Electric Comets

Post a reply


This question is a means of preventing automated form submissions by spambots.
Smilies
:D :) ;) :( :o :shock: :? 8-) :lol: :x :P :oops: :cry: :evil: :twisted: :roll: :!: :?: :idea: :arrow: :| :mrgreen: :geek: :ugeek:

BBCode is ON
[img] is ON
[url] is ON
Smilies are ON

Topic review
   

Expand view Topic review: Electric Comets

Re: Electric Comets

by GaryN » Mon Nov 20, 2023 10:22 pm

IS THIS THE WEIRDEST COMET EVER?
Image
https://spaceweather.com/archive.php?vi ... &year=2023
Of course it is only weird if you are clueless, or pretend to be, about electricity in space.
The comet will not be visible from deep space as we can only see it due to the UV of the coma
being converted to visible light by Earths atmosphere.

Re: Electric Comets

by Robertus Maximus » Mon Sep 21, 2020 10:05 pm

Comets have their own 'Northern Lights'

https://www.dailymail.co.uk/sciencetech ... comet.html
https://www.nature.com/articles/s41550-020-1171-7

"On the Earth, auroras are formed when charged particles from the Sun follow the planet's magnetic field lines to the north and south poles where they strike atoms in the atmosphere and create a shimmering curtain of colourful lights in the sky.

"Similar phenomena have been seen on planets and moons in our solar system and even around a distant star - this is the first time it has been spotted around a comet."

"The team were amazed to find that the UV emissions in the aurora were driven by electrons in the solar wind that break apart water and other molecules in the coma.

"They had 'been accelerated in the comet's nearby environment. The resulting excited atoms make this distinctive light,' said Parker."

Re: Electric Comets

by JP Michael » Mon Jun 22, 2020 1:16 am

Re: Electric Comets

by JP Michael » Fri Jun 12, 2020 12:14 am

Re: Electric Comets

by JP Michael » Sat May 09, 2020 1:18 pm

Is anyone else aware of the 1997 comet that the sun spat out?

Video

Re: Electric Comets

by GaryN » Sat Feb 15, 2020 5:23 am

johnm33 wrote: Sat Feb 08, 2020 7:00 pm Is it possible that UV/Violet light from the sun is what charges comets? [meteorites/asteroids]
Cosmic rays surely would.

Re: Electric Comets

by johnm33 » Fri Feb 14, 2020 10:00 pm

Re: Electric Comets

by johnm33 » Sat Feb 08, 2020 7:00 pm

Is it possible that UV/Violet light from the sun is what charges comets? [meteorites/asteroids]

Re: Electric Comets

by Robertus Maximus » Fri Feb 07, 2020 6:49 pm

Rosetta's 'rubber ducky' comet changed color as it neared the sun

https://www.livescience.com/rosetta-com ... ar-sun.htm

https://www.nature.com/articles/s41586- ... cience.com

"In other words, all those microscopic grains of carbon-rich dust that melted off the comet's surface stopped reddening the surface and started reddening the coma.

"Once the comet moved away from the sun again, its solid core reddened again as dust once again settled on the surface of the nucleus."

Comet 67P looked pretty dry to me, I don't recall a great deal of melting?

Re: Electric Comets

by paladin17 » Thu Feb 06, 2020 3:10 pm

JP Michael wrote: Tue Jan 14, 2020 5:25 am I have a question about electric comets and more generally planets/stars.

In a NASA image of Comet Holmes it shows several distinct layers and boundaries:
Image
My question is whether these plasmapheric boundaries represent double layers of electrical potential drop?

A secondary question is the physics of the tail-side of the coma where the double layers seem to be breaking down. Would these be apt observations?
These aren't double layers, but current sheets. They separate areas with different magnetization (also different plasma temperature and such).
Double layers do exist in the tails of comets, where they are (sometimes) disrupting the tail currents and producing various anomalous phenomena. Perhaps the tail current disruption would also impact the coma and nucleus (as the current would have nowhere to go other than there) - akin to Earth's magnetic substorm phenomenon, where the energy from the tail curcuit is redistributed to auroral circuit.

Re: Electric Comets

by LaSuisse1 » Mon Feb 03, 2020 5:42 pm

The Great Dog wrote: Tue Jan 14, 2020 3:26 pm Here's a Picture of the Day about electric comets:

http://www.thunderbolts.info/tpod/2009/ ... aments.htm

TGD
Yikes! No offence, but whoever wrote that piece knows nothing about comets!

