Does ball lightning really exist?

When you rub your socked feet on the carpet and zap yourse­lf on a doorknob, you're experiencing static electricity. Lightning is static electricity but on a scale your socks could never produce: It's three times hotter than the surface of the sun and could power a 100-watt bulb for more than three months [source: National Lightning Safety Institute]. Lightning has long fascinated people, motivating them to create myths about its origin and inspiring legendary experiments with electricity.

While we're all familiar with lightning, it's estimated that between one in 30 and one in 150 people around the world believe they have seen balls of lightning hovering over the ground, floating through walls and even killing people [source: National Geographic]. Stories of these glowing spheres go as far back as the Middle Ages, maybe even as far back as the Ancient Greeks. However, a recorded case didn't occur until the 18th century when Georg Richmann, a pioneer in research on electricity, was killed by what's believed to have been ball lightning.

erhaps one of the most famous ball lightning sightings was by a young Czar Nicholas, grandson to Czar Alexander II, who witnessed a flaming orb during a church service in the 19th century. But even sightings by tsars left people skeptical. Were these balls actually lightning? Perhaps otherworldly phenomena? The skepticism began to wane in 1963 when a group of scientists flying from New York to Washington, D.C., witnessed a blazing orb drift down the aisle and disappear through the rear of the plane. Looking to explain what they saw, research began.

Explanations and Theories of Ball Lightning

Ball lightning appears as glowing orbs that seem to occur during thunderstorms, usually following a lightning strike. These floating fireballs shine as brightly as a 100-watt lightbulb; can be white, yellow, orange, red or blue in color and are typically about the size of a small grapefruit, although sightings suggest they can range in size from golf ball to beach ball.

                            Silicon, which occurs in the ground, could be the culprit behind ball lightning.

Emanating from the fireball are little tendrils that seem to jerk the ball around as if it was under the power of a spastic puppeteer. They move slowly and erratically and are followed by smoke trails that form spirals around them. And after a moment, they disappear.

There's no scientific explanation for balls of lightning, although there are several proposed theories.

Throughout history, speculations about the cause of ball lightning have ranged from the existence of standing waves of electromagnetic radiation to plasma clouds and from short-circuiting power lines to St. Elmo's Fire. The more unusual explanations suggested mini black holes created during the big bang or a possible alien presence. While no theory has yet to explain ball lightning, a promising theory focuses on silicon.

The most popular current theory, proposed by John Abrahamson at the University of Canterbury in Christchurch, New Zealand, suggests that ball lightning is the result of a chemical reaction of silicon particles burning in the air.

When lightning strikes the ground, silicon that occurs naturally in soil combines with oxygen and carbon and turns into pure silicon vapor. As the vapor cools, the silicon condenses into a fine dust. The particles in this fine dust are attracted to each other by the electrical charge created by the lightning strike, binding together into a ball.

The glow and heat come from the chemical energy created as the silicon recombines with oxygen in the air. And once the silicon has burned out, the ball lightning disappears.

This theory also suggests materials other than silicon -- such as aluminum and iron metals -- may also cause the orbs, and that any atmospheric discharge, not necessarily lightning, may explain why ball lightning has been sighted near power poles, electrical fitters, and even active faults.

Scientists are taking this hypothesis into their labs. Researchers Antônio Pavão and Gerson Paiva of the Federal University of Pernambuco in Brazil have been working with the silicon hypothesis and believe they have verified the theory with silicon substrate and a high-voltage arc. They applied 140 amps of electricity to silicon substrate, which vaporized the substrate and sometimes produced golf ball-sized fireballs.

Eli Jerby and Vladimir Dikhtyar, of Tel Aviv University in Israel, successfully (and accidentally) recreated ball lightning with a device they call a "microwave drill." This microwave drill is made from a 600-watt magnetron taken from a conventional kitchen microwave oven and a powerful microwave beam capable of penetrating solid objects. 

The tip of the drill -- a pointed rod -- aims the beam at a solid substance (silicon, glass, alumina were among the materials tried) and creates a hot spot in the solid. When the drill is pulled away from the hot spot, the drag produces a fireball resembling ball lightning.

