Ik Posted: Sat Nov 24, 2007 11:14 pm Post subject: Reply with quote - I did a netsearch for spectral analysis of comet Holmes and got a little info here: http://www.godlikeproductions.com/forum ... 54148/pg85 __GREY LENSMAN said: Quote: MAYBE HIGH COPPER CONTENT, SEEING THE GREEN SPECTRUM [I think he means the green halo around Holmes]. ONLY DIFFERENCE BETWEEN A COMET AND AN ASTEROID IS ITS ORBIT. COMETS ARE GENERALLY FAR MORE ECCENTRIC AND THUS BUILD A LARGE CHARGE DIFFERENTIAL. AT AN POSITION RELATIVE TO THE SUN, DEPENDING UPON RELATIVE CHARGE, IT "IGNITES, SAME AS A NEON TUBE IGNITES WHEN YOU RUN A LARGE CURRENT THROUGH IT AND IN THE SAME WAY, WHEN LIT, IT ONLY NEEDS A SMALL CURRENT TO MAINTAIN IT.
__FreeFlow replied: Quote: I don't think so GL, I saw another spectral analysis and it said C too, not Cu. Tho this was from an earlier date at a time when the outer gas cloud wasn't that pronounced, it had also detected CN = cyanide and some H-alpha and beta components. Unfortunately I can't recall the link at the moment ... Btw carbon is conductive too ...
__GREY LENSMAN replied: Quote: I DONT THINK SO. C2 IS AN UNSTABLE BOND, THE CHARGE DIFFERENCE WOULD RIP IT APART TO C. NEED TO LOOK UP SPECTRAL COLOUR OF PLASMA C. GL
__FreeFlow replied: Quote: "Relative to the Oct. 24 observation, the C2 emission near 516 nm is very evident. The gazes emission is clearly more extended then the dust coma." Same there .. Plasma would be interesting, guess it would have the same spectral absorpion line as C2.
__GREY LENSMAN replied: Quote: A LOT OF WORDS FROM ONES LACKING APPROVED TERMS OF REFERENCE QUOTE Quote: Scientific observations of the comet led to several discoveries. Most surprising to cometary scientists was the first discovery of X-ray emission from a comet, believed to have been caused by ionised solar wind particles interacting with neutral atoms in the coma of the comet." UNQUOTE SIMPLY - ELECTRIC CURRENT - BUT AS THEY CANT ADMIT THAT THEY REFER TO SOLAR WIND (ELECTRIC CURRENT) INTERACTING WITH PARTICLE. HOWEVER THE ELECTRIC CURRENT STRIPS THE PARTICLE IONISES THEM AND HENCE THE X-RAYS. THINK CRT TUBE, THINK KLYSTRON FOR GENERATING X-RAYS. GL
- That's very interesting. Has anyone here heard of other comets brightening in the same place as Holmes, around Perseus?
Posted: Sat Nov 24, 2007 11:33 pm Post subject: Reply with quote - Here's a spectrograph of comet Holmes: http://www.spaceweather.com/comets/holm ... Carlo1.jpg It shows CN, Hg, C2, Na, H-beta, H-alpha. I don't know if the analysts are certain that nothing else is there. It also might vary over time. - Also, someone here was asking about what triggered the brightening, or discharging, of Holmes. Wal Thornhill says the electric field of the solar system varies with distance, so, when a body moves from one distance away from the sun to another distance, the change in the field can trigger a discharge, if the change in voltage overpowers the charge sheath around the body. Perihelion, when the body is nearest the sun, often triggers comets, in which the tails and jets are discharges, because that's where the change in voltage is the greatest. - Jim McCanney says that the alignment of planets can also trigger discharges, including those of weather conditions on planets and moons. He says the magnetotails of each planet reaches nearly to the orbit of each succeeding planet and these tails are more strongly conducting than surrounding space. So, when planets are aligned, the field from the sun to the heliopause is somewhat shorted out and anything on that path will tend to discharge. He said Earth, Mars and perhaps other planets were aligned with Holmes at the time of its brightening. Meteor streams may act in the same way as shorts in a circuit and there is a meteor stream each mid-November, I think the Leonids.
StefanR
Re: Recovered: Holmes gets very bright
DustyDevil Posted: Mon Nov 26, 2007 6:56 pm Post subject: Reply with quote Chandra can now be added to the orbital assets that have studied comet Holmes and its outburst. No news release yet, but here are some links that I found, along with the names of the investigators, that we should be keeping an eye on for Chandra news:
That takes care of Hubble and Chandra. Does anyone know if there are any IR and UV telescopes that have been tasked to study Holmes?
Is the data ready yet?
