337 Responses to “A Galactic glitch”

1. John Gribbin Says:
   10 March 2008 at 7:42 AM

   I agree with the tenor of this post, but I’d like chapter and verse on how we know “the Milky Way is a completely normal spiral galaxy.” It’s only recently been established that it is average sized for as disc galaxy!

   John Gribbin

2. Neil B. Says:
   10 March 2008 at 7:54 AM

   Sure, I couldn’t understand in those claims why the sun would move much relative to spiral arms - isn’t it part of the stars making those arms? But in any case, we have to take dark matter into account (or MOND if that offbeat theory turns out to be true) whenever we talk about rotation in galaxies. BTW, how about the idea that now the sun is primed for a cool spell, and that will compensate to whatever extent for global warming stimuli? It had a big splash recently, but I haven’t heard much since.

3. Arch Stanton Says:
   10 March 2008 at 9:06 AM

   Thank you for addressing this issue.

   It amazes me how quickly and unquestionably the skeptically hopeful accept the minimally substantiated claims of Svensmark, yet refuse to believe science that has been much better substantiated.

4. Gsaun039 Says:
   10 March 2008 at 9:50 AM

   It seems that a couple of years ago, that new evidence suggested that the Milky Way was likely a barred spiral type.

   Also something else that I seem to remember is that our Solar system is likely slightly inclined from the galactic plane ecliptic. The slight pertubations of the gravitational field as the solar system make’s it’s transit through the plave could be a good source of comets from the Oort cloud.

5. Nick Says:
   10 March 2008 at 9:50 AM

   The two different rotating velocities of arms and stars have a different radial dependence - to first order the arms get preserved as entities while the stars further out have much smaller angular velocities than stars further inside - so the relative velocity of a star with respect to the nearest spiral arm will depend on its distance from the centre of the galaxy. At a certain radius, the radius of co-rotation, the two velocities are identical and a star at this radius has zero relative velocity with respect to the spiral arm pattern. It stays “forever” in the same spiral arm – or outside of it.

   Actually, it doesn’t. You’ve made a whooping assumption that the star stays in the glactic plane

   In the case of the sun, it doesn’t. It ossilates from above to below the galactic plane over time.

   As such it periodically passes though the plane, and that’s where the gasses are concentrated.

6. John P Says:
   10 March 2008 at 9:52 AM

   I am reminded of Pauli’s comment when showed a paper - “This isn’t right. This isn’t even wrong.” Denialists such as Shaviv and the producers and broadcasters of this piece of drek have serious ethical issues. They don’t have a standard of proof, they merely spread disinformation with an agenda. The bar for publication of denialist nonsense is set far lower than that for publication of science in a respected journal such as Nature or Geophysical Letters.

7. gusbob Says:
   10 March 2008 at 10:32 AM

   Knud Jahnke and Rasmus Benestad says “The rotation is not rigid, but depends on the encircled mass inside the orbit of a star, including the Dark Matter, a yet unknown but solidly established source of gravitational attraction.”

   I am curious when something is unknown and close to impossible to measure, what does it mean to be solidly established.

   Dark matter was created because current explanations regarding orbital velocities were missing the required mass for gravitational calculations to work. Now every time there is a gravitational anomaly it becomes “verification” of this unknown dark matter.Dangerous circular reasoning, and not very scientific.

   [Response: You are confusing matters quite seriously. The point is simply the gravitational attraction of dark matter (whatever it is) is known, and so can be used in calculations. See #33 below for a more detailed explanation from an astronomer.–eric]

8. Craig Allen Says:
   10 March 2008 at 10:56 AM

   Going out on a limb here:

   An analogy for how galaxy arms and stars can move at different speeds can be found found in weather patters. I have noticed on my local online weather radar loop that clouds and storms move a lot faster than the cloud bands in which they form. I assume that the cloud bands are troughs in atmospheric pressure waves and that clouds and storms form as air mass passes across the waves. Obviously the physics of the weather patters has no connection with the dynamics of galaxies, but it demonstrates how structures at different scales in a medium such as air, water or space can move at different speeds.

9. Hank Roberts Says:
   10 March 2008 at 11:02 AM

   > barred
   Perfectly normal, innit?

   “Bars in spiral galaxies seem to be ubiquitous in our local universe. Up to two-thirds of all spirals contain bars. …”
   http://www.space.com/scienceastronomy/astronomy/hubble_bar_010302.html

   > ossilates
   Oscillates? We assume this? or we know this how?
   Cite, please?

10. Walt Bennett Says:
    10 March 2008 at 11:35 AM

    Amazingly,

    Still no post on the differences between Hadley and GISS anomalies.

    Instead, a steady stream of “Why the debunkers are full of it” posts.

    Is RC in the business of discussing climate science, or being the repository for anti-denialist rebuttals?

    It’s almost as though you guys sit around exclaiming “Look what they wrote about us TODYAY! Let’s get right to work on that one…”

    Quit taking your eyes off the ball, please. There are no doubt legitimate topics worthy of your brainpower and expertise.

    In the 2 years I’ve been coming here, your focus on refuting what “the other guys” say has never been narrower, and you are attracting an enormous crowd who want nothing more than to bash denialists. This is ceasing to become a “climate science” blog and becoming just another back-and-forth blog, as if we (a) could afford to lose the former and (b) needed another of the latter.

    [Response: Hey you know what? I have a real job as well and sometimes things just need to be done. This is on my to do list because it’s of interest - but the nature of a volunteer spare time blog is that one doesn’t get to devote unlimited resources to it. Sorry about that, but he who pays the piper… - gavin]

11. Ben M Says:
    10 March 2008 at 12:05 PM

    I could buy Shaviv’s argument to a point, but it doesn’t change the fact that human influence is causing warming as well. If anything, it means we picked a really lousy time to start heating up our planet.

12. Arch Stanton Says:
    10 March 2008 at 12:25 PM

    Re Nick @ #5:

    Actually Rasmus is right. Even if is a body oscillates “up and down” through the galactic plane (as our sun does) if the body is located at “the radius of co-rotation” it will remain indefinitely (essentially ‘forever’ for the purposes of this discussion) within (or without) of a spiral arm. Perhaps he could have been more accurate by saying “aligned with”. A body can remain in the spiral arm even as it oscillates up and down thorough the center of it. The “arm” is not limited to the “plane” within it.

13. Lynn Vincentnathan Says:
    10 March 2008 at 1:12 PM

    Do we really have to know all about this? I got to “But is this true? Most likely not,” and took your word for it. Not even looking further to see what it had to do with global warming.

    Seems to me a good old ploy of the denialists is to come up with far-flung, convoluted hypotheses that side-track us to such an extent, we don’t have time to deal with the real issue of GW.

    So while scientists may have to be on hand to refute these hypotheses, it seems to me a waste of precious time for the laypersons out there who need to keep on (or start) reducing their GHGs.

    So if a denialist crosses my path using this “galactic cosmic ray hypothesis,” I’ll just say I don’t have time for those kind of far-fetched hypotheses, but I know it’s been roundly refuted at RealClimate, and here is their webpage…..

14. Henry Says:
    10 March 2008 at 1:19 PM

    What happened to your paper submitted to A&A in 2005 that also criticized Saviv’s work?
    http://de.arxiv.org/abs/astro-ph/0504155
    Was it rejected by A&A or is it still being revised?

    I think that New Astronomy has reasonable standards in general (although I never published or referred anything for that journal myself).

15. Vern Johnson Says:
    10 March 2008 at 1:33 PM

    Astrophysics, gentlemen, is in it’s infancy. What is unknown far exceeds what is “known”. Cosmic rays, for example, are unknown as to source or what accelerates them. Gravity waves from theorized radiative sources like black holes have never been confirmed to exist and thus black holes themselves have never been triangulated as to location, not one. Leonard Krause extrapolates 100 billion years into the future and boldly states that our local group of galaxies will have coalesced into an “island universe” ( with nothing else in sight) and forecasts that the whole kit and kaboodle will eventually collapse into a black hole! We think we do know something about interstellar dust that is now flowing thru our solar system in larger amounts because of the reversed polarity of the sun that cyclically occurs. I would like to see this apparent fact discussed if it is true because that dust could have cooling effects?

16. Jim Galasyn Says:
    10 March 2008 at 1:37 PM

    Re Nick’s suggestion in 5, claiming that oscillation above and below the galactic plane causes variation in GCR flux:

    If find it hard to believe that the amplitude of this oscillation is great enough to significantly vary the galactic magnetic field incident on Earth. Do you have any evidence that this is the case?

17. Walt Bennett Says:
    10 March 2008 at 2:16 PM

    Re: #10 inline,

    Gavin,

    I appreciate the entirety of your comment, and I look forward to that post.

    My point this time was about what has become of the orientation of this blog: pugnacious, defensive, and heavily “interested” in debunking denialism. Less and less original commentary on the work you and others do.

    I miss that, personally.

18. Paul Middents Says:
    10 March 2008 at 2:36 PM

    Perhaps the post by Tamino on his blog “Open Mind” might satisfy Walt’s impatient demand:

    http://tamino.wordpress.com/2008/01/24/giss-ncdc-hadcru/#more-556

19. Henry Says:
    10 March 2008 at 2:39 PM

    f find it hard to believe that the amplitude of this oscillation is great enough to significantly vary the galactic magnetic field incident on Earth.

