the heliosheath in 2004, while a little ways down, it gives a 2006 date. (talk) 04:20, 7 April 2008 (UTC)Steve

The 2nd reference should have been 2006. So now I think they match fairly well considering that the termination shock boundary fluctuates. The 1st reference suggests Dec 2004 and the 2nd reference suggests it was a done deal by May 2005. -- Kheider (talk) 05:30, 7 April 2008 (UTC)

I added IBEX and Cassini observation info. which conflicts with the info describing the bow shock and tail. However, since that info is presented as a hypothesis and since the observations I added are so recent, I made no further modifications. This does result in there being conflicting info. on the page, which is inevitable, I guess, when suddenly new data changes prior theories. Hopefully someone more knowledgeable than me will revise the entire article for consistency as more data is available.Canuck100 (talk) 21:16, 22 October 2009 (UTC)

consistency ?[edit]

The 2nd paragraph talks of 10 billion miles, then kilometers per hour. Shouldn't the article use the same units (miles/kilometers) throughout? —Preceding unsigned comment added by (talk) 17:26, 18 September 2007 (UTC)

Speed of sound[edit]

In "Outer structure" the speed of sound is stated as 340 m/s, while in "Termination shock" it is 100 km/s. Which one is correct? (seems like 100 km/s, but I am not sure...) Reminiscenza 20:42, 8 October 2007 (UTC)

In the section on Termination shock it currently says: "while the speed of sound (in the interstellar medium) is about 100 km/s. (The exact speed depends on the density, which fluctuates considerably.)". This does not sound right. The speed of sound in an ideal gas (and the very low density interstellar medium should be well approximated by an ideal gas) does not depend on density. It is however proportional to the square root of the temperature. At the temperature of the Local Interstellar Cloud of about 6000 °C I would thus expect a speed of sound of perhaps 1.5km/s only. Does someone know where the figure of 100km/s comes from? --Gustav (talk) 14:21, 15 September 2011 (UTC)
A good reference about speed of sound in interstellar medium is --Gustav (talk) 14:46, 15 September 2011 (UTC)

"outer border of the solar system"?[edit]

The article, in its discussion of the Voyager findings, hints that the heliopause might be 70 - 94 AU from the Sun. Another quote states that the bowshock (outside the heliopause) is perhaps 230 AU away.

This is far less than the aphelion of many long-term comets. It is also far less than the aphelion of Sedna (976 AU, according to the Wikipedia article on it) and 2000 CR 105 (396 AU) (ditto). Not to mention the hypothetical Oort Cloud, which is 50,000 AU away!

If the heliopause is that close, the "outer border of the Solar System" sentence should be deleted. Captcrisis 02:42, 12 October 2007 (UTC)captcrisis

WikiProject class rating[edit]

This article was automatically assessed because at least one WikiProject had rated the article as start, and the rating on other projects was brought up to start class. BetacommandBot 09:54, 10 November 2007 (UTC)

Temperature of the termination shock?[edit]

According to "",

Voyager scientists had expected the temperatures within the termination shock to be about 1,000,000 degrees Fahrenheit (555,500 C) as material normally slows down and is heated up when it encounters an obstacle in a normal shock wave.

But according to Edward Stone of California Institute of technology, the temperatures registered were much lower, at around 200,000 degrees F (111,100 C). Also, Voyager 1 made only one crossing into the termination shock while Voyager 2 has made at least five shock crossings over several days which allowed them to collect more data.

What does this mean? How can one measure temperature in space -- and what do such high temperatures mean? Chip Unicorn (talk) 18:20, 12 December 2007 (UTC)

the temperature is of the material that makes up the heliosphere. There are only little molecular bits flying by, but they are all very hot. Serendipodous 16:39, 4 November 2008 (UTC)

By Hot, what is really meant is that they, the little bits (Hydrogen nucelii for the most part) are moving VERY quickly. Because there's so few of them, (which partially allows them to go so fast and thus be so hot), you won't get cooked.DanOrbis (talk) —Preceding undated comment added 03:36, 6 February 2013 (UTC)

Image copyright problem with File:I screenimage 30579.jpg[edit]

The image File:I screenimage 30579.jpg is used in this article under a claim of fair use, but it does not have an adequate explanation for why it meets the requirements for such images when used here. In particular, for each page the image is used on, it must have an explanation linking to that page which explains why it needs to be used on that page. Please check

  • That there is a non-free use rationale on the image's description page for the use in this article.
  • That this article is linked to from the image description page.

