The strange object was discovered on January 6 by the Lincoln Near-Earth Asteroid Research (LINEAR) sky survey. The object appears to be in an orbit inside the main asteroid belt — not a place where comets usually dwell.
The distinction? Comets swoop along elliptical orbits close in to the sun and grow long gaseous and dusty tails as ices sublimate off their solid nucleus and release dust. But asteroids are mostly in more circular orbits and are not normally expected to be as volatile as comets.
The mystery object is both an asteroid and a comet. A comet is an electrically active (discharging) asteroid. An asteroid is a comet without a sufficient charge differential to be electrically active. Otherwise, both are rocky /metallic in various proportions, relatively small bodies in our solar system. Some comets have short periods, some have long periods, and some seem to have no period because their hyperbolic orbits imply that they depart the solar system after rounding the Sun (or disappearing into it).
The elongated elliptical orbit with high eccentricity used to be a calling card of comets, but the presence of comets orbiting "nicely" in the main asteroid belt make the orbital shape no longer such a great distinction, and of course some perfectly normal asteroids have Earth-crossing orbits that definitely puts them out of the more circular main belt orbitals outside Mars. Of more interest might be the question, "why does this or that otherwise "normal" asteroid occasionally light up like a comet when its neighbors apparently do not?" Coma and jets and tails aside, The EU interpretation is that there appears to otherwise be no difference between a cometary body and an asteroid body, short of the electrical condition.
I used to believe that to be a comet, the body had to traverse a great voltage differential in order to "light up" - such as from the theorized Oort Cloud or deep in the Kuiper Belt and in toward the Sun, but seeing reports that main belt orbiting bodies occasionally also light up makes me wonder what the cause is, in those cases.
And collisions? Still exceedingly rare, or so gentle as to avoid observation, in most cases. Popular among astronomers and copy writers, but apart from small bodies (bolides, asteroids, occasional comets, dust grains and the like) impacting MUCH large bodies (planets, larger moons, Stars), collisions in space are really rare. At the smaller scales, things are just large distances apart, and in plasma motion they may be following fairly collimated paths, for the most part. At larger scales, fairly stable orbital conditions generally have been established, and big things do not go bump in the night, as a very general rule. Never say that they can't or won't collide - that's hubris and leads to Black Swan events - but I could list the number of verified stellar and planetary and moon collisions on the back of a napkin without anything to write with. Death spirals of binary neutron stars? >snork>! Colliding galaxies? Look good in simulations. I don't think that verified proof that any two suspected galaxy "collisions" exists simply because our distance estimating procedures are now so suspect that we hardly know where things are, any more, once they are out of Hipparcos's parallax reach (which is well inside our neighborhood of our galaxy only). Other than educated guesses, I think we do not actually know how far we are from our galaxy's center. Guesses can be dead on, and they can be wildly off, when it comes to galaxies.
So, comets = asteroids + electromagnetic phenomena, and they don't whack together and explode. As a rule.
mharratsc
Re: Another main belt comet
Is it suspected that Earth's plasma-tail flows through the asteroid belt? If so- wouldn't it be possible that some of the asteroids that are in the right place at the wrong time could pick up a differential with respect to the relative charge of the rest of the rocks when it mechanically punched through the DL?
If so- it might maintain that differential charge until it came into proximity with one or more of the other asteroids, or possibly it could go arc in the solar wind under the right conditions, exhibiting cometary phenomena as has been occasionally witnessed?
It seems to me that could be a possible explanation for a larger rock in the belt with a fairly standard orbit to exhibit these uncharacteristic, cometary discharge effects. o.O
solrey
Re: Another main belt comet
Thanks Mike for reminding me of something. Being into "backyard" astronomy I know that Mars is approaching "opposition", but even more relevant is the alignment that happened around the 2010-01-03. Unfortunately this thing is just mag. 20 and I can only get to 13.5 otherwise I'd check it out for myself.
Position of planets on 2010-01-03. P/2010 A2 was probably lined up too. Earth is the little blue sliver above Mercury (the green circle). It's kind of hidden in this diagram, sorry. Venus is in the lineup too, on the other side of the Sun. Mars just missed being in alignment.