    Possibly of relevance is this paper:

    http://arxiv.org/abs/astro-ph/0602092
    Do extragalactic cosmic rays induce cycles in fossil diversity?
    Authors: Mikhail V. Medvedev, Adrian L. Melott

    Abstract: Recent work has revealed a 62 (+/-) 3-million-year cycle in the fossil diversity in the past 542 My, however no plausible mechanism has been found. We propose that the cycle may be caused by modulation of cosmic ray (CR) flux by the Solar system vertical oscillation (64 My period) in the galaxy, the galactic north-south anisotropy of CR production in the galactic halo/wind/termination shock (due to the galactic motion toward the Virgo cluster), and the shielding by galactic magnetic fields. We revisit the mechanism of CR propagation and show that CR flux can vary by a factor of about 4.6 and reach a maximum at north-most displacement of the Sun. The very high statistical significance of (i) the phase agreement between Solar north-ward excursions and the diversity minima and (ii) the correlation of the magnitude of diversity drops with CR amplitudes through all cycles provide solid support for our model. Various observational predictions which can be used to confirm or falsify our hypothesis are presented.
    

20. Khebab Says:
    10 March 2008 at 2:46 PM

    What’s the point in looking a the hypothetical impact of the galaxy given the stated lack of a trend in the GCRs with the climatology (http://www.realclimate.org/index.php/archives/2004/12/recent-warming-but-no-trend-in-galactic-cosmic-rays/)!!

21. Nick Says:
    10 March 2008 at 3:00 PM

    Nothing like giving you a reference or two

    http://en.wikipedia.org/wiki/Milky_Way

    Sun’s location

    The Sun (and therefore the Earth and Solar System) may be found close to the inner rim of the Galaxy’s Orion Arm, in the Local Fluff or the Gould Belt, at a hypothesized distance of 7.62±0.32 kpc from the Galactic Center.[28][29][30][31] The distance between the local arm and the next arm out, the Perseus Arm, is about 6,500 light-years.[32] The Sun, and thus the Solar System, is found in what scientists call the galactic habitable zone.

    The Apex of the Sun’s Way, or the solar apex, is the direction that the Sun travels through space in the Milky Way. The general direction of the Sun’s galactic motion is towards the star Vega near the constellation of Hercules, at an angle of roughly 60 sky degrees to the direction of the Galactic Center. The Sun’s orbit around the Galaxy is expected to be roughly elliptical with the addition of perturbations due to the galactic spiral arms and non-uniform mass distributions. In addition the Sun oscillates up and down relative to the galactic plane approximately 2.7 times per orbit. This is very similar to how a simple harmonic oscillator works with no drag force (dampening) term.

    It takes the Solar System about 225–250 million years to complete one orbit of the galaxy (a galactic year),[33] so it is thought to have completed 20–25 orbits during the lifetime of the Sun and 1/1250th of a revolution since the origin of humans. The orbital speed of the Solar System about the center of the Galaxy is approximately 220 km/s. At this speed, it takes around 1400 years for the Solar System to travel a distance of 1 light-year, or 8 days to travel 1 AU.[34]

    http://www.americanscientist.org/template/AssetDetail/assetid/21173/page/2

    a bit longer quote, because of some of the details

    Our sun is also in motion. Relative to the average motion of the most commonly measured nearby stars, the sun moves with a speed of about 16.5 kilometers per second, or nearly 50 light-years per million years. The sun’s path is inclined about 25 degrees to the plane of the galaxy and is headed toward a region in the constellation of Hercules near its border with Lyra. The sun oscillates through the plane of the galaxy with an amplitude of about 230 light-years, crossing the plane every 33 million years. However, the sun’s motion relative to the local stellar neighborhood should not be confused with its movement around the center of the galaxy, since the whole solar neighborhood (including the sun) orbits the galactic center once every 250 million years. Just as we do not include the earth’s velocity around the sun when calculating the speed of an airplane (we are only interested in the ground-speed), astronomers do not include the sun’s galactic orbital velocity when describing its local motion.

    The interstellar cloud currently surrounding the solar system—often referred to as the Local Interstellar Cloud—is warm, tenuous and partially ionized. Like all interstellar clouds, our local cloud is made of dust and gas, with the dust fraction making up about one percent of the cloud’s mass. The elemental composition of interstellar clouds is much like that of the sun, about 90 percent hydrogen and 9.99 percent helium. The heavier elements make up the remaining 0.01 percent.

    The sun is on the edge of what is sometimes called the Local Bubble, a great void in the distribution of interstellar gas in the nearby galactic neighborhood. As voids go, the Local Bubble interior is one of the most extreme vacuums yet discovered. The very best laboratory vacuum is about 10,000 times denser than a typical interstellar cloud, which in turn is thousands of times less dense than the Local Bubble. The Local Bubble is not only relatively empty (with a density of less than 0.001 atoms per cubic centimeter); it is also quite hot, about one million degrees kelvin. By comparison, the interstellar cloud around the solar system is merely warm, about 7,000 degrees, with a density of about 0.3 atoms per cubic centimeter.

    The Local Bubble lies within a ring of young stars and star-forming regions known as Gould’s Belt. The Belt is evident in the night sky as a band of very bright stars that sweeps in a great circle from the constellations Orion to Scorpius, inclined about 20 degrees relative to the galactic plane. The north pole of Gould’s Belt lies close to the Lockman Hole, a region in the sky with the least amount of intervening interstellar gas between the sun and extragalactic space. Star formation regulates the distribution of interstellar matter, including the boundaries of the Local Bubble. The closest star-forming region on the outskirts of the Local Bubble is about 400 light-years away in the Scorpius-Centaurus association. The molecular clouds from which stars are formed are both cooler (less than 100 degrees) and denser (over 1,000 atoms per cubic centimeter) than the Local Interstellar Cloud.

    A plot of the sun’s course through our galactic locale shows that the sun has been traveling through the Gould’s Belt interior in a region of very low average interstellar density for several million years. The sun is unlikely to have encountered a large, dense interstellar cloud in this relatively benign region during this time. Although our solar system is in the process of emerging from the Local Bubble, the sun’s trajectory suggests that it will probably not encounter a large, dense cloud for at least several more million years. The consequences of such an encounter for the earth’s climate are unclear; however, one wonders whether it is a coincidence that Homo sapiens appeared while the sun was traversing a region of space virtually devoid of interstellar matter.

    Despite the absence of massive clouds within 100 light-years, it seems likely that the local galactic environment changes in subtle ways on much shorter time scales. The low density of the Local Bubble permits the products of supernova explosions—such as superbubbles and shock fronts—to expand easily into the void and sweep past the sun. Indeed, within the past 250,000 years the sun has entered the outward flow of material from the star-forming region of the Scorpius-Centaurus association. There is even some suspicion that the interstellar environment may have changed within the past 2,000 years! This is uncertain, however, because astronomers have an incomplete understanding of the structure of the local interstellar cloud complex.

22. Hank Roberts Says:
    10 March 2008 at 3:52 PM

    This is rather old — 1984.

    “… the time needed for the Solar System to oscillate vertically about the plane of the Galaxy, which is 33 plus/minus 3 Myr according to the best current astronomical evidence.”

    Has anyone the time to follow citing publications forward in time, or to find another cite to look into?

    http://www.nature.com/nature/journal/v308/n5961/abs/308709a0.html

23. tom ward Says:
    10 March 2008 at 4:09 PM

    Papers on solar variability and cosmic-rays continue to surface even though many would prefer they go away from the climate variability debate. We find yet another case for solar variability and cosmic rays in an article in Physics Today March, 2008, pgs 50-51, “Is Climate sensitive to solar variability?” by Nicola Scafetta and Bruce West. References therein detail considerable work in progress. I would like to see a discussion of the method these folks are using who come to the conclusion that 15-70% of the warming is due to solar variability.

24. Arch Stanton Says:
    10 March 2008 at 4:31 PM

    Lynn (13) This is significant due the galactic cosmic ray (GCR) hypothesis popularized by Svensmark and others (and popular with some denialists). Accordingly; as our solar system passes through the more dense parts of the Milky Way galaxy found in the arms and along the center of the galactic plane, it is subject to increasing amounts of GCRs. According to the hypothesis; during these increased periods of terrestrial GCR bombardment the earth experiences increased high clouds (and subsequent cooling) because the GCR- ionized atoms in the upper atmosphere (allegedly) make dandy cloud droplet/crystal nuclei.

    The timing of these events is very significant to the hypothesis.

    Fans of the GCR hypotheses often tend to cite them as gospel and are frequently not aware of the tenuousness of the components they are based on are.

25. Nick Says:
    10 March 2008 at 4:59 PM

    Seems a comment went missing.

    http://en.wikipedia.org/wiki/Milky_Way

    he Sun (and therefore the Earth and Solar System) may be found close to the inner rim of the Galaxy’s Orion Arm, in the Local Fluff or the Gould Belt, at a hypothesized distance of 7.62±0.32 kpc from the Galactic Center.[28][29][30][31] The distance between the local arm and the next arm out, the Perseus Arm, is about 6,500 light-years.[32] The Sun, and thus the Solar System, is found in what scientists call the galactic habitable zone.

    The Apex of the Sun’s Way, or the solar apex, is the direction that the Sun travels through space in the Milky Way. The general direction of the Sun’s galactic motion is towards the star Vega near the constellation of Hercules, at an angle of roughly 60 sky degrees to the direction of the Galactic Center. The Sun’s orbit around the Galaxy is expected to be roughly elliptical with the addition of perturbations due to the galactic spiral arms and non-uniform mass distributions. In addition the Sun oscillates up and down relative to the galactic plane approximately 2.7 times per orbit. This is very similar to how a simple harmonic oscillator works with no drag force (dampening) term.