StefanR
Re: Recovered: Holmes gets very bright
Stefanr Posted: Mon Nov 26, 2007 7:16 pm Post subject: rotation of comet nucleus Reply with quote Quote: It is shown that the sense of rotation determined in this fashion is consistent with the results established for three of the four comets from the transverse component of the nongravitational force affecting their orbital motions. It is found that in general the time lag is strongly time dependent and that lag angles approaching 90° are rather common near perihelion, suggesting a complex surface structure that involves an insulting crust of dust of variable thickness and strength. These results are compared with the observed lightcurves of the four comets and with the calculated distributions of integrated insolation at the nuclear surface as functions of the cometocentric latitude and time. Noticed is a tendency of the comets to turn their spin axes to the Sun near perihelion and to replace, on the outbound leg of orbit, the established fan-orientation pattern by a "late"-tail pattern indicative of old, slowly accelerated particles. It is suggested that the motion of P/Schwassmann-Wachmann 3, which is due for a favorable return in 1979, was affected by a secular deceleration in 1930. http://adsabs.harvard.edu/abs/1979Icar...37..420S Quote: Fan-shaped coma, orientation of rotation axis, and surface structure of a cometary nucleus. I - Test of a model on four comets
So many factors... Shocked , but maybe an electric factor is also influencing the spin or spin-axis of comets?
Posted: Mon Nov 26, 2007 7:30 pm Post subject: non-gravitational forces/mainstream Reply with quote Quote: non-gravitational forces : Forces that are not of gravitational origin which act on asteroids and comets and that can sometimes significantly alter their orbits. Examples include reaction forces due to outgassing of volatile materials and the Yarkovsky and Poynting–Robertson forces.
Poynting–Robertson effect: A deacceleration and spiraling inward of small dust particles orbiting the Sun due to their interaction with solar radiation.
Yarkovsky effect : Acceleration due to recoil force caused by the thermal reradiation from an irregular object. This can cause substantial changes to asteroidal orbits and also affect their rotational states.
Posted: Mon Nov 26, 2007 7:45 pm Post subject: rotation rate comets/asteroids Reply with quote Quote: Over the past 25 years the number of reliably determined rotation rates of asteroids has increased by an order of magnitude, from 157 in 1979 to 1686 in 2005. As the numbers have increased, various special classes and features have emerged. Asteroids larger than $sim 50 ,
m{km}$ diameter have a dispersion of spin rates that is well represented by a single Maxwellian distribution. Smaller asteroids have a more dispersed distribution, with both slow and fast spinning populations. We see a "spin rate barrier" in the size range of 1–10 km diameter that suggests that even rather small asteroids are "rubble piles". Among the very slow rotators are some (but not all) that are "tumbling" in non-principal axis rotation states. Among the smallest asteroids (less than a few hundred m diameter) are some that spin dramatically faster than the "spin barrier", indicating that they must have some tensile strength rather than consisting of loose regolith. In the last few years it has been recognized that the spins of asteroids smaller than a few tens of km diameter are affected by radiation pressure torques that tend to either speed up or slow down asteroid spin rates, thus providing an explanation for the dispersion of small asteroid spins, and also their non-random axis orientations. Lightcurves have also revealed the presence of binary asteroids among both Near-Earth and Main-Belt populations. Automated robotic observatories and next-generation survey instruments promise to increase the rate of production of asteroid lightcurves so that we may soon have tens of thousands of lightcurve results, extending down to even smaller sizes. In contrast, there are only about 20 rotation rates known for comets, and 15 for TNOs. Very little can be said from such meager statistics; the mean spin rate of TNOs appears to be comparable to that of asteroids, without extremes of fast or slow rotation; the mean spin rate of comets appears to be a bit slower than asteroids, perhaps due to lower mean density, and there may be an excess of slow rotators, probably due to gas jetting effects. The future is promising for studies of these objects as larger telescopes become available to do photometry to fainter magnitudes, so that comet nuclei can be studied at greater heliocentric distance with less coma interference, and more TNOs can be observed. http://journals.cambridge.org/productio ... tid=414822
Quote: Data on the rotational characteristics of more than 300 asteroids are currently available and it is now clear that the distribution of the rotation rates is non-random. A plot of rotation rate against asteroid diameter shows large dispersion but is distinctly V-shaped. The minimum of this curve at ca. 120 km may separate primordial asteroids from their collision products. There is also evidence that rotation rate depends on type classification, and weak evidence that it may also depend on family membership. Recent bias-free observations suggest that the marked rise of rotation rate with decreasing diameter D for those asteroids with D < 120 km cannot be completely accounted for by observational selection effects. A significantly large subset of the small asteroids have exceptionally long rotation periods suggestive of either a different nature and origin, or a peculiar history http://links.jstor.org/sici?sici=0080-4614(19841127)313%3A1~
Posted: Mon Nov 26, 2007 8:06 pm Post subject: DE's/solar wind/comets Reply with quote Quote: This work compares cometary and solar wind data with the purpose of determining the solar wind conditions associated with comet plasma tail disconnection events (DEs). We conclude that our results corroborate the idea that DEs are associated with sector boundary crossings and that the magnetic reconnection plays an important role in the formation of DEs and can be considered as the triggering mechanism (Niedner & Brandt 1978; Brandt et al. 1999). http://www.edpsciences.org/10.1051/aas:2000259
Posted: Tue Dec 04, 2007 2:14 am Post subject: jupiter juggles perihelion holmes Reply with quote Quote: Close approaches to planets: During the 20th century, this comet made two close approaches to Jupiter. There are also two close approaches to Jupiter during the 21st century. (From the orbital work of Kazuo Kinoshita and G. W. Kronk)
0.54 AU from Jupiter on 1908 December 9 increased perihelion distance from 2.12 AU to 2.34 AU increased orbital period from 6.86 to 7.33 years 1.03 AU from Jupiter during 1968 April decreased perihelion distance from 2.35 AU to 2.16 AU decreased orbital period from 7.35 to 7.05 years 1.50 AU from Jupiter during 2004 January decreased perihelion distance from 2.17 AU to 2.05 AU decreased orbital period from 7.07 to 6.88 years 0.85 AU from Jupiter on 2051 April 8 increased perihelion distance from 2.06 AU to 2.21 AU increased orbital period from 6.89 to 7.21 years
Nick C Posted: Tue Dec 04, 2007 5:26 pm Post subject: Reply with quote Stefan: Interesting information on Jupiters' influence on Holmes' orbit. That may explain something about which I have been wondering. On my computer I have a program, Celestron's The Sky, which is designed for use by amateur astronomers, to show the positions of various celestial objects. Well Holmes is shown to be in Andromeda (during the present flare up) when it is actually in next door Perseus. Perhaps the 2004 perturbation of Holmes by Jupiter accounts for this discrepency? Also, Holmes was discovered during it's first flare up in early November (1892) in the constellation of Andromeda. The present flare up occurred in late October in nearby Perseus. That would mean that the Earth, Sun, and Holmes were in similar positions (close but not exact) during each flare up. Curious, though I am inclined to think it is just coincidence(?) considering the distances involved.
