First Full Science Results in From Herschel

Article written: 7 May , 2010
Updated: 24 Dec , 2015
by

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Just days before the first anniversary of the Herschel space observatory’s launch, the first full science results – along with some very pretty images – were released at a symposium in the Netherlands. “Herschel is a new eye on a part of the cosmos that has been dark and buried for a long time,” said the mission’s NASA project scientist, Paul Goldsmith at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

Above, Herschel’s observation of the star-forming cloud RCW 120 has revealed not only the huge blue bubble of gas, but also the small white spot is what some astronomers have called an “impossible” star.

It already contains eight to 10 times the mass of the sun and is still surrounded by an additional 2,000 solar masses of gas and dust from which it can feed further.

“This star can only grow bigger,” says Annie Zavagno, Laboratoire d’Astrophysique de Marseille in France. Massive stars are rare and short-lived. To catch one during formation presents a golden opportunity to solve a long-standing paradox in astronomy. “According to our current understanding, you should not be able to form stars larger than eight solar masses,” says Zavagno.

A region the the galactic center in the Eagle constellation. Credits: ESA/Hi-GAL Consortium

This image is taken looking towards a region of the Galaxy in the Eagle constellation, closer to the Galactic center than our Sun. Here, we see the outstanding end-products of the stellar assembly line. At the center and the left of the image, the two massive star-forming regions G29.9 and W43 are clearly visible. These mini-starbursts are forming, as we speak, hundreds and hundreds of stars of all sizes: from those similar to our Sun, to monsters several tens of times heavier than our Sun.

These newborn large stars are catastrophically disrupting their original gas embryos by kicking away their surroundings and excavating giant cavities in the Galaxy. This is clearly visible in the ‘fluffy chimney’ below W43.

Click the images for larger versions.

Learn more in this video released by the ESA, or see this ESA website



87 Responses

  1. Lawrence B. Crowell says

    The impossible star at 8 to 10 solar masses does not strike me as that impossible. I thought the upper limit on stellar mass was 100 solar masses or so. O-class stars can exceed 15 solar masses.

    LC

  2. Jason Dukleth says

    @Lawrence B. Crowell

    This article leaves out a key point from the original. Even though we call them “impossible stars”, there are many that we know to exist. As far as our current theories go, the intense light emanating from stars > 8 solar masses should blow away the surrounding dust/gas before they are able to get any larger.

    Having an active example gives us an opportunity to figure out where our thinking is faulty.

  3. Surak says

    What commonly bothers me about these kinds of articles … not so much this article, which was pretty good, but the same story read elsewhere about the bubble and the impossible star is that there are always unexplained or unmentioned contradictions.

    The furiously bright star blew out the bubble in the nebula by the pressure of its intense radiation … yet the impossible star, also being a massive and furiously bright star apparently blows nothing out and doesnt make a bubble .. and can only grow bigger.

    I get that the impossible star is younger or newborn and may not have had time, but its stated as if it will just sit there feeding on all that gas.

  4. DrFlimmer says

    Yes, but also our own bubble of plasma is blown away by the sun. Normally we call that the solar wind. Young stars tend to be much more efficient doing this.

    One way to solve this “paradox” is an accretion disk. A lot of disks around young stars are found these days (a colleague of mine has found hundreds of accretion disks in the Orion nebula; there are also a lot of disks in M17). This is a very efficient way to get around the “blowing”, since an accretion disk is (as the name implies) thin and therefore not so much attributed to be blown away. (There is a lot more to say about this, but I spare you with the details.)

    This “new” star is a good candidate to test our theories, when we can watch it grow in almost real time. Some close-ups would be fine, I think 😉 . I bet one would find a nice disk-like feature.

  5. Lawrence B. Crowell says

    @ Jason: I pondered whether something of that sort was taking place. The usphot is that a Bclass star with M >= 8M_sol can’t get bigger by accreting nebular material.

    LC

  6. Torbjorn Larsson OM says

    A mass cut off problem, who knew? 😉 Herschel will give a lot more value for the money than I knew about. (Well, duh.)

    It was Hannes Alfvén who noted that plasmas may form cellular structure (ie. bubbles).

    But that isn’t the explanation here, where radiation pressure predicts the bubbles. EU pattern recognition is daft, it isn’t even using inappropriate “common sense” to use ad hocs when you have theory in place.

    There is a lot more going on here AFAIU, some of which I had the opportunity to study lightly on an astrobiology course starting with solar system formation. The basic process is of course gravitational as always, but there seems to be interesting radiation and magnetic phenomena overlying the accretion phase and later accretion disk, assuming I understood the material correctly.

    Even in the off-plane X-ray radiation model (including the X-wind model, I believe), by the time you have the disk the ionization is claimed to be down to the interstellar medium at ~ 10^-7. At that time there is still solar accretion going on, AFAIU.

    That kind of ionization shouldn’t give much of (EU) plasma interactions I think, outside of ambipolar drift along the magnetic fields of the star-disk object.

  7. Member
    Aqua says

    “…These mini-starbursts are forming, as we speak, hundreds and hundreds of stars of all sizes: from those similar to our Sun, to monsters several tens of times heavier than our Sun….”

    And so does this means that the current estimate(s) of one new star formed in the Milky Way Galaxy per year is wrong? – Consider that the image of the Eagle nebula shown here is taken from a single perspective and there may very well be a number of similar yet unseen companion nebula….

  8. David R says

    It looks like an opening of a worm hole …

  9. rassa says

    Eddington Limit:

    Astronomers have long theorized that as a protostar grows to a size beyond 120 solar masses, something drastic must happen. Although the limit can be stretched for very early Population III stars, if any stars existed above 120 solar mass, they would challenge current theories of stellar evolution.
    The limit on mass arises because stars of greater mass have a higher rate of core energy generation, which is higher far out of proportion to their greater mass. For a sufficiently massive star, the outward pressure of radiant energy generated by nuclear fusion in the star’s core exceeds the inward pull of its own gravity. This is called the Eddington limit. Beyond this limit, a star ought to push itself apart, or at least shed enough mass to reduce its internal energy generation to a lower, maintainable rate. In theory, a more massive star could not hold itself together, because of the mass loss resulting from the outflow of stellar material.

  10. Member
    IVAN3MAN_AT_LARGE says

    iantresman:

    Of course it is not a gas, but a plasma, which some people may not realise, is what is meant.

    Dude, the reason why most astronomers/cosmologists prefer to use the term “ionized gas” instead of “plasma” is due to the fact that “plasma” generally implies a more medical interpretation — e.g., blood plasma — to the general public. It has got nothing to do with “modern astronomers” ignoring electromagnetic phenomena, as is often alleged by “Electric Universe” cranks.

  11. Hon. Salacious B. Crumb says

    iantresman Says:
    I think a hint of there being more going on, is suggested by the statement “the huge blue bubble of gas”. Of course it is not a gas, but a plasma, which some people may not realise, is what is meant.
    It was Hannes Alfvén who noted that plasmas may form cellular structure (ie. bubbles). And plasmas have properties that gases do not, that may explain why 8M stars not “blow away” the surrounding “gas” and dust.
    Our own bubble of plasma, the Solar System’s plasmasphere, shows there is a lot more going on than a simple gas could account for.

