A New Spin On NGC 2403

Article written: 5 Mar , 2011
Updated: 24 Dec , 2015
by

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No. You’re not looking at a Hubble image. This incredibly detailed photo was taken with a 14.5″ telescope from right here on the surface of planet Earth. When Allan Sandage turned the Hale telescope its way, he discovered the first Cepheid variables beyond our local galaxy group. At the time he concluded its distance as about 8,000 light years away, but today it is believed to be as distant as 8,000,000. What’s its name? NGC 2403…

Discovered in 1788 by Sir William Herschel, this intermediate spiral galaxy is part of the M81/M82 group… and like its contemporaries, is a product of a galaxy merger. Its northern spiral arm connects to NGC 2404 – riddling the halo with young stars. In this masterful astrophoto done by Warren Keller, the pink and red regions denote active star formation, while clusters of neophyte suns gather in the blue OB associations. Like a fine piece of Irish lace, dark regions appear like holes where dust blocks the light. But NGC 2403 doesn’t follow the rules. Here the galaxy’s arms rotate at a different speed.

“High sensitivity H I observations of the nearby spiral galaxy NGC 2403 obtained with the VLA are presented and discussed. The properties of the extended, differentially rotating H I layer with its H I holes, spiral structure and outer warp are described. In addition, these new data reveal the presence of a faint, extended and kinematically anomalous component. This shows up in the H I line profiles as extended wings of emission towards the systemic velocity. In the central regions these wings are very broad (up to 150 km/s) and indicate large deviations from circular motion.” says F. Fraternali (et al). “We have separated the anomalous gas component from the cold disk and have obtained for it a separate velocity field and a separate rotation curve. The mass of the anomalous component is 1/10 of the total H I mass. The rotation velocity of the anomalous gas is 25-50 km/s lower than that of the disk. Its velocity field has non-orthogonal major and minor axes that we interpret as due to an overall inflow motion of 10-20 km/s towards the centre of the galaxy. The picture emerging from these observations is that of a cold H I disk surrounded by a thick and clumpy H I layer characterized by slower rotation and inflow motion towards the center. The origin of this anomalous gas layer is unclear. It is likely, however, that it is related to the high rate of star formation in the disk of NGC 2403 and that its kinematics is the result of a galactic fountain type of mechanism. We suggest that these anomalous H I complexes may be analogous to a part of the High Velocity Clouds of our Galaxy.”

Does this different rotational curve have an cosmological implications? According to the work of E. Battaner and E. Florido: “We review the topic of rotation curves of spiral galaxies emphasizing the standard interpretation as evidence for the existence of dark matter halos. Galaxies other than spirals and late-type dwarfs may also possess great amounts of dark matter, and therefore ellipticals, dwarf spirals, lenticulars and polar ring galaxies are also considered. Furthermore, other methods for determining galactic dark matter, such as those provided by binaries, satellites or globular clusters, have to be included. Cold dark matter hierarchical models constitute the standard way to explain rotation curves, and thus the problem becomes just one aspect of a more general theory explaining structure and galaxy formation. Alternative theories also are included. In the magnetic model, rotation curves could also be a particular aspect of the whole history of cosmic magnetism during different epochs of the Universe.”

Yet on the other hand, perhaps the differing rotations were caused by the merger itself – with no dark matter involved. “Quite a point has been made about deviations of some galaxies from flat rotation curves, specifically the decreased velocity in outer parts of the curves. Such cases can be explained under the diffusion model by considering collisions and tidal interactions between galaxies. In this explanation, the excess gravitational force is considered to be caused by a “cloud” of the agent that carries gravitational force that always is diffusing freely, although more concentrated in some regions than others as a result of the time required for the diffusion process and the size of the regions involved.” says Roy J. Britten. “When tidal interactions have occurred between galaxies, some momentum could be transferred between stars, gas, and dust that would not be shared by the diffusing clouds, and therefore, asymmetries in the gravitational forces would result. For example, the cloud and galaxies could separate if the two galaxies merged because the galaxies would share their momentum and the clouds would remain independent and continue to diffuse. Then, new gravitational clouds would be built slowly by diffusion from the merged galaxy.”

Dark matter or no dark matter, NGC 2403 (07h 36m 51.4s, +65° 36′ 09″) is a pleasure to observe. Located in the northern constellation of Camelopardalis, this 8.4 magnitude spiral galaxy can be spotted under dark sky conditions with ordinary 10X50 binoculars. In 1954 Fritz Zwicky reported a supernova event and 50 years later it happened again, keeping astronomers wondering about this galaxy with the low-luminosity “dwarf” Seyfert nucleus. SN2004 is the bright yellow “star” in this portrait and it is the closest – and brightest – stellar explosion discovered in more than a decade…

As close as your eyepiece on the next dark night!