This is an automated notice by FairuseBot. For assistance on the image use policy, see Wikipedia:Media copyright questions. --03:24, 5 January 2009 (UTC)

Effects of the shocks on spacecraft?[edit]

So do these termination shock and bow shock have any effect on spacecraft passing through them? Will they damage or destroy them, or will they pass through unharmed? JIP | Talk 18:07, 17 January 2009 (UTC)

No; an unfortunate aspect of discussing the heliosphere is that any attempt to describe it makes it seem like a winter storm on Mount Washington. In fact the heliosphere is essentially vacuum; the changes in temperature and pressure are marked in the context of the solar wind, but negligible when compared to the winds on Earth. Serendipodous 19:48, 17 January 2009 (UTC)
The Finnish article fi:Heliosfääri states: Virtually all matter inside the heliosphere comes from our own solar system, as only interstellar atoms can penetrate it. This made me wonder if the edge of the heliosphere is indeed hazardous to spacecraft. This would effectively prevent interstellar travel. Is the Finnish article wrong, or not detailed enough, or am I just not understanding something here? My own speciality is computer science and mathematics, astronomy is still mostly a mystery to me. JIP | Talk 19:52, 17 January 2009 (UTC)
I think what the sentence is trying to say is that only atoms and anything larger can penetrate it. Certainly interstellar atoms do pass into the heliosphere (they're called cosmic rays), as presumably would any interstellar bit of rock or dust (though distances between stars are so vast that this would be highly unlikely). What the sentence appears to be saying is that the heliosphere deflects the ionic winds from other stars, which is true, but again, these winds are so astoundingly insubstantial that it's basically like one cloud of smoke blocking another cloud of smoke. Less in fact. Serendipodous 20:04, 17 January 2009 (UTC)

The entire heliosphere has shrunk?[edit]

I read this on the Wikipedia page of the Sun at topic: Present anomalies

Its magnetic field is at less than half strength compared to the minimum of 22 years ago. The entire heliosphere, which fills the Solar System, has shrunk as a result, resulting in an increase in the level of cosmic radiation striking the Earth and its atmosphere.

I couldn't find any reference ... sounds a bit bold Michel_sharp (talk) 21:38, 4 March 2010 (UTC)

It's the dynamic pressure of the solar wind that determines the size of the heliosphere, not the strength of the solar (or interplanetary) magnetic field. So unless the solar wind density or velocity has had a similarly dramatic decrease in recent times (it has changed, but I'm not sure in what way or how much) the size of the heliosphere won't be significantly effected. Cosmic rays are effected by the magnetic field though - their fluxes appear to be higher near solar minima.

Reminiscenza 20:42, 8 October 2007 (UTC)

Move all pre-2009 stuff in History section?[edit]

This article continuously mentions pre-2009 model and then disproves it with the current one. I think all mentions about pre-2009 model should be moved into separate History section. (talk) 15:18, 2 June 2011 (UTC)

I believe the 2009 'update' which suggests there is no heliotail is not as standard as it seems to be presented in this article. I seem to recall that the pressure was miscalculated in the key paper that set forth this idea. This led to the erroneous conclusion that the magnetic & thermal pressures were comparable and thus that the heliosphere might have a 'bubble' shape.

Unfortunately I have not found any sources which explicitly refer to this. However, all recent artistic renditions from NASA press releases (including the 'bubble region' image from 2011) show a heliotail, which seems to suggest that this is once again the standard picture.