    It takes the Solar System about 225–250 million years to complete one orbit of the galaxy (a galactic year),[33] so it is thought to have completed 20–25 orbits during the lifetime of the Sun and 1/1250th of a revolution since the origin of humans. The orbital speed of the Solar System about the center of the Galaxy is approximately 220 km/s. At this speed, it takes around 1400 years for the Solar System to travel a distance of 1 light-year, or 8 days to travel 1 AU.[34]

26. Nick Says:
    10 March 2008 at 5:00 PM

    More references

    http://www.nature.com/nature/journal/v308/n5961/abs/308712a0.html

    Raup and Sepkoski1 have recently reported evidence fora 26-Myr periodicity in the occurrence of mass extinctions based on a study of marine fossils. The data baseline of 250 Myr suggests events of variable amplitude, with some of the strongest peaks associated with boundaries between major geological periods which have been defined by previous palaeontological studies. In a more limited quantitative study, Fischer and Arthur2 earlier cited evidence for a 32-Myr period of major extinction events. Hatfield and Camp3 were among the first to suggest that mass extinctions might be correlated with periodic galactic phenomena, noting intervals of 80−90 Myr between major mass extinctions with an exceptionally strong mass extinction every 225−275 Myr. Here we point out a possible correlation between the 26-Myr extinction period and the Sun’s oscillation about the galactic plane.

27. Eyal Morag Says:
    10 March 2008 at 5:04 PM

    As Mach as I like to find mistake in shaviv theory the last paragraph is enough.
    I can live without paleozoic climate and skip the mesozoic. I guess that if someone will put error bars on the radiation in that time they will fill the the page.

    as a Hebrew climate blogger who write 10% of what I would like I can’t complaint But I’l be glad to have more on non deniers things.

    P.S. Surely I will put link to this post in my shaviv post

28. dws Says:
    10 March 2008 at 5:05 PM

    Re 10) Hadley and GISS anomalies
    I’m not familiar with the history of your prior posts but the
    subject is discussed well at:
    http://tamino.wordpress.com/2008/03/02/whats-up-with-that/#more-614

    Seems ok!

29. Ray Ladbury Says:
    10 March 2008 at 5:51 PM

    Vern Johnson–It would appear that you know neither what we know, nor what we do not know. We have seen black holes, and we know GCR are accelerated by supernovae. We know that the density of interstellar dust is infinitesimal and has no effect on solar irradiance (which we can measure), and we know that GCR fluxes are not varying appreciably. What nobody knows is how you would take a putative tiny variation in said GCR flux measuring on average 6 particles per cm^2 per second and turn it into a global effect–especially one that only made clouds during the daytime. Neat trick, that.

30. Jon Gradie Says:
    10 March 2008 at 5:53 PM

    The orbital inclination of the solar orbit is about 5.5 deg with respect to the galactic plane. Simple trig gives an “oscillation” amplitude such that the solar system moves +2,600 l.y. above and -2,600 l.y. below the galactic plane at the semimajor axis of the solar system during its 250 million galactic year. Two import points derived from orbital mechanics: (a) the sun spends most of its time above or below the galactic plane and transitions only twice (up one, down once) per galactic year and (b) the “velocity” of the sun perpendicular to the galactic plane is highest during the transit through the galactic plane which means the sun spends very little time passing through the disk. We would expect two “short” periods of increased GCR exposure every 250 m.y.

    Dark Matter: the presence of dark matter was known ever since astronomers in the early 20th century recognized the odd orbits of the stars around the Milky Way and eventually other galaxies (via Doppler spectroscopy of the “gross” spiral arms — stars do not need to be resolved). The Dark Matter was known to be large quantities of mass exterior, but in close proximity, to the galaxy that was not luminous (hence “dark”). The issue has always been “what is it?” Not, is it really there. 20th century theories included dark (nonluminous) H regions, nonluminous substars (e.g., MACHOs), neutrinos, etc., but not until cosmology and particle physics began to converge in the late 20th century (and the other theories were ruled out by observation) did the “weirdness” of dark matter come to the forefront (weird in that it does not interact with the rest of the mass in the universe except through gravity. We can see evidence of dark matter, as a primordial substance, in galactic cluster collisions, thanks to the Great Observatories (Hubble, Chandra, Spitzer and Compton) combined with ground-based radio astronomy (e.g., http://www.nasa.gov/audience/forstudents/postsecondary/features/F_NASA_Great_Observatories_PS.html)

    Astrophysics as an immature science: age is relative. Read both the history and current status — not in popular science, but in the real world, and you will find a robust, young adult.

31. Lawrence Brown Says:
    10 March 2008 at 6:13 PM

    Regarding comment #10. This is an unjust accusation(about ‘being the repository for anti-denialist rebuttals’). Several of the most recent posts didn’t take issue with the basic premise and/or the conclusions of the paper reviewed- e.g. ‘536 AD and all that’,The papers on Tropical Cyclone History, and ‘A Day When Hell Was Frozen’, to name a few.

    On this particular topic, the astronomers gave their results and conclusions based on their findings and Rasmus and Knud Jahnke, gave theirs in more mathematical detail than presented in the film. The latter presenters are on more solid ground in rebutting the spike in temperatures over the last 2 and a half decades than the cosmic ray people.

    If you disagree with this, present your findings and conclusions, or establish a site where you can choose the subject matter. Don’t expect volunteers working without remuneration to march to the beat of your drummer.

    When I was sick a while back, the Dr. asked my wife what my main symptoms were and she answered “Whining and complaining.” Instead of that, set up your own site and pick your own topics.

32. Hank Roberts Says:
    10 March 2008 at 6:32 PM

    Walt,
    http://tamino.wordpress.com/2008/01/24/giss-ncdc-hadcru/
    http://tamino.wordpress.com/2008/03/02/whats-up-with-that/#more-614

33. Ralph Says:
    10 March 2008 at 6:44 PM

    I am an astronomer, so I hope I can help clear up some of the confusion here.

    Post #1: “I agree with the tenor of this post, but I’d like chapter and verse on how we know “the Milky Way is a completely normal spiral galaxy.” It’s only recently been established that it is average sized for as disc galaxy!”

    Chapter and verse are way too specific — you need a whole book. Try Galactic Astronomy by Binney & Merrifield. The size scale of the Milky Way has been established for many decades — the existence of spiral arms was discovered over 40 years ago and has been confirmed numerous times since then. Pulsars, molecular gas, and atomic gas all trace the spiral structure very nicely (and independently). As for the galaxy being a disk, look for a google image of “COBE galaxy” to put the nail in that coffin. That the Milky Way is a typical-sized spiral is beyond dispute at this point. It’s not a “new” result.

    Post #2:”Sure, I couldn’t understand in those claims why the sun would move much relative to spiral arms - isn’t it part of the stars making those arms? But in any case, we have to take dark matter into account (or MOND if that offbeat theory turns out to be true) whenever we talk about rotation in galaxies.”

    No, the Sun is not part of the stars that make up the spiral arms. Spiral arms are obvious because the brightest stars are formed in them. These stars have very short lives, however, compared to the pattern speed of the arms. There are almost as many stars between the arms as in them (the Sun is between arms right now). The arms trigger star formation, which creates bright, short lived stars, which quickly burn out. When the arm moves on, the bright stars go away.

    No, you don’t need to worry about dark matter here (or MOND, which has been repeatedly shown to be an inaccurate description of gravity, despite its success in limited applicaitons). The rotational velocity of the Galaxy is well measured for both the stars and the gas. It is what it is — WHY it has that speed doesn’t change the arguments made in the main post. You don’t have to buy that dark matter is an exotic weakly interacting massive particle to believe that the Sun orbits the Milky Way every 250 million years.

    #4:”It seems that a couple of years ago, that new evidence suggested that the Milky Way was likely a barred spiral type.

    Also something else that I seem to remember is that our Solar system is likely slightly inclined from the galactic plane ecliptic. The slight pertubations of the gravitational field as the solar system make’s it’s transit through the plave could be a good source of comets from the Oort cloud.”

    Current evidence of the kinematics of stars near the Galactic Center indeed suggests the Milky Way is a barred spiral. It also could be the case that as the Sun bobs up and down through the Galactic plane it may encounter more stars during plane crossings, which may induce more comets. It’s not clear if this is a strong effect, though.

    #5:”Actually, it doesn’t. You’ve made a whooping assumption that the star stays in the glactic plane
    In the case of the sun, it doesn’t. It ossilates from above to below the galactic plane over time.
    As such it periodically passes though the plane, and that’s where the gasses are concentrated.”

    It’s true that the gases are concentrated in the plane, but it’s very patchy (and concentrated in the arms) — most of the time the Sun will pass through the plane without encountering much molecular gas.

    #7:”I am curious when something is unknown and close to impossible to measure, what does it mean to be solidly established.

    Dark matter was created because current explanations regarding orbital velocities were missing the required mass for gravitational calculations to work. Now every time there is a gravitational anomaly it becomes “verification” of this unknown dark matter.Dangerous circular reasoning, and not very scientific.”

    The existence of a smooth source of gravity in galaxies is overwhelming. This conclusion is completely scientific. We know that the stars in the Galaxy orbit at a rate that cannot be explained by adding up the gravity of the stars themselves. This is not a small effect. Either gravity operates differently at large scales, or there is matter that isn’t bright. Evidence for the former option is strongly lacking. Evidence for the latter option is ubiquitous and self-consistent (not circular — there’s a difference). If there dark matter in the Universe, then our models of cosmology, galaxy clusters, and the Galaxy itself are essentially complete and very simple. Occam’s razor dictates that the easiest explanation is that there is simply matter we cannot see. The alternative is that, although Einstein’s theory of General Relativity has been demonstrated to amazing levels of accuracy in some places, it somehow fails spectacularly in others. This would be very hard to understand. Dark matter requires no new physics. Neptune was the original dark matter (look up the story of its discovery). The neutrino was another.

    #8: I don’t know much meteorology, but that sounds like an excellent analogy.

    #9:”> barred
    Perfectly normal, innit?

    “Bars in spiral galaxies seem to be ubiquitous in our local universe. Up to two-thirds of all spirals contain bars. …”
    http://www.space.com/scienceastronomy/astronomy/hubble_bar_010302.html

    > ossilates
    Oscillates? We assume this? or we know this how?
    Cite, please?”

