Infrasound and Meteors

Humans typically can hear sound waves in the range 20 Hz to 20,000 Hz. Frequencies below 20 Hz are called infrasound and frequences above 20 kHz are called ultrasound. The speed of sound in dry air at a temperature of 20˚ C (68˚ F) and an atmospheric pressure of 1 bar (slightly less than the average air pressure at sea level) is 343 m/s. Dividing the speed of sound by the frequency (in Hz) gives us the wavelength of the sound waves: 17 m (56 ft.) at 20 Hz, and 17 mm (0.67 in.) at 20 kHz.

Meteoroids enter the Earth’s atmosphere (thus becoming meteors) at hypersonic velocities, 35 to 270 times the local speed of sound (Mach 35 to Mach 270). Only a small portion of the total energy of the incoming meteoroid is transformed into visible light: most of the energy dissipated goes into acoustic shock waves. If the meteoroid is on the order of a centimeter (0.4 inches) or larger, infrasound waves are generated that can be detected on the ground, albeit after a delay of many seconds to minutes.

Infrasound waves can travel long distances, but higher frequencies are attenuated due to spreading losses and absorption over much shorter distances. There are many natural and man-made sources of infrasound waves, so identifying an incoming meteoroid as the source of the infrasound requires that we also “see” and record the meteoroid optically (the “meteor”), through radar, or VLF radio emissions from the meteoroid’s ionization trail in the Earth’s atmosphere. Ideally, all of these methods should be used at each observing station to best characterize the size and kinetic energy of each incoming meteoroid.

Infrasound detectors are not yet an off-the-shelf commodity. Chapparal Physics (http://www.chaparralphysics.com) is one good source, but seeing as they do not list any prices you know the equipment will be expensive.

An infrasound detector is basically an extremely sensitive microphone that can detect tiny changes in air pressure. A peak sensitivity around 1 Hz is probably a good place to start for detecting meteors. Meteors large and/or energetic enough to be detected on the ground are rare, not even one a day for a given station, so automated recording will be necessary.

Finally, it is important to know that louder sounds that we cannot hear (infrasound and even ultrasound) can sometimes have adverse physical and psychological effects on humans. The cause can be as simple as a malfunctioning piece of mechanical or electrical equipment, or as nefarious as a sonic weapon. It would be advantageous to have a readily available and affordable infrasound and ultrasound detector to detect problem emissions.

For example, you might want an

  • Infrasound detector that maps 0.02 Hz – 20 Hz to the 20 Hz – 20 kHz audible range
  • Ultrasound detector that maps 20 kHz – 20 MHz to the 20 Hz – 20 kHz audible range

References
Silber, Elizabeth A. (2018). Infrasound observations of bright meteors: the fundamentals. WGN, Journal of the International Meteor Organization, 46:2.


Tax Choice

Wouldn’t it be nice if you got to choose where some of your income tax money goes? Where you the taxpayer have some say in how your hard-earned tax dollars are allocated?

Here in the dis-United States, about 50% of us want lower taxes, and 50% of us would be receptive to higher taxes provided that it pays for things we believe in like universal health care and low-cost or no-cost education.

Short of amicably splitting up our country (a civil separation), changing our tax policy may help alleviate some of the frustration many of us have that half of the country is keeping us from building the kind of country we want for ourselves and for our children.

Federal income tax, and state and local income tax (where in effect) would be divided into a non-discretionary portion (100% currently) and a discretionary portion.

When you fill out your tax return each year, you would designate the government agencies and programs where you want the discretionary portion of your taxes to go.

Going one step further, I would like to see taxpayers given the option to choose either the standard or a supplemental tax tier. Those who opt to pay higher taxes by choosing the supplemental tax tier would pay a fixed percentage more, regardless of income (like a true flat tax).

To be fair, those paying in at the higher supplemental tax rate should receive additional benefits compared to those paying in at the standard rate. This could mean lower medical costs, lower education costs, or increased social security payments during retirement, for example.

Would this be easier to implement than partitioning the U.S.? Perhaps. Would it be the more effective solution to satisfy those with very different viewpoints about the proper role of government? Perhaps not.

In my view, society is far too reliant on volunteers. If a job is worth doing, and if it is a benefit to society, then, more often than not, it needs to be a paid position. There is so much work of a humanitarian, educational, and environmental nature that needs to be done that cannot and will not be done by any capitalistic enterprise. As members of society, we all have an obligation to help fund these activities through strong government and non-sectarian non-profit partnerships.

