It was discovered that extraterrestrial magnetic spherules larger than 10 μm in diameter contain internal cavities. The possible origin of cavities is discussed. It is suggested that the primary particles contain ferrous carbonate or ferric hydroxide that upon heating during entry of micrometeorite releases carbon dioxide or water vapor that produces cavity in the molten spherule. The chemical composition of magnetic spherules is similar to that of the crust of the Earth

Kras, G. A.

Rosinski, Jan

English

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DOI 10.1393/ncc/i2005-10029-1IL NUOVO CIMENTO Vol. 28 C, N. 1 Gennaio-Febbraio 2005On the origin of cavities in extraterrestrial magnetic spherules(∗)J. Rosinski(∗∗) and G. A. KrasDipartimento di Fisica, Universita` di Ferrara – Via Paradiso 12, 44100 Ferrara, Italy(ricevuto il 2 Maggio 2005; approvato il 24 Giugno 2005)This contribution is dedicated to thememory of the late Clarence T. NagamotoSummary. — It was discovered that extraterrestrial magnetic spherules largerthan 10 µm in diameter contain internal cavities. The possible origin of cavities isdiscussed. It is suggested that the primary particles contain ferrous carbonate orferric hydroxide that upon heating during entry of micrometeorite releases carbondioxide or water vapor that produces cavity in the molten spherule. The chemicalcomposition of magnetic spherules is similar to that of the crust of the Earth.PACS 96.50.Dj – Interplanetary gas and dust (including gegenschein and zodiacallight).Sampling of aerosol particles in the southern hemisphere during October and Novem-ber of 1967 and in 1969 revealed the presence of extraterrestrial particles [1-7]. Theseparticles, called spherules, were magnetic, mostly round and were associated with whatwas thought to be an unknown meteor stream.Under that hypothesis these particles, during entry into the atmosphere, at about80 km altitude above the Earth, would be heated, through collisions with atoms andmolecules present at this altitude, to the temperature at the melting points of the chemi-cal compounds they were made of. The particles would, upon entry into the atmosphere,become molten spheres that would subsequently cool down to the temperature of theenvironment [8, 9].Particles between 2 µm and 5 µm in diameter were solid spherules. X-ray photographsof the spherules larger than about 10 µm in diameter (fig. 1, from [6]) have shown thepresence of internal cavities. The first X-ray photograph of an extraterrestrial particle(spherule) with an internal cavity was made by F. Prodi in 1968. The largest hollowspherule that was found was 25 µm in diameter with a skin thickness of 1 µm. The(∗) The authors of this paper have agreed to not receive the proofs for correction.(∗∗) E-mail: janros@earthlink.netc© Societa` Italiana di Fisica 5556 J. ROSINSKI and G. A. KRASFig. 1. – Scanning electron microscope photographs of five magnetic spherules and one spherulefragment. Diameters range from 15 to 20 µm. The photograph of the fragment shows thatlarger spherules may contain cavities.particles were analyzed by means of a scanning electron microscope and an ion probemicroanalyzer. The chemical analysis of the solid part of magnetic spherules has shownthat they consisted of a mixture of iron oxides with traces of: Na, Mg, Al, Si, P, S, K,Ca, Ti, Cr, Mn, and Ni. Chemical analysis of interiors of magnetic spherules revealedthe presence of methane, ethane, carbon dioxide, water vapor and in some, nitrogenand oxygen only. The outer layer of the spherules consisted of FeO 1.3 and the layerbelow was FeO 1.1. The melting point of FeO is 1420 ◦C, and Fe2O3 is 1560 ◦C. TheseON THE ORIGIN OF CAVITIES IN EXTRATERRESTRIAL MAGNETIC SPHERULES 57molten spherules must have, therefore, probably been at temperatures higher than thetemperatures of their melting points at some time in their lifetimes. When a spherulewas molten, there was mixing of oxides in the outer layer, evaporation and dissociation ofoxides (oxygen leaving the surface) and later, mixing of the still molten interior with thesub-surface of the shell. The whole process probably took place in less than one second(0.1 to 0.3 