    You just can help doing this can you. You are like a drug addict desperately searching for their next hit.

    An expanding HII region and everything is back to plasma and some magnetic field explaining all the phenomena.

    It is funny, isn’t it, that a whole astrophysical paper regarding this object for some reason doesn’t even mention the word plasma at all. Why is that? Methinks someone here doesn’t know what he is talking about!

    Question: What is the difference between plasma interaction and fluorescence? here. You always talk about plasma but you always neglect the important bits like how we actually see the nebulosity itself. Frankly, I don’t think you know.

    As to the rest of you, perhaps you should read the arxiv article before making sweeping and unfounded commentary. (especially pg.3 and pg.22)

    Martins, F. Near–IR integral field spectroscopy of ionizing stars and young stellar objects on the borders of HII regions. (especially pg.3 and pg.22)

    The SIGNIFICANT error in this story is actually considering these as normal star when they are technically known as YSO (Young Stellar Objects), whose spectra is quite different than run-of the-mill ZAMS (Zero Aged Main Sequence) or Main Sequence stars. I.e. They show Carbon Monoxide emissions, for example.

    As the article says; “They probably have an optically thick envelope. The other objects are more consistent with YSO surrounded by disks.”

    As for this star, it is not the only one illuminating this HII region nor is it the sole cause of the observed expansion. The increasing of mass in this star is caused by interacting nebulosity front that is within the expanding HII region – probably entering from outside the area of RCW 120. [The central ionsing star of RCW 120 is actually the star CD?38?11636 – not this ‘impossible star”!] There are eighteen (18) other YSOs around RCW 120 also in this region!!! (See Table 4 on pg. 13.)

    Also look at Fig. 14 and 16 to see the interacting gas (and the obvious ionisation front) around it, especially the YSO RCW120 C4-67 (Fig.16)

    The killer quote in the article is;

    “The exception is RCW 120, for which most sources move 20 to 50 km s?1 faster than the ionized gas.”

    That explains a lot!!

    Also the distance, incidentally, of RCW 120 is of 1.35+/-0.3 kpc., which should have been said in both the original and this page – if only to get a sense of scale!

    Please guys. Learn something generally about stellar evolution.

  12. Hon. Salacious B. Crumb says

    I the above quote, iantresman said is the first three paragraphs:

    I think a hint of there being more going on, is suggested by the statement “the huge blue bubble of gas”. Of course it is not a gas, but a plasma, which some people may not realise, is what is meant.
    It was Hannes Alfvén who noted that plasmas may form cellular structure (ie. bubbles). And plasmas have properties that gases do not, that may explain why 8M stars not “blow away” the surrounding “gas” and dust.
    Our own bubble of plasma, the Solar System’s plasmasphere, shows there is a lot more going on than a simple gas could account for.

    My words follow with “You just can help doing this can you…”

    Apologies.

  13. iantresman says

    @Hon. Salacious B. Crumb says “The existing plasma comes from the stars not the nebula.”

    What existing plasma comes from the stars? I’ve not said where any plasma comes from.

    I’ve said that the article mentions “gas” when it should be called “plasma”, and that H II regions are plasma. Period.

    Of course most cosmic plasma comes from the stars. Where else would it come from?

  14. iantresman says

    @Lawrence B. Crowell
    At last some sensible comments.

    But you mentioned “To generate a plasma and usually to maintain it there must be some power source to set it up”

    Indeed, if we produce plasma from a cold gas, such as during the reionization epoch. But if the dominant state of matter is now the plasma state, how and where is it going to loose sufficient energy to recombine? It’s the plasma temperature that overcomes the Coulomb force, not the distance between the ions.

    So in a sense, plasma is its own power source. One region gets cooler, another gets hotter. It can also convert between kinetic and electromagnetic energy (eg. via inertial drift). Basic conservation of energy.

  15. iantresman says

    @DrFlimmer

    Agreed.

  16. iantresman says

    @Olaf

    Thanks for your clarification. Which begs the question:

    When defines when an “Ionized gas” DOES NOT MEAN plasma. It is called “Ionized gas”?

  17. solrey says

    Crumb wrote:

    A plasma is like a super-ionised gas – where SIGNIFICANT number of atoms are hot enough (and energetic enough) so the atomic nucleus can no longer hold to their electrons

    Wrong

    Degree of Ionization

    “A gas may begin to behave like plasma when the degree of ionization is as little as 0.01%”

    Solid State Plasma Phenomena

    This paper reviews the similarities and differences between gaseous and solid state plasmas. A discussion is then given of the principal solid state plasma phenomena. These include analogues of known gaseous phenomena, such as passive propagation of electromagnetic waves, growing waves and magnetohydrodynamic and gas discharge analogues. Some specifically solid state phenomena are also described, including acoustoelectric interaction and plasmon excitation.

    Plasma is not limited to gases either. Both solids and liquids can be in a plasma phase under certain conditions. The solid state plasma phenomenon is being studied in semiconductors such as thyristors.

    In a dusty plasma, the dust grains are an active component of the plasma due to electrostatic charge and polarization of the grains.

    Question: If fluorescence mostly occurs in ionised gases. Does it occur in plasmas too?

    What a ridiculous question. Of course fluorescence occurs in plasma. Yes, ionized gas ( as little as 0.01% ionized) is plasma.

  18. Member
    IVAN3MAN_AT_LARGE says

    iantresman:

    So in a sense, plasma is its own power source. One region gets cooler, another gets hotter. It can also convert between kinetic and electromagnetic energy (eg. via inertial drift). Basic conservation of energy.

    O RLY?! So then, when can we expect the press announcement from you on this perpetual fluorescent light bulb/tube in which the cold gas within, once energized from a power source, is then converted into a self-sustaining “plasma”, indefinitely, without any further power input?!

  19. Member
    IVAN3MAN_AT_LARGE says

    @ iantresman,

    The technical term for clouds in the sky is “water vapour”, but weathermen on TV often say “clouds” or “cloudy”; however, I don’t recall anybody writing to the meteorological office to complain: It’s NOT “clouds”, it’s STEAM!!!11!1!

    So, what’s this bloody obsession with the term “plasma” amongst you EU/PC guys, then?!

  20. Lawrence B. Crowell says

    @ rassa: The Eddington limit does prevent stable stars with masses over 120 M_sol. PopIII stars may be interesting transient exceptions. They are composed of nearly pure hydrogen, which makes them far less opaque than PopI-II stars. They are similar to the hyperstars Feynman and Wheeler proposed back in the 1950s. They may be able to grow to thousands of solar masses or more for some transient period before blowing themselves to bits in hypernova explosions.

    LC

  21. Hon. Salacious B. Crumb says

    iantresman said;

    @IVAN3MAN_AT_LARGE
    My comment regarded the use of the word “gas”, not “ionized gas”, in place of the word plasma, as used in the original ESA article.