I dream of a day when paying for our medical care is no longer tied to having health insurance through an employer, when each of us will have the freedom to work in a variety of capacities, for both profit and non-profit organizations, throughout our careers, and to receive adequate training and pay for those efforts.


A Warm Day on Pluto

The coldest weather I’ve ever experienced occurred January 30-31, 2019. Here in Dodgeville, Wisconsin, I measured a low temperature the morning of Wednesday, January 30, 2019 of -31.0° F and a high that day of -14.4° F. It was even colder the following night. On Thursday, January 31, 2019 the low temperature was -31.9° F.

Thanks to the National Weather Service, we had advance notice of the arrival of the Arctic polar vortex that was to bring the coldest weather to Wisconsin in a generation. Concerned about the effect this would have on my observatory electronics, I started running my warming room electric heater continuously from 8:30 p.m. CST Monday, January 28 until 9:45 a.m. CST Friday, February 1. Of course, I left the warming room door open to the telescope room to ensure that some of the heat would reach the telescope and its associated electronics.

During this time, I made a number of temperature measurements from an Oregon Scientific weather station inside the house, connected by 433 MHz radio frequency signals to temperature sensors inside the observatory and on the north side of my house.

Here are those observations:

And here is graph plotting both temperatures at each time:

Air (north side of house) and Observatory (inside the observatory) temperatures January 28-February 1, 2019.

And here is a plot of the temperature difference vs. the outside Air temperature:

Temperature difference vs. Air temperature with a linear regression line

There seems to be a general trend that the colder it was outside the observatory, the bigger was the temperature difference between inside the observatory and outside the observatory. Why is that? The electric heater is presumably putting out a constant amount of heat, so you might think that the temperature difference would remain more or less constant as the temperature goes up and down outside. It doesn’t.

There are a number of factors influencing the temperature inside the observatory. First, there is the thermal mass of the observatory itself, and some heating of the inside of the observatory should occur when the sun is shining on it. There is the wind speed and direction to consider. There may be some heating through the concrete slab from the ground below. It seems to me that thermodynamics should be able to explain the general downward trend in ΔT as the outside air temperature increases. Can you help by posting a comment here?

You’ll notice three outliers in the graph above where ΔT is quite a bit lower than the regression line. The points (-22.0,16.6) and (-10.5,10.1) were consecutive measurements just 76 minutes apart (8:32 a.m. and 9:48 a.m.), the first readings I made after the lowest overnight temperature of -31.9° F on 1/31. The point (8.2,7.6) was my first reading on 1/28 at 8:42 p.m., soon after turning the space heater in the observatory on. The points (-16.4,25.2), (-17.9,26.0), (-19.5,26.3), (-25.1,27.2), and (-26.9,27.4) all are above the regression line and are consecutive readings between 8:29 p.m. on 1/29 and 3:20 a.m. on 1/30 before the -31.0° F low on the first really cold night.

My weather station keeps track of the daily high and low temperatures, but not the time at which those temperatures occur. On 1/30 when the outside low temperature of -31.0° F was recorded, the low inside the observatory was -4.0° F (though not necessarily at the same time). ΔT = 27.0°. The high temperature that day was -14.4° F and 6.4° F inside the observatory (ΔT = 20.8°). The next night, 1/31, the low temperature was -31.9° F and -6.2° F inside the observatory (ΔT = 25.7°).

So, despite the many factors which influence the temperature differential between outside and inside the observatory, the clear trend of smaller ΔT at warmer outside temperature begs for an explanation. Can you help?

Pet Peeves

Here is a list of 10 irritations, in no particular order, that make me feel like an alien on my own planet.

