EMP blast - what would happen really?

Would you mind explaining that to Eeore?

There are good reasons for them being above ground in a lot of places. Overhead wires don't get flooded out in heavy rain, and you don't have to remove lots of rocks and trees to put the lines in place. Do you have any idea how many million trees would have to be cut down to put all of our electric lines underground? They have to use dynamite to set power and telephone poles around Cincinnati, Ohio. The standard work order is marked. R. I. P. which means "Replace in Place". They cut the old pole off a little above ground level and remove the piece from the ground. The new pole goes back into the same hole, and the lines are transferred.

On the other hand, a lot of telephone and CATV lines are buried, because they can use above round pedestals for splices and access points.

Tim - yes, corrrect, Einstein hated quantum theory, but but the numbers do work out. And Einstein spent all of his time to the day he died trying to get the Unified Field theory to work out, but it didn't happen for him.

Also correct, EM radiation is photons, zero rest mass, but a nuclear explosion, or reactor meltdown gives off all kinds of nasty things, although I can't name them off the top of my head. Possibly gamma rays. Gamma rays are photons, but they are commonly referred to as Gamma particles.

This is from the EPA site: "Gamma radiation is very high-energy ionizing radiation. Gamma photons have about 10,000 times as much energy as the photons in the visible range of the electromagnetic spectrum. Gamma photons have no mass and no electrical charge--they are pure electromagnetic energy."

And the 18,000 volts? As someone pointed out about lightning, it ain't the voltage, it's the current that'll kill you

Also, E=mc**2. So, the gamma particle has no mass, except when it's moving, then it has mass, but it can't be measured directly due to the exclusion principle, which get's back to quantum mechanics, and who's on first, what's on second, and I am outta here. I concede defeat. I'm going to pick up Einstein's Unified Field Theory, where he left off, and get the math worked out this afternoon. Maybe I'll hop on over to sci.math :-)))).

Right out of my head! ;-)

Sorry, Rich

The energy content of fields from a lightning strike are really quite low. For example, a few hundred foot long antenna may suffer a few thousand volts from a nearby lightning strike. But the energy content is so low that the voltage drops to near zero when milliamps are conducted through an NE-2 neon glow lamp.

Meanwhile the fields from a thermonuclear blast are completely different. For starters, the frequency response from NEMP is totally across the spectrum - all frequencies. Electric power grids were not destroyed by this field. Those grids became unstable when their long wires (acting like antennas) simply caused control and safety equipment to see a failure condition and shutdown. The grid did not blow. It simply crashed just like a computer crashes - without hardware damage.

Too many see big voltage numbers and then assume massive energy. Lightning, for example, has massive power but far less energy at a strike location. It is why most all trees struck by lightning leave almost no indication.

NEMP is different from lightn> No, I was talking about the voltage in wires(low resistance,high current,

(Why is your reply appearing in response to Sjouke?)

Oh, it gives off trash literally across the spectrum. The worst offenders, high-energy (say, more than 10 or 20eV) ionizing radiation (UV-B or UV-C to x-rays to gamma) is all absorbed by a sufficient thickness of atmosphere (since the molecules have dissociation energy circa 4-10eV, and are rich with electrons and nuclei which attenuate x- and gamma rays by momentum exchange).

Visible light is the 1.5-3eV range (more or less), so that puts gamma rays starting at 15-30keV -- hard x-rays I would say, personally. But they'll be picked up on most "gamma" detectors.

-- It's always moving. A photon with energy five billionths of an electron-volt (5 x 10^-9) still moves at the speed of light. It's nigh impossible to detect a single such photon (carrying merely 1.6 x 10^-28 joule!), but a couple oh, say, ten trillion trillion million, per second, travelling together, represents about the output of a commercial transmitter (maybe 10kW in this case).

It NEVER has mass. It does, however, follow space-time (relativistic gravity lensing), and carries energy and momentum (p = m*v classically, but relativistically p = gamma*m*v, where gamma --> infinity at light speed, allowing mass --> 0). The relation is E = p*c (c is speed of light).