    Semantic bull. You comment just to confuse, as per usual. So blinded are you with the propaganda even you can’t tell the difference. Next you will be saying that ionised solutions are plasma too!

    @Hon. Salacious B. Crumb
    You are correct that I can’t help mentioning this. Clearly our understanding of what is going on is incomplete. I think it’s because plasmas are treated like gases.

    See above.

    Actually what you mean to say is that YOUR understanding of what is going on is incomplete. As usual you assume that PC/EU gives the only other definitive explanation (which is actual even more incomplete.) – how arrogant are you here? Now let’s see. This article or associated paper doesn’t mention plasmas, magnetic fields or any other perverse PC/EU bull. Why? There are absolutely NO observations here of plasmas or magnetic fields!
    So instead of drawing conclusions on real observations, you think its is absolutely OK to supplant it with the usual irrelevant unsubstantiated claptrap.
    If you think that is how science works, then you really do have a serious problem.

  22. iantresman says

    @DrFlimmer

    Sure, a hot plasma will radiate energy. But where does a universe with 99.9% of plasma, radiate that energy to? The universe does not have “cold sides”.

  23. Hon. Salacious B. Crumb says

    iantresman said;

    “Gas” is not the correct term for a “plasma”, even if it can be modelled as a gas, and may appear gaseous. You’d be the first to mention, if someone mixed up comets and meteors, weight and mass, photons and protons, etc etc.

    Even more bull.

    Gas can be either neutral or partly ionised. Plasma is matter that is HIGHLY ionised.

    Atoms with one or two electrons removed (ions) IS NOT PLASMA. Ionised gas can still partially conduct electric current. A plasma is like a super-ionised gas – where SIGNIFICANT number of atoms are hot (and energetic enough) enough and the atomic nucleus can no longer hold them.

    Clearly ionic gases are NOT the same as plasmas.

    So enough of this semantic nonsense please!

    Question: If fluorescence mostly occurs in ionised gases. Does it occur in plasmas too?

    If it doesn’t then ionised gas is not plasma.
    If it does, ionised gas is plasma.

    Which is it?

  24. Hon. Salacious B. Crumb says

    Correction:

    A plasma is like a super-ionised gas – where SIGNIFICANT number of atoms are hot enough (and energetic enough) so the atomic nucleus can no longer hold to their electrons

  25. Hon. Salacious B. Crumb says

    Ah!! Thanks again, iantresman.

    Another one of your wicked deception is now yet again exposed.

    According to your own webpage, YOUR definition of a nebula is is an interstellar cloud of dust, gas and plasma.

    This is statement is absolutely wrong.

    A nebula is really an interstellar cloud of dust, hydrogen gas, helium gas and other ionised gases. They are called emission nebula for a good reason – emissions from ionised gas – and NOT any kind of plasma nebula!

    [Interesting. Just Goggle “plasma nebula”, and blow me down, your page is the No.1 hit! Looking through some of the list of pages here and we see all of the grubby work of PC/EU proponents trying to change the world! Wikipedia recently seems to have been poisoned too. I.e. Nebula and HII region, for example, but at least this has been now properly corrected! Sneaky little people these guys are.]

    For this reason alone, HII regions are not considered to be made of plasma, but only mostly of neutral gas and other ionised gas!

    So again, HII and any HII region is NOT a plasma! (As is HeII, OIII, OII, Ne II, and sulphur lines, etc., say, in planetary nebulae.)

    Any plasma made in nebulae are mostly created by their own radiating stars or energetic objects like pulsars, which have the energy to HIGHLY ionise the gas.

    Your usual totally dishonest deception here is again shown to all and sundry!

  26. iantresman says

    I believe that the diffuse intergalactic plasma is considered to be a hot plasma. It has nowhere to loose energy to, and consequently does not require energy to maintain its temperature. (I’m ignoring expansion of the universe)

    But I agree that stellar plasmas obviously require an energy source, and no plasma self-generate energy.

  27. iantresman says

    Plasmas (ionized gases) emit energy in a variety of ways, from recombination which gives rise to emission lines at certain wavelengths (eg, the plasma in neon tubes), to black body smooth spectrum continuum, to bremsstrahlung to synchrotron radiation.

  28. Hon. Salacious B. Crumb says

    Love those “personal theories”…

    iantresman in the discussion area of Wikipedia on HII regions as plasma” (Dated: 8 October 2005), defines;

    * H II regions are completely ionized, so by definition, are plasma.
    * All plasmas, by definition, have the characteristic of plasma.
    * Any magnetic field entering a plasma is carried by the plasma, just as the Sun’s “open” magnetic field extend to infitinity.

    All statements that are not true, and have been used via Wikipedia to spread the falsehoods!

    (Now we know why the individual wantonly said;

    I think a hint of there being more going on, is suggested by the statement “the huge blue bubble of gas”. Of course it is not a gas, but a plasma, which some people may not realise, is what is meant.
    It was Hannes Alfvén who noted that plasmas may form cellular structure (ie. bubbles). And plasmas have properties that gases do not, that may explain why 8M stars not “blow away” the surrounding “gas” and dust.
    Our own bubble of plasma, the Solar System’s plasmasphere, shows there is a lot more going on than a simple gas could account for.

    ,,,and there is the SAME old delusion folks!

  29. iantresman says

    @Lawrence B. Crowell

    While I do not disagree with your comments on how radiation density varies with the scale factor of the universe, your typical thermodynamic equations do not take cosmology into account, on the time scales and dimensions we are interested in. As you mentioned, intergalactic plasma remains in its state for a long time.

  30. Hon. Salacious B. Crumb says

    Sorry guys, but those references are really totally irrelevant.

    Fluorescence cannot occurs in a plasma. Why? SImple. The transitional states are so unstable that they do not emit light at one wavelength.

    It is clear to me you totally don’t understand that nebula have very very low densities, and that plasmas do not interact very well in near vacuums.

    The ONLY fluorescence with plasmas is caused by so-called impact ionisation. It has absolutely nothing to do with the processes going on in nebulae!!

    We see nebula because of the UV fluorescence with ionised element in the nebula via the generated spectra. If fluorescence were caused by plasma, the nebula would be bathed in light from all frequencies. It is not observed.

    Bottom line. HII regions are called that because of a dominate wavelength, shown by the spectra. HII is not plasma, it is ionised gas that undergoes UV fluorescence. Plasma, under nebula densities, does not. End of story!

    As for your silly Francis F. Chen quote, clearly you can’t read, and frankly it is just his opinion! (As for ad hominems, it is all that seems to sink in for you!)

    As for; “But I’ll try and give you an explanation that is not too technical.” Oh please! I seems to be lately every time, it is me handing you out the lessons!

    Sorry! It is about time you guys are handed you hat and shown the door!

  31. Member
    IVAN3MAN_AT_LARGE says

    @ iantresman,

    Because of your ‘legalistic’ obsession with terminology, you could make more money as a goddamn lawyer than trying to sell this EU/PC crap!

  32. Hon. Salacious B. Crumb says

    You call these citations?