    Yes, barred spirals are common, as large galaxies go.
    The bobbing of the Sun through the Galactic plane is firmly established by measurements of what is known as the “local standard of rest”. The Sun has significant velocity in the direction perpendicular to the plane of the Galaxy (as most G stars do). This is expected from stellar dynamics, and produces a small, slow oscillation. We are now about 30pc or so from the plane, although that number has big error bars.

    #15:”We think we do know something about interstellar dust that is now flowing thru our solar system in larger amounts because of the reversed polarity of the sun that cyclically occurs. I would like to see this apparent fact discussed if it is true because that dust could have cooling effects?”

    The dust in the Galaxy is nothing like “dust” that would effect climate for several reasons. 1) It’s not “dust” like in your room. It’s many times finer than cigarette smoke. 2) It’s incredibly sparse. There isn’t nearly enough of it to have any effect on the atmosphere compared to the amount of much bigger particles in the atmosphere naturally, to say nothing of the man-made contribution.

    #16: The magnetic field near the Earth is dominated by the Earth’s own field. This field is strongly distorted by the magnetic field and “wind” of the Sun. The galactic field is stopped many billions of miles away by the Sun’s field. The Voyager and Pioneer spacecraft are just now starting to find this boundary (called the “heliopause”). The galactic field cannot penetrate the heliopause (far beyond the orbit of Pluto) so the galactic field is not important here.

    [Response: Ralph, thanks for stopping by RealClimate. Your helpful and clear responses are much appreciated. –eric]

34. Ray Ladbury Says:
    10 March 2008 at 6:58 PM

    Gusbob, your “dangerous circular reasoning” is the same type of reasoning that Enrico Fermi employed to posit the neutrino. It is the same sort of intuitive leap Newton made from the falling apple to the motion of the planets. In a self-correcting discipline like science, being wrong is not the greatest sin–and taking the risk of being wrong is the only way to fundamentally advance understanding.

35. Gary Says:
    10 March 2008 at 7:19 PM

    Interesting. But I am hard pressed to figure out why if astrophysicists should not be commenting on climate, why climatologists (physicist for Rasmus) should be commenting on astrophysics?

36. Robert A. Rohde Says:
    10 March 2008 at 7:37 PM

    Let’s clarify a couple things.

    Re #5, 9, 12, 16: The vertical oscillation of the sun is moderate. It results in a ~50% change in local galactic density at the extreme vertical displacement relative to the plane of the disk. This is enough to matter, but one would have a semantic argument about whether a 50% drop is really large enough to say that the sun ever meaningfully leaves the disk of the galaxy. Medvedev and Melott, writing after Shaviv and for entirely different reasons, suggest that this much oscillation translates to as much as a factor of 5 change in cosmic ray flux with a 50-80 Myr timescale. (For those keeping track, this factor of 5 change would actually be larger and on a different timescale than the factor of ~3 that Shaviv and Veizer suggested occurs on a 140 Myr timescale.) I’m not entirely convinced Medvedev and Melott are right about the magnitude, but it is a point to be aware of.

    Re #1: If the Milky Way is really a four armed spiral (as opposed to the more mundane two armed variety), then we are actually living in a fairly rare type of galaxy. That has no bearing on the validity of the co-rotation argument however.

    Re #2: The spiral pattern is created by a “supersonic” “shock wave” in the gas of the galaxy. The shock front moves at its own speed seperate from the velocities of stars, much the same way that ripples on a pond move faster than the water itself. In fact, the concentrations of stars we see in spiral arms are actually created that way. The passage of the shock front leads to compression that squeezes the gas just enough that some of it collapse to form new stars, and it is this concentration of new stars that make the spiral arms appear brighter. After the shock wave passes, the normal motions of the stars will cause them to disperse. (Note: both “supersonic” and “shock wave” have technical meanings that aren’t really important to the qualitatively understanding.)

    Re #4: The solar system is highly inclined relative the galactic plane, making an angle of nearly 60 degrees.

37. Ray Ladbury Says:
    10 March 2008 at 8:12 PM

    Scafetta and West have been eviscerated on RC previously:
    http://www.realclimate.org/index.php/archives/2007/11/a-phenomenological-sequel/

    http://www.realclimate.org/index.php/archives/2006/03/solar-variability-statistics-vs-physics-2nd-round/

    http://www.realclimate.org/index.php/archives/2006/10/how-not-to-attribute-climate-change/

    The biggest problem with this work is that it completely ignores the known physics of greenhouse forcing and adopts a “blackbox” approach of comparing time series–epidemiology applied to physics devoid of a mechanism.
    It is numerology. I look forward to the future editorials in Physics Today on astrology, phrenology and other pseudoscientific topics. I would have expected better.

38. William Astley Says:
    10 March 2008 at 9:51 PM

    The article above presents a link to this paper,

    http://www.nature.com/nature/journal/v448/n7149/full/448008a.html

    , which purports to show that solar changes were not responsible for a significant portion of the 20th century warming. The paper in question looks at only two of the three mechanisms by which solar changes affected planetary temperature. These are the three mechanisms.

    1)Solar irradiation changes. (No the sun did not get hotter in the 20th century.)

    2)Solar heliosphere modulation of Galactic Cosmic Rays. (No, for the time period in question, GCR changes did not cause global warming. The strength and the extent of the solar heliosphere changes throughout the solar cycle, which modulates the amount of GCR that strikes the atmosphere. Changes in GCR has been shown to affect planetary cloud cover. More GCR more clouds colder planet and visa versa.

    3)Electroscavenging. Yes that is mechanism by which the solar magnetic field is purported to have caused a significant portion of the warming in the 20th century. Solar wind bursts (caused by coronal holes moving towards the solar equator for example, particularly at the end of the solar cycle.) create a space charge in the ionosphere which removes cloud forming ions. Less ions, less clouds. Less clouds warmer planet.

    Look at figure 12 in the attached which shows the number of solar magnetic storms per year, from 1865 to present and the solar cycle number. There is roughly a 10 times increase in the number of magnetic storms at the end of the solar cycles, when comparing the 20th century to the 19th century. It is not just the number, but the magnitude of the solar storms.

    http://www.geomag.bgs.ac.uk/earthmag.html#_Toc2075558

    This paper by Brian Tinsley and Fangqun Yu “Atmospheric Ionization and Clouds as Links Between Solar Activity and Climate” outlines solar mechanisms 2) and 3), if you are interested in more details concerning the mechanisms.

    http://www.utdallas.edu/physics/pdf/Atmos_060302.pdf

    Now as the sun appears to be entering a long term minimum the solar wind bursts should drop off, in frequency and magnitude. There will therefore be less electroscavenging to remove cloud forming ions. In addition, with the solar magnetic cycle in a minimum, the large scale magnetic field and solar heliosphere should be reduced. A reduced solar heliosphere should result in increased GCR.

    The following is a link that shows GCR has increased by about 12%.

    http://cosmicrays.oulu.fi/Request.dl…=00&mR=00&PD=1

    If there was more cloud forming ions, there should be more clouds over the ocean which should over time result in colder ocean surface temperatures. What are your thoughts?

    http://www.osdpd.noaa.gov/PSB/EPS/SST/data/anomnight.3.10.2008.gif

39. wayne davidson Says:
    10 March 2008 at 10:05 PM

    #10, Walt, I find debunking contrarians just as instructive as any other topic here. A contrarian stance is always seriously flawed in one way or another, and knowing this error is just as good as being taught about climate reality in some topical way… Keep up the good work RC!

    Surface temperatures should be taken with the idea that they represent the bottom of an ocean of air. It is hardly possible to determine what is going on from just surface information, or to say that surface temperature leads and what happens above follows.

40. gusbob Says:
    10 March 2008 at 10:17 PM

    Ralph said, “The existence of a smooth source of gravity in galaxies is overwhelming. This conclusion is completely scientific. We know that the stars in the Galaxy orbit at a rate that cannot be explained by adding up the gravity of the stars themselves. This is not a small effect. Either gravity operates differently at large scales, or there is matter that isn’t bright. Evidence for the former option is strongly lacking. Evidence for the latter option is ubiquitous and self-consistent (not circular — there’s a difference).”

    Ralph thank you for your thoughtful post. However I must disagree that it is not circular reasoning. I agree that the Dark Matter hypothesis is scientific but only in the sense that it is a hypothesis to explain current astronomical conundrums. And I agree that the missing gravity is not a small effect. It is huge! But what we are observing in outer space is evidence of “attractive forces” that can not be explained by the calculations of observable mass. Yes, the evidence is indeed ubiquitous, that this force is accounted for by visible mass.

    However it is most definitely circular reasoning to hypothesize this missing force is the result of dark matter and then every time you observe the missing force to claim it must be the very same hypothesized dark matter.

    I find it easier to believe, and eventually prove or disprove, that the missing force results from electromagnetic interactions. The electromagnetic force is at least a trillion, trillion, trillion, times more powerful than gravity. Occam’s razor suggests to me, that a theory that incorporates electromagnetic forces is an easier explanation than creating a new form of matter that has not been observed and so far is impossible to observe.

    The idea of Birkeland currents (http://en.wikipedia.org/wiki/Birkeland_current) connecting the sun to the earth and elsewhere in outer space was believed to be impossible because space was believed to be a vacuum. It seems then Occam’s razor made it was easier to deny their existence than let go of the erroneous idea of the “space vacuum”. Dark matter only serves Occam’s razor because we need not re-think our theories. Electromagnetic ideas do not replace gravitational effects or nuclear effects but fills in the holes with a force that is observable and testable.

