Radio Telescope Reveals How Lightning Begins (quantamagazine.org) 22
"Scientists have never been able to adequately explain where lightning comes from," writes Quanta magazine, sharing a remarkable new animation of a lightning flash recorded by the LOFAR radio telescope network"
In a new paper that will soon be published in the journal Geophysical Research Letters, researchers used the observations to settle a long-standing debate about what triggers lightning — the first step in the mysterious process by which bolts arise, grow and propagate to the ground. "It's kind of embarrassing. It's the most energetic process on the planet, we have religions centered around this thing, and we have no idea how it works," said Brian Hare, a lightning researcher at the University of Groningen and a co-author of the new paper....
[T]he electric fields inside clouds are about 10 times too weak to create sparks. "People have been sending balloons, rockets and airplanes into thunderstorms for decades and never seen electric fields anywhere near large enough," said Joseph Dwyer, a physicist at the University of New Hampshire and a co-author on the new paper who has puzzled over the origins of lightning for over two decades. "It's been a real mystery how this gets going." A big impediment is that clouds are opaque; even the best cameras can't peek inside to see the moment of initiation. Until recently, this left scientists little choice but to venture into the storm — something they've been trying since Benjamin Franklin's famous kite experiment of 1752...
LOFAR, a state-of-the-art astronomical telescope, can map lighting on a meter-by-meter scale in three dimensions, and with a frame rate 200 times faster than previous instruments could achieve. "The LOFAR measurements are giving us the first really clear picture of what's happening inside the thunderstorm," said Dwyer...
Long-time Slashdot reader g01d4 summarizes their results: It seems to be something of a chain reaction starting with clusters of [charged] ice crystals inside the cloud... "More electrons flow in from air molecules that are farther away," according to the article, "forming ribbons of ionized air that extend from each ice crystal tip." These are called streamers which build up numbers until one becomes hot and conductive enough to turn into a leader — a channel along which a fully fledged streak of lightning can suddenly travel.
Quanta magazine adds that the key role of ice crystals "dovetails with recent findings that lightning activity dropped by more than 10% during the first three months of the COVID-19 pandemic. Researchers attribute this drop to lockdowns, which led to fewer pollutants in the air, and thus fewer nucleation sites for ice crystals."
[T]he electric fields inside clouds are about 10 times too weak to create sparks. "People have been sending balloons, rockets and airplanes into thunderstorms for decades and never seen electric fields anywhere near large enough," said Joseph Dwyer, a physicist at the University of New Hampshire and a co-author on the new paper who has puzzled over the origins of lightning for over two decades. "It's been a real mystery how this gets going." A big impediment is that clouds are opaque; even the best cameras can't peek inside to see the moment of initiation. Until recently, this left scientists little choice but to venture into the storm — something they've been trying since Benjamin Franklin's famous kite experiment of 1752...
LOFAR, a state-of-the-art astronomical telescope, can map lighting on a meter-by-meter scale in three dimensions, and with a frame rate 200 times faster than previous instruments could achieve. "The LOFAR measurements are giving us the first really clear picture of what's happening inside the thunderstorm," said Dwyer...
Long-time Slashdot reader g01d4 summarizes their results: It seems to be something of a chain reaction starting with clusters of [charged] ice crystals inside the cloud... "More electrons flow in from air molecules that are farther away," according to the article, "forming ribbons of ionized air that extend from each ice crystal tip." These are called streamers which build up numbers until one becomes hot and conductive enough to turn into a leader — a channel along which a fully fledged streak of lightning can suddenly travel.
Quanta magazine adds that the key role of ice crystals "dovetails with recent findings that lightning activity dropped by more than 10% during the first three months of the COVID-19 pandemic. Researchers attribute this drop to lockdowns, which led to fewer pollutants in the air, and thus fewer nucleation sites for ice crystals."
Science is lit (Score:2)
Nope (Score:3, Insightful)
This might be the single most absurd, specious summary I've ever seen on slashdot.
"we have no idea how it works"
This is stupid on the level "it is impossible for bees to fly."
This is just a paper about using a radio telescope to take new readings of a lightning bolt starting.
There are a bunch of different situations that can cause lightning bolts. This measurement proved that this particular lightning bolt was caused by the most common theoretical explanation for lightning bolts. That's it.
Re: (Score:2)
Wait, wait, you thought media reporting on scientific papers was peer reviewed?! Wow, you're really stupid.
You weren't even able to figure out what I was talking about.
Re: (Score:2)
Yeah. I read it this way too.
Re: (Score:2, Informative)
"Not having the exact process pinned down from start to finish with complete certainty due to measurement difficulty, but still having a robust model" isn't "we have no idea how it works"
Re: Nope (Score:3)
News for people told STEM is important (Score:1)
Indeed. (Score:2)
This has been known since ancient times. The Elder Cyclopes forge the bolts, and Zeus throws them down at the earth.