    *”The Orion Nebula (an H II region of ionized plasma”(ref)
    *”The radio spectrum of an H II region is that of a plasma “(ref)

    Both are opinions, which you have taken out of context.

    The Orion Nebula doesn’t exhibit much of a continuous spectra does it? (If it were not true, it would not be as bright as it is Hydrogen-alpha.) Most of the continuous spectra is due to the stars by reflection! This statement is clearly wrong.

    Also the radio spectrum is mostly caused by weak magnetic fields. As already said; Atoms with one or two electrons removed (ions) IS NOT PLASMA. Ionised gas can still partially conduct electric current. Considering the nanotesla size of the fields, the plasma must be quite insignificant!

    Besides. Funny though, I think I could find +1,000 reference on the Orion Nebula that DO NOT claim this!

    You say just two, Hell, therefore you must be absolutely right! (Yeah right!)

  33. Hon. Salacious B. Crumb says

    IVAN3MAN_AT_LARGE said;
    :
    “Because of your ‘legalistic’ obsession with terminology, you could make more money as a goddamn lawyer than trying to sell this EU/PC crap!”

    Quite right, He just does this to hide the deceptions and the blatant deceit. He thinks it might make these bizarre ideas more palatable, clawing out of the mud so to speak. We knew all of this is in a hidden agenda, so OK then, let’s continue to expose this hidden agenda at every opportunity.

    The more they say, the weaker they become!

  34. Hon. Salacious B. Crumb says

    @ iantresman

    You say; “The Orion Nebula (an H II region of ionized plasma”

    The Cern Courier

    “Observations with the XMM-Newton satellite have revealed soft X-ray emission from an extended region in the Orion nebula. The most massive stars in the heart of the nebula are probably at the origin of this million-degree plasma flowing through it.”

    and

    “The nebula hosts the Trapezium group of four recently formed very massive stars – seen by eye as a single star called theta Orionis – which illuminate and ionize the surrounding gas”

    As I’ve already said. The existing plasma comes from the stars not the nebula.

    As they say. If you tell a lie long enough, and cherry-pick what you want, it will eventually become the truth, (Pity Wikipedia is closed to you for sock-pupperty. You could do something about it!)

  35. Hon. Salacious B. Crumb says

    @ iantresman

    To back up my previous statements here regarding that the existing plasma comes from the stars not the nebula, appears in conclusion of; OPTICAL OUTFLOWS IN THE ORION NEBULA. I : The Giant Outflow HH 400 and the irradiated jet HH 502. ; Astron.J. 122, 1508, (2001)

    “We have identified a giant, low-velocity bow shock, HH 400, propagating from the general direction of the Trapezium or the OMC-1 cloud core. The HH 400 flow may be responsible for detecting the HH 502 jet. This flow is either propagating into the PDR at the rear of the Orion Nebula, or if it is sweeping up plasma from the nebular interior, its shell is sufficiently dense to form a neutral core required to explain the large observed [S II]/H-alpha line ratio. The driving source remains unidentified. However, we consider the possibility that either a Trapezium star, the source of the Orion A outflow, or a lower mass YSO near OMC-1 is the source.”

    This has none of the games your playing here, and clearly shows what I’m saying. The formation of the shell in the HII region are driven outward by the energy from the radiative power of the central stars (as in RCW 120). The plasma from the YSO’s from their stellar winds drives the weak magnetic fields and the nebulosity weakly interacts with it. UV fluorescence produces the visible part of the nebulosity via spectral lines at discrete wavelengths, while the weak plasma interactions via photoionisation is mostly around the central star (as Dr.Flimmer has already said here) – the latter mostly exhibiting continuous spectra. This highly ionised material then over time interacts with the nebulosity. Ths is the plasma interaction (which is minor compared to the gravitational and rotational forces within the nebula. The exhuming plasma from the stars mostly removes the angular momentum so the stars cab form – explaining in part the accretion of increasing mass around the forming star (the YSO.). This overall process (but not all of it) mostly likely forms the basis of the final mass of the star itself.

  36. Member
    IVAN3MAN_AT_LARGE says

    @ solrey,

    “A gas may begin to behave like plasma when the degree of ionization is as little as 0.01%” — Degree of Ionization (Wikipedia).

    Hmm… you seem to exhibit the same hypocrisy of creationists, who desperately quote-mine articles for anything that they think supports their ‘theory’, but dismiss or ignore everything that does not — such as your tendancy cite Wikipedia in the former case, but you rubbish it in the latter case!

    Referring to terminology, you will note that the quote from Wikipedia states the term “may”, not “must”, “can”, or “does”; the definition of may is “a possibility”.

  37. Lawrence B. Crowell says

    These plasma wars don’t get far. Plasmas are any gas where some of the species are charged. That is all there is to a plasma. There may be weakly ionized plasmas, such as in a Crookes’ tube where maybe one out of 10,000 atoms is singly ionized. Those plasma bulbs sold in novelty stores are of this variety. There are diffuse plasmas such as the charged particles in the Van Allen belt, where collisions between particles are negligible. There are conversely high temperature dense plasmas such as at the center of the sun. There are even QCD plasmas composed of quarks and gluons, where the charge involved with the ionization is the color index of the strong interaction.

    Plasmas require some energy or high temperature to drive charged particles apart. In the case of this bubble the source of that energy is from the UV radiation of the central type O star. The photons from the star scatter electrons off of neutral atoms. In the case of a QCD plasma generated at RHIC the energy which puts quarks in this asymptotically free state comes from the high energy collisions between gold ions. A diffuse plasma where the ions and electrons have been driven apart can persist in that state for a very long time. The intergalactic space contains such a plasma left over from the so called reionization period of the universe. Here the hydrogen and electrons have been driven apart far enough so they don’t appreciably interact with each other.

    Where the PU/EU people go wrong mostly is the insistence that plasma physics explains phenomenon outside its proper domain, and further with some ideas about how plasmas somehow bootstrap themselves as their own energy source. To generate a plasma and usually to maintain it there must be some power source to set it up, say photons from the first light of PopIII stars, or nuclear fusion in the solar interior or … . A plasma is not its own power source just be virtue of being in that state.

    LC

  38. Member
    IVAN3MAN_AT_LARGE says

    Aw, nuts! I’ve just noticed that somebody pinched the preposition “to” in my post above: “… your tendancy [to] cite Wikipedia…”

  39. Olaf says

    The question a EU/PC never ask is:
    * What causes the gas to become plasma in the first place?
    * What prevents it form revering to normal gas when an electric current is going through.

    It needs an EXTERNAL energy source to create the plasma. And you need an EXTERNAL energy source to keep the electrons from binding to the plasma gas but shake them loose again so the current keeps flowing.

  40. DrFlimmer says

    @ LBC

    Thanks. I was about to say something similar, but in less detail. All you say is correct. I have nothing to add.