Sorry for not being able to uncover the research myself at this moment, but I thought it was important to point this out so that someone can track it down. (talk) 05:29, 22 June 2012 (UTC)

New updates[edit]

New updates from NASA: 1. Uploaded the "new heliopause" image here. Rehman 03:16, 10 June 2011 (UTC)

That image is... awesome. Thanks for the update. Info added. Serendipodous 05:55, 10 June 2011 (UTC)
No problem, and thanks for updating. Didn't have much time to update myself. :) Rehman 06:03, 10 June 2011 (UTC)

Use of "solar" applied to other stars[edit]

Some parts of the article use solar to describe features of stars in general. E.g. under the section "Termination Shock" we have "solar wind particles are emitted from stars at about 400 km/s". Even "the solar wind slows down to subsonic speed (relative to the star)" seems unnecessarily vague. Am I being pedantic, shouldn't solar only be applied to our Sun? JBel (talk) 17:57, 15 June 2012 (UTC)

bow shock repetition[edit]

The article mentions at least 8 separate times the fact that there is no bow shock-this seems repetitive and unnecessary. Could these mentions be consolidated, and some mention of what current theories speculate the boundary is like? Mynameisntbob1 (talk) 20:48, 5 December 2012 (UTC)

Definitely. This article also needs an illustration of an up-to-date model of a heliosphere with magnetic highway and no bow shock. --Artman40 (talk) 13:17, 11 December 2012 (UTC)


This article needs definitions of the area which is inside the termination shock. --Artman40 (talk) 13:15, 11 December 2012 (UTC)

Historical theory[edit]

Is it worth including in the article that the edge of the heliosphere was once speculated to be in the vicinity of Jupiter? Apparently that's where it was expected to be encountered when the Pioneer probes of the early 1970s flew past Jupiter. I think it would be worthwhile to mention, especially since it might instigate some thought about how being in the interstellar region might have affected conditions on the planets further out. That the heliosphere extends out beyond the known planets means they exist in basically the same electric environment as Jupiter and the inner planets, and there's no reason those planets' conditions should be any different. But, how would a planet like, say, Neptune, be affected if it was outside the heliosphere? Is there any scientific thought published about this? GBC (talk) 17:47, 28 January 2013 (UTC)

Voyager passed the heliopause?[edit]

In the article it states that:

"On March 20, 2013 a study was released that suggested that Voyager 1 likely cleared the heliopause on August 25, 2012, judging by drastic changes in Radiation levels."

However, NASA made a press release shortly after correcting this:

...I'm not a specialist though, and I have no idea what this means, so rather than editing, I thought I might just note it and let you guys figure it out. (talk) 07:55, 1 April 2013 (UTC)

[1] Kittybrewster 20:49, 27 June 2013 (UTC)

New data about heliosphere[edit]

New data from IBEX shows that the heliotail does exist. Here is the webpage that has photos and news related to this. Please update.

NASA marks with video/articles the polarity flipping now[edit]

Headline: "Video: Sun has 'flipped upside down' as new magnetic cycle begins" (Dated Sunday 29 December 2013)

Reader-comments under the UK article are interesting. — Charles Edwin Shipp (talk) 13:35, 30 December 2013 (UTC)

I've found a lot of repetitive text, and I've cleaned it up![edit]

The repetition was mainly about Voyager 1 and 2 going through the termination shock. Got that fixed! DSCrowned (talk) 12:38, 13 July 2014 (UTC) DSCrowned (talk) 12:38, 13 July 2014 (UTC)

what happens to the material?[edit]

Naive question from an intelligent but ignorant reader. What happens to the particles of the solar wind at the heliopause? Do they eventually escape and become part of interstellar matter? --Richardson mcphillips (talk) 18:58, 1 June 2015 (UTC)

Solar wind section[edit]