Zaraida Posted: Tue Dec 04, 2007 9:40 pm Post subject: Comet Holmes' Position Reply with quote My astronomy software also shows Holmes in Andromeda and very close to Earth. I use Starry Night. Does anyone know why we are having this error in our software?
BiknewB Posted: Wed Dec 05, 2007 8:56 am Post subject: Re: Comet Holmes' Position
I suppose the software is not calculating the effect of giant Jupiter pulling on the tiny Holmes.
SeaSmith Posted: Thu Dec 06, 2007 1:51 am Post subject: Reply with quote ~ As per Biknewb:
Quote: Because of occasional close approaches to Jupiter, the orbit of Comet Holmes has been altered a few times. In fact the comet was considered "lost" for nearly 60 years before it was finally recovered with a large observatory telescope in 1964. http://www.space.com/spacewatch/071025- ... olmes.html
BiknewB Posted: Thu Dec 06, 2007 8:23 am Post subject:
Great, so it is not only the software for amateur astronomers, but even the software of the "real" astronomers that is unable to correctly calculate an orbit in these circumstances. Question Is this gravity driven clockwork model too complicated to keep track of a baked potato using state of the art mathematics? Wink
Stefanr Posted: Thu Dec 06, 2007 10:45 am Post subject: Comet's orbital determination Reply with quote Quote: Of course, apart from the gravitational attraction of the Sun, there are other factors that affect cometary dynamics. The main ones are:
- Planetary perturbations including close encounters with a planet - Mean Motion and secular Resonances - Non gravitational forces
Quote: Different procedures are used for the three common cases: the planets, the moon, and comets. The procedures are similar; the biggest differences are caused by two facts: comets have more eccentric orbits than planets, and comets sometimes get close to the sun or a planet (usually Jupiter). The eccentric orbits and the close approaches make computations more complicated.
Posted: Wed Jan 02, 2008 5:01 pm Post subject: tuttle/holmes Reply with quote
It was neat to compare tiny comet 8P/Tuttle with M33 and comet 17P/Holmes. This is a composite of two images taken with the same equipment Michael Borman, Evansville, Indiana, USA Dec. 30, 2007 http://spaceweather.com/comets/tuttle/3 ... orman1.jpg
Here are two images of two very different comets combined at the same scale to illustrate just how massive Comet Holmes now looks compared to another periodic comet, 8P/Tuttle, which is set to brighten as we pass into January 2008. Pete Lawrence, Selsey, West Sussex, UK Dec. 10, 2007 http://spaceweather.com/comets/tuttle/2 ... rence1.jpg
What a surprise it was to record a beautiful thin gas tail streaming from the comet on this evening. Our deep exposures of the pair show not only the fine details in the M33 Galaxy, but a huge cyan comets coma, sharp stellar nucleus, and a long thin plasma tail extending to the upper right. Chris Schur Dec. 30, 2007 Payson, Az http://spaceweather.com/submissions/lar ... 209022.jpg
StefanR
Re: Recovered: Holmes gets very bright
Biknewb Posted: Thu Jan 03, 2008 7:25 am Post subject: Re: Tuttle/Holmes... Reply with quote davesmith_au wrote: Last night I was looking through some of the pics that many amateur photographers/astronomers/space watchers have taken of Holmes, (funny how there's considerably more of these than of 'proffessional' astronomers) and I can't help but come up with the following question/answer.
Q. How can gravity explain a coma some 2 million miles across as observed around comet Holmes?
A. It can't. Cool
Cheers, Dave Smith.
This might be a nice case to calculate some numbers. I am no good with math, but I would calculate the gravity pull at the coma edge from both Holmes and the Sun. At the far and the near edge. See which way the particles should be moving.
Who is good with numbers?
Stefanr Posted: Thu Jan 03, 2008 4:04 pm Post subject: calculations? Reply with quote Indeed it would be nice to do some calculations, it seems only quite difficult because a lot more is happening than just gravity even in mainstream view.
