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Meta Research Bulletin ©2007

The Great Comet Holmes Outburst of 2007

         Sources for this story: “Obscure comet brightens suddenly”, Joe Rao, http://space.com for 24 October 2007; “What happened to Comet Holmes?”, J. Kelly Beatty, http://www.skyandtelescope.com/news/11372856.html for 15 November 2007; “Dazzling comet outburst continues to mystify”, New Scientist. [Communicated first by Boris Starosta and Don Jewett.]

         Comet Holmes was discovered in 1892 by Edwin Holmes in London England. It is a Jupiter-family comet with a period a bit less than 7 years and a nucleus about 3 km in diameter. In mid-October this year, the comet was magnitude 17, visible only in fairly large telescopes. Then almost overnight, it shot up to magnitude three, easily visible to the naked eye as a faint, fuzzy “star” in the constellation Perseus. (See left photo on cover of this Bulletin issue.) The brightness change was a factor of about half a million. No tail was visible during the outburst, while the coma expanded at a rate of about half a kilometer per second. Zdenek Sekanina estimates that 100 million tons of dust ware released in this event – about 20% of what was ejected in the 1980 Mt. Saint Helens eruption. The comet had reached its perihelion outside the orbit of Mars in May 2007, and has been receding from the Sun since then. Although explosive outbursts by various comets have happened before (one of them a double outburst by Comet Holmes in 1892, leading to its discovery), this is the largest such outburst event for any known comet. The cause and energy source powering these outbursts remains unknown to mainstream astronomers. It is not even clear if the energy comes from within or outside the comet.

         It is very unlikely the comet was struck by an asteroid. For one thing, the 19° orbital inclination keeps it away from the main asteroid belt. The probability of collisions in space is very low, and three collisions would be needed to explain the three outbursts Comet Holmes has had. Another possibility is collision with satellites orbiting the nucleus, which was first proposed by Fred Whipple in 1984, not long after our article about comets having satellites first appeared in print. [“Do comets have satellites?”, T. Van Flandern, Icarus 47:480-486 (1981).] But the preferred mainstream explanation is repeated warmings by the Sun causing a dusty, ice-free "crust" to form on the nucleus, sealing the interior. Over time the pressure beneath this seal would steadily grow as ice became gas, eventually resulting in an explosion.

         One clue about why outbursts occur at some apparitions but not others was mentioned by Gary Kronk: “The comet's orbit was altered by Jupiter during December 1908 so that the perihelion distance increased from 2.12 AU to 2.34 AU. The comet was lost until 1964 and it remained faint during that apparition. An approach to Jupiter during April 1968 decreased the perihelion distance back to 2.16 AU, but no outbursts were observed at any apparition between 1972 and 2000. Another approach to Jupiter in January of 2004 decreased the perihelion distance to 2.05 AU, [followed by] an outburst at the very next apparition."

         In Meta Science, the EPH tells us that the nucleus is a rock covered by a thick dust regolith (material decayed from orbit) – a rock that is not active in any way that might cause jets or eruptions. It is surrounded by a debris cloud of dust and larger explosion fragments that we call “satellites”. In the mainstream’s dirty snowball model, the nucleus is the only mass available to produce such an event, which is why they are called "giant outbursts" and thought of as caused by internal processes.

         In the EPH's satellite model for comets, the large masses in orbit around the nucleus (also seen for Comet Shoemaker-Levy 9, where 21 large "fragments" impacted onto Jupiter) are abundant enough for tidal forces to occasionally bring one or two of them down. This can happen in the months or first few years immediately following a perihelion passage, when the Sun disturbs loosely bound comet satellite orbits. A perihelion passage that is at a new low for distance from the Sun (or a planet) is a time when this is especially prone to happening. And as we noted above, that was exactly what had happened to Comet Holmes not long before this outburst.

         Note that all the elements of this explanation were already in place in the EPH's satellite model for comets. Nothing new had to be added for this explanation. The only challenge-type objection raised to date is that satellites can’t travel at 0.5 km/s, the expansion speed of the dust cloud. However, impacts produce both craters and dust eruptions by exploding, not by excavation. And 0.5 km/s is a reasonable dust cloud expansion speed following a satellite impact explosion. Meanwhile, the mainstream’s dirty snowball model would be hard-pressed to specify any particular source for these "giant outbursts" without them sounding like comet volcanoes, which would be totally at odds with the primitive, low-density, icy nature of comets that model requires.