    And now we know that space is filled with plasma and our Local Bubble of plasma is being investigated by CHIPS. And Themis cinfirms what Birkeland suggested 100 years ago: “”The satellites have found evidence for magnetic ropes connecting Earth’s upper atmosphere directly to the Sun,” says Dave Sibeck, project scientist for the mission at the Goddard Space Flight Center. “We believe that solar wind particles flow in along these ropes, providing energy for geomagnetic storms and auroras.”

    http://science.nasa.gov/headlines/y2007/11dec_themis.htm

    Magnetic fields are caused by electric currents and as Themis and Ulysses reveal, the evidence mounts that electromagnetic forces must be incorporated into our cosmological understanding. Much of the electromagnetic ideas can be demonstrated and tested in plasma labs and are scalable. meanwhile the actuality of dark matter remains a fairy tale, a nice story of inferences but not testable and nor falsifiable. And thus it is not science. It is a galactic glitch.

41. gusbob Says:
    10 March 2008 at 10:36 PM

    RL,

    “Gusbob, your “dangerous circular reasoning” is the same type of reasoning that Enrico Fermi employed to posit the neutrino. It is the same sort of intuitive leap Newton made from the falling apple to the motion of the planets. In a self-correcting discipline like science, being wrong is not the greatest sin–and taking the risk of being wrong is the only way to fundamentally advance understanding.”

    In my above post I relate why I think the risk of exploring an electrical idea of the universe is at least as valid as seeking a dark matter solution. And it would be in keeping with Fermi and Newton’s risk taking.

    I responded to your aggressive denunciation of the electric universe on the Antartica thread but those posts were deleted. So perhaps you missed the 3 questions I asked you to answer w(ithout evoking elctromagnetic forces). I think the elctromagnetic answers to those questions are plausible and testable.

    First why does the solar wind accelerate away from the suns and past the planets. Gravitational theory alone suggests it should decelerate.

    Second why does the temperature beginning at the photosphere,5800K , drop in the chromosphere and then jump to over 1 million K in the corona. Shouldn’t we get cooler as we stand further from the fireplace.

    And 3rd if Themis’ magnetic ropes are not Birkeland currents then what are they?

    And since you mention the neutrino, why are we missing the predicted neutrinos postulated for a strictly nuclear sun?

42. cce Says:
    11 March 2008 at 12:03 AM

    If we could shift the discussion to clouds, Nexus6 pointed out over a year ago with the problems with the ISCCP cloud dataset. That the decrease in cloud cover is either mostly or entirely due to the addition of satellites, improving the field of view. This is described in this paper:
    http://cimss.ssec.wisc.edu/clavr/amato/2006GL028083.pdf

    Joel Norris recently did a presentation on cloud cover, i.e. satellite vs surface observations:
    http://meteora.ucsd.edu/~jnorris/presentations/12469 (real video)

    This data is described in this paper:
    http://meteora.ucsd.edu/~jnorris/reprints/NorrisGwattRevised.pdf

    In particular, look at the graphs on page 4 (figure 1) and the map of the cloud cover anomalies on page 6 (figure 2). I don’t see how anyone can still cling to the cosmic ray theory of climate change (at least as an explanation for current warming) given these facts.

43. Jim Galasyn Says:
    11 March 2008 at 12:09 AM

    Thanks to Ralph in 33 for helpful explanations. Re my suggestion about the galactic magnetic field, this was the only relevant variable I could imagine that would affect the GCR flux as the Sun oscillates about the galactic plane.

    Very interested to know what other effects might modulate the GCR flux. Surely not dust and gas…?

44. Peter Erwin Says:
    11 March 2008 at 12:56 AM

    #36:
    Re #2: The spiral pattern is created by a “supersonic” “shock wave” in the gas of the galaxy. The shock front moves at its own speed seperate from the velocities of stars, much the same way that ripples on a pond move faster than the water itself. In fact, the concentrations of stars we see in spiral arms are actually created that way. The passage of the shock front leads to compression that squeezes the gas just enough that some of it collapse to form new stars, and it is this concentration of new stars that make the spiral arms appear brighter. After the shock wave passes, the normal motions of the stars will cause them to disperse. (Note: both “supersonic” and “shock wave” have technical meanings that aren’t really important to the qualitatively understanding.)

    Actually, the spiral pattern is probably a combination of this and a gravitational density wave in the old and young stars. Many young stars are indeed born in the compressed gas, and their light makes the arms stand out, especially in blue light (young stars are generally hot, and thus blue).

    But the arms in many spirals can still be seen when one looks in the infrared, where the light comes more from older stars. Faint spiral arms can even be seen in disk galaxies that lack gas and young stars entirely (and such arms also produced in gravitational n-body simulations of galaxies, without needing gas).

    A gravitational density wave like a spiral arm can be thought of as something like a traffic jam: it’s a moving region of higher density, which stars join and then leave.

45. vijay Says:
    11 March 2008 at 3:43 AM

    Sorry I do not belive on the astronomy.

46. pete best Says:
    11 March 2008 at 4:32 AM

    Re#1 is this John Gribbin of popular science writing fame in the UK and quantum theorist / scientist ?

47. Barton Paul Levenson Says:
    11 March 2008 at 7:35 AM

    Shouldn’t that r0 * 3 be r0 ^ 3? If it were a scalar coefficient it would come before the variable, not after it. I’m pretty sure the 3 should be an exponent.

48. Barton Paul Levenson Says:
    11 March 2008 at 7:40 AM

    gusbob says:

    [[I am curious when something is unknown and close to impossible to measure, what does it mean to be solidly established.]]

    Dark matter is easily measured by its gravitational effect.

49. Barton Paul Levenson Says:
    11 March 2008 at 7:43 AM

    The idea that the Sun “oscillates” above and below the galactic plane seems to me to defy celestial mechanics. What would make it do that?

    If it has a nonzero orbital inclination, it would pass the galactic midplane exactly twice per orbit — once on the way down and once on the way up — at the descending and ascending “nodes,” respectively. For a galactic orbital period of 225 million years, that would be once every 113 million years. And Shaviv’s 250 MY (which I think is too high) => once in 125 MY, not 150.

50. Barton Paul Levenson Says:
    11 March 2008 at 7:55 AM

    gusbob writes:

    [[I find it easier to believe, and eventually prove or disprove, that the missing force results from electromagnetic interactions. The electromagnetic force is at least a trillion, trillion, trillion, times more powerful than gravity.]]

    Doesn’t matter how powerful it is if the electric charges involved are balanced, and they are. There is no good evidence for huge charge differences on a galactic scale. Enough to account for the galaxy’s differential rotation would have other noticeable effects which we don’t see (e.g. the galaxy either expanding or contracting).

51. Barton Paul Levenson Says:
    11 March 2008 at 7:59 AM

    gusbob says:

    [[First why does the solar wind accelerate away from the suns and past the planets. Gravitational theory alone suggests it should decelerate.]]

    Because we’re not dealing with “gravit[y] alone.” There’s photon pressure.

    [[Second why does the temperature beginning at the photosphere,5800K , drop in the chromosphere and then jump to over 1 million K in the corona. Shouldn’t we get cooler as we stand further from the fireplace.]]

    No, that’s simplistic. It depends on what the radiative balance of the corona is, and that isn’t well modeled at this time. But a hot corona is certainly not ruled out by distance. By that logic, temperature inversions should never happen in Earth’s atmosphere, and the ozone layer should have a positive lapse rate.

    [[And since you mention the neutrino, why are we missing the predicted neutrinos postulated for a strictly nuclear sun?]]

    We aren’t. Your information on this appears to be obsolete (1960s or so). Neutrinos appear to switch type with time and that accounts for the missing neutrinos.]]

52. Ray Ladbury Says:
    11 March 2008 at 8:11 AM

    Gusbob,
    What you fail to realize is that electromagnetic forces are important in stellar dynamics–there’s just no way they can explain the energy generation of stars. And it is the nuclear forces that drive the plasma that is responsible for the electromagnetic interactions–not the other way around.
    As to neutrinos, why would there be neutrinos at all unless there were nuclear interactions going on? And the missing neutrinos have been accounted for in terms of neutrino oscillations.

    Heating of the solar corona is likely due to magnetic recombination and wave heating–both of which have been observed occuring. In my opinion, magnetic recombination seems to be a strong candidate–as it becomes significant as a transport mechanism when the magnetic field lines extend far enough to have significant energy. BTW, the energy here is not huge–only about .0025% of TSI.
    As to the magnetic connection of Earth and the Sun, I’m not sure what you even mean. The Sun has a magnetic field as does Earth, it is not surprising that some of the field lines should connect. However, the energy exchange here is trivial. You are falling victin here to a common pitfall among interested laymen–you don’t want to do the math. If you did, you would quickly see that the “electric Universe” simply isn’t energetically viable–there is no energy source that can power the sun except fusion–and we know fusion is going on from the spectrum of neutrinos we receive here on Earth.

53. Nick Gotts Says:
    11 March 2008 at 8:22 AM

    Re #41 [gusbob] “why are we missing the predicted neutrinos postulated for a strictly nuclear sun?”

    I thought that had been resolved through the discovery that neutrinos can change type (electron neutrino / muon neutrino / tau neutrino), and the detectors were only picking up the electron neutrinos. Or are you saying there are still some missing?

54. Richard Wakefield Says:
    11 March 2008 at 9:30 AM

    Re #23 “Papers on solar variability and cosmic-rays continue to surface even though many would prefer they go away from the climate variability debate.”

    Why??? What are you afraid of that you would wish ligitimate science to “go away”? This is what dogmatic orthodoxy does, not ligitimate science. If solar has an influence, major or minor, we MUST let science do it’s work!!

55. Arch Stanton Says:
    11 March 2008 at 10:03 AM

    Barton Paul Levinson #49 wrote:

    [[If it has a nonzero orbital inclination, it would pass the galactic midplane exactly twice per orbit — once on the way down and once on the way up — at the descending and ascending “nodes,” respectively. For a galactic orbital period of 225 million years, that would be once every 113 million years. And Shaviv’s 250 MY (which I think is too high) => once in 125 MY, not 150.]]