Let's try to go through it sequentially;

Whoever said that comets can only become active close to the Sun? I'm afraid the author is only considering water ice. Quite true that water ice will not usually sublimate below ~ 150 K, which will only be achieved within ~ 4 AU. However, he has not considered all the other types of ice known to exist at comets. In particular, CO and CO2. Both of these have a considerably lower sublimation temperature than water ice. CO, iirc, is around 30 K. CO2 ~ 70 K. I can't be bothered searching through the literature, but I'm pretty sure that CO was detected around Hale-Bopp at considerable distance from the Sun. Can't remember if that was on the way in or the way out. Likely not the only such detection, either. So, this is a made up claim, based on a lack of knowledge of the relevant subject. Actually, I changed my mind about searching the literature! This took me seconds to find. Not sure why the author of the linked article was incapable of doing the same;

Substantial outgassing of CO from comet Hale–Bopp at large heliocentric distance
Biver, N. et al. (1996)
https://www.nature.com/articles/380137a0

So, that is that particular claim easily falsified. What else have we got?
Comet Linear? Would be good to have a link to whatever paper the author was reporting on. Suffice to say that a number of extraordinary cometary outbursts have been observed. That of 17P/ Holmes was seen to contain water ice. So, I'll take the authors report with a pinch of salt.

COMET 17P/HOLMES IN OUTBURST: THE NEAR INFRARED SPECTRUM
Yang, B. et al. (2009)
https://iopscience.iop.org/article/10.1 ... 137/5/4538

And, unknown to the author at the time, as it hadn't then occurred, comet Hartley 2 was seen by a visiting spacecraft to be a veritable snowstorm of ice. This was detected visually and spectroscopically.

https://science.nasa.gov/science-news/s ... tsnowstorm

As for Halley, I have no idea what he is trying to say! Yes, we now know that there is more dust than ice. How did we discover that? By going to one and looking. That is what science does. Idea and theories evolve as more information is gathered. The fact remains that Halley was producing ~ 25 000 l/s of water vapour.

Ditto with the comment on Shoemaker-Levy 9. The article was written in 2009. By then, there was definitive evidence for water at a few dozen comets. All of which was available in the scientific literature for anybody to read. The first definitive detection was from the Kuiper Airborne Observatory, studying Halley in 1985! By 2009 we had impacted Tempel 1 and blasted out thousands of tonnes of ice. As observed. So, his point (whatever it is) is moot.

And as for 'helical Birkeland currents', I'll treat that with the disdain it deserves! Most likely the author has not understood the paper, assuming he's read it.

The following paragraphs are pure fantasy, and owe nothing to actual science and observation. As mentioned, none of the author's fantasies were observed at Halley, or since then at 67P. The whole piece has zero scientific merit, I'm afraid. What on Earth is he talking about re 'increased charge density'????? Where has this been observed in decades of spaceflight? How would this work? Remember, the solar wind, and its associated magnetic field, are getting nowhere near the comet nucleus for a considerable amount of time. And at the times when the aforementioned do have access to the nucleus, is the time when the comet is at its most quiescent!

Sorry, but that chap needs to enrol in a science course.

Re: Electric Comets

by LaSuisse1 » Mon Feb 03, 2020 4:51 pm

JP Michael wrote: Tue Jan 14, 2020 5:25 am I have a question about electric comets and more generally planets/stars.

In a NASA image of Comet Holmes it shows several distinct layers and boundaries:
Image
My question is whether these plasmapheric boundaries represent double layers of electrical potential drop?

A secondary question is the physics of the tail-side of the coma where the double layers seem to be breaking down. Would these be apt observations?
Answer to first question: No.

Answer to second question: No.

If you follow the extensive peer-reviewed literature from the Rosetta mission to 67P, as well as the older material from the various probes at Halley, in 1986, you'll find that no such double layers exist. And there is no 'potential drop'.
There are a number of interesting plasma boundaries at comets, and the aforementioned missions were the best equipped to study them. In '86 they were fly-by missions, albeit through a very extensive coma of a particularly active comet. The main boundary of interest, predicted to exist pre-mission, was the diamagnetic cavity boundary. This was duly encountered by Giotto, at ~ 4500 km from the nucleus. This is a boundary where the Interplanetary Magnetic Field (IMF), carried by the solar wind, piles up, and no longer reaches the cometary nucleus. The solar wind itself has long since been getting nowhere near the nucleus. From memory, it died away at ~ 10 000 km at Halley. In other words, it is slowed and deflected due to mass loading from cometary ions. Within the diamagnetic cavity are only neutrals (overwhelmingly) and ions of cometary origin, heading outwards. Mostly neutral water and water ions. The neutrals are not affected by the boundary on the way out, for obvious reasons, while the ions get involved in some interesting stuff. Plenty of literature on that, if you're interested.
Similar was seen at 67P, albeit this was a far less active comet. Therefore the boundaries were a lot closer to the nucleus. The diamagnetic cavity was very unstable but, at peak, was a few hundred km from the nucleus. As this was a much longer lasting mission than the Halley fly-bys, the behaviour of the solar wind could be monitored over a longer timespan. To all intents and purposes, the solar wind disappeared from the location of the spacecraft from ~ 4 months before and after perihelion. An excursion sunward to ~ 1500 km, in October 2015 (# 2 months post-perihelion), failed to detect it. On the way back, it was briefly detected, as the coma was hit by a CME, at 800 km.
Another boundary of interest in the bow shock, which was detected at Halley, but not 67P, although there are indications that it exists. It has also been encountered at other comets.
As for the tail, there was little in the literature before Rosetta, the only mission to directly fly through the tail being the ICE mission to Giacobini-Zinner, in 1985. Previous literature had proposed that double layers may be possible in the tail (but not on the sunward side), mostly by D. A. Mendis.
No such was seen at G-Z, or Halley, although Mendis thought there might have been some indication at the latter. He was probably wrong, and seemed to drop the idea thereafter. Rosetta did have a dedicated tail excursion, and no such indications were seen. There are a few papers in the literature detailing that excursion.
Regarding 'potential drops', I'm not overly sure what you are getting at. Rosetta was equipped with various instruments that would detect such things. It also had a magnetometer, as did Giotto. Inside the diamagnetic cavity at both comets, the magnetic field (as indicated by the name of the cavity!) is seen to drop to zero. The comet itself, of course, has no intrinsic magnetic field. This was also confirmed by the Philae lander at 67P.
Out of interest, the confirmation of the formation of the predicted diamagnetic cavity did not come at a real comet. It was observed during a set of artificial comet experiments performed in space, known as AMPTE, back in 1984-5. If you are interested in that, there is quite a bit in the literature, including;

