Lightning SUPERBOLTS!

A typical stroke of lightning stretches as long as eight miles, and forms when a negatively charged region in a storm cloud begins to send out a stepped leader. This leader is met by another leader rising from the earth, allowing the cloud to discharge to the ground, reducing the negative electrical charge. That's typically how it works…

…but not always.

And when it doesn't work that way, things get interesting.

Occasionally, a severe storm will create a large thunderhead which develops a very strong positive charge in its upper reaches. When this charge becomes strong enough, it can produce what's called a positive bolt of lightning. Positive lightning develops in the same way as typical lightning bolts, but the positive bolt draws electrons upward from the ground. These lightning bolts tend to be much, much stronger than regular lightning, and may carry as much as a hundred times the energy of a normal flash of lightning.

These "superbolts" of lightning, thankfully, are very rare. Only about five superbolts occur for every ten million normal lightning strokes; typically, they're found only in severe storms during the winter, and are more common in and near Japan than anywhere else in the world.

Superbolts can reach way beyond the normal eight to ten miles of a typical lightning stroke. The longest superbolt on record reached from Waco, Texas to Dallas, after having traveled about a hundred and ten miles.

A hit from one of these positive superbolts tends to be a "no survivors" event. Such bolts often strike the ground twenty-five miles or more away from the storm front, without warning at all.

And it could be worse.

Lightning superbolts here on earth are downright feeble compared to superbolts in the upper reaches of Jupiter's atmosphere.

Lightning on Jupiter is very similar to lightning on earth, and is common in the planet's belt of water clouds. Weather conditions on Jupiter are far more intense, though, and produce much more violent storms than any that occur here.

On earth, weather patterns are driven by the sun. As we rotate, the sun heats the side of the planet facing it; uneven heating and cooling form the basic engine that drives our weather. On Jupiter, weather is driven by heat escaping from deep inside the planet's gas envelope.

The New Horizons satellite probe, currently on its way to Pluto, made a very close flyby of Jupiter in March of this year. Armed with instruments more sensitive than those on the Cassini probe before it, New Horizons detected for the first time massive superbolts near Jupiter's poles, a thousand times more powerful than superbolts on earth. Previous superbolts had been observed by the Galileo probe near the planet's equator (pictures of which are shown below), but the new images show that these massive lightning discharges are not confined to the turbulent zones around the planet's center.