    @ HSBC, Ivan3man, iantresman, solrey

    A 0.01% degree of ionization is still referred to as a plasma. The Chen quote is correct. This is due to the “collective” behavior.
    It is, btw., also not important if an HII cloud is called a plasma or not. Obviously, it does behave more like a gas, since the most outstanding effect is the equilibrium between ionization and recombination, which leads to the strong line-emission. That also shows that an HII cloud cannot be fully ionized, because that would lead to a rather strong continuum emission, which is not observed.
    However, one should note that “collective” effects are possible in an HII cloud since we obviously have ionized particles and definitely some sorts of magnetic fields.

    Still, and this is the note to our EU/PC friends here, the “collective” effect is of far lesser importance than the equilibrium effect outlined above.

    So, it is ok, to name this plasma a gas, since the plasma-effects are not so important in the case of HII clouds.

    And another still: This is basically a non-issue!

  41. Olaf says

    “and that H II regions are plasma. Period.”

    NO!

    Wikies:

    “An H II region is a large cloud of GAS and IONIZED GAS of glowing low density in which star formation has recently taken place.”

    “In physics and chemistry, plasma is a gas in which a CERTAIN PORTION of the particles are ionized.”

    “Gas” is NONE-Ionized.
    “Ionized gas” DOES NOT MEAN plasma. It is called “Ionized gas”
    “Plasma” COULD be ionized gas, but in NO WAY “have” to be ionized gas.

    H II does not mean that the gas and ionized gas are intermingled. Some parts is gas, some parts is ionized gas. The gas is just gas, not plasma.

  42. Olaf says

    My wording for this:
    “Plasma” COULD be ionized gas, but in NO WAY “have” to be ionized gas.

    Is not really correct. but I think you get the meaning.
    If you have more ionized gas than normal gas then you cannot call it plasma any-more. It is called ionized gas.

  43. Member
    Aqua says

    Ongoing and abundant nucleosynthesis in our galaxy! Fountains of energy being transformed into matter! Seeing is believing! @ GO Herschel!

  44. Hannes says

    Talking about gas or plasma, what about the actual definition of a star ?

    How dense a certain region in space must be before talking about the actual concept of a star?

    I like the article, but the lack of definitions is in my opinion only a cause for annoyances.

  45. Lawrence B. Crowell says

    In the case of the intergalactic plasma there is one ion and electron per cubic meter, more or less. So the force of attraction between these species is very small and is not able to over come the small thermal energy these particles have. This plasma is at equilibrium with the CMB temperature T ~ 2.7K and the energy equivalent for each particle is E ~ = kT/2 = 1.863e^{-23}J, or in the milli-electrovolt range. The electrostatic force is

    F = -(1/4??)e^2/r^2 e = 1.6e^{-19}C, (1/4??) = 10^{-11}c^2 ~ 10^6m^2/s^2.

    So for the average distance between ionized species comparable to 1m this is an electrostatic potential energy of -2.5e^{-32}N. Now the energy this imparts to these charged particles by moving them one meter is E = F*Delta X, where for Delta x ~ 1 m, is then easily seen to be -2.5e^{-32}J. The electrostatic force is far too small to generate enough work in moving the particles together to overcome the thermal motion of these ions and electrons.

    In a sense the energy or temperature source which maintains the intergalactic plasma is the CMB temperature. We might be tempted to say that as the universe expands and the T_{CMB} gets smaller that the plasma will recombine. However, in the accelerated expansion of the universe the ions and electrons will be dragged apart further by the commoving of particles on the frame dragging of spacetime.

    As for defining a plasma, this argument does seem to be a bit of a tweedle-dee tweedle-dum sort of problem. The earliest plasmas studied at the end of the 19th century were in no ways fully ionized. Fully ionized iron or comparable larger atoms on the periodic table occurs in the million-K range, and no lab had those abilities.

    LC

  46. DrFlimmer says

    @ iantresman

    To add something technical to Ivan3man…

    So in a sense, plasma is its own power source. One region gets cooler, another gets hotter. It can also convert between kinetic and electromagnetic energy (eg. via inertial drift). Basic conservation of energy.

    You should make this more clearly. This statement contradicts the basic laws of thermodynamics which prohibit any form of perpetual motion machines. But that’s what you propose.

    But if the dominant state of matter is now the plasma state, how and where is it going to loose sufficient energy to recombine? It’s the plasma temperature that overcomes the Coulomb force, not the distance between the ions.

    1) Well, the radiation power of a blackbody is P=s*T^4, where s is the Stefan-Boltzmann-constant. To say it again: A blackbody radiates its energy with the temperature to the power of FOUR!
    I think a hot plasma can be some kind of a blackbody to a good approximation.

    2) “The plasma temperature overcomes the Coulomb force not the distance between the ions.”
    Well, yeah, but how to achieve the high temperature? Something does not gain temperature just out of nothing. Maybe the fall into a gravitational well can produce heat. Maybe the gravitational pressure of a large amount of matter can produce heat (which is basically the ideal gas law….).
    But a plasma in free space with the “normal” density of 1pccm will never overcome the Coulomb barrier.
    However, the density and pressures in the large plasma balls we normally refer to as stars are high enough in the core of the ball. So, fusion can happen there (you referred to fusion, didn’t you?) which is quite a good power source, btw.
    Too bad, that some PC/EU theories dismiss fusion as the power source……

  47. Lawrence B. Crowell says

    @iantresman: It is one thing to argue this for the intergalactic plasma which is very diffuse and is sustained in a very cold state. For a hot plasma with a temperature far above the CMB it is clear that it will radiate photons away until it is in equilibrium with the CMB or the cold local environment. If you disagree with this then you might want to prepare yourself to state that plasma physics reverses the laws of thermodynamics. Be then prepared for howls of laughter on that one!

    No phase state of matter, whether it is a quantum phase of matter (something I work with) or a solid or gas or plasma generates its own energy soley by virtue of being in that phase state. Energy must be input into the plasma if it is hot. The plasma state may act as a catylist for the energy source, such as with nuclear fusion in a stellar core. Yet a thermodynamic phase of matter is not itself a source of energy. Nowhere will you find such a claim or experimental result supporting such a theory.

    LC

  48. Hon. Salacious B. Crumb says

    Is light emitted from HIGH energy plasmas?

  49. Member
    IVAN3MAN_AT_LARGE says

    iantresman:

    Sure, a hot plasma will radiate energy. But where does a universe with 99.9% of plasma, radiate that energy to? The universe does not have “cold sides”.

    “Space is big. Really big! You just won’t believe how vastly, hugely, mindbogglingly big it is. I mean, you may think it’s a long way down the road to the chemist, but that’s just peanuts to space, listen…”
    —The Hitch-hiker’s Guide to the Galaxy, Chapter 8.
    😎

  50. Hon. Salacious B. Crumb says

    Correction.

    Is light emitted from HIGH energy plasmas the same way as ionised gas?

  51. Hon. Salacious B. Crumb says

    Correction.
    Is light emitted from HIGH energy plasmas in the same way as ionised gas?

  52. Lawrence B. Crowell says

    Q: where does a universe with 99.9% of plasma, radiate that energy to?

    If the unvierse were static there would be no place for radiation to radiate to. However, the universe is expanding and this means that even the CMB radiation (from a plasma or radiation dominated phase in the earlier universe) is “radiated away.