COMETARY MAGNETOSPHERES: A TUTORIAL http://www2.ku.edu/~kuspace/aeronomy/comet-tutorial.pdf Magnetic field strength (color scale shown in figure) and field lines in the inner coma of comet Halley from a numerical global 3-dimensional MHD model. From Gombosi et al. (J. Geophys. Res., 1996); copyright 1996 American Geophysical Union
this coma is a gravitationally unbound atmosphere in free adiabatic expansion. Near the nucleus (≤102 km), it is in collisional equilibrium, at larger distances (≥104 km) it is in free molecular flow. Ultimately the coma components are swept into the comet's plasma and dust tails or simply dissipate into interplanetary space. Clues to the nature of the cometary nucleus are contained in the chemistry and physics of the coma, as well as with its variability with time, orbital position, and heliocentric distance. http://www.springerlink.com/index/knl1113157841245.pdf
it is difficult to estimate the gravitational force acting on the coma. There are some mathematical tools hidden in the pdf's above. But differences in dust composition, nucleus size, solar wind force, ion composition and more of such variables will probably make it just an 'educated' guess, I think. But it still astounds me to see the sudden jump in magnitude and diameter of Holmes+coma. diameter x earth magnitude till jan 2 Magnitude Data of Comets in order of Day of Perihelion 17P/Holmes (2007) http://www.aerith.net/comet/catalog/0017P/2007.html
StefanR
Re: Recovered: Holmes gets very bright
Kovil Posted: Sat Jan 05, 2008 5:54 am Post subject: Reply with quote Hmmm,
As I cross the synthetic carpet and then turn the light switch on, Zap !
As 17P Holmes crossed the solar current sheet from below to above, Zap !
Now there may have also been a flare current flowing backtowards the Sun at the time which is why Holmes litup before the Sun got more active, as the charts showed early on. Complex situation here, but the big idea herein was;
As Holmes moved thru the ISSM (inter solar system medium) it developed a 'charge' that it usually doesn't have, and that added to, or was responsible for Holmes dramatic brightening.
Could moving thru the ISSM generate a static charge? Did Voyager have any problems of this sort? Any other satellites have potential build ups that caused problems? Like all the failed missions to Mars, were electrical effects a cause of failure, as the probe approached Mars it suddenly discharged or equalized and burned out something? As todays T'bolts POD shows Mars has a lot of electrical activity, and as its atmosphere is almost nonexistent the electrical effects reach down to the surface unimpeeded, raising dust 40km and planet wide as a result of the double layer discharging space differentials when the potentials build up too high.
Quote: Additionally, spacecraft surfaces are exposed to space plasma environments that may create a surface electrostatic charge build-up. The charge build-up, if not controlled, may reach levels where discharges will occur that may damage spacecraft components or structure or may create deleterious electromagnetic interference of electronic components and circuitry, rendering a satellite system inoperative.
Quote: Electrostatic discharge protection may be measured in terms of surface resistivity, also known as surface resistance. Surface resistivity (.rho.) is the resistance of a material to the flow of electrical current over the surface of a material. Consequently, a low resistivity (106 to 108 Ohms/square) is preferred in order to prevent electrostatic charge from collecting or "building up" on a surface.
Quote: Therefore, it is highly desirable to have a thin coating with low thermophysical properties for heat control and low surface resistance for electrostatic discharge control. It is especially desirable for such a coating to be flexible and adhere to surfaces.
Quote: Currently, the preferred method for producing and applying a very thin (t<2000 Angstroms) coating on membrane or rigid structural surfaces is through sputtering deposition. Sputter deposition, or sputtering, refers to the process of bombarding a solid (referred to as the target) with high energy ions from a plasma
Quote: Types of Spacecraft Anomalies Spacecraft anomalies are grouped into broad categories based upon the effect upon the spacecraft. A list of potential effects follows:
Surface charging* Deep dielectric or bulk charging* Single Event Upset (SEU) * a) Galactic cosmic rays and b) Solar proton events* Spacecraft drag (<1000 km)* Total dose effects* Solar radio frequency interference and telemetry scintillation* Debris Spacecraft orientation* Photonics noise* Materials degradation Meteorite impact
Building Space Instruments in the Space Science Applications Laboratory http://www.aero.org/publications/crossl ... 01/02.html Quote: Surface-Charge Analysis To provide a complete picture of the in situ spacecraft environment, Aerospace also developed a surface-charge monitor with greater resolution and sensitivity than previous scientific instruments. The development effort was made possible in part through support from the National Aeronautics and Space Administration (NASA). Energy spectra from a surface-charge monitor showing a satellite surface-charging event.
So what might the accumulation of "dust" on the surface (by sputtering-proces?) have for an effect on the abillity of a comet to have a proper charge-exchange with it's environment?
StefanR
Re: Recovered: Holmes gets very bright
Biknewb Posted: Sat Jan 05, 2008 9:23 am Post subject: Re: static satellites Reply with quote StefanR wrote:
So what might the accumulation of "dust" on the surface (by sputtering-proces?) have for an effect on the abillity of a comet to have a proper charge-exchange with it's environment?
That's a good one StefanR Let me daydream about Holmes: The dust layer builds up, insulates the comet and for some time charge can hardly escape. A sudden change in the environment triggers the discharge, blowing off the dust layer. This could form a cycle. It depends upon the properties of the dust, I guess.