Many thanks to Warren Keller of Billions and Billions and David Plesko for sharing their incredible work!


18 Responses

  1. MontrealSEOExpert says

    Very nice picture of a small part of the universe.

  2. Torbjorn Larsson OM says

    From structureofexistence.com by Dan Echegoyen

    Used to be an UT rule to the effect “do not promote own theories in the comments.”

    Which is good, because I go here to read about the science.

  3. Hon. Salacious B. Crumb says

    Simply foolish nonsense by someone who is out of their depth.
    Please. Just go away!

  4. Hon. Salacious B. Crumb says

    Anti-science is on the rise and just getting crazier an crazier.

    Wannabe scientist with dreams of glory to change the world so they can be remembered as ground breakers just ain’t gonna happen. Sorry guys. You’re just to intellectually challenged.

    Sadly, crazy guys like these are organised by attacking all legitimate science sites at every opportunity. They are both dangerous and aim to subvert all science into religious or unsubstantiated mumbo-jumbo. Dan Echegoyen is an example of another main sect, whose designed argument is mostly against relativity.They see the opportunity of dark matter and dark energy as an opportunity of “weakness” — in the dismal hope that some crackpot astronomical or cosmological theory will eventually supplant it.
    Sadly, Universe Today is showing considerable weakness in its moderation. I’ll happily stand against the tide, but it can never be stopped except for moderation.

    Perhaps it is coming to the stage of being ‘time to leave”, because unless you are prepared to instigated the guideline, most of these comments are just a waste of time. The only option I see is to only allow discussions on the BAUT form, where there is considerable moderation and kill the discussions in UT Today. Alternatively, you could just select those who are “invited” to comment and dump the rest of the nutters. I fear soon, either way, that comment on UT will become just a thing of the past. Pity.

  5. Lawrence B. Crowell says

    These people who promote such ideas come in a number of forms. Many such people learn about Galileo and Newton and their work. They get some sense of it and how it changed things back then. They sense how this could happen today again, if all they do is get a hold of some “big idea.” However, they are looking from a modern perspective, not from the times itself. If anyone has read or looked at Newton’s Principia and de Motu it is quite apparent it is far from easy to read. Our freshman college physics texts distill this to a certain essential set. So then some of these people with their pet idea have found some grand guiding idea and think that by talking about waves going in and out, or of tubes of pre-field fluid flow or …, that they have found the solution to everything.

    Of course if these guys really hit something it has been explored elsewhere by others. Usually these guys come from some completely bad idea to start with. Often these people are genuine in their intentions, but are way out of their element — and they don’t know it.

    The other types are those who invent some new science in order to build their new type of spaceship, or a free energy machine or … . There are probably right now in the US about 100,000 garages filled with the “creation” and hard labor of some “lone inventor,” which in about half the cases is some new way of getting a flying saucer to levitate up (anti-gravity) and get into space. When I was in 4-5th grade I and two other guys labored to build a spaceship as well, using stuff from a junk yard not far where we lived. These guys end up throwing together lots of stuff in order to make their invention sound workable.

    Then there are the EU/PC types, who seem to have an agenda behind what they promote. This is a movement of sorts, and it has a kind of political if not almost quasi-religious sense to it. This stuff seems inherently dishonest at its root. This is some kind of wacko movement which “brain washes” people into quasi-physics that is clearly wrong, and where there is a sense of some ulterior purpose to it.

    LC

    • renoor says

      please, if somebody here would be so kind to explain what EU/PC means? I see these abbreviations only on universetoday.com and these two (“EU” and “PC” alone) are so generic, that they are practically ungooglable

      • Hon. Salacious B. Crumb says

        EU/PC is abbreviated Electric Universe and Plasma Cosmology.

        These are terms used for the unsubstantiated explanation of the nature of the universe, which for the most part, have been proven as false because it does not explain properly observational evidence in the universe.

        It refers to a pseudoscience, which wrongly believes that most of the phenomena observed in the universe is related to electromagnetism and magnetic fields rather than the influence of gravity. Much of the ideas on this are mere speculation. Those who support such unsubstantiated notions have been kindly abbreviated here as just PC/EU’ers. Science, in general, does not general support these people’s explanation as being possible.

        Note: This is quite different than the definition of plasma physics, which is the science of plasma (highly ionic elements, where the electrons are removed from their shells.) and their interactions. I.e. Especially in the Sun.

      • renoor says

        Thank you very much for explanation and good work with google, sir! 🙂

      • Hon. Salacious B. Crumb says

        The term is practically ungooglable as this has been done deliberately. I.e. Especially by me.