         For the interest of our readers, we include here an exchange on this subject that appeared on the Cambridge Conference Network (CCNet) (http://www.staff.livjm.ac.uk/spsbpeis/CCNet-homepage.htm) in November 2007, issues #177 through #181, operated by Benny Peiser.

TAKING THE MYSTERY OUT OF THE COMET HOLMES OUTBURST

Tom Van Flandern, Meta Research (tomvf@metaresearch.org)

Benny,

         Your reprinted article from the Baltimore Sun in CCNet 177/2007 of 1 November touts the recent Comet 17P/Holmes outburst as a “cosmic mystery”, and quotes Brian Marsden saying "This is really a remarkable event" and "I've never seen anything like it" and "We're at a loss" [to explain the explosiveness of the outburst]. However, it is a mystery only to those fixated on the “dirty snowball” comet model and who, for whatever reason, ignore viable competitive models.

         In particular, the satellite model for comets (originally published in “Do comets have satellites?”, Icarus 47, 480-486, 1981) proposes that comets and certain asteroids are basically identical objects with a common origin in the explosion of a major solar system body 3.2 million years ago. Large debris fragments hurled from the explosion each gravitationally capture other co-moving debris of all sizes right down to dust. This means all comets and asteroids start out rich in satellites. For comets, some of those are removed by collisions or by tidal processes, with many ending up as boulders on the surface accompanied by a thick dust regolith. For asteroids, the same is true, with the smaller dust particles and volatiles comprising the coma also removed by solar baking because of their long-term proximity to the Sun. Like asteroids, comets are basically rocks, not dirty snowballs.

         Evidence supporting this scenario has been published repeatedly, with the latest comprehensive review article out just a few months ago: “The challenge of the exploded planet hypothesis”, Int’l J.AstroBio. 6, 185-197 (2007). Those without access to the journal can find a preprint at http://metaresearch.org/publications/bulletin/2006issues/1215/Mrb06dp3.asp. The same model has also had an outstanding prediction success record, the latest being its predictions for the “Deep Impact” mission in 2005, which sent a probe into Comet Tempel 1. See “Deep Impact prediction”, CCNet 83/2005 - 29 June (2005).

         As for Comet Holmes, its outburst is probably greater than any previously seen, but not by so much as was implied. Comet Halley had a sudden 6-magnitude outburst at a distance of 2 billion km from the Sun in 1991. Comet 29P/Schwassmann-Wachmann 1 experiences one or more outbursts in brightness nearly every year, some of them as great as 7-8 magnitudes, despite a fairly circular orbit out near Jupiter’s distance from the Sun.

         Such major outburst events are a natural occurrence in the satellite model for comets because there is a large supply of candidate satellites vulnerable to tidal decay or gravitational disruption, especially in the months or years following a perihelion passage or close approach to a planet. And when these satellites impact the comet primary nucleus, there is a thick dust regolith available for ejection. Even the meter-size probe that impacted Comet Tempel 1 in the 2005 mission stirred up so much dust that it obscured the ability of the passing spacecraft to photograph the comet’s post-impact surface.

         Your CCNet article from the Baltimore Sun also mentioned that the late comet expert Fred Whipple once theorized that Comet Holmes might have had a satellite that crashed into it in 1892, causing that year's odd flare-up. But Brian Marsden dismisses that, saying “But even if he were right then, that satellite is long gone. And yet the same thing has happened again, and at the same, outbound leg of Holmes's orbit.” We can readily see that, in the satellite model for comets, no such limited supply of satellites is applicable.

