Saturday, May 10, 2008

Thunder, Lightning and Vog

The Chaiten volcano in Chile continues to erupt, having forced the evacuation of thousands. Chaiten has also produced spectacular displays like this one. Lightning is powered by an excess of electric charge, which occurs in storms but also in volcanic clouds. We learned this in school, but what triggers the discharge? The tracks of lightning bolts resemble the shower of particles from cosmic rays. Since Earth is bathed constantly in cosmic rays, some have suggested that they trigger lightning bolts. If the frightening bursts of thunder should someday shown to result from cosmic rays, it is one more example of how are lives are intertwined with Space.

Our Cassini spacecraft has photographed a huge thunderstorm on Saturn that has raged for five months. Some theories suggest that Saturnian thunderstorms are connected with the mysterious "spokes" seen in the rings. Aided by a network of "amateur" astronomers, Cassini has also observed a wave pattern in the atmosphere. Temperatures vary at different latitudes in a hot-cold pattern. Sometimes the equator is wamer than surrounding latitudes and sometimes it is colder, switching at half-year intervals when the Sun is directly over the equator. Previously we have seen that Saturn's poles are hot spots, with the highest temperatures of the surface. Source of this hot-cold pattern is considered a mystery, but Saturn's interior is an excellent place to seek a Black Hole.

Though Hawaiian shield volcanoes are gentler than Chilean volcanoes, the eruption of Halema'uma'u Crater continues. It has left the nuisance of "Vog," or volcanic smog. Sulfur dioxide regularly issues from Kilauea, but with the eruption it has spread throughout the islands. Neighbours have complained about respiratory ailments. Certain plants, like eucalyptus and Asiatic lilies, are particularly harmed. Our coffee and macadamia nut trees appear unaffected. We are fortunate that our volcanoes are more nuisance than danger.

Volcanoes may be tied to cosmology. As longtime readers of this blog know, internal heat could be product of a tiny Black Hole in Earth's core. Human life exists in a very thin surface between Earth and Space. Cosmic rays rain from the heavens, causing showers of energetic particles in the atmosphere and possibly lightning discharges. Lightning storms have been observed on Jupiter and Saturn. At Chaiten, Earth's internal heat leads to spectacular lightning displays. Space and cosmology are part of our lives whether we like it or not.

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Anonymous Anonymous said...

Louise, was it at school in Hawai'i where you learned about the vog ?

For the most part Hilo has been little effected as the wind has blown it towards Kona. Once the vog from the Halema Ľuma Ľu vent reached Oahu, it made national news.

7:42 PM  
Blogger L. Riofrio said...

HI Sam: Vog has been part of my language so long I forgot where I learned the word. Fortunately the tradewinds blow reliably East to West. Hilo and even Volcano Village are mostly free of vog. For the same reason the air atop Mauna Kea is remarkably clean, creating ideal observing conditions.

8:35 PM  
Blogger nige said...

Beautiful pictures of volcanic lightning and of Saturn! It is certainly true that cosmic rays can trigger lightning bolts. There is a large electric potential between the Earth's surface and the ionosphere, which is at high altitude and hence low pressure air. This is similar to conditions in a Geiger-Muller tube, where you have low pressure gas and a strong electric field. Any cosmic ray can potentially set off an electron avalanche, which in the absence of a quenching agent (Geiger-Muller tubes include some inert gases like helium, neon or argon which have filled outer-shells of electrons, in order to limit the size of the electron avalanche and thus quench each small discharge). Since there is little quenching gas in the Earth's atmosphere, you get major lightning bolts develop.

One pretty impressive lightning situation which demonstrates the connection between ionizing radiation and lightning, was lightning filmed around the periphery of the fireball from the "Mike" nuclear test on 1 Nov. 1952 at Eniwetok. The yield was 10.4 Mt, and the gamma rays set off at least five lightning flashes in the ionized air just around the fireball. All the lightning bolts were essentially vertical, from the scud cloud just above the fireball down to the lagoon water. This confirms that nuclear radiation, via causing ionization in the atmosphere, definitely can trigger a shorting of the natural vertical electric potential gradient in the atmosphere, resulting in a bolt of lightning:

12:52 AM  
Blogger Red River said...

Lets not forget that Cosmic Rays also cause condensation nuclei to form in water vapor which leads to cloud formation from 3 to 15 Angels altitude. These low clouds then block more sunlight causing reduced radiation at the Earth's surface. Combined with the heat of condensation loss caused by the improved efficiency of the condensor in the cloud-water vapor heat cycle, the increase in Cosmic Ray flux due to Solar quiescence leads to global cooling and the triggering of Ice Ages. Of course, this Science is outside the maintstream as well.

6:34 PM  
Blogger mark drago said...


5:05 AM  

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