Quote: Surface resistivity is defined as the ratio of the dc voltage drop per unit length to the surface current per unit width for electric current flowing across a surface.1 In effect, the surface resistivity is the resistance between two opposite sides of a square. It is independent of the size of the square (as long as the size is much greater than the film thickness) or its dimensional units. Surface resistivity is expressed in ohms per square (Ω/sq) and is traditionally used to evaluate insulative materials for electrical applications.
Surface resistance is defined as the ratio of dc voltage to the current flowing between two electrodes of a specified configuration that contact the same side of a material. This measurement is also expressed in ohms.2 It is applicable to materials regardless of construction.
Influence of carbon black in polyethylene on space chargeaccumulation http://ieeexplore.ieee.org/Xplore/login ... 634557.pdf Quote: In several studies regarding space charge accumulation in peroxide crosslinked polyethylene (XLPE) it is identified that the products from the crosslinking process give rise to heterocharge accumulation in a DC-field. Several ways to reduce this accumulation have been proposed. We have studied polyethylene compounds containing 1 wt% carbon black of different types. It is found that compounds containing carbon black with very large surface area have somewhat lower accumulation of space charges in samples that are not degassed. One possibility may be increased adsorption of low molecular weight species formed at the crosslinking process. Measurements show that the addition of a low amount of carbon black gives higher resistivity but lower DC breakdown strength compared to unfilled XLPE
The electrostatic charging of spacecraft surfaces is the result of the spacecraft attempting to achieve a balance of currents to surfaces corresponding to an equilibrium state:
Ie+Ii+Ise+Ib+ Iph+IR=0
Here, Ie and Ii are currents of ambient electrons and ions, Ise and Ib are the secondary currents emitted by the surface as a result (secondary emission (SE), backscatter and ion-induced SE), Iph is the photoemission current and IR the bulk currents to the surface. These currents are obviously functions of the environment which is complex but can often be simplified for analysis to a Maxwellian or double-Maxwellian distribution. During geomagnetic substorms, hot plasma (10-30 keV) is introduced at geostationary orbit. The currents also depend on surface potentials and electric fields on and around the spacecraft and on the many material properties which are not always well-behaved. In the simple case where we only consider the ambient terms, Ie + Ii = 0 a surface floats at 2 to 3 times the electron temperature (in Volts). This results from the higher current of more mobile electrons, requiring a high negative surface charge to repel them. However, the modifying factors can be very important in space.
The important material properties are:
Dielectric thickness; Dielectric constant; Dielectric resistivity - this is not generally a constant in space but is illumination, temperature, radiation and field-dependent; Surface resistivity; Secondary electron emission yield as a function of incident electron or ion energy; Photoemission current (from solar illumination).
HIGH VOLUME & SURFACE RESISTIVITY ,INSULATION RESISTANCE http://www.electricinsulations.com/hvs.htm Quote: Insulating material are used to isolate the live electric parts i.e. which are at an elevated electric potential. Ideally, the insulating material should be totally non-conductive i.e. the resistivity should be infinity. However, materials employed in practice do carry a certain, usually very weak current (leakage current) when a direct voltage is applied. Thus the resistivity of electrical insulating material is finite, although of extremely high value. The higher is the resistivity of the material, the better is its quality.
The leakage current passing through the insulated portion at a stable process of conduction i.e. a sufficiently long time after a direct voltage is applied, is also constant and is known as residual current. The resistance R in of an insulation equals to the ratio of direct voltage V applied to this insulation to the residual current Im passing through the portion i.e. R in =V / I in Ohms.
The total current passing through the insulation may be considered as consisting of two components of current - one which flow through the volume of insulation Iv, and the other passing over the surface of insulation Is. Unlike conduction current in metals, this component currents through volume and surface, in case of insulating materials has special significance. Hence the resistance is looked upon differently corresponding to volume and surface leakage current. Resistance which is obtained by the ratio of applied voltage V to volume leakage current Iv is known as volume resistance and that due to surface leakage current Is is known as surface resistance. The volume and surface resistance as obtained are dependent on the electrode geometry and physical dimension of the insulating material under test. Hence to define the basic insulation properties, the following two quantities are used - (i) Volume Resistivity (ii) Surface resistivity.
Quote: Comet dust consists of organics (poorly characterized) + partially crystalline silicates + ... High O/C and H/C ratios for Halley's dust (Fomenkova '94,'99). Low O/C, H/C and high N/C ratios for 81P/Wild 2 (Kissel et al. '04). )Dust composition varies among comets but is rich in heteroatoms (O or N).
Interplanetary Dust Particles (IDPs) Quote: IDPs are collected in the stratosphere and some have cometary origin. They mainly consist of silicate grains coated by carbonaceous material. The carbon fraction in IDPs is amorphous carbon with different degrees of hydrogenation, i.e. a poorly graphitized carbon with aromatic size domains 1.6 nm, linked by aliphatic chains with CH2/CH3=2.8-5.5. The O and N contents, relative to C, in IDPs is low compared to organics made by ice UV or ion irradiation.
