Genuine Question Of Electic Comets

[Jarvamundo]

From a comet group:

I have a question brought up by one of the comets-ml members.

"I expect one piece of evidence lacking, given the proposal that comet jets
are caused by electric discharge, is the absence of emission spectra
characteristic of such discharges. For comets, we generally only see
emission spectra from the faster-moving, more tenuous gaseous fraction
activated by irradiation from the Sun and solar wind. The claims are that
the electrical discharges are most intense at or near the comet nucleus and
are so great as to lead to 'electric discharge machining' of the surface
with the jets comprising excavated material moving along the electric field
lines or arcs. So what is their explanation for the lack of emission
spectra in and around these jets?"

[Siggy_G]

I'm not an expert, but is there any reason why the elctric discharge itself should have an emission spectra? Isn't it the whatever gaseous material it excavates that has emission spectra - something they've already received data of?

The electric discharge vaporizes a portion of the sample and excites the elements in the sample to emit characteristic spectra.

(http://www.britannica.com/facts/5/62253 ... metallurgy)

Surface electrical discharges don't have an emission spectra by itself, unless it for some reason creates different elements or molecules in that specific process and region. Unsure about how high resolution they have for measuring what happens where around a comet nucleus.

[Siggy_G]

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

The photoelectric effect is a phenomenon in which electrons are emitted from matter (metals and non-metallic solids, liquids or gases) as a consequence of their absorption of energy from electromagnetic radiation of very short wavelength, such as visible or ultraviolet light.

Now, what happens when a comet nucleus emits electrons as a reaction of the absorbed ultraviolet light from the Sun? It's near environment of sublimated gasses (coma) gets ionized / electrically charged, hence a plasma. This would happen increasingly as the comet approaches the Sun, exactly like observed.

Hertz observed and then showed that electrodes illuminated with ultraviolet light create electric sparks more easily.

In other words, electrical discharges. From previous post: "The electric discharge vaporizes a portion of the sample and excites the elements in the sample". So, empirically, we have matter excavation and dusty plasma at the nucleus surface. Since dusty plasma consist of heavier grains and is less charged than the main plasma, it will interact and move differently. Hence, two different tails form, during interaction with the radially emitted solar plasma ("solar wind" and to some degree the Sun's light momentum). One that points directly away, the other that appears to lag behind. According to some, the dust tail moves trajectory with the comet - but it really originates away from the nucleus in the same manner as the main tail. Since it consist of heavier particles, it just moves in a more mechanical manner as it enters wider orbital paths away from the Sun.

[Siggy_G]

I should also add:

Light from the sun hitting lunar dust causes it to become charged through the photoelectric effect. The charged dust then repels itself and lifts off the surface of the Moon by electrostatic levitation.

( http://en.wikipedia.org/wiki/Photoelect ... #Moon_dust )

On the Moon the photoelectric effect and electrons in the solar wind charges fine layers of moon dust on the surface forming an atmosphere of dust floating in "fountains" over the surface of the moon.

( http://en.wikipedia.org/wiki/Electrosta ... Levitation )

The same thing would happen on a comet, and it's related to the dusty plasma mentioned in the previous post.

[Jarvamundo]

Thanks Siggy, appreciated. Alot of basics to explore to build a picture of what's happening. cheers.