Lightning Found On Venus

[Mr. Milton Banana]

After much speculation, it has finally been confirmed-lightning occurs on Venus. Here's the link:

http://www.cbsnews.com/stories/2007/11/28/tech/main3549985.shtml

Pretty cool!

[Romanus]

This has been a frustrating controversy for a long time, with seemingly as much evidence for as against (and increasingly, against). Assuming it's confirmed at last, this is great, exciting news!

:)

[Mr. Milton Banana]

This has been a frustrating controversy for a long time, with seemingly as much evidence for as against (and increasingly, against). Assuming it's confirmed at last, this is great, exciting news!

:)

I'm a bit puzzled about why lightning flashes haven't been seen in the clouds. Is it because Venus's atmosphere is so much thicker than Earth's?

[01101001]

(By the way, this was also reported in an article in topic Venus Express - the ESA mission to Venus (http://www.bautforum.com/1122602-post104.html), in Space Exploration.)

I'm a bit puzzled about why lightning flashes haven't been seen in the clouds. Is it because Venus's atmosphere is so much thicker than Earth's?

It's been suspected for a long while, but Venus Express apparently had the magnetometer to clinch it.

Suspicion: ESA: Acid clouds and lightning (http://www.esa.int/SPECIALS/Venus_Express/SEMANY808BE_0.html)

During previous ground and satellite observations, visible flashes in the atmosphere have been observed, and localised emissions of radio waves have also been reported. Are they due to lightning?

Confirmation: NASA Scientist Confirms Light Show on Venus (http://www.nasa.gov/vision/universe/solarsystem/venus-20071128.html)

The confirming measurements of the electrical discharges were made with data obtained by the Venus Express magnetometer instrument provided by the Space Research Institute in Graz, Austria.

[Noclevername]

From the ESA article:And why do such differences between day and night sides not cause the strong winds we would expect? This behaviour is unique in the Solar System.

Two reasons. One, the sheer mass of the atmosphere. Even upper-atmosphere winds have to fight a lot of friction. Two, because such long exposure of the thick atmosphere to heat has evenly distributed energy over both hemispheres. No big temperature differential, no high winds.

[George]

Is the lightning bright enough to contribute to the Ashen light question?

[tusenfem]

Is the lightning bright enough to contribute to the Ashen light question?

It is supposedly cloud-to-cloud lightning and according to the accompanying article in Nature, the atmosphere and clouds are so dense that standing on the surface you will not see the lightning. Depending on where the lightning is taking place, the same might be argued for being outside of the atmosphere.

According to a web document (http://www-ssc.igpp.ucla.edu/personnel/russell/papers/ashen/) by Chris Russell (the lead author of the lightning paper) and J.L. Phillips the ashen light has many of the same characteristics as would be expected for lightning.

I am not sure whether any groups are looking at this phenomenon with VEX.

[George]

Thanks. Your linked paper is excellent on the story of Ashen Light. The evidence for and against lightning as a cause has added to the enchantment. It seems lightning may occur intermittently.

George

[Mr. Milton Banana]

Of course, the next question would be-are we talking about thunderclouds of sulphuric acid? If so, what are the differences between a Venusian thunderhead as opposed to a terrestrial thunderhead?

[tusenfem]

The more often I read Russell's paper, the more doubt I have about his evidence (I am sad to say), but I am checking out things.

I don't think, that if there is any lightning going on, which is supposedly cloud-to-cloud, there will be a lot of difference. Naturally, the different composition of the atmosphere will create different discharge strengths, and a different composition of the clouds will most likely give a different "capacitance". So, they might either be stronger or weaker (well, isn't that a nice conclusion).

[mgmirkin]

Thanks. Your linked paper is excellent on the story of Ashen Light. The evidence for and against lightning as a cause has added to the enchantment. It seems lightning may occur intermittently.

George

Intermittently...?