    The density of matter varies as 1/a^3 and for radiation as 1/a^4. This is the source of the cross over from radiation to matter dominated phase of the universe. So the density of radiation is rho_r(a) ~ rho_m(a)/a. So let us ignore the dependency of ~ rho_m(a), or just think of this as a box which expands and we are not interested in that. So The FLRW equation reduce to a Newtonian-like version of local energy conservation

    (1/2)rho_mu(da/dt)^2 ~ 8pi Grho_ra^2,

    where rho_mu is a mass density ~ ?_m. We now multiply both sides by volume a^3 so that rho_ra^3 ~ (rho_ma^3)/a = m/a (m = h*freq/c^2 mass equivalent of radiation in the volume), and the equation of energy conservation is

    (mu/2)(da/dt)^2 ~ 8piGma = 8pi Gh*freq*a/c^2. (where mu = h*freq/c^2)

    This then reduces to the simple equation for the motion of a photon moving upwards in a constant Earth gravity in the Pound-Rebka experiment. The photon redshifts and the lost energy goes into the gravity field. Here the gravity field is that of the entire spacetime cosmology.

    LC

  53. Lawrence B. Crowell says

    I actually don’t know the temperature of the intergallactic plasma. The simple fact is that the motion of the ionized species is with a much higher energy than the mutual electrostatic force or potential can recombine the charged species. For the intergalactic plasma to radiate photons it has to interact with itself. In other words protons and electrons must scatter off each other. Such interactions are infrequent, so the plasma remains in its state for a long time. One way to think about it is that it has a huge specific heat and is very insulating. It holds its heat because it is so diffuse.

    I might be wrong, but I had thought the intergalactic plasma was pretty cold, and not much warmer than the CMB background. However, if it is much warmer than the CMB, this reinforces my argument that the kinetic energy of the charged particles is much larger than the magnitude of their mutual electrostatic potentials.

    LC

  54. iantresman says

    @Hon. Salacious B. Crumb

    You don’t differentiate a plasma from an ionised gas. An ionised gas is a plasma, though one has a greater degree of ionisation.

    A gas which has not ionised sufficiently to become a plasma, is a gas (though there may be a tiny proportion of ionisation).

  55. Hon. Salacious B. Crumb says

    @ iantresman

    Plasmas (ionized gases) emit energy in a variety of ways, from recombination which gives rise to emission lines at certain wavelengths (eg, the plasma in neon tubes), to black body smooth spectrum continuum, to bremsstrahlung to synchrotron radiation.

    Then how do you really differentiate them? I.e. Plasma from ionised gas then?

    They aren’t mutual, I know it, you know it. (As an alleged chemist, you ought to know why.)

  56. Lawrence B. Crowell says

    The intergalactic plasma will in 10 billion years be defined by not one proton and electron per cubic meter, but one proton and electron per 100m^3. We can still call it a plasma if we want. At this future time, if not now, this is really less of a plasma and really just charged particles moving around in space. It would be stretching things further if we called the cosmic radiation in the universe a plasma.

    However, the main point is that plasmas are not their own power source by virtue of being in that state.

    LC

  57. Member
    IVAN3MAN_AT_LARGE says

    iantresman:

    I believe that the diffuse intergalactic plasma is considered to be a hot plasma. It has nowhere to loose [sic] energy to, and consequently does not require energy to maintain its temperature.

    A Plasma is only deemed ‘hot’ if it fully ionized and has its electrons and the heavy particles (ions) at the same temperature (i.e., they are in thermal equilibrium with each other), such as in the Sun, stars, thermonuclear fireball, etc., but ‘cold’ if only a small fraction (e.g.,1%) of the gas molecules are ionized — even where the “electron temperature” can be several magnitudes greater than the “ion temperature”; e.g., the ions can be at “room temperature”, whereas the electron temperature may be at several thousand degrees Celsius.

  58. Member
    IVAN3MAN_AT_LARGE says

    Correction: “A Plasma is only deemed [to be] ‘hot’ if it [is] fully ionized…”

    (When the bloody hell are we going to get a preview/edit facility here?!)

  59. iantresman says

    @Torbjorn Larsson OM says “Some are mostly rain drops I believe, others are mostly ice crystals, others are mixes of phases.”

    I stand corrected. By “cloud” is still the correct meteorological term.

    >”Not only don’t you know physics,”
    >But I’m saying this in a _nice_ way!”

    I’m sure that if I claimed I knew your degree of knowledge and learning capabilities, you’d tell me where to go.

    I’ve merely stated my opinion on the use of a term. I think the general reaction is completely out of proportion.

  60. iantresman says

    @Olaf: “even if you call HII regions gas, ionized gas, plasma or “George”, it does not support any PC/EU claims.”

    Why should how we name something have anything to do with supporting a particular theory?

    And by the way, a significant proportion of standard astrophysics is based on PC claims. Alfvén won the 1970 Nobel Prize in physics for his work on MHD.

    >”Changing the name to plasma still keeps the standard model intact.”

    What on earth has any of this to do with the Standard Model? I’ve just been discussing terminology.

  61. Member
    Aqua says

    So, what plasma experiments are there aboard the ISS? Try this one?

    http://www.nanotech-now.com/news.cgi?story_id=36480

  62. Torbjorn Larsson OM says

    On star formation:

    perhaps you should read the arxiv article before making sweeping and unfounded commentary

    True. I was referring to star formation in general, which is the foundation of my commentary.

    OT on plasmas and gases:

    These plasma wars don’t get far. Plasmas are any gas where some of the species are charged.

    Quite, in the general definition, which is why I have worked with low pressure process plasmas of low degree of ionization.

    Of course, in other cases “plasma” can take on other connotation, in the same way that a gas can do. This is the basis for what IVAN3MAN_AT_LARGE identified as the crackpot EU anti-scientist using his pattern recognition thinking to “quote-mine articles for anything that they think supports their ‘theory’, but dismiss or ignore everything that does not”. They pitifully believe that it convinces others, because they are unable to fathom that others actually know how to make analysis and learn.

    Here iantresman is still trying to run around an equivocation on the terms “plasma” vs “ionized gas” vs “gas”.

    Nitpicks:

    “Cloud” is the correct meteorological term. All clouds are water vapour,

    Nope. Some are mostly rain drops I believe, others are mostly ice crystals, others are mixes of phases.

    Here again you are trying to equivocate, as by your analogy “gas”, the correct astronomical term for collections of particles that behaves as gases for the characteristics of study (say, gravitation), applies to among other thing plasmas. While of course not all plasmas are considered gases when such characterization becomes meaningless.

    Ask yourself, if your own argument falsifies your claims, what use are they to you and how do you think we can’t find you anything but laughable?

    Not only don’t you know physics, not only do you damage a subject you likely try to love, but you don’t know how to analyze and obviously you don’t know how to learn. You only know how to dodge and weave and quote-mine and blind yourself for the facts.