    This is an interesting point. According to Svensmark (The Chilling Stars) the sun passes the midplane of the disc every ~34MY (a cycle period of ~68MY). Is it possible that the sun can “…dive through the midplane of the Milky Way Galaxy like a dolphin.” (Svensmark) independent of its galactic orbital cycle?

    Thanks.

56. Robert A. Rohde Says:
    11 March 2008 at 10:20 AM

    Re Barton #49:

    If it has a nonzero orbital inclination, it would pass the galactic midplane exactly twice per orbit — once on the way down and once on the way up — at the descending and ascending “nodes,” respectively. …

    Your intuition is based on the orbital dynamics of a small mass orbiting around a large point mass, e.g. the Earth around the sun. Unlike the solar system, much of the mass of the galaxy is smeared out across the disk. This gravitational potential function is far more complicated than the gravitational potential from a simple point mass, and leads to more complicated results. In particular, orbits do not close into simple ellipses and there is no expectation that as one completes one revolution that you will end up back where you started.

    Think of it this way, if you move above the disk, you aren’t merely being pulled back towards the center of the disk, but you are also being pulled vertically towards the portion of the disk nearest to you. In this way the potential for vertical oscillations is largely decoupled from the orbital motions around the center of the disk.

57. Uli Says:
    11 March 2008 at 10:35 AM

    Re #49:
    Barton Paul Levenson, this would only hold, if the galactic mass would be spheric symmetric or concentrated in the center.
    Due to the massive disc the force on the sun is not in the direction to the galactic center but more towards the disc plane.

    Values of about 30Myr for the oscillation are from overestimated masses of the disc prior to recognizing a massive dark matter halo. A recent value, I cite
    “A by-product of this study is the determination of the half period of oscillation by the Sun through the Galactic plane, 42+/-2Myr …” from [1].

    Due to the small amplitude of this oscillation for the sun no remarkable effects are expected.

    [1] Vertical distribution of Galactic disk stars - III. The Galactic disk surface mass density from red clump giants
    O. Bienaymé, C. Soubiran, T. V. Mishenina, V. V. Kovtyukh, and A. Siebert
    Astronomy & Astrophysics 446 (3) 933 (2006)
    DOI: 10.1051/0004-6361:20053538

58. kevin Says:
    11 March 2008 at 10:42 AM

    gusbob’s comments made me curious enough to do some poking around and learn a bit about this “electric universe” idea. It seems to not work in its basic assumptions, for example it necessarily predicts a big influx of electrons going to the sun which is simply not there: (from http://www.bautforum.com/against-mainstream/28596-electric-universe-model-2.html)
    “In the case of the absence of evidence of electrons approaching the sun, this absence is compelling. It’s not just one, or even a few spaceraft, in a few choice locations. It’s literally dozens of spacecraft, scattered all over the solar system, but concentrated mostly at the equator. That’s why Thornhill changed his tune some years ago, pointing to the solar pole as the place where the electron influx would be, since he knows as well as anyone else does, that the absence of electrons in the equatorial plane is too severe to deal with. Granted Ulysses is only one spacecraft, but it has covered both solar poles twice now, and nary an inbound electron in sight. But the magnetic field is streched radially even at the pole, and does not show a polar cusp. There is only one way anyone knows to do that, a steady outbound flow of electrons (an inbound flow would bend the field in the opposite direction). So all of the evidence, for decades, and both particles & fields, clearly indicates an absence of incoming electrons. But more than that, the configurations of fields & particles that we actually obvserve constitute an intolerable conflict with the hypothesis that there is an incoming stream. For one thing, an incoming flow of electrons would either rip the solar wind apart, or be ripped apart by the solar wind (the bigger flow wins). The radial magnetic field can only be maintained by an outward flow of electrons. The electrons cannot have an “undetectable energy” for several, simultaneous spacecraft (you might pull that off for one, but not two or more at once).” (Tim Thompson)

    Also, proponents of this theory also posit that Saturn used to be the center of the solar system, and the Earth and all the other planets orbited it. Also, one site made frequent breathless mention of “the Light of Creation” which was exhaled by Yahweh. So, My impression at this point is that gusbob has hold of a superficially interesting idea that is at odds with physical observation and gets odder the deeper one digs.

    So gusbob, now that your neutrino question has received a few responses, allow me to pose a couple of questions to you: 1) Why are we unable to detect any influx of electrons to the sun, either equatorially or at the poles? 2) Did the planets orbit Saturn in the past?

59. Nick Says:
    11 March 2008 at 11:04 AM

    So is the orginal blog going to be changed?

    It is claimed in ‘The Cloud Mystery’, the book ‘The Chilling Stars’, and related articles that our solar system takes about 250 million years to circle the Milky Way galaxy and that our solar system crosses one of the spiral arms about every ~150 million years (Shaviv 2003).

    But is this true? Most likely not. As we will discuss below, this claim is seriously at odds with astrophysical data.
    

    It clearly isn’t at odds with the data, since the logic ignores the inclination aspect to the suns movement.

    Given that this is wrong, the whole article falls.

    It’s also a pretty daft argument about climate change anyway. The timescales of current climate change are short, and these changes are of a different timescale.

60. Jan Lindström Says:
    11 March 2008 at 11:11 AM

    you often claim on this website that there is no trend in cosmic radiation but as I understand it, isn’t it the modulation of cosmic rays from the sun that is worthwile to take a look into?

61. Jim Galasyn Says:
    11 March 2008 at 12:08 PM

    Re Barton’s question in 49, I believe the answer is that stars don’t follow Keplerian orbits. Iirc, the trajectory is called a “rosette” and comprises a wacky, non-repeating curve around the galactic center, as various gravitational influences tug on it.

62. aaron Says:
    11 March 2008 at 12:18 PM

    Rather than calculating where the earth was precisely throughout time, I thought Shaviv used metorites and other proxies to calculate the perodicity empirically. Like described in his papers.

63. Richard Pauli Says:
    11 March 2008 at 12:28 PM

    “Not even wrong”

    Delightful to rediscover Wolfgang Pauli’s comment: “That’s not right, it is not even wrong.”

    from: http://en.wikipedia.org/wiki/Not_even_wrong

    “An apparently scientific argument is said to be not even wrong if it is based on assumptions that are known to be incorrect, or alternatively theories which cannot possibly be falsified or used to predict anything…Such theories are non-scientific, even when they are speaking in scientific language”

64. Steve Bloom Says:
    11 March 2008 at 1:13 PM

    Re #35 (Gary): “But I am hard pressed to figure out why if astrophysicists should not be commenting on climate, why climatologists (physicist for Rasmus) should be commenting on astrophysics?”

    Possibly because the climatologist co-authored this post with an astrophysicist specializing in galaxies? Could be! Physics is a very common degree type for climatologists, BTW.

    Re #10 (Walt): Re your feeling that there’s excessive debunking here lately, I would remind you that the very name of this blog suggests that there will be quite a lot of that. I haven’t noticed a major change in the proportions, BTW.

    Regarding articles by the authors on their own work, I think it’s been said that there’s a conscious effort to avoid doing too much of that. Since the realities of limited time mean that there’s no way this blog can comprehensively cover all of the important new developments in the science anyway, I don’t see the relative lack of self-referential material as being a particular problem. In case you didn’t know, if you follow the links to the personal web pages of the authors you’ll find that for the majority their papers are available to be read.

65. Martin Vermeer Says:
    11 March 2008 at 1:46 PM

    gusbob writes:

    I find it easier to believe, and eventually prove or disprove, that the missing force results from electromagnetic interactions. The electromagnetic force is at least a trillion, trillion, trillion, times more powerful than gravity. Occam’s razor suggests to me, that a theory that incorporates electromagnetic forces is an easier explanation than creating a new form of matter that has not been observed and so far is impossible to observe.

    Where do I begin? I picked this one as the most obviously absurd to refute. How do you explain the rotation of the galaxy by electrostatic forces? It has to be an attractive force to do the job. Dark matter gravitation is. Electrostatic forces are repulsive between like charges, so we must have a distribution of opposite charges to do the job.

    The smaller problem here is to find a distribution of positive and negative charges that would produce the observed change in rotational behaviour: you won’t. The bigger problem is that the net electrostatic charges won’t stay put: as they attract each other, they will flow together (as in electric current; plenty of conductive plasma out there) and will annihilate each other on a very short notice.

    …and don’t even think of bringing up an electromagnetic explanation: we know how strong the galactic magnetic field is, by a variety of observation techniques. Not even close.

66. Frank Lansner Says:
    11 March 2008 at 2:57 PM

    Interesting.
    The authers mentions ONE point from this film - i had the same thought when i saw the film, and i may agree about the galaxy argument.

    BUT BUT BUT:
    WHY IS THIS THE ONLY THING YOU MENTION??
    It is not at all the central point in the film, its just a little corner you for some reason chooses to focus on!
    Why do you not deal with the SUBSTANCE of their SPLENDID WORK??

    Are you afraid to touch the 99% of topics where they have made a very very good point?
    This theory explains practically ALL historic temperatures 1000 times better than the CO2 hypothesis.

    Please be objective, honest and scientific.

67. Hank Roberts Says:
    11 March 2008 at 3:00 PM

    Google:
    +solar +”missing force” “electromagnetic interactions”

68. Ralph Says:
    11 March 2008 at 3:08 PM

    gusbob:

    You are correct about one thing: it is much easier to disprove that electromagnetic effects are responsible for the rotation rate of the Galaxy than to understand the dark matter. The charge of the Sun is approximately known (planetary probes have measured the interplanetary magnetic and electric fields well). The field strength of the Galaxy is approximately known (by many methods, including studies of cosmic rays and the polarization of starlight). The resulting force of the charged Sun moving through the Galactic field, is infinitessimal compared to that of the gravitational force of the other stars, which itself is still only 10% or so of the force required to explain the rotation rate.