  1. High color temperature headlights – Traditional automotive headlights have a yellowish-white color temperature of 3200K. Xenon headlights emit a bluish-white light around 4500K. LED lights are even bluer at around 6000K. These new “blue” headlights make me want to give up night driving altogether. They are too glary and too bright for oncoming traffic. Add in the same for so-called “fog” lights, and the result is often blinding for other drivers.
  2. High color temperature LED lights – While we’re on the topic of lighting, most indoor and outdoor LED lighting should have a color temperature between 2700K and 3000K. This provides a soothing yellow-white light instead of the garish and glary blue-white LED lights in common use today with a color temperature of 4000K or even higher.
  3. Dusk-to-dawn lighting – With the availability of modern light sources, control, and dimming technologies, most outdoor lighting does not need be on or running at full brightness all night long.
  4. Television advertisements – I don’t know how anyone can stand to watch television because there are so many advertisements. I’ve given up watching anything that has advertisement propaganda embedded within the program.
  5. Dystopian movies and television programs – Why would anyone find a dystopian portrayal of the future entertaining or even desirable? I find it utterly horrifying and we should do everything possible to make sure such a future never occurs. Furthermore, I find the amount of violence and aggression in movies and television appalling. This is entertainment? No thanks, I’ve got better things to do with my time.
  6. TV Screens in Restaurants – When I’m dining at a restaurant, just about the last thing I want to see is the distraction of one or more television screens. I’m there to enjoy the food and the company I’m with and screens of any kind are intrusive.
  7. Overuse of smartphones – So many people seem addicted to their smartphones. I don’t generally use one and get along just fine. As much as I use computers in my everyday life, I don’t want one with me everywhere I go. I am really thankful I grew up before personal computers and smartphones existed. Gives one a different perspective.
  8. Sports – I have absolutely no interest in sports. Physical fitness and healthful living, yes, but sports seems like a big waste of time. I don’t see how so many folks can get so excited about something that does absolutely nothing to make the world a better place.
  9. Hunting – I don’t see how anyone can derive pleasure out of depriving another animal of its life. It’s just sick. It is one thing to kill an animal if it is necessary for survival, or self-defense, but for sport it is disgusting. For necessary animal population control, why not use high-tech science-based birth control methods instead?
  10. Pets – I love seeing animals in nature, but have no interest in owning or taking care of a domesticated animal. I much prefer solitude or the company of people. I’m too busy to have any time for a pet, anyway. Don’t like it when you visit someone and their dog or cat jumps on you or licks you. Yuck.

Blue Light Blues

One by one, all of our warm white lights are being replaced by cold, harsh, bluish-white LEDs.  And it is happening fast.

Everywhere.  In our streetlights, our workplaces, even our homes.  How do you like looking into those blue-white vehicle headlights as compared with the yellow-white ones we have been using since the automobile was invented?

LED lighting is the way of the future, don’t get me wrong, but we should be specifying and installing LED lights with a correlated color temperature (CCT) of 2700K or 3000K—with few exceptions—not the 4000K or higher that is the current standard.

Why is 4000K the current standard?  Because blue-white LEDs have a slightly greater luminous efficacy than yellow-white LEDs.  Luminous efficacy is the amount of light you get out for the power you put in, often measured in lumens per watt.  But should luminous efficiency be the only consideration?  What about aesthetics?  In addition to luminous efficacy, there are other, more significant ways to reduce power consumption and greenhouse gas emissions:

  • Use the minimum amount of light needed for the application; no need to overlight
  • Use efficient light fixtures that direct light only to where it is needed; near-horizontal light creates annoying and visibility-impairing glare and light trespass, and direct uplight into the night sky is a complete waste
  • Produce the light only when it is needed through simple switches, time controls, and occupancy sensors; or, use lower light levels during times of little or no activity

Even the super-inefficient incandescent light bulb (with a CCT of 2400K, by the way), operating three hours each night uses less energy than the light source with the highest luminous efficacy operating dusk to dawn.  Think about it.

In my town, as in most now, the soothing orange 1900K high pressure sodium (HPS) streetlights are being replaced with 4000K LEDs.  That’s a big change.  It will completely transform our outdoor nighttime environment.  Warm-white compact fluorescents are 2700K, and even tungsten halogen bulbs are 3000K.  Do we really want or need 4000K+ LEDs?

We are currently witnessing a complete transformation of our illuminated built environment.  Not enough questions are being asked nor direction being given by citizens, employees, and municipalities.  The lighting industry generally wants to sell as many lights as possible at the highest profit margin.  We as lighting consumers need to make sure we have the right kind of light, the right amount of light, and lighting only when and where it is needed.

Bike Path to Nowhere

The Dodgeville area is badly in need of an off-road paved (asphalt) bike path.  Every time I go to Madison, I am envious of all the bike trails they have.  Why can’t small towns like Dodgeville and rural areas have some paved bike paths, too?  Brigham County Park in rural Dane County has a beautiful new trail.  Why not Iowa County?