Done. Next!
Re: (Score:1)
Just the part about "It's the most energetic process on the planet..." really got me. Lightning can be pretty impressive, but "most energetic"? Compared to, for example, a tsunami, or an earthquake? If you've ever seen video of the crater of an active volcano filled with roiling lava with globs of it weighing hundreds of tons leaping into the air, a lightning bolt can seem pretty puny in comparison.
Re: (Score:2)
Energetic as in emitting X-rays, gammas, and showers of positrons.
Doesn't specify this anywhere in the article that I can see. So does the huge amount of EM radiation produced by the roiling lava I mentioned not count? Xrays generated by piezo-electrical effects in seismic events? Not to mention that even you're admitting here that lightning itself can occur as a secondary effect of geophysical processes. In context, it didn't seem like they were talking specifically about the highest energy level found in radiation produced by the event, otherwise you'd have to compare i
Re: (Score:2)
but not in the caldera
Now look up the radiation difference between a brick house and a wood house, and hang your head in shame. You'll never get a nerd card at this rate!
Pop quiz... how many millions of cubic meters has Kilauea erupted in the last 3 months? How much radiation is it emitting?
Re: (Score:2)
Just the part about "It's the most energetic process on the planet..."
volcano filled with roiling lava
Forget the volcano, what about the processes within the body of the planet bringing it to the surface?
And you can't get pedantic about "on" the planet being the surface, when the context is something... above the planet!
Re: (Score:2)
Forget the volcano, what about the processes within the body of the planet bringing it to the surface?
Sure. I didn't mean for that to be an exhaustive list. My point was just that, unless you're using a custom made definition of "most energetic process on the planet" that's designed specifically so lightning wins, there are plenty of other processes that beat it. Heck, it doesn't even specify that they need to be natural processes.
So plasma? (Score:3)
It's the most energetic process on the planet, we have religions centered around this thing, and we have no idea how it works
Yeah... generally that's how many religious' approaches are -- attempts to explain things that are beyond our reasoning or base justification.
It seems to be something of a chain reaction starting with clusters of [charged] ice crystals inside the cloud
So it's a plasma? I don't get how this is different than any reasonable scientific approach to what lightning is. Don't get me wrong, these observations seem interesting in that they could better our ability to simulate lightning especially in more of it's different forms which will be great work but this writing seems like crap and the layman explanations seem equally meh.
Re: (Score:2, Interesting)
So it's a plasma?
Yup. They've confirmed that it is indeed a lightning bolt.
In all seriousness, they've confirmed (supposedly) one of the leading hypotheses for how a leader starts- ice crystals.
Another neat one is showers of relativistic electrons coming in from above, but I kind of figured ice crystals would end up being the right answer.
Authors of the paper are, regardless of their ability to produce scientific results, fucking morons for saying shit like "we have no idea how it works"
Glorifying your scientific res
Re: So plasma? (Score:3)
The way I'm reading this is that it's not about whether it's a plasma, but rather how that plasma forms, on what scale, and why.
I can't exactly tell from what's linked, but I'm wondering if this is related to the fact that the electric field at sharp corners and tips of charged insulator can be very high. I used to build mass spectrometers and a major issue was always making sure you had no sharp edges, because if the edge ever gets insulated (like coated in an oxide layer) and charged, it can lead to very
Re: (Score:2)
Yeah. This is fair. The article being popsci doesn't seem to outline that very well. Another poster mentioned they don't seem to really explain where the charge is coming from in the first place but I assume this is a matter we can better explain when we combine these observations with simulation. I agree, it does seem to focus on "why" but this is kind of one of those questions that can lead to the magical approach of magnetism Feynman outlines -- when alternatively with enough of a basis in the science, w
Re: So plasma? (Score:2)
For my PhD I built/modified/used home-made tandem time of flight mass specs, with the first stage being Wiley-Mclaren designs and 2nd/3rd stages being reflectrons. Between stages the ion packets were intercepted by infrared lasers that fragmented the ions (the we're "re-weighed" by the next stage)
It was all electrostatic-based, using voltages that were 1-20 kV. But if a component got oxidized (they all do eventually), the surface charge could build up at edges causing massive fields that steered the ion be
Yes, plasma (Re:So plasma?) (Score:1)
Better teaser from the preprint (Score:2)
Our observations show that for a system of streamers the properties are entirely different, and cannot be explained by a simple superposition of individual streamers. This poses a significant challenges [sic] to models, as the velocity of the front of the discharge of many individual streamers remains constant with radiation increasing exponentially. There must be a process which maintains this velocity and growth which has yet to be explained.
The preprint needs editing, but the time and spatial resolution reveal a process in ensemble propagating at c/62. Single event: yes, but interesting.