Deathblow to Electric Comet Theory - BBC - Rosetta's 10-billion-tonne comet

a reply to: myselfaswell

Not science. Not based on science.


Your source is incorrect.

Latest Rosetta blog will please the EU supporters, though. blogs.esa.int...

From data collected over the last month, the Alice team discovered that the comet is unusually dark in the ultraviolet and that the comet’s surface – so far – shows no large water-ice patches. Alice is also already detecting both hydrogen and oxygen in the comet’s coma, or atmosphere.

“We’re a bit surprised at just how unreflective the comet’s surface is and how little evidence of exposed water-ice it shows,” says Dr. Alan Stern, Alice principal investigator and an associate vice president of the SwRI Space Science and Engineering Division.

There's already a comment from an EU supporter:

Well isn't that SHOCKING, no water ice detected on the surface, yet hydrogen and oxygen exist in the coma. How can this be without photodissociation of water?? Solar wind's electrical influence is eroding the comet surface. The silicates in the nucleus release oxygen, which react with hydrogen of the solar wind and you've got hydroxyl, which scientists in the past so eagerly used as evidence of water. If you haven't at least tried to "debunk" the electric comet theory, I recommend looking it over so you can get a head start for when we observe it directly.

So, what can we say about the comets' apparently ice-less surfaces, but with plenty of OH in their comas? And can solar wind really react with the silicates on comets to produce OH?

a reply to: wildespace

And can solar wind really react with the silicates on comets to produce OH?

The oxygen is released from silica by a process of electrochemical reduction, and the comet will become more and more porous every time it interacts with the stronger electric field as it gets closer to the Sun, and not from the heat of the Sun melting ice on the surface or in the interior. The solar wind reacts with that released oxygen to produce the OH that they have always called water. IMO.

a reply to: GaryN

Doesn't electrochemical reduction of oxygen from silica involve very high temperatures?

www.ncbi.nlm.nih.gov...

a reply to: wildespace
I think it can also be done by microwaves, or microwave assisted anyway, and comets produce microwaves. Possibly due to the ion tail acting as a plasma antenna and creating the microwaves somehow, though not sure on that.
It will be interesting to see, if the probe and lander hold up, if the comet does get heated, and if it is by microwaves then there should also be an increase in the electrical charge state, and a larger corona. Hopefully the instruments have the capability to figure out just what is happening as the comet moves closer to the Sun.

a reply to: GaryN

There are a wide range of instruments on both Rosetta and Philae:

Alice Ultraviolet Imaging Spectrometer
CONSERT Comet Nucleus Sounding Experiment by Radio wave Transmission
COSIMA Cometary Secondary Ion Mass Analyser
GIADA Grain Impact Analyser and Dust Accumulator
MIDAS Micro-Imaging Dust Analysis System
MIRO Microwave Instrument for the Rosetta Orbiter
OSIRIS Optical, Spectroscopic, and Infrared Remote Imaging System
ROSINA Rosetta Orbiter Spectrometer for Ion and Neutral Analysis
RPC Rosetta Plasma Consortium
-> ICA Ion Composition Analyser
-> IES Ion and Electron Sensor
-> LAP Langmuir Probe
-> MAG Fluxgate Magnetometer
-> MIP Mutual Impedance Probe
-> PIU Plasma Interface Unit
RSI Radio Science Investigation
VIRTIS Visible and Infrared Thermal Imaging Spectrometer

Rosetta Intruments

APXS Alpha-p-X-ray spectrometer
CIVA Panoramic and microscopic imaging system
CONSERT Radio sounding, nucleus tomography
COSAC Evolved gas analyser - elemental and molecular composition
Ptolemy Evolved gas analyser - isotopic composition
MUPUS Measurements of surface and subsurface properties
ROLIS Imaging
ROMAP Magnetometer and plasma monitor
SD2 Drilling and sample retrieval
SESAME/CASSE Surface Electric Sounding and Acoustic Monitoring Experiment / Comet Acoustic Surface Sounding
SESAME/DIM Surface Electric Sounding and Acoustic Monitoring Experiment / Dust Impact Monitor
SESAME/PP Surface Electric Sounding and Acoustic Monitoring Experiment / Permittivity Probe

Philae Lander Instruments

Other than spectral analysis, of particular interest will be the results from the Rosetta Plasma Consortium suite of instruments and ROMAP on Philae.

Of course, I will expect:
1) Cries of data falsification when the results do not back up EU theory
2) EU theory being drastically changed to accommodate the results. And not 'we need to re-examine existing ideas, build a new type of neutrino detector and - look there are the missing neutrinos, they changed flavour' type changes but the usual baseless ones with no data to back them up.
3) The 6 month data proprietary period being conveniently 'forgotten' and the start of next year being filled with claims that data is being covered up and withheld - which will partly be true, due to the aforementioned proprietary period.
Ironic that people who claim to be scientists suddenly become conveniently unaware of this fact, especially considering if they had carried out any original research which had taken many years of fighting and preparation for they would insist on the same conditions.

But regardless, the point is the spacecraft is more than perfectly equipped to carry out a fully detailed analysis to prove/disprove electric comet theory and as the Project Scientist for the mission's field of expertise happens to be Space Plasma Physics - no one else could really be better qualified for the task.

a reply to: AgentSmith

But regardless, the point is the spacecraft is more than perfectly equipped to carry out a fully detailed analysis to prove/disprove electric comet theory

One problem they MAY have is that the Langmuir probe does not have a wide enough range if the electric fields are stronger than expected i.e the readings may be off-scale, so the electric field values can not be determined.
Obviously the comet has many electrical and magnetic properties they are interested in, so you can't say the electric comet idea is dead, it's a matter of how major a role electricity plays, and the instruments will hopefully be able to give us a better idea. Discussion on the nature of comet tails goes back to the 70's, such as "On the size of the cometary tail magnetic field", and all kinds of electric/magnetic/plasma terms are used, so they have known for many years that these objects are electrically active.

And this is perhaps the killing blow right here ....

Other analyses suggest the comet's surface is largely water-ice covered with a thin dust layer.

www.bbc.com...