Earth’s glow is growing. NASA imagery reveals the brightest regions...

While true, unfortunately the article is inaccurate. Most outdoor lighting has been "directional" since the increase of LEDs. Within my lifetime, the old mercury vapor bulbs constituted outdoor lighting from street-lights to yard lights. Remember how it took several minutes for stadium lights to come up to full brightness? That was mercury vapor lights, AKA MVLs. Stadium lights were/are directional; street lights originally weren't and were a bulb that hung down in the middle of a diffuser. Lights mounted on the corners of houses tended to be incandescent directional lights.

MVLs became HIgh Pressure Sodium. MVLs used about 175W on the average, and I think HPS used about 155 but won't swear to it. Remember the orange street lights? Those were HPS. Installing HPS was a simple as changing the bulb, and unless something something like a stadium or auto dealership wanted white lights, HPS took over.

Note that from right before the MVL - HPS changeover started, some utilities went to cobra head style lights. Instead of a bulb hanging down, it was mounted horizontal in a fixture aimed downward. Since it was pretty much flat, they were dubbed cobra head fixtures. These were the fixtures pushed by dark skies advocates because you don't have so much light wasted by shining parallel to the ground rather than toward it.

Both MVLs and HPS in standard fixtures contributed to a lot of sky glow. One night, before our children were born, my wife and I got lost and I didn't want to worry her. I found our way back to familiar territory by following the sky glow toward a town. To me, that HPS orange glow stood out more, and on a foggy night could be quite eerie. Against a snowy sky they were quite striking.

Paradoxically, the human eye doesn't see quite as well at that end of the spectrum, so the HPS lights tended to look dimmer. We had all sorts of complaints from customers who ended up with HPS yard lights and who wanted the whiter MVLs.

With LEDs, while there were some screw-in replacements, utilities went to the flat type which are a bank of white LEDS. This automatically makes them cobra heads, with the light directed downward. Sidebar: Standard LED street lights use about 40W. That's a savings of 135W per light compared to the old MVLs. Something I was curious about was how much sky glow these lights would produce. It seems to be less, but it's still present. When I'm out at night, I usually pick out towns by the glow on the horizon. When I don't see some glows, that tells me how much power is out. But it's just doesn't look as much to me as it did before LEDs.

Remember that bit about HPS looking darker? The whiter LEDS look brighter because the human eye can see that part of the spectrum better. While a lumen to lumen to lumen comparison might show similar numbers, you get more usable light from the whiter color.

True dark skies are incredible. In the aftermath of a widespread event like Hurricane Helene, all lights are out and there's no sky glow to be seen anywhere. Once your eyes adjusted, you could see by starlight. Not read a newspaper type see, but it wasn't like there was no light at all. You could make out landscapes and somewhat surroundings. I found I could walk without a flashlight. From the lightless house, opening the blinds and drapes provided some light. Clouds passing overhead looked black. Maybe the seasonal haziness acted as a diffuser for the starlight, but that it was enough to see by was startling. In a regular outage, you usually have some sky glow glow toward the towns, but since the towns had no power, too, even that was gone.

So, what are my complaints about the article? Most outdoor lights are already directional. Skyglow is reduced. The warm lights it touts aren't seen as well as the whiter lights, which could lead to the use of lights with higher lumens, creating more light pollution. That increase in outdoor lighting NASA picked up might well be less than when the old style MVL street lights reigned supreme. And despite the "What you can do" aspect the article tried to sell readers, most light pollution comes from the large street-light type fixtures, not what someone might install on the corner of their house. Oh, and the turtles? Beaches typically restrict outdoor lighting when sea turtles swim ashore to lay their eggs.

The main thing that struck me though was how outdoor lighting moved toward the cobra head type long ago. I wonder if the author of the article knew that.