I’d really like to see the Military Ridge Trail between Dodgeville and Ridgeway paved.  Anyone interested in serving on an ad hoc committee with me to make that happen?

There is a 5.1-mile paved trail called the Shake Rag Trail which runs along US Highway 151 between Dodgeville and Mineral Point, but it is far from ideal.  First of all, there is no safe way to bike to it from Dodgeville!  You can ride through the hospital parking lot to Heritage Lane, head south until you get to Brennan Rd., turn right, but when you get to WI Highway 23, you have to ride along the east shoulder of that busy road with fast-moving vehicles for 0.4 miles to get to the bike path, as shown in the map below.

What a relief!  You’ve now reached the paved bike path, and it is off-road!

But, after traveling only 0.5 mile, the bike path suddenly ends at Chris-Na-Mar Road.

You now ride 0.7 miles on Chris-Na-Mar Road, and then the off-road bike path starts up again.

Now, you get to ride 1.3 miles on an off-road paved bike path.  Yay!  But the bike path again abruptly ends at County Road YD.  It is not clear what you should do next except maybe turn around?

Persistence pays off, and if you soldier on you’ll find that you can ride 2.1 miles on County Road YD until you reach the off-road bike path again.  You’re almost to Mineral Point!

The bike path goes another 0.5 mile until it ends at Shakerag St. in Mineral Point.  You’ve traveled a total of 5.1 miles on the Shake Rag Trail, but less than half of it was on a bona fide bike path.

Don’t get me wrong, I’m really glad that the Shake Rag Trail got built.  But for any of you who have ridden the crushed rock Military Ridge Trail between Dodgeville and Ridgeway (all off-road), you’ll understand how much nicer Military Ridge Trail would be than the Shake Rag Trail if only it were paved.

Earth’s Changing Climate

The Intergovernmental Panel on Climate Change (IPCC) issued an important special report yesterday on climate change.  In the accompanying press release, they state the following:

    • Limiting global warming to 1.5°C would require “rapid and far-reaching” transitions in land, energy, industry, buildings, transport, and cities.  Global net human-caused emissions of carbon dioxide (CO2) would need to fall by about 45 percent from 2010 levels by 2030, reaching ‘net zero’ around 2050. This  means that any remaining emissions would need to be balanced by removing CO2 from the air.
    • This report will be a key scientific input into the Katowice Climate Change Conference in Poland in December, when governments review the Paris Agreement to tackle climate change.
    • We are already seeing the consequences of 1°C of global warming through more extreme weather, rising sea levels and diminishing Arctic sea ice.
    • Warming of 1.5ºC or higher increases the risk associated with long-lasting or irreversible changes, such as the loss of some ecosystems.

In the Summary for Policymakers, the IPCC states that “warming from anthropogenic emissions from the pre-industrial period to the present will persist for centuries to millennia and will continue to cause further long-term changes in the climate system, such as sea level rise, with associated impacts.”

This last point is very important.  Even if humanity disappeared from the face of the Earth tomorrow, it will take centuries to millennia for greenhouse gases in our atmosphere to return to pre-industrial levels.

Richard Wolfson, Professor of Physics at Middlebury College in Middlebury, Vermont, states in his excellent 2007 video course, “Earth’s Changing Climate” (The Great Courses, Course No. 1219),

The atmosphere, living things, soils, and surface ocean waters all represent short-term carbon reservoirs.  Cycling among these reservoirs occurs mostly on relatively short time scales.  In particular, a typical carbon dioxide molecule remains in the atmosphere only about five years.  But the rapid cycling of carbon through the atmosphere-biosphere-surface ocean system means that any carbon added to that system remains there much longer—for hundreds to thousands of years. Because the added carbon cycles through the atmosphere, the level of atmospheric carbon dioxide goes up and stays up for a long time.

We’ve known about this aspect of climate change for a long time.  It is based on solid science.  Any action we take now, either positive or negative, will affect Earth’s environment many generations into the future.

I know of no better introduction to climate science than Richard Wolfson’s video course.  Even though it was produced 11 years ago, it is still completely relevant.