From NASA News 79-12 (4-19-1979) p 1.:

"The Russian Venera spacecraft found continuous lightning activity from
32km down to about 2km altitude, with discharges as frequent as an amazing
25 per second. The Pioneer Orbiter also observed this lightning, measuring
such discharges during every pass across the planet's night hemisphere. The
eye would not be able to separate such frequent flashes and an observer on
Venus might see the landscape and dense atmosphere bathed in a continuous
eerie electrical glow, accompanied by continuous peals of thunder."

25 per second isn't exactly "intermittent." It's like, non-stop (to the point that a human eye would hardly be able to tell where one stopped and the next started)...

Granted, perhaps not "all the time at 25/second." But, yeah, a little more than "intermittent." Venus has a bit of a light show going on in its atmosphere. Granted it's buried where it's not "visible," per se...

~Michael Gmirkin

[George]

Intermittently...?

From NASA News 79-12 (4-19-1979) p 1.:

"The Russian Venera spacecraft found continuous lightning activity from
32km down to about 2km altitude, with discharges as frequent as an amazing
25 per second. The Pioneer Orbiter also observed this lightning, measuring
such discharges during every pass across the planet's night hemisphere. The
eye would not be able to separate such frequent flashes and an observer on
Venus might see the landscape and dense atmosphere bathed in a continuous
eerie electrical glow, accompanied by continuous peals of thunder."

25 per second isn't exactly "intermittent." It's like, non-stop (to the point that a human eye would hardly be able to tell where one stopped and the next started)...

Granted, perhaps not "all the time at 25/second." But, yeah, a little more than "intermittent." Venus has a bit of a light show going on in its atmosphere. Granted it's buried where it's not "visible," per se...

~Michael Gmirkin
Yes, but don't discount Cassini's two flybys where AM static was found passing Earth but none when passing Venus.

[Sean Clayden]

Lightning does occur on venus, however, it never strikes the ground, air density (lack of atmosphere) prohibits it from grounding and confines itself to the gaseous clouds

[Kaptain K]

Lightning does occur on venus, however, it never strikes the ground, air density (lack of atmosphere) prohibits it from grounding and confines itself to the gaseous clouds
Lack of atmosphere?
Don't you mean too much atmosphere?

[Acolyte]

From the ESA article:
Two reasons. One, the sheer mass of the atmosphere. Even upper-atmosphere winds have to fight a lot of friction. Two, because such long exposure of the thick atmosphere to heat has evenly distributed energy over both hemispheres. No big temperature differential, no high winds.
OK, I'm puzzled by all this.

1. The given explanation for the night-side glow of Venus is that solar radiation breaks down the CO2 & high speed winds transport the atoms around the planet to the night side where they recombine into O2, giving off the 'glow.' It is stated that the atmosphere of Venus is rotating significantly faster than the surface. This would seem to preclude the idea of no high-speed winds.

2. Venus Express has confirmed the presence of lightning on Venus using a magnetometer. As I can't find anywhere that mentions 'unusual' magnetometer readings, does that mean the VE is confirming Earth-type lightning?

3. If Earth-type lightning is occurring, particularly if it's occurring at rates like 25 times per second, why wouldn't Cassini have picked up the AM signature?

4. Wouldn't an atmosphere containing sulphuric compounds be more conductive than Earths? Could this affect the production of lightning & if so how?

Any en-lightning :D would be appreciated.

[Jerry]

Cassini hasn't picked up much in the way of lightning/static at Titan, either.

[Acolyte]

Cassini hasn't picked up much in the way of lightning/static at Titan, either.OK... But why is that germane? From what I've read, it is only theory that Titan would have lightning isn't it? So the non-detection would just be evidence of an incorrect theory.

The Venus situation seems much more unsettled with evidence that there IS lightning contradicting the Cassini lack of detection. Is Cassini faulty somehow?

[tusenfem]

Next week is the EGU general assembly. In the VEX session there will be more information about the lightning at Venus, by Russell.

