Dusty fireball: can lab-made blob explain ball lightning?
By trapping and X-raying a mysterious kind of artificial fireball fireball, very bright meteor leaving a trail in the sky that can remain visible for several minutes; often a distinct sound, perhaps caused by very low frequency radio waves, is associated with it. , researchers have demonstrated a technique that may help answer whether chemical reactions This is the 18th episode of television drama Men in Trees. It originally aired on June 25, 2007 on the TV2 network in New Zealand as a continuation of season 1. Recap
Marin and Cash have a stew cook off, she admits his is better than hers. power the ball lightning occasionally seen in nature.
The fireballs first showed up in the late 1990s in the lab of Vladimir Dikhtyar and Eli Jerby, engineers at Tel Aviv University Tel Aviv University (TAU, אוניברסיטת תל־אביב, את"א) is Israel's largest on-site university. in Israel. The researchers were testing their newly invented type of drill. Made in part out of pieces from conventional microwave ovens, the drill has a tip that concentrates microwave radiation into a 2-millimeter-wide spot that can pierce many materials and liquefy liquefy /liq·ue·fy/ (lik´wi-fi) to become or cause to become liquid. its way through.
One day, as the researchers extracted the drill tip from a sample, a glowing blob unexpectedly blew out of the molten material. The blob made its way back inside the drill and into the microwave generator. "It caused a lot of damage," Jerby says.
With some tinkering, the researchers learned how to reproduce the phenomenon with consistency by drilling into glass. They also found a way to cage a fireball and sustain it for up to several minutes by zapping it with additional microwaves inside a glass-walled "oven" the size of a tissue box.
Like other, similar phenomena that scientists have learned to create in the lab, the fireballs only partly resemble natural ball lightning. Ball lightning appears after lightning strikes soil, not after microwaves strike glass. It's often the size of a basketball or larger, tends to float in midair or bounce on the floor, and can last several seconds or even minutes. By contrast, Dikhtyar and Jerby's fireballs were only centimeters wide, tended to travel upward, and, if left alone, vanished within 30 milliseconds.
Still, the researchers were interested in testing one of the more plausible among the many mechanisms scientists have proposed to explain ball lightning (SN: 02/09/02, p. 87). In 2000, chemical engineers John Abrahamson and James Dinniss of the University of Canterbury
(SiO2) A hard, glassy mineral found in such materials as rock, quartz, sand and opal. In MOS chip fabrication, it is used to create the insulation layer between the metal gates of the top layer and the silicon elements below. , releasing silicon that then recombines with oxygen, which emits the energy that keeps the plasma glowing.
Dikhtyar and Jerby teamed up with scientists in France to measure how their plasma scattered an intense beam of X rays. As reported in an upcoming Physical Review Letters Physical Review Letters is one of the most prestigious journals in physics. Since 1958, it has been published by the American Physical Society as an outgrowth of The Physical Review. , the researchers found particles around 50 nanometers wide. That "supports the Abrahamson and Dinniss model," Abrahamson says, and the particle size "lies in the range that we observed after simulated lightning strikes on soils."
Lightning expert Martin Uman of the University of Florida University of Florida is the third-largest university in the United States, with 50,912 students (as of Fall 2006) and has the eighth-largest budget (nearly $1.9 billion per year). UF is home to 16 colleges and more than 150 research centers and institutes. in Gainesville says the result is interesting, "but it's problematic whether it has anything to do with ball lightning."