StefanR
Re: Recovered: Holmes gets very bright
Posted: Sat Jan 05, 2008 5:45 pm Post subject: adding circuit-element? Reply with quote resistors http://www.doctronics.co.uk/resistor.htm Quote: What do resistors do? Resistors limit current. In a typical application, a resistor is connected in series with an LED... Enough current flows to make the LED light up, but not so much that the LED is damaged..... In other circuits, resistors are used to direct current flow to particular parts of the circuit, or may be used to determine the voltage gain of an amplifier. Resistors are used with capacitors (Chapter 4) to introduce time delays.
World of Carbon http://invsee.asu.edu/nmodules/Carbonmo ... where.html Quote: Graphite :Natural: It is formed in high-grade metamorphic rocks as a final product of the carbonization of organic materials... Diamond: A rare form of hexagonal "diamond" known as Lonsdaleite is found in certain meteorites, such as those from Canyon Diablo, (USA). Buckminsterfullerenes: Natural: Minute quantities of the Buckminsterfullerenes, in the form of C60, C70, C76, and C84 molecules are produced in nature, hidden in soots and formed by lightning discharges in the atmosphere... Electrical Resistivity: The electrical resistivity measures the ability of a substance to conduct electricity. The resistivity of the various carbon allotropes span that between semiconducting to insulating. This behavior is a consequence of the bonding nature between the carbon atoms within the substance. Magnetic Susceptibility: The magnetic susceptibility measures how the electrons within the carbon interacts with one another. The diamagnetic (negative, repelled by a magnetic field) behavior indicates that the electrons within the carbon allotropes are paired, strongly indicative of covalent bonding.
Stefanr Posted: Sun Jan 06, 2008 7:18 am Post subject: carbon comet Reply with quote Observations of rotating jets of carbon monoxide http://66.102.9.104/search?q=cache:3Ggb ... d=35&gl=nl http://www.lesia.obspm.fr/~crovisier/bi ... _EMP.ps.gz. Quote: The maps show evidence for asymmetrical patterns, due tothe existence of CO jets. Analysis of the spectra and their velocity shifts shows thatthere is a spiral CO jet rotating in a plane almost perpendicular to the sky plane.This is the rst time that rotating jets are observed for parent molecules. We havedeveloped a 3-D model simulating rotating spiral jets of CO gas...... The velocity shift (the rstorder moment of the spectrum) is moving from positive to negativevelocities. This is indicative of a jet which direction is moving fromanti-Earthward to Earthward. The time evolution of the line velocityshift is plotted in Fig. 1.b. This curve is well tted by a sinusoid witha period equal to the nucleus rotation period ..... Since the comet rotation axis was close to the sky plane(Jorda et al., 1999), the small negative valuev0= 0:05 km s1thatis observed is indicative of a northern jet located slightly above the equator..... The real structure of the jet may be more complicated than assumed, especiallywithin the rst thousand of kilometres from the nucleus. The ques-tion of its physical origin remains open. Here, we observed that nearly half of the CO was released in a small opening angle. It is then hard to explain how a highly volatile molecule can expand is such a wayfrom a porous nucleus, as expected for comet Hale-Bopp.
Hale-Bopp Fails Emission Tests but Reveals Comet Origin http://www.solarviews.com/eng/halebppr.htm Quote: Thrill seekers may want to hitch a ride on the giant comet Hale-Bopp, but they would fail vehicle emission tests miserably. When it was the same distance from the Sun as Earth, Hale Bopp produced carbon monoxide (CO) emissions equal to that given off by 5.5 billion cars every day.
Carbon Monoxide in Comet 9P/Tempel 1 before and after the Deep Impact Encounter http://arxiv.org/abs/astro-ph/0607185 Quote: Following the impact we detected an increase in brightness, which if all due to CO corresponds to 1.5 x 10^31 molecules or a mass of 6.6 x 10^5 kg, an amount that would normally be produced by 7-10 hours of quiescent outgassing from the comet. This number is less than or equal to 10% of the number of water molecules excavated, and suggests that the volatile content of the material excavated by the impact did not differ significantly from the surface or near sub-surface material responsible for the quiescent outgassing of the comet.
Carbon suboxide in comet Halley? http://www.nature.com/nature/journal/v3 ... 316a0.html Quote: a puzzle about the nature and distribution of elemental carbon and carbonaceous material in its nucleus and coma. The nucleus is darker even than coal (albedo <4%)1, suggesting that its volatile ices contain a few per cent of carbonaceous material in the form of graphitic or amorphous carbon.The very high abundance of light elements in the coma dust2, 3, particularly H, C, N and O, suggests the presence of a significant organic component. The emission feature near 3.4 m also implies the presence of organic material in the dust 4–6. But the parent species for the primary carbon-containing material that have been identified so far (such as CO, CO2 and CH4) are not present in sufficient quantities to account for all of it. Here we propose that an additional contribution from carbon suboxide (C3O2) in the coma dust and the nucleus material is consistent with the observational data
Remnants of 1994 Comet Impact Leave Puzzle at Jupiter http://www.space.com/scienceastronomy/m ... 40823.html Quote: Jupiter's atmosphere still contains remnants of a comet impact from a decade ago, but scientists said last week they are puzzled by how two substances have spread into different locations..... The hydrogen cyanide has diffused some both north and south, mixed by wave activity, explained Michael Flasar of NASA's Goddard Space Flight Center. Jupiter's cloud bands carry material around the planet swiftly, but the bands do not mix easily. Not surprisingly, hydrogen cyanide is most abundant in a belt at the latitude where the comet was absorbed. At five degrees of latitude change in both directions, its presence drops off sharply. The highest concentration of carbon dioxide, however, has shifted away from the latitude of the impact. It is most prevalent poleward of 60 degrees south and decreases abruptly, toward the equator, north of 50 degrees south. Another smaller spike in its presence occurs at high northern latitudes, around 70 to 90 degrees north. Perhaps the two chemicals got distributed at different altitudes, and are being moved around by different currents, Flasar told SPACE.com. Or maybe the formation of the carbon dioxide was more complex than thought. He said it might have involved carbon monoxide first moving away from the impact area and then interacting with other substances at higher latitudes before being converted to carbon dioxide. "At high latitudes, precipitation of energetic oxygen ions probably occurs, associated with Jupiter's magnetically induced lights, known as aurora," Flasar explained. "These energetic ions could react with Jupiter's atmosphere to produce hydroxyl, which can oxidize carbon monoxide to produce carbon dioxide."