No, the Pauli Exclusion Principle only applies to leptons (such as electrons, neutrinos, and the more exotic muons and tauons). Photon wave functions happily overlap, a fortunate occurance given our need of lasers and radio waves.

The Heisenberg Uncertainty Principle, however, states that there is some maximum accuracy that can be obtained when measuring an object's position and momentum, or energy (including rest mass energy (RME)) and time.

An excellent idea. Perhaps they will grill you much better than I have.

Tim

"w_tom" wrote in news: snipped-for-privacy@h48g2000cwc.googlegroups.com:

Uh,I see a lot of trees struck by lightning here in central Florida,and they usually have a trail of bark blown off them where the bolt travels down to ground.Later,the tree dies.

NEMP depends on altitude.

Do you have a link to the Forest Service study.

My experience with lightning-struck trees is limited, but I do recall a pine tree that exploded about halfway down the trunk and scattered wood debris over a large area. I was in a building across a parking lot from the strike looking out a window.

The Forestry Service study is cited by Dr Uman (U of FL) in one of his books. I don't remember which one. Alan Taylor, I believe, did that study.

Many don't realize how often lightning does strike earth. Homeowners typically can expect about 1 direct strike every eight years. But even this number varies widely with geology and even within same town. Neighborhood history would also be an important fact. So how often has your neighborhood been struck every year?

Another myth is that highest objects are struck. For example, mountains instead tend to be struck more often farther down where better conductive geology is located. Often valleys between mountains are struck more often because that is better conductive soil. But myths assume lightning strikes highest point only because that is where lightning strikes are more often observed. Selective data collection also created myths about electric wires and child diseases.

There are lots of trees destroyed by lightning here in Florida, and a lot of fires started by lightning strikes. Tom keeps insisting that there is no current with a lightning strike, but I've seen the end of a

Elsewhere provided were numbers - that Michael now intentionally misquotes. Lightning is most often less than 20,000 amps. Lightning at a strike location does not have the high energy content of myths. High power, but not the high energy that so many claim only using assumptions.

Yes, numerous trees are killed by lightning. And there are far more are struck without that catastrophic damage.

Michael cites a 1/2" steel rod melted by a lightning strike as proof that lightning routinely melts lightning rods? And that would also be proof that lightning routinely vaporizes anything that is struck?

w_tom does not insist that there is no current in a lightning strike. Quite the contrary. Lightning is a classic current source transient. Michael A Terrell is demonstrating personal contempt of w_tom rather than posting logically. Michael Terrell will even completely misrepresent what w_tom has posted.

You made a claim in the past that the damage done to electrical circuits was from the AC power lines, not the lightning.

I don't think the conductivity of the ground vs that of a wet tree has anything to do with it. Before the bolt stikes, there is very little current flow and the top of the wet tree is at essentially the same (ground) potential as a copper pipe in the ground.

And height is a factor but a small one becasue when you consider the bolt is traveling over 5000 feet another 50 feet here or there is not a big deal, so just by random chance a low spot or a high spot may be struck. The 50 foot high spot a little more likely. The 1200 foot hight spot like the Empire State Bld. MUCH more likely.

Mark

Michael, you are now confusing two completely different topics. Learn from those who do this work successfully and also write. From Colin Baliss in his book "Transmission & Distribution Electrical Engineering":

So how did you re> You made a claim in the past that the damage done to electrical

I am a bit disappointed here, I had not thought you could become a troll. Mind you, i had learned the answers to this question by myself by the time i was 16. Perhaps you are just a journalist.

Get an entire 50 pound bag of salt before reading these sites. Most any adequately educated person could find the gross inconsistencies, politically motivated distortions, and some outright lies. Better educated persons could find most of the baloney physics, clearly misunderstood physics, and the skewed thought trains driving the distortions. These sights can best be used as an example to teach the small mindedness of politicians.

On 16 Aug 2006 16:43:52 -0700, "w_tom" Gave us:

I have seen several trees that were split wide open from lightning strokes. I have seen them aflame as well.