Researchers explore how storms on Earth create extreme bursts of radiation • Hacker News Board

Re: Researchers explore how storms on Earth create extreme bursts of radiation

#21

Post by dms_ucsc » Fri, Feb 19, 2021, 7:37 PM UTC

swayvil wrote: post #7

I heard that lightning is triggered by cosmic ray particles. A seed in a supersaturated solution situation. And cosmic rays always come from very very far away. So a lightning bolt is literally an amplified message from beyond.

People in the field have gone back and forth on this, but you might like this paper, which is the best piece of evidence I've seen for it in a specific case of a specific flash. Look in particular at Figure 6 to see the lightning breakdown starting just at the ionization front (curved surface) of the cosmic ray shower: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/201...

Re: Researchers explore how storms on Earth create extreme bursts of radiation

#22

Post by dms_ucsc » Fri, Feb 19, 2021, 7:41 PM UTC

swayvil wrote: post #15

temp0826 wrote: post #13

Earlier quoted context omitted.

I don’t think that’s always the case as it doesn’t really account for ground-to-cloud lightning strikes

Well I dunno about "always the case", but it's certainly accountable for ground-to-cloud. What the seed does is create a place of high potential. I think which way the lightning flows is arbitrary at that point.

The case in the paper I linked above was an intracloud flash, but nearly all cloud-to-ground flashes also start with a breakdown up in the cloud, so I agree that any model of lightning initiation can apply to both intracloud and cloud-to-ground flashes.

Re: Researchers explore how storms on Earth create extreme bursts of radiation

#23

Post by dms_ucsc » Fri, Feb 19, 2021, 7:44 PM UTC

Double_Cast wrote: post #9

maxerickson wrote: post #6

Earlier quoted context omitted.

They want to figure out the details of why and how it happens.

I think snarfy is expressing incredulity that meteorology doesn't already account for these types of emmissions. Analogously, suppose the headline had read > Water flows downhill. Scientists want to know why. "But gravity makes everything flow downhill, right? What makes water especially worthy of investigation." Surely this is a reasonable reaction.

I agree it is. And C.T.R. Wilson was talking about it in 1925. But the TGFs mentioned in the article are incredibly bright, and what we're trying to understand (I work in this field) is why one lightning flash makes only a modest amount of x- and gamma-rays, kind of what you might naively expect, and another makes a mind-boggling million times as many, which is not as simply understood.

Re: Researchers explore how storms on Earth create extreme bursts of radiation

#24

Post by swayvil » Fri, Feb 19, 2021, 9:00 PM UTC

dms_ucsc wrote: post #22

swayvil wrote: post #15

Earlier quoted context omitted.

Well I dunno about "always the case", but it's certainly accountable for ground-to-cloud. What the seed does is create a place of high potential. I think which way the lightning flows is arbitrary at that point.

The case in the paper I linked above was an intracloud flash, but nearly all cloud-to-ground flashes also start with a breakdown up in the cloud, so I agree that any model of lightning initiation can apply to both intracloud and cloud-to-ground flashes.

Navajo mythology says that a man who was struck by lightning cannot be trusted. Not because he's evil or damaged, but because he has been touched by profound alienness. He's too weird to predict.