Diamonds tell tale of comet that killed off the cavemen http://observer.guardian.co.uk/world/st ... 58,00.html Quote: The theory is to be outlined at the American Geophysical Union meeting in Acapulco, Mexico. A group of US scientists that include West will report that they have found a layer of microscopic diamonds at 26 different sites in Europe, Canada and America. These are the remains of a giant carbon-rich comet that crashed in pieces on our planet 12,900 years ago, they say. The huge pressures and heat triggered by the fragments crashing to Earth turned the comet's carbon into diamond dust.
StefanR
Re: Recovered: Holmes gets very bright
Stefanr Posted: Sun Jan 06, 2008 8:04 am Post subject: electric carbon Reply with quote Electrical properties of Precambrian Tien Shan rocksand their thermophysical-chemical activity at highpressures and temperatures http://66.102.9.104/search?q=cache:-Hg0 ... cd=9&gl=nl Quote: The most important result of our analysis of the dis-tribution of the thermoactive rocks over the three zonesis the increased concentration of these rocks found inthe seismic zone itself, i.e., in the South Tien Shan re-gion. Among the 19 rocks studied, 9 samples exhibitthe electric resistivity anomalies, with 8 of them belong-ing to the region mentioned above. This suggests that higher seismicity is related to the petrophysical features of geomaterials.
Electrical conductivity and carbon in metamorphic rocks of the Yukon-Tanana Terrane, Alaska http://www.osti.gov/energycitations/pro ... _id=245147 Quote: The stringer is probably responsible for the anomalous conductivity change with pressure, making the sample the first for which anomalous electrical conductivity behavior can be attributed to carbon associated with a specific feature. The observations indicate that carbonaceous material may exert a primary control on crustal electrical conductivity because it may be present as interconnected arrays in grain boundaries or microfractures or in megascopic, throughgoing fractures.
The next link I sure do advise to read lot of material also relating to Tunguska but also relates to the carbon on comets, formation of fullerenes and lightning balls:
The case of carbonaceous catastrophes http://abob.libs.uga.edu/bobk/caseof.html Quote: Finding of probable Tunguska Cosmic Body material: isotopic anomalies of carbon and hydrogen in peat, published in Planetary and Space Science (vol. 47, 1999) attribute this to the punitive comet having a deuterium to hydrogen ratio more similar to Jupiter or Saturn. However V. A. Alekseev in: New aspects of the Tunguska meteorite problem attributes the depletion of deuterium observed by Kolesnikov to a surface interaction of a hypersonic deuterium plasma....... Holmes! Surely your not suggesting that the Tunguska event was due to a huge ball of lightning! No-no Watson not entirely but I think it likely that this poorly understood natural phenomenon played some role, perhaps a large one, on the morning of June 30, 1908. You have been doping your pipe Holmes! Ball lightning is just transient ionized gas and the weird sounding descriptions of its behavior are most likely due to persistence of vision--rather like being popped by a flash bulb. Ah Watson you speak so confidently and no doubt some observations are flawed but this phenomenon has a long history of observation. The problem is that ball lightning is neither frequent nor reproducible by artificial means so it has been virtually impossible to study closely. Unfortunately theories of the learned have on more than this occasion cast doubt upon observations made by those who are not considered peers, as the following excerpt points out.
One of the reasons that it appeared to be a rare event is shown in anecdotes like the following, which appeared in THE LIGHTNING BOOK by Peter Viemeister. During the summer of 1937 several technical observers on duty at 500 5th Ave, during the Empire State Building lightning program, saw what might be interpreted as ball lightning, not once but four times.
Experimentally, we have determined the ideal set of conditions for producing electric fireballs. They are: 1. Generate a lot of carbon or vaporized metal particles in a small region of space. 2. Create large electric fields in the same vicinity (on the order of 1 to 2 MV/m). 3. Rapidly elevate the temperature of the particles.