These two diagrams have different viewing perspectives so keep that in mind. 2010-01-18 inner planets + P/2010 A2 It looks like it could have been in that lineup on the 3rd, it's orbit would be slower so maybe off line towards Mars a bit. The P/2010 A2 is near perihelion as well. A "perfect storm" for certain charged bodies waiting for a trigger I would think. Apparently there is another asteroid pacing the "comatoid"...hmm, could it be a binary pair, they just haven't tracked the orbit long enough to get that precise perhaps? There are a few binary asteroids actually. A bicomatoid?
mharratsc
Re: Another main belt comet
"Bicomatoid" sounds like something you take for an upset stomach and gas, Sol...
Siggy_G
Strange comet
I recently viewed the SOHO Movie Theater (NASA) and saw a comet that decelerates and disappears.
It's not just accidental noise - it is a spot that clearly decelerates outwards. It came up the last days, so follow up on this. This is best seen in 1024 and with fast play back. From watching both C3 and C2 captures closely, it appears like an object that comes diagonally behind the Sun, slightly towards us. Second strange thing is that it has no tail. It is just a bright point. Third strange thing it decelerates (till it stops), or it is in an ellipse arc, and then NASA caps the 5 next hours away, and it's gone. If it was a comet, one should expect to see it continue somewhere along its extrapolated orbital path...
Lulin's green color comes from the gases that make up its Jupiter-sized atmosphere. Jets spewing from the comet's nucleus contain cyanogen (CN: a poisonous gas found in many comets) and diatomic carbon (C comets) and diatomic carbon (C 2). Both substances glow green when illuminated by sunlight in the near- vacuum of space.
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Any other explanation for the green light?
MrAmsterdam
Re: green comet explanation
" Both substances glow green when illuminated by sunlight in the near- vacuum of space."
read; illuminated by sunlight = radiated by the sunlight. -> lowdensity carbon dust cloud radiated by EM sunlight = plasma
I don't think the properties of the medium are correctly described. Is this a correct assumption?
solrey
Re: green comet explanation
Right. The icy dirtball/dirty iceball hypothesis requires ionization by UV radiation for cyanogen and diatomic carbon to emit electromagnetic radiation.
The chemistry supports the electric comet theory. Cyanogen (C2N2) and diatomic carbon (C2) are not stable molecules.
C2 occurs when in an electric arc (along with some buckyballs), in comets, and in the blue light we see in flames.
I believe Cyanogen reduces to cyanide quite rapidly. Should they even be present and stable on an icy dirtball? Both molecules were detected emitting electromagnetic radiation on comet Lulin. Other CHON groups were also detected including acetylene (C2H2) and molecular nitrogen (N2). As it happens, both cyanogen and diatomic carbon are produced when acetylene and nitrogen react in an electric arc. If oxygen liberated from the surface rock is available, water will also be created.
Something like:
2 C2H2 + N2 + O2 + 2 e+ ---> C2N2+ + 2 H2O + C2+
I think if cyanogen and diatomic carbon concentrations are relative to acetylene concentrations on comets that would be one point of proof for the electric comet theory.
cheers
jjohnson
Re: green comet explanation
Our own auroras radiate in the green due to ionization of nitrogen and nitrogen compounds in our own atmosphere. It seems plausible that the coma of this electric comet is green for similar reasons.
Sunlight, unless it is strong enough to exceed nitrogen's ionization potential of about 14.5 eV, may reflect from or diffuse through the compounds mentioned above, but it won't cause radiation from excited electrons' falling back to a lower state around a nitrogen atom or molecule and radiating a characteristic green photon in the process. The comet, pressing sunward through the outgoing solar wind, on the other hand, may find itself in severely stressed electrical conditions which can exceed the ionization potential of a number of different elements and compounds.
I do not know if there are "dark lines" or absorption bands through the gases in a coma which would create a greenish cast to transmitted or reflected sunlight, as if it were a gassy green "filter".