Earth’s Changing Climate, The Great Courses, Course No. 1219

Bad Lighting at Dodgeville High School

At a school board meeting in November 2017, concerns were raised about inadequate lighting for evening school events, so the Dodgeville School District directed Alliant Energy to install some additional lights.  The lighting was installed during a warm spell in January 2018, and the photographs you see below were taken during the afternoon and evening of June 17, 2018.

Rather than being used only when school events are taking place in the evening, these terrible lights are on dusk-to-dawn 365 nights a year.  They are too bright, poorly directed, poorly shielded, and the glare they cause on W. Chapel St. and N. Johnson St. could pose a safety concern for pedestrians not being seen by drivers experiencing disability glare.  I can imagine that adjacent neighbors are not too happy with the light trespass into their yards and residences, either.

This is a perfect example of poor lighting design and unintended consequences.  How could it be done better?  Look for the solution below the following series of photos documenting the problem.

Bleacher path floodlight produces a great deal of uplight, and illuminates the disc golf course far more than the bleacher path

Bleacher path floodlight is mounted in a nearly-horizontal orientation

Bleacher path floodlight

Bleacher path floodlight

Bleacher path looking towards the bleachers

 

Bleacher path looking towards W. Chapel St.

 

Bleacher path at night

Bleacher path floodlight lighting up the disc golf course. Also note how much brighter the illumination is from the newly-installed blue-white LED streetlight as compared with the orangish light from the older high pressure sodium (HPS) luminaire.

Bleacher path floodlight lighting up the disc golf course and basket

Large tree being brightly illuminated all night long with bleacher path in foreground

Sub-optimal parking lot lighting at Dodgeville High School

Overflow parking floodlight

 

Two additional overflow parking lot floodlights

Overflow parking floodlight

 

Overflow parking floodlights

 

Overflow parking floodlight glare and spill light

 

Overflow parking floodlight glare onto W. Chapel St. in Dodgeville

Overflow parking glare and spill light onto W. Chapel St. in Dodgeville

Solutions

Pedestrian-scale 2700K LED “soft” lighting could be installed along the bleacher path

https://i2.wp.com/www.rabweb.com/images/features/ledbollards/bollard-hero.png?resize=840%2C615&ssl=1
Or vandal-resistant bollards could be used—even low voltage lighting

https://i1.wp.com/5fc98fa113f6897cea53-06dfa63be377ed632ae798753ae0fb3f.ssl.cf2.rackcdn.com/product_images/files/000/053/502/legacy_product_detail_large/86666_a2d8cda8be485702f03dcf2c3085438bb03b8975_original.jpg?resize=600%2C600&ssl=1
If floodlights must be used, shield them, point them more downwards, and turn them off after 11:00 p.m. each night (or have them on only while evening school events are in progress)

In fact, regardless of the lighting solution, the lights should be either turned off or dimmed down to a lower level later at night.  (Security cameras will see just fine at lower light levels if that is a concern.)

Good neighbor outdoor lighting means minimizing GLUT:

Glare—never helps visibility
Light Trespass—no point in putting light where it is not needed
Uplight—sending light directly up into the night sky is a total waste
Too Much Light—use the right amount of light for the task, don’t overlight

Bike Ride to Ridgeway (and back)

Ridgeway, Wisconsin is a special place.  A point right on the central meridian of the Central Time zone and the 43rd parallel (90° W longitude and 43° N latitude) is within the city limits of Ridgeway, and you can almost get there from here.

The point 43° N, 90° W

You can easily bicycle to this location by taking the Military Ridge State Trail into the west side of Ridgeway and turning north onto Ternes Ct.  I wonder if there’s a marker along Ternes Ct. at its closest point to 43° N, 90° W. If not, we need to put one there.

Getting to the point 43° N, 90° W

But wait!  Right where Ternes Ct. intersects Bier St. and becomes a gravel road, there’s a sign that says “Game Farm, No Trespassing”.  Foiled!

You know, we should have regular bike rides from Dodgeville to Ridgeway and back along the Military Ridge State Trail.  Anyone interested?  The distance from the Wisconsin DNR parking lot in Dodgeville to Badger Mart right next to the trail in Ridgeway is 9.2 miles, so it would be an 18.4 mile round trip along pretty flat terrain.  Badger Mart in Ridgeway is a convenient place to stop for a snack and a beverage before heading back to Dodgeville, and they are open from 5:00 a.m. until 9:00 p.m. every day of the week.

Would love to see this trail receive an asphalt surface someday, but the existing screened limestone surface isn’t bad.