Our conclusion is that these fireballs are primarily RF in origin, and not nuclear phenomena. Consistent with Tesla's observations, they can be produced either by high current dump into hot air ["I am satisfied that the phenomenon of the fireball is produced by the sudden heating, to a high incandescence of a mass of air or other gas as the case may be, by the passage of a powerful discharge." CSN page 368] or by the presence of resistively heated material particles ["I attribute them (fire balls) to the presence of material in the air at that particular spot which is of such nature, that when heated, it increases the luminosity."
The prospect of initiating fusion by using pulsed power systems to create intense bursts of x-rays within a small reaction chamber has now emerged from research on a concept called the Z-pinch, which dates back to the beginnings of magnetic confinement fusion research in the 1950s. Theoretical efforts have focused on the energy estimate of the rain barrel observation. To maintain a fully-ionized, perhaps doubly-ionized mass of air requires either a large amount of energy concentrated in a small volume and shielded from the surrounding air by a remarkably stable envelope, or a continuous energy flow into a small volume, presumably by focusing power from the environment.
From 'Three Voyages' by Rene Laudonniere, translated by Charles E. Bennett (The University Presses of Florida, Gainsville, 1975 pp 88-90): http://abob.libs.uga.edu/bobk/iceoxy.html So things moved along, and the hate of Chief Satouriona against me continued. On August 29 there fell on the fort such a stroke of lightning that I think it more worthy of interest and of being recorded than any unusual thing that has yet come to pass, more strange than historians have ever written about. The fields were at that time all green and half covered with water, and yet the lightning in one instant consumed about 500 acres and burned with such a bright heat that all the birds which lived in the meadows were consumed.
Devastation caused by lightning was believed to be the result of sacred fire, sent by Heaven to stop dragon fights. "In the fifth month of the year yih-wei (probably 1295) on a place near the lake at I hing, all of a sudden there were two dragons which twisting around each other and fighting both fell into the lake, Their length had no sharp limits. In a short space of time a heavy wind came riding on the water, which reached a height of more than a chang (ten ch'ih or feet). Then there fell from the sky more than ten fire balls, having the size of houses of ten divisions.
Yes Watson. I think that at minimum, the possible high-energy involvement of these newly recognized, onion-like, molecular structures, cries out for experimental research. This is something that can be resolved in a suitable lab.
StefanR
Re: Recovered: Holmes gets very bright
Starbiter Posted: Tue Jan 08, 2008 5:34 pm Post subject: positive charge Reply with quote if a comet becomes negatively charged the farther it retreats from the sun, does it also become positively charged at close approach to the sun? when returning to deeper space would a reverse imbalance develope? i've read of comets exploding at maximum distance from the sun. michael steinbacher
Stefanr Posted: Tue Jan 08, 2008 10:40 pm Post subject: re:positive charge Reply with quote Quote: The most important feature of the positive column region of a glow discharge is that the plasma is quasi-neutral. That is, sampling will reveal equal numbers of positive ions and electrons. And that is what we find in the solar 'wind.' It merely forms the conducting plasma medium between the cathode region at the heliospheric boundary and the anode region near the Sun. So looking for excess relativistic electrons rushing toward the Sun is no more sensible than looking at a current-carrying wire and asking where are all the excess electrons rushing from one end of the wire to the other.
The next most important feature of the positive column region of a spherical glow discharge is that throughout most of its volume the plasma maintains a weak but constant radial electric field. That field is what accelerates protons from the Sun to produce the solar 'wind' and it assists the drift of electrons to the Sun. That field also creates a mystery for astrophysicists in their discovery of the small but constant radial deceleration of spacecraft that are moving in the solar plasma. The discovery of that deceleration was a striking confirmation of this glow discharge model of the Sun. See 'Mystery Solved.'
Having described the solar electrical environment we can go on to answer the question posed earlier: "How can a comet exhibit electrical effects?" A comet's tail arises from the interaction between the electric charge of the comet and the solar discharge plasma. The comet spends most of its time far from the Sun, where the plasma charge density and voltage with respect to the Sun is low. The comet moves slowly and it easily accumulates enough charge to balance the ambient voltage.
As the comet approaches the Sun, the nucleus moves at a furious speed through regions of increasing charge density and voltage. The comet's surface charge and internal polarization, developed in deep space, respond to the new environment by forming cathode jets and a visible plasma sheath, or coma. The strong electric field in the comet's plasma sheath generates x-rays. The cathode discharge hot spots characteristically jump about the nucleus, and the comet may shed and grow new tails. Or the comet may explode like an overstressed capacitor, breaking into separate fragments or simply giving up the ghost and disappearing. The 'non-gravitational' forces observed perturbing comet orbits are simply due to these electrical interactions.
None of these phenomena were expected from an inert object. The dirty ice ball model was never tenable and has been discredited. It has profound implications for theories of the origin of the solar system and cosmology.
Not all cometary behaving objects need to come so close to the sun to do what a comet can do, but the ones that do stay relatively a short time nearer the sun than they are further. And as an added factor a comet has difficulty in making the charge balance (thus behaving cometary) let alone make it reverse, i think.
Posted: Tue Jan 22, 2008 10:43 pm Post subject: comets and dusty plasma Reply with quote Maybe some background into dusty plasmas can give a better view on charging of dust particles. The next step is translating it to comets.
**** That was page 16 and the end of the thread that I was able to discover ***** **** So only page 9 and 12 and the most recent posts from 22 januari are missing ****