@Isambard Kingdom: IANA expert, so I will defer to you on this one for now, but I have the distinct sense that the solar wind section is confused at best. The main Solar wind article never discusses magnetic fields as part of the solar wind, defining solar wind as "a stream of plasma released from the upper atmosphere of the Sun. It consists of mostly electrons, protons and alpha particles with energies usually between 1.5 and 10 keV." Magnetic fields modulate and propel the solar wind and can be induced by the solar wind's collision with Earth's magnetosphere. But to my (admittedly non-expert) ears, statements like "As the Sun rotates ... the magnetic field transported by the solar wind gets wrapped into a spiral" are patent nonsense. That statement also contradicts the earlier (and also wrong, I think) statement that the solar wind consists partially of magnetic fields-- it's not even self-consistent. A2soup (talk) 15:46, 22 June 2015 (UTC)

There may, indeed, need to be some fixes made in some of these articles. But, generally speaking, a plasma can support electric currents set up be differential motion of constituent charged particles (electrons tend to move differently from ions). These electric currents, in turn, sustain magnetic fields by Ampere's law, and, so, magnetic fields are effectively embedded in the plasma, so much so that they are often considered to be "frozen in". The two can't really be separated. It is also true that as the sun rotates, the solar wind (with embedded magnetic field) tends to wrap up into a spiral, etc. I don't have time, right now, to fix all of this. Hopefully someone else will weigh in and edit things as needed. Cheers, Isambard Kingdom (talk) 15:55, 22 June 2015 (UTC)
@A2soup: Following on from our previous exchange: First of all, some issues of terminology can be confusing, here. When space scientists speak in general terms about the "solar wind", there is an implicit acknowledgment that it is composed of charge particles, it is electrically conducting, and that it supports electric currents. These currents generate magnetic fields. In effect, the "interplanetary magnetic field" (IMF) is a "property" of the solar wind, and summaries of the properties of the solar wind, like this one [2], routinely mention the IMF. Now, depending on context, a subtle distinction is sometimes made, whereby you will see the IMF described as being carried outwards from the Sun by the solar wind. In that sort of usage, it might seem that a distinction is being made, solar wind and IMF. But this is really just a convenience. It allows a picture to be painted. In fact, the two quantities are frozen together and, so, cannot actually be separated. Sometimes, a slightly more technical explanation is given, saying that it is the "solar-wind plasma" or the "flow" of the solar wind that carries the IMF. I know this might sound confusing, and, indeed, when I was younger and new to science, I also found it confusing. More generally, it is, perhaps, worth recognizing that the distinction between matter and fields is, itself, somewhat artificial. Fields exist because there is matter, and vice versa. The two are equivalent. Electric fields are a property of electric charge. We can't have one without the other. And, the interaction of charges with electric fields are the forces that we measure. Insofar as Ampere's law is correct (ignoring something called a displacement current), then electric currents and magnetic fields are equivalent. The interaction of a moving charge and a magnetic field gives a force. Okay, I'm possibly rambling, now, and saying things that are likely obvious to you. But let me say one more thing. Language is kind of squishy. Words have meaning in context. Indeed, depending on the point a scientist might want to communicate about the solar wind, sometimes he/she is thinking of the charged particles and the IMF as being a combined entity. At other times, in discussing the interaction of the charged particles and the IMF, the charged particles might be called the "solar wind" or the "plasma" and this might be said to carry the IMF. Sill, the two always exist together. You will almost never see a discussion of the solar wind that is, say, longer than a few paragraphs, that does not also mention the IMF. Isambard Kingdom (talk) 02:36, 23 June 2015 (UTC)

General editing needed[edit]

This article is important enough that it deserves to be written coherently. The text should not contain (lots and lots of) badly formed sentences and enigmatic statements such as "Due to the particles in the tail, they do not shine..." (talk) —Preceding undated comment added 13:00, 23 June 2016 (UTC)

Likewise: "It was long hypothesized that the Sun produces a "shock wave" in its travels within the ISM. It would occur if the interstellar medium is moving supersonically "toward" the Sun, since its solar wind moves "away" from the Sun supersonically. " This is incoherent, and what it seems to be saying is wrong. (talk) 13:03, 23 June 2016 (UTC)