s [9]).If one takes a molten metal or molten iron oxide and pours it into some colder sub-stance (e.g., water), it will solidify into solid globules, i.e. they would not producecavities. In 1939, the first author of the present paper was preparing chemically purecopper sulfate. To speed up the dissolution of copper in hot, concentrated sulfuric acid,he was melting copper in a crucible and adding sulfur to the molten metal. This causedthe boiling of the crucible contents and the copper began to boil. The copper was thenpoured into a diluted solution of sulfuric acid. The solidified product consisted of largecopper bubbles, some of which were 2 cm in diameter, with a skin thickness of about100 µm. In an analogous way, some gas or vapor, therefore, must have been present inthe extraterrestrial particles to produce cavities.The chemical compound that should be considered in production of cavities containingcarbon dioxide is ferrous carbonate. It decomposes upon heating and releases carbondioxide. When carbon dioxide leaves that compound it releases ferrous oxide, FeO. Thevolume of 22 µm diameter spherule (diameter of the cavity is 20 µm) is about 4000 (µm)3.The volume of the released gas is a thousand times more. Most of the carbon dioxide willbe released from the surface into the atmosphere upon heating of the entering particle.A cavity will be formed when the interior of the entering particle is still hot (maybe evenmolten) and the surface of the particle is still liquid. A candidate for the productionof a cavity containing water vapor is ferric hydroxide, Fe (OH)3. This compound, uponheating, releases 1.5 molecules of water per molecule of hydroxide, and leaves Fe2O3(ferric oxide).Ferric oxide was never found in the spherules. There was always less oxygen in thosemixtures of oxides. Oxygen was lost when the particle was molten at a high temperatureat an altitude between 80 and 70 km. What was left, therefore, was a mixture of ironoxides, as has been shown by chemical analysis. When the surface of a molten particlesolidifies, water molecules are still released from Fe(OH)3 present in a still molten interiorof a particle, and a cavity is formed. Particles made of ferrous oxide, when heated to theboiling point produced a bubble of FeO vapor. This vapor condensed on the interior ofthe cavity and produced a spherule with a vacuum inside.Such may be the mechanism of formation of spherules with internal cavities. If thisis the case, then ferric hydroxite or ferrous carbonate must exist in the primary particlesin the meteor stream, which produces magnetic spherules. As an example, we can take a22 micrometer diameter spherule with a cavity of 20 micrometer diameter. The volumeof the cavity is 4 × 103 (µm)3, and the volume of water vapor available from the wholeparticle is 6.3 × 106 (µm)3, at STP; more than enough to form the cavity. Most ofthe water vapor released from Fe(OH)3 is left at high altitudes during the entry of themicrometeorites into the atmosphere.Rosinski et al. [4] found carbon dioxide, water vapor and methane, in three spherules.These chemical compounds indicate that those particular particles contained some or-ganic compounds that, during the heating and formation of spherules, were decomposed.Carbon was oxidized to carbon dioxide, hydrogen was released from water vapor andproduced some methane with carbon. Water vapor was released from ferric hydroxide.All these chemical reactions took place in a fraction of a second, and those reactions,58 J. ROSINSKI and G. A. KRAStherefore, could not reach chemical equilibrium.Discovery of a meteor stream that contains magnetic particles consisting of spheruleswith cavities was made at ground level in the southern hemisphere. Attempts to observethese meteoritic particles entering the Earth’s atmosphere in subsequent years failed andtherefore those particles must enter our atmosphere at very low velocities. They arenot heated probably to the melting point because they are not visible and therefore themechanism of formation of cavities in those spherules must be different than describedearlier.Kerrigan [10] suggested that those spherules might be premade (in some other