Jim
nick c
Re: green comet explanation
MrAmsterdam wrote: Lulin's green color comes from the gases that make up its Jupiter-sized atmosphere. Jets spewing from the comet's nucleus contain cyanogen (CN: a poisonous gas found in many comets) and diatomic carbon (C comets) and diatomic carbon (C 2). Both substances glow green when illuminated by sunlight in the near- vacuum of space.
The green glow is not caused by the illumination from sunlight but rather an electric current emanating from the sun. It makes sense that the tenuous plasma in glow mode, of the comet's coma, would be of a color dependent upon the chemical composition. A similar process to that in a neon light.
Nick
allynh
Re: Recovered: Holmes gets very bright
In October of 2007 I was out for my evening walk, and in the west the sun was filling the sky with that gold glow we get here in Santa Fe (because we are at 7,000 foot elevation). In that gold glow was a bright pearl that didn't make sense. I kept watching it as I walked, trying to figure out what it was.
It is common for high altitude research balloons to fly overhead. They shine like small teardrop pearls and are usually visible in the evening or dawn when the sun hits them while the sky is still dark. This was not a small teardrop pearl, this was a big pearl, fuzzy, not sharp like the balloons; and it was clearly visible in the gold glow of the evening sky.
I checked the local news and there was no comment. That is important to remember because the news always talks about the research balloons, since they get so many calls reporting them and asking for information. There was nothing on the news and I was not aware of the Thunderbolts site at the time. I only knew what was going on when I read through all the TPODs and read about Comet Holmes, six months later.
This is a recovered thread discussing the event. Some of the links are broken, but there is enough to make clear what happened. Bookmark the thread and come back to it at least once a year. This event screams EU, and everybody should be familiar with the discussion and links.
The important thing to remember, is that the orbit of Holmes is between Mars and Jupiter, and did not come anywhere near the Sun.
If anybody comes across current information, please keep the thread up to date.
Thanks...
fosborn
ESA Rosetta Stone 2014
Concerning the ESA Rosetta Stone mission in 2014, when its Philae lander touches down on the the comet surface.
Could it have the same effect as the Deep Impact Mission, Temple 1, copper slug, with its preflash impact? Or do they plan on it, and are taking measures to neutralize the voltage differentials between the to bodies?
Didn't Japan's probe experience a shut down when it made contact?
"TOKYO — A Japanese research probe failed to touch down on an asteroid Sunday after developing trouble just yards away from the surface, Japan's space agency said."
"When Hayabusa was 130 feet above the asteroid Itokawa, it dropped a small object as a touchdown target, then descended to 56 feet, officials from Japan's space agency, JAXA, said. At that point, ground control lost contact with the probe for about three hours, the officials said."
4realScience
Re: ESA Rosetta Stone 2014
Yes you are right, I believe. I remember that, too. But it does depend on there being a big voltage difference between the two, which there probably will be but I have no numbers here. If the Rosetta has been in a highly elliptical orbit I would assume there's a big charge and voltage difference. If its orbit is fairly circular then bets are off. The ESA will be equalizing its charge all the way there.
NASA and others still don't respect / expect big voltage offsets and don't design for them. Remember when they tried those two or three TETHER experiments, when they unreeled a kilometer long wire out the Shuttle bay? On both occasions their spools failed, hung up, probably got welded by EU effects.
mharratsc
Re: ESA Rosetta Stone 2014
That's interesting about the Japanese probe- I hadn't seen that article.
I don't think you're going to see as dramatic an issue with a lander as they did with that big copper slug. They wanted that sucker to hit hard and fast, so there's no time for the projectile to equalize charge and you get a big discharge.
A lander would be a different story. I'm sure there is a much slower approach, so thus there is more time for some slow charge equalization to take place (barring the formation of a double layer around the thing, which is possible I suppose.)
I wouldn't put it past the NASA engineers to try and put some shielding on the thing... but I don't think that is going to be the key for this stuff. Something along the idea of static wicks like on an aircraft- to equalize the charge of the thing with the charge of the environment around the probe. If it equalized itself with the tail prior to attempting to set down, I would think that the eventual physical charge exchage upon contact wouldn't be that severe.
However, I'm no engineer. Solrey or Wal Thornhill or Prof. Scott would be able to put forth a more solid answer.