Dynamics of the AMPTE artificial comet
G. Haerendel, et al.
https://www.researchgate.net/profile/Wo ... c807cf.pdf

Hopefully, that has answered your questions in reasonable detail. There is a lot of literature out there on cometary missions, some of it free access. Worth a read if that is your thing.

Re: Electric Comets

by The Great Dog » Tue Jan 14, 2020 3:26 pm

Here's a Picture of the Day about electric comets:

http://www.thunderbolts.info/tpod/2009/ ... aments.htm

TGD

Re: Electric Comets

by JP Michael » Tue Jan 14, 2020 5:25 am

I have a question about electric comets and more generally planets/stars.

In a NASA image of Comet Holmes it shows several distinct layers and boundaries:
Image
My question is whether these plasmapheric boundaries represent double layers of electrical potential drop?

A secondary question is the physics of the tail-side of the coma where the double layers seem to be breaking down. Would these be apt observations?

Electric Comets

by allynh » Fri Jan 10, 2020 11:16 pm

[Moderator Edit] This thread is a continuation from:
https://www.thunderbolts.info/forum/php ... 49#p128649


To continue the discussion.

Visit a Comet by Hitching a Ride on the Rosetta Space Probe
https://www.dailygrail.com/2020/01/visi ... ace-probe/
Friday, January 10th
It’s always a blast watching a good sci-fi film or TV series that takes us on a journey through space (e.g. Ad Astra and The Expanse). There’s something about feeling like you are exploring ‘the final frontier’ that makes you realise we live right at the beginning of a new era in which humans have become a space-faring species.

It’s easy to forget though that we already are exploring our solar system (and beyond) currently via robotic space probes – from the gas giants Saturn and Jupiter through to expeditions to individual comets and asteroids.

One of those latter expeditions was the Rosetta spacecraft’s visit to comet Churyumov-Gerasimenko (67p) a few years ago – and if you’d like to experience what it would have been like to be riding on board, check out this amazing video constructed from photos taken by the probe, augmented with some digital enhancement:

In 2016 an exciting mission was ended. The Rosetta spacecraft made its final manouevre: a controlled hard-landing on the comet Churyumov-Gerasimenko (67p).

Before that Rosetta accompanied the comet for more than 2 years. It researched valuable scientific data, brought a lander on to the comet’s surface and took a vast number of pictures.

In 2017 the European Space Agency (ESA) released over 400000 images from Rosettas comet mission. Based on this material motion designer Christian Stangl and composer Wolfgang Stangl worked together to create this short film. The sequences are digitally enhanced real footage from the probe.

Watch the beauty of an active alien body, far out in the depths of our solar system.

(via Randall Carlson)
Here is the video on YouTube if the Vimeo video vanishes.(Say that ten times, fast.)

the Comet
https://www.youtube.com/watch?v=GEgMRjl76NY

The Electric Comets thread in the old Forum is at:

Electric Comets
http://www.thunderbolts.info/forum/phpB ... =4158#p194

As you read the old thread, you may find broken links. If that happens, then access:

The Way Back Machine
https://archive.org/web/

Simply copy the broken link from the Forum page, and paste it into the Way Back Machine to see if it was ever archived. Find a valid copy of the missing web site and read the article.

- Learn how to use the Way Back Machine.

- The Way Back Machine is your friend.

Top