    [“But I’m saying this in a _nice_ way!” :-~]

  63. Olaf says

    @iantresman:

    “You don’t differentiate a plasma from an ionised gas. An ionised gas is a plasma, though one has a greater degree of ionisation.”

    What is it? You do not differentiate but in the same sentence you do differentiate.

    And even if you call HII regions gas, ionized gas, plasma or “George”, it does not support any PC/EU claims. Changing the name to plasma still keeps the standard model intact.

  64. iantresman says

    I wonder whether rain clouds become plasmas.

  65. Member
    IVAN3MAN_AT_LARGE says

    @ iantresman:

    All clouds are water vapour,…

    This just occurred to me: what about clouds of smoke, gas, dust, locusts, and birds?

    Are those also ‘water vapour’?!

  66. Member
    IVAN3MAN_AT_LARGE says

    P.S. I think that iantresman is just trying to ‘cloud’ the issue!

  67. Member
    IVAN3MAN_AT_LARGE says

    Erratum: At my previous post, that should be “or birds”, not “and birds”.

  68. iantresman says

    @ND

    Sorry, I disagree. This has nothing to do with semantics, which I think is a trivialisation of the issue. I also have no desire to discredit anybody.

    But it is important to know whether people mean “gas” (non-plasma) or “ionised gas” or “plasma”, and I think the discussion above shows that it is still not clear.

    Alfvén himself also highlighted the differences between using the terms “ionized gas” and plasma, which he wrote “although in reality synonymous, convey different general notions”(ref)

    Alfvén et al was indeed sometimes at odds with the scientific consensus. His Nobel Prize in physics in 1970 shows that persistence, backed up with hard science, demonstrates that his form of scientific enquiry was not without merit.

    The “game” here, is played by all those contributors who resort to insults and ad hominems, and hide behind pseudonyms. Not my idea of open scientific enquiry.

  69. Member
    IVAN3MAN_AT_LARGE says

    *Crickets*

  70. ND says

    iantresman,

    Please stop playing these semantic games with “gas” and “plasma”. It’s clearly a game to discredit scientists in the field by making it look like they don’t know what they’re talking about. And you’re not the only one doing this. The gas/plasma game appears to be a recent one played by the usual suspects.

    It’s a game played by many a group who are at odds with the scientific consensus and don’t have the scientific evidence to back up their ideas. If you can’t beat the science, discredit and ridicule the people behind it.

  71. iantresman says

    @ND: “the [Nobel] prize means nothing”

    That’s funny.

    @ND “It’s all about the evidence”

    I’m glad you agree with Alfvén who stressed the importance of an empirical approach.

    @ND: “Use of pseudonyms is a red herring. It has not prevented in-depth discussion”

    I think that if people did not cower behind pseudonyms, the tone of many of these discussions will change.

    @ND: “Why don’t you guys stick to coming up with testable hypothesis, ”

    As to whether we should be using the term “plasma” or “gas” or “ionized gas”? I think you’re reading too much into this. But the onus is on all sides to justify their terms.

  72. ND says

    iantresman,

    That’s another game. Alfvén and his Nobel Prize. I can throw Nobel laureates in your direction too but the prize means nothing. It’s all about the evidence. Winning the Nobel for one idea does not impart any credibility of another idea the individual is promoting. I keep seeing Nobel Prize inserted into sentences that mention Alfvén, like a talking point.

    Use of pseudonyms is a red herring. It has not prevented in-depth discussion of any topics here. And as far as I can tell people here have been posting under a single handle, real or pseudonym and that includes individuals like solrey and anaconda whom I consider to play games in discussions as well.

    Why don’t you guys stick to coming up with testable hypothesis, then the science community will be more interested.

  73. iantresman says

    @DrFlimmer

    I agree with most of what you say. The quibble I have, is that not everyone who reads about astronomy, knows that each discipline has its own vocabulary. When some people read “gas”, they have preconceptions of what a gas is.

    Suggesting that “plasma” is a better term, is no big deal, but you wouldn’t get that impression from reading this thread. That is not only my opinion, but also of other scientists whose work I have cited. People here need only agree or disagree, and/or give their reasons.

  74. iantresman says

    @Hon. Salacious B. Crumb: “Plasma is highly ionised”

    Correct, no dispute. Unless you are saying that plasmas are only highly ionized. In which case, would you care to put a figure on the degree of ionization that makes an “ionized gas” a plasma? (specifically an interstellar plasma).

    @Hon. Salacious B. Crumb: “any scientifically trained person worthy his salt ”

    Scientists don’t go around accusing others of half-truths, using ad hominems. They rely on discussion and evidence.

  75. iantresman says

    ‘DrFlimmer Says: “It’s just as annoying and senseless as this whole debate!”

    I agree. Your original response was exactly the right tone.

    But I feel that others have responded all out of proportion to my original comment.

  76. DrFlimmer says

    But it is important to know whether people mean “gas” (non-plasma) or “ionised gas” or “plasma”, […].

    Not at all. I will try to explain why.

    Every profession on this earth has its own language, a way how to talk about certain things. And sometimes things can become confusing, when people of different professions meet and try to talk about their respective fields.
    This is, of course, also true for astronomy and other parts of physics, say plasma physics.
    Astronomers really have a different way of saying some things than other parts of physics. That’s mainly due to the fact that astronomy was regarded as another science, parted from physics a rather long time ago. And astronomers tend to stick to some “old” terminology – change is slow, so to speak (but only for the terminology!); they are some kind of traditionalists 😉 . Astronomers stick to things and ways of saying it, because they have always done it that way. Why else would the Hertzsprung-Russel-diagram still have the temperature axis the other way around (with higher temperatures to the left instead to the right)?

    A little side-note: There is also a certain way how physics is done. Given a certain problem a physicist will first try to simplify the problem, in order to simplify the calculation. Some useful results will still emerge from this much simpler form of the problem, however not the whole “truth” – but the physicist knows that! Adding a few more complications will maybe give some new insights or will be closer to observations. That’s the way physics is ALWAYS done!

    So, sticking these two points together, we have an astronomer observing, say, a young star, maybe a lot of young stars in order to get a good picture of what’s happening there.
    He concludes that matter is collected by a central mass, which may become a star.
    First, we try a simple model, just to keep things easy. Let’s assume the in-falling matter would be a gas (so we can neglect effects of magnetic fields, etc).
    I don’t go into any details, but if you do the calculations with this assumptions the result you obtain is astonishing. You can really come very close to what’s going on, and you can describe a lot of properties of stars just with simple gas laws.
    However, a lot of details cannot be explained by that model; we have to invoke some complications.
    Well, the gas could be fairly hot. That means it interacts with magnetic fields. That’s bad, because things can become nasty rather quickly. Nonetheless, we assume a hot gas and magnetic fields…..
    oh, sorry, did I say hot gas? My bad. Obviously, this is a plasma now. But still it is some kind of gas that just happens to react to magnetic fields. So since we know that, we can stick to the old term, because it’s convenient and simpler.