    Put another way, there are many observable consequences of charges or electromagnetic fields of the strength required to explain the rotation curve of the Galaxy. People have looked for these consequences and they have not just failed to find them — they have definitively shown their absence.

    Ergo, electromagnetic forces cannot be responsible.

69. Ralph Says:
    11 March 2008 at 3:16 PM

    gusbob wrote:
    [First why does the solar wind accelerate away from the suns and past the planets. Gravitational theory alone suggests it should decelerate.]

    The solar wind is composed of subatomic particles. The solar magnetic field accelerates them as they move away from the Sun, because the magnetic forces are stronger than gravity on these particles. This process does not scale to larger objects though. The charge to mass ratio of an electron is enormous compared to a star or planet. Stars and planets are not appreciably accelerated by magnetic fields. This is both a firm theoretical result and an observed fact.

70. Russell Seitz Says:
    11 March 2008 at 3:48 PM

    Given that the transient ionizing radiation flux from short lived fission products raised the condensation track density in the downwind wake of above ground nuclear tests, one would expect those adducing cosmic ray modulation of climate to show off photos of contrails following fallout around the globe, and cloud cover indices spiking after major H-bomb tests

    I don’t see Fred Singer volunteering . Where are they ??

71. Dodo Says:
    11 March 2008 at 4:16 PM

    Lynn at 13: “if a denialist crosses my path using this “galactic cosmic ray hypothesis,” I’ll just say I don’t have time for those kind of far-fetched hypotheses, but I know it’s been roundly refuted at RealClimate, and here is their webpage…”

    But you just said you didn’t even read the post, meaning you will believe anything with the RC seal of approval on it. A scientific attitude?

72. William Astley Says:
    11 March 2008 at 10:15 PM

    Other authors appear to support Shaviv’s hypothesis. (The authors of this paper reference four spiral arms.)

    “Ice Age Epochs and the Sun’s Path Through the Galaxy” by D. R. Gies and J. W. Helsel

    Center for High Angular Resolution Astronomy and Department of Physics and Astronomy, Georgia State University

    “We present a calculation of the Sun’s motion through the Milky Way Galaxy over the last 500 million years. The integration is based upon estimates of the Sun’s current position and speed from measurements with Hipparcos and upon a realistic model for the Galactic gravitational potential. We estimate the times of the Sun’s past spiral arm crossings for a range in assumed values of the spiral pattern angular speed.”

    “We find that for a difference between the mean solar and pattern speed of … the Sun has traversed four spiral arms at times that appear to correspond well with long duration cold periods on Earth. This supports the idea that extended exposure to the higher cosmic ray flux associated with spiral arms can lead to increased cloud cover and long ice age epochs on Earth.”

    http://arxiv.org/abs/astro-ph/0503306

73. Peter Erwin Says:
    11 March 2008 at 10:18 PM

    Nick @ 59:

    There’s nothing wrong with the blog post. Shaviv’s argument is that the flux of GCRs should increase when the Solar System is close to supernovae, and this should happen when the Sun passes through spiral arms, since that’s where you find the most supernovae. Shaviv argued for a particular value of the spiral arm pattern speed, such that the Sun would pass through spiral arms every 150 million years or so. Jahnke and Benestad argue that Shaviv has the wrong value for the spiral arm pattern speed (or, to put it another way, the wrong value of the corotation radius), and therefore the wrong periodicity for when the Sun passes through spiral arms.

    The Sun’s vertical oscillations are irrelevant to Shaviv’s argument, and to J & B’s counter-argument.

74. Joel Shore Says:
    11 March 2008 at 10:19 PM

    Re #66 (Frank Lansner): RealClimate has already discussed the problems with the cosmic ray hypothesis a few times before. One of the posts is linked to in the first paragraph of this post. Also relevant to this is the Rahmstorf et al. 2004 paper that is linked to in the 3rd-to-last paragraph here.

    I think the point of this post was to note one additional failing that they had not previously discussed.

    Since your opinion that “this theory explains practically ALL historic temperatures 1000 times better than the CO2 hypothesis” does not seem to be shared by most of the experts in the field, perhaps it is you and not the authors of this post who are being less than “objective, honest and scientific” in evaluating the relative merits of these two explanations.

75. Jim Galasyn Says:
    11 March 2008 at 10:24 PM

    At the risk of muddying the galactic waters further and veering further off-topic, what’s the general opinion of the Cooperstock-Tieu model?

    I personally find it ineluctably attractive to do away with dark matter in favor of relativistic effects.

76. Petro Says:
    12 March 2008 at 12:01 AM

    Dodo ejects:

    “But you just said you didn’t even read the post, meaning you will believe anything with the RC seal of approval on it. A scientific attitude?”

    To date, natural sciencs form a large body of knowledge. An individual can study deeply only a minor part of it. On the subjects when there is simply not enough time to comprehend some topic, it is justified to take a stance established scientists has created with scientific method.

    How then distinguish a scientific blog? Well, avoiding trivial errors in math and statistics and basing argumentation in observations and logic is a good indication for a scientific attitude in blog.

77. gusbob Says:
    12 March 2008 at 12:55 AM

    The neutrino problem and its “resolution” is a very good illustration of just how some confuse hypothetical evidence with reality.

    • Ray Ladbury Says: As to neutrinos, why would there be neutrinos at all unless there were nuclear interactions going on? And the missing neutrinos have been accounted for in terms of neutrino oscillations.

    Nick Gotts Says: I thought that had been resolved through the discovery that neutrinos can change type (electron neutrino / muon neutrino / tau neutrino), and the detectors were only picking up the electron neutrinos. Or are you saying there are still some missing?

    • Barton Paul Levenson Says: We aren’t. Your information on this appears to be obsolete (1960s or so). Neutrinos appear to switch type with time and that accounts for the missing neutrinos.]]

    RL you must have missed the post where I said electrical hypotheses support fusion. They just suggest that it is not due to gravitational confinement by electromagnetic z-pinch. And to generate neutrinos here on earth don’t we use particle accelerators created by electromagnetic forces?

    Three of you interpret the neutrino problem as resolved. Let me present my interpretation of the SNO conclusion and then we can compare realities vs possibilities.

    First a snippet of SNO’s announcement in 2001(not 1960):

    http://www.sno.phy.queensu.ca/sno/first_results/

    “We now have high confidence that the discrepancy is not caused by problems with the models of the Sun but by changes in the neutrinos themselves as they travel from the core of the Sun to the earth,” says Dr. Art McDonald, SNO Project Director and Professor of Physics at Queen’s University in Kingston, Ontario. “Earlier measurements had been unable to provide definitive results showing that this transformation from solar electron neutrinos to other types occurs. The new results from SNO, combined with previous work, now reveal this transformation clearly, and show that the total number of electron neutrinos produced in the Sun are just as predicted by detailed solar models.”

    My interpretation:

    The Standard Solar Model states that the PP fusion in the sun will generate a specific type of neutrino, the electron neutrino. However only one third of that amount had been detected. Detectors were “seeing “ 1 every 3 days. Thus the SSM had a big observational hole in its theory. To the rescue comes SNO with “neutrino oscillation”. Although neutrinos were once thought to be mass-less and move at the speed of light, another theory had to be proposed that neutrinos can oscillate but this meant they must have mass and therefore also need to move slightly lower speeds. It’s hard enough to detect neutrinos never mind weigh them, but if you need to save your theory Occam’s razor says invent the ecliptic or equant or dark matter of oscillating neutrinos. But now SNO had results that revealed neutrino “transformation clearly” . They now measured all 3 types of neutrinos, the other 2 types were harder to detect. Thre only real evidence is that all three types added up to what the SSM predicted. Except SSM predicts electron neutrinos, not all 3 types. So the solution was that all three types can change into any other type. I must admit that having all three add up to the predicted value is an attractive coincidence.

    So I ask myself questions to make sure I understand as should any good critical thinker. “How could they tell they changed flavors?”. They certainly did not follow the neutrinos from the sun’s core all the way to the earth monitoring changes. So how do they “know”. Well they don’t know. They speculate because it fits their SSM theory.

    But more disturbing I then ask, “if these oscillating neutrinos can change back and forth, maybe the measured electron neutrinos are the result of transformed tau neutrinos or muon neutrinos.How do we know hich ones changed into which other one. So to be fair I’ll first assume they all can interchange equally. But then we are right back to having only 33% of the needed electrons.

    I even wondered how they knew that the one electron neutrino they detected about every 3 days is a solar neutrino? Why not from neutrinos proposed in the cosmic radiation background. Why not from the center of the earth or the atmosphere or left over from ancient supernovas? But you guys seem dang sure the accounting is done and solid proof. Maybe I don’t know what science is as RL gently suggested.

    So perhaps you could answer my questions so I too can feel so positive. Right now it seems like this proof is “turtles all the way down”

78. gusbob Says:
    12 March 2008 at 1:36 AM

    Kevin,

    I appreciate that you would be interested enough to investigate what I suggest. But any minority theory as well as any consensus theory has many adherents that are odd bedfellows. Your mention of the breath of Yaweah, etc has never been something I have discussed here. Others have used the association with fringe elements as a means of “scientific argument” to debase what I say. I know a man who was an astronomer, believer in the SSM and a convicted child molester. For me to offer that as evidence against the SSM would be totally absurd. I would hope we all can avoid such nonsense.