How ball lightning seems to float through walls, however, is still up for debate.

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Magnetic Waves Could Replace Microwaves

A simulation of a magnetic nanocontact shows how it causes spin waves to spread like rings on water.

The microwave technology used in applications such as mobile phones and wireless networks may be on its way to being replaced - with parts that are smaller, less expensive, and that consume less resources. Instead of microwaves, devices of the future may use spin waves, which are nanoscale magnetic waves.

For almost ten years, it has been theorized that spin waves could be propagated using magnetic nanocontacts. Recently, scientists from the University of Gothenburg and the Royal Institute of Technology, Sweden, became the first people to demonstrate that the theory meshes with observable phenomena.

 

The study began two years ago, when the researchers started construction of their magnetic nanocontacts. Using one of the world's three advanced spin wave microscopes, at the University of Perugia in Italy, they were able to visualize the movement of the spin waves created by those contacts. The waves rippled out through a thin film of nickel-iron alloy, which was three nanometers thick.

According to the scientists, these results have opened the way for a new field of research known as "magnonics," that utilizes spin waves. The technology could reportedly be integrated into traditional microwave-based electronic circuits, although the added magnonic components would be much better suited to miniaturization than their present-day microwave counterparts.

"I believe that our results will signal the start of a rapid development of magnonic components and circuits," said the University of Gothenburg's Prof. Johan Akerman. "What is particularly exciting is that these components are powered by simple direct current, which is then converted into spin waves in the microwave region. The frequency of these waves can be directly controlled by the current. This will make completely new functions possible."

Below is a video depicting a simulation of six wave-producing magnetic nanocontacts placed in a circle, illustrating how the contacts can be placed in any pattern.

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Gold From Heaven

When our planet was still forming, collisions with other planetesimals — and a Mars-sized object that sheared away the moon — turned the embryonic Earth into a roiling ball of molten rock. Iron and other heavy elements sank toward the core, and other iron-loving elements did, too. As a result, there’s plenty of gold at our planet’s center. So why, then, is there also gold in the hills? A new study supports the theory that it was all a gift from above.

Meteorites seeded the Earth with a fresh, crust-level supply of noble metals half a billion years after the planet coalesced, British scientists say. And given how the Earth’s crust has been mixed since then, the researchers speculate that meteorites may have even given us plate tectonics.

The Late Heavy Bombardment was a cataclysmic era between 3.8 and 4.1 billion years ago in which waves of meteorites rained billions of tons of material onto the Earth, moon and the other terrestrial planets. These meteorites brought gold, tungsten and other precious elements, explain Matthias Willbold and Tim Elliott of the University of Bristol.

To test this theory, the team studied 3.8 billion-year-old rocks from Isua, Greenland, some of the oldest rocks on the planet. The rocks formed after the bombardment era, but they contain isotopic information that can tell scientists about earlier Earth conditions. 

Willbold and Elliott zeroed in on an isotope of tungsten, ¹⁸²W, of which there’s an elevated ratio in the Earth’s mantle. This is because the tungsten isotope is a daughter product of another radioactive element present amid crustal silicates. Which is to say, an added veneer of metals from meteorites would have a relatively lower ratio.

Using incredibly precise analysis — this tungsten ratio is measured in units of parts-per-10,000 — the researchers were able to tell that Greenland rocks do have a higher tungsten-182 ratio than modern-day rocks. The small difference is in agreement with how a bombardment would have added material to the Earth’s crust. This bombardment explains the otherwise surprisingly high abundance of precious metals in the crust, the researchers say. 

“Our work shows that most of the precious metals on which our economies and many key industrial processes are based have been added to our planet by lucky coincidence,” Willbold said in a statement.

There’s one other cool aspect of this study. Willbold and Elliott discussed that the ratio in modern rocks means plate tectonics must have stirred in the new, meteorite-delivered rocks relatively quickly. Thus the Late Heavy Bombardment, in addition to giving us precious metals, may have initiated mantle dynamics that still exist, they write. 

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