event)and that they enter the atmosphere already formed. If that is the case, then authorssuggest that 65 million years ago, when a collision took place between an asteroid andthe Earth in the Yucatan Peninsula, vapors (because material of the asteroid and the soilwith which it collided were vaporized) were thrown into an orbit which should be verysimilar to that of the Earth [11-13]. It is also possible that some undocumented collisionstook place at some later times. These recondensed into particles, and it may be thatthose particles which ended up as magnetic spherules were formed during this process.This cloud which was vapor of the Earth’s material and of the asteroid, recondensedand formed particles which were not spherical particles with cavities but were slightlymagnetic particles which were thrown into an orbit similar to the Earth’s orbit. Theseparticles are floating in the orbit around the Sun.Microscopic particles are attracted by the Sun. Some are attracted and some arerepulsed. In any case, they almost certainly were removed from the Earth’s orbit in 65million years. This may be the origin of the magnetic particles, which were collected. Wecollected magnetic spherules with cavities plus large numbers of some particles, whichwere maybe coagulation products of vapors. The coagulation products, called Rosinskisecondary particles (Rosinski and Snow, 1961) are left at high altitudes. The source ofmagnetic spherules and slightly magnetic particles, which we discovered, is still a mystery.The authors are now making the suggestion that material ejected into orbit after thecollision of an asteroid with the Earth is the source of magnetic particles collected in thesouthern hemisphere. The orbit would be that of the Earth, plus a displacement by thejet which ejected these materials into space.The suggestion that methane could be formed in the spherule is difficult to accept,because the atmosphere in a spherule is oxidizing, that is, FeOx and would preventthe formation of methane, because hydrogen and carbon would be oxidized to carbondioxide and water. This would support this hypothesis, and what we analyzed might bethe atmosphere present on Earth 65 million years ago. At the time of this collision withthe asteroid, the Earth was covered with vegetation.This is all that can be done at this time because further study would require sam-pling. The samples originally collected were destroyed in an accident at the Max PlanckInstitute in Germany (about 1980) and the only way to look further is to start samplingagain (in the southern hemisphere in October for about one hundred days and then alsoin April in the northern hemisphere, perhaps in Alaska).Very remote possibilities exist that the presence of methane discovered in cavities ofthree spherules indicate the existence of extraterrestrial life in the solar system.∗ ∗ ∗We would like to acknowledge the help of Ms. P. Warfel, NCAR, Boulder, Coloradoin preparing this manuscript.ON THE ORIGIN OF CAVITIES IN EXTRATERRESTRIAL MAGNETIC SPHERULES 59REFERENCES[1] Rosinski J., J. Atmos. Terr. Phys., 32 (1970) 805.[2] Rosinski J., J. Atmos. Terr. Phys., 34 (1972) 487.[3] Rosinski J., Nagamoto C. T. and Kerrigan T. C., J. Atmos. Terr. Phys., 35 (1973)95.[4] Rosinski J. Nagamoto C. T. and Bayard M., J. Atmos. Terr. Phys., 37 (1975) 1231.[5] Rosinski J., Nuovo Cimento C, 19 (1996) 417.[6] Rosinski J. and Kerrigan T. C., Nuovo Cimento C, 24 (2001) 815.[7] Kerrigan T. C. and Rosinski J., Nuovo Cimento C, 25 (2002) 57.[8] O¨pik E. J., Physics of Meteor Flight in the Atmosphere (Interscience, New York, NY)1958.[9] Kornblum J. J., J. Geophys. Res., 74 (1969) 1893.[10] Kerrigan T. C., (2001) personal communcation.[11] Alvarez W., EOS, 67 (1986) 649.[12] Roddy D. J., Schuster S. H., Rosenblatt M., Grant L. B., Hassig P. J. andKreyenhagen K. N., Int. J. Impact Eng., 5 (1987) 525.[13] Melosh H. J., Impact Cratering (Oxford University Press, New York, NY) 1989.

On the origin of cavities in extraterrestrial magnetic spherules

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On the origin of cavities in extraterrestrial magnetic spherules

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