    You asked, “1) Why are we unable to detect any influx of electrons to the sun, either equatorially or at the poles? I will get the links when I can but there was at least one paper that told of electrons flowing back towards the sun after a maybe a flare. I forget all the specific. The source of the electrons wasn’t clear. But the migration of electrons towards the sun is in keeping with the electric sun’s model of a positive sun .

    2) Did the planets orbit Saturn in the past? That specific question I have not seen before, except as a discussion that if the solar system found itself in the middle of a strong plasma stream that exerted electromagnetic attractions or repulsions on the planets then could that re-arrange the current solar system’s orbital arrangement. I don’t know and it is low on my list to explore as there would be too many ifs. Is it as theoretically as possible as the big bang? Maybe.

    But one solar system question that I have entertained I will share for those of you that have ever put a telescope on the moon or seen pictures of the craters on other planets. yYou must be struck by the near perfect circularity of those craters. Literally sitting on a mountaintop peering through my dobsonian, I was struck with the question. The theory of meteorite formed craters implies to me that there should be a lot of craters more elliptic in shape. This being so because the causative space debris would most likely be captured and fall at an angle to the surface. To be so circular they would need to fall straight down. However if instead, electric arcing is attributed to these craters, that would make sense as arcs like lightning do strike at very perpendicular angles. And that suggest a lot of electric activity in the solar system’s past.

79. gusbob Says:
    12 March 2008 at 2:10 AM

    Martin Vermeer Says: Where do I begin? I picked this one as the most obviously absurd to refute. How do you explain the rotation of the galaxy by electrostatic forces? It has to be an attractive force to do the job. Dark matter gravitation is. Electrostatic forces are repulsive between like charges, so we must have a distribution of opposite charges to do the job.”

    Martin you can begin you should really begin with this youtube clip for a homopolar motor

    http://www.youtube.com/watch?v=3aPQqNt15-o

    then try http://www.electric-cosmos.org/galaxies.htm
    Martin Vermeer Says: “The smaller problem here is to find a distribution of positive and negative charges that would produce the observed change in rotational behaviour: you won’t”.
    Plasma labs and computer simulations would beg to differ. They can generate galaxy type behavior.
    Martin Vermeer Says: The bigger problem is that the net electrostatic charges won’t stay put: as they attract each other, they will flow together (as in electric current; plenty of conductive plasma out there) and will annihilate each other on a very short notice.”
    Martin I once held those same assumptions. Have you ever heard of the Van Allen belts? One is mostly positive ions, the other mostly electrons. Yes there is diffusion and leakage of charge but the charge is replenished via at least 2 mechanisms. And for another analogy perhaps think of the transistor. In plasma physics there is the double layer that separates to differentially charged plasma fields. This double layer sets up an electric field analogous to transistors where which prevents the further diffusion of charges. It is at the boundaries of double layers that high voltages can build. Here is a diagrammatic representation
    http://upload.wikimedia.org/wikipedia/en/thumb/0/07/Double_layer_formation.png/320px-Double_layer_formation.png
    and discussion
    http://en.wikipedia.org/wiki/Double_layer_%28plasma%29

80. gusbob Says:
    12 March 2008 at 2:28 AM

    Ralph Says: The solar wind is composed of subatomic particles. The solar magnetic field accelerates them as they move away from the Sun, because the magnetic forces are stronger than gravity on these particles.”

    Ralph I suggest that you may confuse a magnetic field with an electric field. A magnetic field according to Maxwell’s equations should lead these charged particles in a motion as seen in Coronal Loops or similar to iron filing, that leave one pole and reconvene at the other.Magnetic fields loop around with zero net flux.

    http://atmos.nmsu.edu/~nchanove/images/sun_coronal_loop.jpg

    But the solar winds leave the sun and keep accelerating out to the ends of the heliosphere. This suggests not a magnetic field but an electric field with one end anchored in the sun and the other at the heliosphere’s edge.

    And if you could be so kind, I would appreciate a few links to your sources on how well the electric fields have been measured. The explosive failed results of the space tether or “space elevator” experiments from the shuttle, suggests that your putative accurate measurements were woefully underestimated. And that was close to home. So I would suspect the error bars on galactic and intergalactic measurements would be even greater.

81. Knud Jahnke Says:
    12 March 2008 at 4:44 AM

    William @72:

    The Gies & Helsel paper is *not* independent evidence of Shaviv’s claim. On the contrary, they use ice age data to judge whether they can infer the spiral arm pattern speed, so this is the same as Shaviv, just starting at the other end. They explicitely state that current studies predict a much smaller difference in the arm pattern speed and the sun’s motion than Shaviv claims to have found.

    Knud

82. Ray Ladbury Says:
    12 March 2008 at 5:28 AM

    Gusbob, I worked on a neutrino oscillation experiment back in the 80s. I can assure you, that the measurements that established neutrino oscillations are solid. Several different experiments report consistent results.
    Your suggestion that some acceleration mechanism accounts for neutrino production is risible. It shows we can add accelerator physics to the list of processes of which you are ignorant.
    Those of us who have pointed out the errors in your arguments are certain precisely because we have “done the math”. I suggest you do the same.

83. Barton Paul Levenson Says:
    12 March 2008 at 7:30 AM

    gusbob writes:

    [[The theory of meteorite formed craters implies to me that there should be a lot of craters more elliptic in shape. This being so because the causative space debris would most likely be captured and fall at an angle to the surface. To be so circular they would need to fall straight down. ]]

    No. When something falls from space onto a planetary surface, at whatever angle, the speed at impact is so great that it blows up, and you get a circular crater pretty much every time. Even large bodies tend to get vaporized, and they simply do not have enough time to form noticeably elliptical craters.

84. Kevin Says:
    12 March 2008 at 8:28 AM

    I am in the odd (for me) and strangely exciting position to have carried out my own scientific experiment that bears on one of the topics brought up on this thread. Gusbob asserts that “The theory of meteorite formed craters implies to me that there should be a lot of craters more elliptic in shape. This being so because the causative space debris would most likely be captured and fall at an angle to the surface. To be so circular they would need to fall straight down.” He goes on to speculate that maybe these craters are caused by electric arcing rather than meteorites.

    Well, the summer between my 6th and 7th grade years, my family took a road trip in the Western US. One of the sites we visited was Meteor Crater (AKA the Barringer crater) in Arizona. This guy Daniel Barringer was the one to suggest it was formed by a meteor, and he mined the crater trying to find it, digging hundreds of feet straight down, never finding anything. The conventional wisdom now seems to be that the meteor mostly vaporized, but at the time, according to our tour guide at least, it was thought that perhaps the main mass was off-center, since (as gusbob notes) a non-perpendicular strike seems much more likely than a perpendicular strike. “But…,” I asked, “wouldn’t the crater be elliptical?” I was assured that impacts from any angle resulted in a circular crater. This was very counterintuitive to me. I thought is was B.S. So, for my 7th grade science project, I tested the theory. I made pans of fairly wet (but not soupy) modeling clay, and used a BB gun to fire into them from a variety of angles. It was a pump gun, i.e. the more pumps, the more compressed air propelling the projectile, so I also varied the impact speed by using different numbers of pumps. The result? Lo and behold, all the craters were circular. The ejecta patterns were asymmetric, but the holes were all circular.

    Now, I realize that modeling clay isn’t a perfect analogue for every different surface on which we observe impact craters. I also realize that BB guns aren’t perfect simulators of meteor strikes. But nonetheless I proved to myself that non-perpendicular impacts, even at low angles, could produce circular impact craters, and I failed to come up any way to create an elliptical impact crater. Go figure. It’s a little weird to me even today, but there you are.

    BTW I got first place at my school, and I think I did OK at the county level as well, but I don’t remember that part exactly.

    BTW gusbob, I completely see your point about guilt by association, and I apologize for playing that game.

85. Martin Vermeer Says:
    12 March 2008 at 9:31 AM

    gusbob: I looked at your links, and none of them appear relevant to your claim. Especially not the monopolar motor one (fun though). The others contain lots of hand waving, pretty pics, but no real (relevant) explanations. The galaxy’s rotation curve isn’t even mentioned. Yes, plasma physics is deeply involved with galactic jets and the like, no surprise there.

    I see another problem: the EM force you’re postulating should affect gas, dust and stars (and comets, and planet-like objects) orbiting in the galaxy in exactly the same way. Only gravitation does that. Within the solar system, celestial mechanics based on gravitation only is uncannily precise. Robert Dicke established the equivalence principle (on Earth) to within 1:10^8. That’s also how much smaller EM effects acting on the Earth should be than gravity.

    It just doesn’t work, and we have perfectly good theories that do. Give it up already.

86. Martin Vermeer Says:
    12 March 2008 at 9:42 AM

    Kevin #84:

    But nonetheless I proved to myself that non-perpendicular impacts, even at low angles, could produce circular impact craters, and I failed to come up any way to create an elliptical impact crater. Go figure. It’s a little weird to me even today, but there you are.

    I’m not sure how relevant your clay experiments are but for meteorite impacts, the simple reality is that the speed of impact is so great (at least 11 km/s, even up to 45 km/s for parabolic cometary objects hitting frontally), that they just vaporize explosively, with a lot of ground rock too. Barringer was like a small nuclear explosion, without the radiation.

    http://www.barringercrater.com/science/

87. Nick Gotts Says:
    12 March 2008 at 9:54 AM

    Re #78 [gusbob] On crater shape - when I read your post I recalled reading that angled impacts produce circular craters, although I don’t know why, and knew more knowledgeable people would respond, so didn’t post myself. However, human motivation and reasoning are within my professional purview, and in the interests of scientific understanding, I’d be grateful if you would tell me whether you thought either:

    a) That the entire planetary astronomy community had never noticed such a problem with the meteoritic theory of crater origins?

    or

    b) That they knew it was a problem, but pretended not to?

    or

    c) Something else? (Please specify)

    Whatever your answer, do you still hold to the same op