    What I tried to show here is, if an astronomer, or an astrophysicist speaks of a hot gas, you can be sure that he knows that he talks about a plasma. The terms are practically the same for him.
    A plasma physicist may shake his head about this – but this is just the way different groups name the same thing.
    What I want to say is, this debate here is meaningless. Everyone here KNOWS that we deal with a plasma and all the nasty things that come into play, then. Just because it is labeled a hot gas doesn’t make it any different.
    I’d like to quote Luke Skywalker and Yoda from “The Empire strikes back”:

    “[…] Moving rocks is one thing, but this… this is totally different!”
    “No! No different! Only different in your mind!”

    This is exactly what we are dealing with here. So, please stop with these semantics.

    And another thing:

    @ND: “the [Nobel] prize means nothing”

    That’s funny.

    Actually, this is quoted out of context. Because, what ND meant, was not that the Nobel Prize is worthless, or undeserved. He just meant that someone can earn the Nobel Prize for one very good idea (and for such things it is given – Stephen Hawking will never earn the Nobel Prize, although no one will dispute that he is one of the greatest minds of our times!), but that very person can be very wrong in other fields or with other ideas.
    This is true for Alfvén. This is true for Einstein. This is true for Max Planck, and I guess you can find a lot of other examples.
    And this can become especially important when the scientist leaves his/her particular field of work.
    I am an astrophysicists, but I would not even try to give advice to someone in the field of solid state physics. Even plasma physics, although strongly related to what I do, can have applications I don’t want to debate about with a plasma physicist, because I just lack the expertise!
    And the latter is a critical point – in this forum especially!

    I don’t know, if my points are somewhere near to be clear, I just had to say it!

  77. Hon. Salacious B. Crumb says

    iantresman said;

    “You don’t differentiate a plasma from an ionised gas. An ionised gas is a plasma, though one has a greater degree of ionisation.
    A gas which has not ionised sufficiently to become a plasma, is a gas (though there may be a tiny proportion of ionisation).”

    Bull. All this is is narrow semantics.

    Then you say;

    “As to whether we should be using the term “plasma” or “gas” or “ionized gas”? I think you’re reading too much into this. But the onus is on all sides to justify their terms.”

    …and yet you here claim your a scientific university trained chemist. Yet any scientifically trained person worthy his salt does nor rely on half truths or deceptions – nor do they rely on pseudo-definitions like what plasma might or might not be.

    Plasma is highly ionised. Why, because the extreme ionisation interacts with the surround magnetic field. Furthermore its interaction is based on the electron density on the environment the plasma is within.

    I talk of the process of fluorescence in chemistry you then glibly talk about fluorescent lights. Why?

    Frankly, you just know no better.

  78. ND says

    “@ND “It’s all about the evidence”
    I’m glad you agree with Alfvén who stressed the importance of an empirical approach.”

    I was agreeing with scientists and the scientific method in general. Any scientist will stress this.

    A Nobel prize is just icing on the cake and irrelevant to these discussions. It does not impress or sway anyone here.

    DrFlimmer,

    Thanks for expanding on what I was trying to say. Well written.

  79. DrFlimmer says

    @ iantresman

    Yes, but in many cases it just doesn’t matter if you call it a gas or a plasma, because the “plasma” properties are unimportant for the related problem.
    And thus, it really starts to become really annoying that every time the word “gas” is used some people here scream out loud “but it’s a plasma”.
    It’s just as annoying and senseless as this whole debate!

  80. Jean Tate says

    It is rather odd, isn’t it, that “gas” vs “plasma” seems to attract such a lot of attention, yet when astronomers (astrophysicists, cosmologists, etc) refer to oxygen as a “metal”, and when a Universe Today writer repeats that reference in an article (even indirectly), no one bats an eyelid?

    Then there’s “baryons”, a term used to refer to one kind of matter in the WHIM (warm-hot intergalactic medium) for example. Now electrons are not baryons, and are just as much a part of the WHIM as protons, helium ions, etc. But no one even comments on this!

    What I find particularly curious, even irritating, is the implication – or outright assertion – that the scientists who are engaged daily in astrophysical research do not understand or appreciate the relevant physics (there are several examples of this in the comments here, and many more elsewhere).

    This wouldn’t be too bad if those making the comments demonstrated that they knew what they are talking about; however, universally they don’t (or, more accurately, haven’t so far).

  81. iantresman says

    @Jon Hanford: “Sites like these do science a great injustice by proclaiming that these notions are scientifically sound”

    Unlike “mainstream” science which has just come up with scientifically sound “impossible stars”.

  82. Jean Tate says

    iantresman,

    Your original comment included this: “It was Hannes Alfvén who noted that plasmas may form cellular structure (ie. bubbles).” To which Torbjorn Larsson OM replied: “But that isn’t the explanation here, where radiation pressure predicts the bubbles.

    I cannot be sure, of course, but from the huge number of comments you’ve made on Universe Today stories, and the exchanges you’ve had with others, I think you already knew a great deal about these bubbles and also a fair bit about the astrophysical explanations of them (i.e. what Torbjorn Larsson OM referred to). If so, then many of the responses to your initial comment may not have been “all out of proportion“.

    May I make a suggestion? If you are interested in the contemporary astrophysical explanations, and models, of phenomena involving space plasmas, why not take a course? Or, if it’s more suited to your learning style, go through an introductory textbook (I can recommend a few, if you’re interested)?

  83. Jean Tate says

    Tom Bridgman makes some good points relevant to the “gas” vs “plasma” discussion, in his blog entry Electric Universe: Lunar electric fields; be sure to read the comments on it, including his own!

  84. DrFlimmer says

    @ Jean Tate

    Well said! Thanks!

    @ iantresman

    You agree with me, good. But on what, I wonder. Do you agree with everything I said, or just with the very last point?
    Just to make it clear:
    It would be nice if you (and your friends) would STOP with this senseless shouting “IT’S A PLASMA!”. Stop it at once!
    That is the point. I hope you agree with it, too!

  85. Jon Hanford says

    I’ve been following the thread since it was posted(this is my first reply, though) and feel compelled to point out one factor not yet mentioned concerning this issue, one I feel is of equal importance. That being, iantresman’s link to his Plasma Universe site. Once a layman or noobie clicks on this link, they are confronted with heaping amounts of blatant misinformation. Good luck trying to separate fact from fiction there! Sites like these do science a great injustice by proclaiming that these notions are scientifically sound and are considered mainstream (it sure is easy on the eye and looks authoritative).

    I know no overt mention of this site has been made by iantresman on this thread, but the link is there for the curious to follow, and I worry about those who accidentally fall into this vortex of pseudoscience. This thread may be winding down, but does anyone here think that this issue has been resolved (after 90+ comments) never to appear here again? My guess is no!

    Like Dr. Flimmer plead before, I just had to say it.

  86. DrFlimmer says

    The only impossible thing here is you….

    If you have problems with descriptions like that, then we can’t help you. “Impossible star” just DESCRIBES the situation that our theories are not complete, nothing more and nothing less.

    And if you meant to be sarcastic or ironic… well, that failed completely.

    Sorry, but I had to speak my mind.
    This is impossible….

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