         We even have a precedent for numerous kilometer-sized satellites from a single comet nucleus. Comet Shoemaker-Levy 9 “broke up” into 21 large "fragments" that impacted Jupiter in 1994. This was another mystery for the dirty snowball model because the tidal forces from Jupiter responsible for breaking up this multi-kilometer nucleus had roughly the strength of a puff of breath as needed to disperse a bit of cigar ash. But the satellite model gives us a more plausible picture. The “fragments” were independent satellites in orbit around the primary nucleus. Then when the comet first approached Jupiter closely, the satellites escaped into the comet’s orbit around Jupiter as the comet’s own gravitational sphere of influence shrunk in competition with Jupiter’s gravity. There was no nucleus break-up.

         Note that all the elements of these explanations from the satellite model for comets were already in place before being applied to any of these comets. Nothing new had to be added. Meanwhile, the dirty snowball model does not dare attempt a specific mechanism for these "giant outbursts". Any such mechanism operating on the primary nucleus would be the energy equivalent of a “comet volcano” and at odds with the primitive, low-density, snowball nature of comets required by that model.

METEORITES AS SAMPLES OF COMETS AND ASTEROIDS

Tom Van Flandern / Meta Research / tomvf@metaresearch.org

Benny,

         E.P. Grondine [epgrondine@yahoo.com] commented in CCNet 180 (#14) about the exploded planet hypothesis’s corollary that comets and asteroids are basically the same type of rocky bodies surrounded by orbiting debris. This was at the basis of the explanation I described in CCNet 178 for the Comet Holmes outburst.

EPG: the data do not seem to support Tom's hypothesis in any way...

TVF: I am sympathetic to the limitations imposed by the medical condition Grondine mentioned, but nonetheless urge that he read the citations I provided and grasp the quantity and quality of the evidence available before taking pot shots at the idea. The main reference I provided was “The challenge of the exploded planet hypothesis”, Int’l J.AstroBio. 6, 185-197 (2007); also at http://metaresearch.org/publications/bulletin/2006issues/1215/Mrb06dp3.asp. This article contains many additional citations on the subject, with over 100 lines of supporting evidence, including discussions of the same points Grondine mentions.

EPG: The comet samples [in meteorites] are very very different from the asteroid samples.

TVF: But this merely reflects very different source bodies with widely differing masses. Most asteroids sample crust and upper mantle from the explosion of terrestrial-sized parent bodies, where everything below about 40 km depth is vaporized when suddenly depressurized by an explosion. The remainder of the asteroid population and all current comets sample the interior from the explosion of Ceres-to-Moon-sized parent bodies. Present evidence suggests six planet explosions over the solar system’s 4.6-billion-year history, and an unknown number of smaller explosions, the most recent being at 3.2 million years ago.

EPG: The carbonaceous meteorites are known to have cometary sources, and besides carbon compounds these also contain calcium and aluminum...

TVF: In fact, direct samples of Comet Wild 2 from the Stardust sample-return mission showed the presence of these plus magnesium, olivine, and titanium -- high-formation-temperature minerals usually associated with volcanic outputs from deep inside planets. The mainstream is still struggling to come up with a credible explanation from this major surprise. Yet there is no mystery here if comets sample a Moon-sized parent body.

EPG: the spheres of the chondritic meteorites most likely reflect events occurring during the first condensation of our solar system...

TVF: That dating is *assumed* by the standard model. The only direct evidence we have of the ages of these bodies is their cosmic ray exposure ages, which are measured in millions, not billions, of years.

EPG: the iron and stone meteorites appear to most likely reflect the later break up of one or more large proto-planetary bodies.

TVF: Powerful evidence has now converged on the conclusion that there was nothing “proto” about the parent bodies. Even the oldest explosion event, the one responsible for the “late heavy bombardment”, occurred 700 million years after planet formation was complete.

EPG: there are asteroids which are carbonaceous, but these appear to simply be dead comets which have been captured in the inner solar system.

TVF: In the EPH, all asteroids are “dead comets”, meaning their volatiles have been baked away. There is still no known unique distinguishing feature between asteroids and comets. The more we have learned in this space age, the more the identities of these two classes of bodies have tended to merge. The last few close-up spacecraft images of comets and asteroids are visually indistinguishable. This is just as the exploded planet hypothesis first suggested in “A former asteroidal planet as the origin of comets” in Icarus 36:51-74 (1978), at a time when asteroids and comets still seemed to have little in common.

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