I, myself, have looked at one event by Russell, and have found that there is the usual frequency change in the whistler mode waves, that are associated with lightning. However, as the frequency of the whistler waves is above the Nyqvist frequency of the magnetometer (being 62 Hz) the waves are "folded around" in the spectra, moving them from 100 Hz to 40 Hz and changing the direction of dispersion.

So, wait till after next week, then I can give more info on what Russell has done.

[Acolyte]

Next week is the EGU general assembly. In the VEX session there will be more information about the lightning at Venus, by Russell.

I, myself, have looked at one event by Russell, and have found that there is the usual frequency change in the whistler mode waves, that are associated with lightning. However, as the frequency of the whistler waves is above the Nyqvist frequency of the magnetometer (being 62 Hz) the waves are "folded around" in the spectra, moving them from 100 Hz to 40 Hz and changing the direction of dispersion.

So, wait till after next week, then I can give more info on what Russell has done.Google is my friend :) Normally. But after reading about slow waves, packets, planes & propagation I guess I just have to settle for something like 'the evidence for lightning on Venus lies outside the expected result to be seen by the Cassini magnetometer.'

So is it a strange thing that Cassini saw results for Earth but not Venus?

[Kaptain K]

Post deleted because of stupidity on my part!

[tusenfem]

Google is my friend :) Normally. But after reading about slow waves, packets, planes & propagation I guess I just have to settle for something like 'the evidence for lightning on Venus lies outside the expected result to be seen by the Cassini magnetometer.'

So is it a strange thing that Cassini saw results for Earth but not Venus?

Here (http://esoads.eso.org/abs/2001Natur.409..313G) is the paper by Don Gurnett and co-workers on the data from Cassini during its Venus flyby, on its way to Saturn. It seems that they did not measure the characteristic whistler mode waves. As to why, I have no idea. It can have everything to do with the only induced magnetic field of Venus, or the composition of the atmosphere or ... or ...

Checking here the waves on the couch at home, I see that they are of very small amplitude, the wavelet transform gives a power of log2(nT2) ≈ 3, which means an amplitude of sqrt(8) nT, but take these numbers with a grain (or a barrell load) of salt.

This would have to be compared with the distance of Cassini and of VEX. Then compare the amplitude of these waves at the Earth in a similar location that VEX is etc. etc.

I will leave that to Chris to figure out, I have enough other waves to concern myself about at Venus. I just had my "First observation of mirror mode waves in Venus' magnetosheath?" paper basically accepted by GRL.

[tusenfem]

Thought this might be useful in this thread.

http://www.universetoday.com/2008/05/15/elusive-molecule-found-in-venus-atmosphere/


Actually, this has absolutely nothing to do with this thread, but at least you give the source now.

Something I had not thought about, and a collegue of mine pointed me to, is that the characteristic waves of lightning at Earth, the whistler mode waves, exist because the Earth has a magnetic field. Whistlers are "electron waves" that travel along the field lines, highly dispersed, i.e. the higher frequencies are faster than the lower frequencies, giving the characteristic "whistle tone" on AM radios.

Venus has no magnetic field, only an "induced magnetosphere" created by the draping of the solar wind magnetic field. This makes the creation of whistler mode waves more difficult to create these waves.

This means that lightning may exist on Venus, but the detection is rather complicated, when one has to consider the different system Venus (and Titan) is.

Unfortunately, I did not hear Chris Russell's talk due to scheduling conflicts, so I am not up to date with the latest investigations by him, but I am sure he will publish something soon.

[Mr. Milton Banana]

Bumping to ask this question...

What about sprites? Would there be any way to see them as you would above terrestrial thunderclouds?

[Invader Xan]

Venusian sheet lightning... I wonder what effect it has on the planet's atmospheric chemistry...

[tusenfem]

FYI
There will be a paper pubished soon by Russell et al. on whistler mode waves and lightning in the Journal of Geophysical Reseach (Planets). It shows up here (http://www.agu.org/contents/journals/ViewPapersInPress.do?journalCode=JE) but as I have no subscription to "planets" I cannot get at the paper.

More later.