Please post a comment here or email me if you’re interested in making this ride with me from Dodgeville to Ridgeway and back!

Turn Down the Lights, Turn Up the Stars

We are presently witnessing a rapid transformation of our outdoor nighttime environment as many older lighting sources such as high pressure sodium, metal halide, and fluorescent are being replaced with solid state lighting, specifically light emitting diodes (LEDs).  Many of the lighting decisions being made today with little or no citizen input will have consequences that impact our nighttime environment for decades.

Rather than continuing to subscribe to the “more is better, dusk-to-dawn” approach to outdoor lighting, we need to utilize this new technology in creative and innovative ways (many already available) to improve our nighttime built environment while minimizing lighting’s deleterious effects on the natural world.  Three paradigm shifts are needed.

Paradigm Shift #1
Less light will usually work just fine (a little light goes a long way)

Paradigm Shift #2
Dusk-to-dawn lighting → Lighting on Demand

Paradigm Shift #3
Full intensity lighting → Multi-Intensity Lighting (dimmable)

When choosing the amount of light you need, one should always consider the task or tasks needing to be performed.  For example, the amount of light needed to identify a rural intersection is much less than is needed to play a baseball game at night.  In both cases, though, the light needs to be restricted to only the area needing to be illuminated: the intersection or the playing field.

Another example.  When my wife and I bought a house in Dodgeville, Wisconsin back in 2005, our front porch had a 100-watt frosted incandescent light bulb to light the porch that we could turn on whenever we had company in the evening.  Thinking it too bright, we replaced the 100-watt bulb with a 60-watt bulb, then tried a 40-watt bulb, and finally a 25-watt bulb.  The 25-watt bulb adequately illuminated the porch and the stairs leading up to the porch, so in it stayed.

Then there is the issue of dusk-to-dawn lighting.  Many years ago, we switched outdoor lighting on or off as needed, but technological advancements later allowed us to have a light come on at dusk and stay on all night until dawn.  Now, think of all those lights burning when no one is there to use them.  If security is a concern, there is even newer technology that will do a far more effective job of detecting intruders than simply leaving a light on all night long.  In fact, a dusk-to-dawn light is not needed at all as part of an effective security system.  So, why not use 21st-century technology to have outdoor lights automatically turn on when needed and turn off when not needed?  Some LED light bulbs even come now with integrated occupancy sensors.  Lighting on demand could and should be replacing most dusk-to-dawn lighting within the next few years.

What about some roadway and parking lot lighting that must remain on all night long?  Those lights could be at full brightness during times of high traffic such as during the evening hours, but dimmed to 50% when traffic is lower, such as after midnight.  Once again, 21st-century technology makes this easy to do.

LED lighting lends itself very well to frequent on-off switching and dimming, but much of what is currently being installed is too blue.  As you can see in the table below, typical LED light sources have a substantial “spike” at the blue end of the visible light spectrum as compared with other white light sources.

Not only does blue light scatter more in the atmosphere and within our eyes, but many people perceive bluish-white light as colder, more clinical, than the warmer white light where this blue spike is absent, as shown below.  The blue spike in LED lighting can be removed either by using filtering, or by using a different phosphor that gives a warmer white spectrum.  Strongly preferred for both indoor and outdoor lighting are LED light sources with a correlated color temperature (CCT) of 2700K or 3000K.  2700K is the standard for indoor lighting, and yet 4000K is most often used for outdoor lighting.  Why?  Let’s move the standard for outdoor lighting to 2700K or 3000K.

By properly shielding lights so they only shine downwards, by using lights that are no brighter (or bluer) than they need to be, and by turning lights off when they are not needed—or dimming them during times of lower activity—we all will be helping to improve both our natural and celestial environment.

Turn Down the Lights, Turn Up the Stars *

* Suzy Munday, May 11, 2018

Additional Thoughts

In thinking about 21st-century lighting, one’s thoughts naturally towards 21st-century power generation.  We do not think often enough about the many advantages of a more decentralized power grid, where nearly everyone is generating some power with solar panels and small-scale wind turbines, as well as other local sources of energy such as geothermal.   As we once again consider building nuclear power plants (which will still be quite vulnerable to terrorism) and continue to build expensive fossil fuelish power plants and ugly high-voltage transmission lines, why not a paradigm shift towards decentralized energy production instead?