  6. Paul Eaton-Jones says

    While I agree almost 100% with LBC/HSBC et al about the EU/anti gravity nitwits we shouldn’t ridicule or despise people who come here and ask questions as to why the EU idea is bonkers or why a perpetual mootion machine is ludicrous. The only way to dispel these notions is to confront them or explain to the curious as to why it’s foolish. To take the p*ss out of the curious and those lacking knowledge is arrogant in the extreme, only fosters resentment and is likely to drive certain people into the arms of those we’re trying to fight.

    • Hon. Salacious B. Crumb says

      Agreed with the point on novices who generally ask genuine questions. Most here are more than happy to guide and point such people in the right direction.

      The ultimate weakness is with the organised groups and individuals, who used the same naïvety to their advantage. (Often found out after just a few posts.) Like many of the PC/EU crowd, they clearly state to their brethren to act as a “interested and curious observer” and never refer to some organisation or group.
      Worst is that these people use ‘good faith’ and ‘guidance’ to their own advantage, so they can just hone and sharpen their knowledge then just “up the ante.” Wasting those the time of those who talk to them.
      Another stated motive is to desire be “treated like equals” no matter how obviously foolish or nonsensical the anti-science propaganda is. They just want to do this to gain a foothold.
      As to resentment, well that is true, but if someone has a really genuine, you would expect them to do some groundwork and search for some facts before asking a question. If they are using a computer, the information can be found using a few keywords Google or in Wikipedia. (What they read might or might no be absolutely true, but if multiple sources happen to say the same thing, then you could believe something might be true. I curious, wouldn’t you argue X says A and Y says B, so which is it, for example?)
      You can mostly tell the nutters from the genuine by the approach of their argument. Nutters just go boot and all into their own notions, where a genuine blogger will go from the knowledge of theory or the facts, then speculate or ask questions on particular aspects of the theories or facts. I.e Coming out and just saying the Big Bang never happened, rather than doesn’t evidence of X and Y infer the Big Bang never happened.
      You can also tell the also fringe element from their other post and sites across the internet by Google or Bing searches. I.e. We know Dan Echegoyen is slightly wacky, because we can read his statements in his website. You can find, for example, the exact same text is posted on the “Power News Network.” on the 19th February, 2011 at 11:17am and again at About.com Physics in the article “Universe Born in a Black Hole?” 19th July 2010. he tried this on the BAUT forum, and he was removed by moderator ‘Swift’ because it “…appears to be a personal theory” . He is doing this to gain a profile, where multiple documents is inferring the theory is mostly plausible!
      We also know lately of our “Mr.Hologram” crazy notions from his website and by what he says. I.e. His avatar blog name is his website!

      In the ideal world we should all “Have a sense of humor, be friendly and be polite.” However, with anti-science or pseudoscience rising, and the knowingly attack n basic science with unsubstantiated ideas or unproven or unprovable ‘alternative’ theories, this sure can test your patience. Anti-science or pseudoscience is becoming more militant and well organised. To ignore it or be nice to it, would be plain foolishness.
      Although my approach by some has some ‘irritating nuisance factor’, it makes sure those who don’t now any better are not generating more wannabe pseudoscientists. Do you want science to stand on its merits or spend all its time just denying the undeniable instead of learning new science and educating the public about it? (That’s exactly what the pseudoscience wants to happen! Doubt is the main means of espousing actual facts or theory into mere belief and faith.)

      As I’ve often said before; “I might be rancid butter, but at least I’m on your side of the bread.”

      Note: I’d like to discuss about NGC 2403, and all I’m doing is defending by obvious abilities of already learnt science itself! I can’t now, because the story has been made deliberately murky — and few would now listen. Tammy’s motive for her story is now mostly quite irrelevant. This situation should never had happened!

      • Paul Eaton-Jones says

        Good points HSBC. The rising tide of anti-science and anti-intellectual thinking is truly alarming. I’m particularly concerned that the so-called ‘thinking classes’ [sweeping generalisation I know] are turning their back on scientific thought and processes.In Britain it seems that the philosophy prevalent in th elate 1960’s is making a comeback in a slightly different form – nature/magick/brown rice good; science/technology/mass production bad.
        Point taken about NGC 2403 though!!

  7. Member
    Aqua says

    HSBC… oTay… So you are saying that giga Tesla nanoscale magnetic fields would NOT influence nuclear synthesis processes within stars… right? Lessee here.. there’s the strong and weak force, gravitational force AND the electromagnetic force…. right? It sounds as though you are saying there is no electromagnetic force? Or that force is so well understood there’s no possibility that it has unknown influences in our universe? Eh?

    • Hon. Salacious B. Crumb says

      No. I never said or implied that at all. All I’ve said EU/PC claim that electromagnetic forces dominate the universe, which has little or no support by observational evidence. I.e. Intergalactic magnetic fields.

      As for the rest, I’m unsure of your deference, here. Could please quote me, so I can reply for your consideration of.

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