Italy’s Mount Etna has turned on again, spewing lava and gas in its first big eruption in 2013. The volcano is one of the most active in the world, and is Europe’s tallest active volcano, currently standing about 3,329 m (10,922 ft) high.
The volcano has been “simmering” for 10 months, but on February 19 and 20, the famous volcano came to life, providing dramatic visuals from the ground (see the video below) as well as from space, with three outbursts in less than 36 hours. This image from the Advanced Land Imager (ALI) on the Earth Observing-1 (EO-1) satellite captured Etna on February 19 at 9:59 a.m. Central European Time, about 3 hours after the end of the first outbursts.
The false-color image combines shortwave infrared, near infrared, and green light in the red, green, and blue channels of an RGB picture. This combination differentiates the appearance of fresh lava, snow, clouds, and forest.
Fresh lava is bright red—the hot surface emits enough energy to saturate the instrument’s shortwave infrared detectors, but is dark in near infrared and green light. Snow is blue-green, because it absorbs shortwave infrared light, but reflects near infrared and green light. Clouds made of water droplets (not ice crystals) reflect all three wavelengths of light similarly, and are white. Forests and other vegetation reflect near infrared more strongly than shortwave infrared and green light, and appear green. Dark gray areas are lightly vegetated lava flows, 30 to 350 years old.
The video from the ground was captured by Klaus Dorschfeldt, a videographer and webmaster at Italy’s National Institute of Geophysics and Volcanology.
In an update today on the Italian National Institute of Geophysics and Vocanology website, a fourth episode of lava fountains was reported. “Like the previous paroxysms, this event produced fountains and lava and an ash cloud that has shifted to the northern sector of the volcano.”
The official name is “extra-vehicular activity,” (EVA) but most of us like to call it a spacewalk. However, when you think about it, you don’t really walk in space. You float.
Or more properly speaking, clutch on to handlebars as you make your way from spot to spot on your spacecraft as you race against the clock to finish your repair or whatever outdoor tasks you were assigned. But hey, the view more than makes up for the hard work.
Some astronauts actually got to fly during their time “outside.” During STS-41B 29 years ago this month, Bruce McCandless was the first one to strap on a jetpack and, in science fiction style, float a little distance away from the shuttle.
He called his test of the manned maneuvering unit “a heck of a big leap”. Nearly 30 years after the fact, it still looks like a gutsy move.
What other memorable floating NASA spacewalks have we seen during the space age? Here are some examples:
The first American one
The pictures for Ed White’s spacewalk on Gemini 4 still look amazing, nearly 48 years after the fact. The astronaut tumbled and spun during his 23-minute walk in space, and even tested out a small rocket gun until the gas ran out. When commander Jim McDivitt ordered him back inside, the astronaut said it was the saddest moment in his life.
The dancing-with-exhaustion one
On Gemini 9, which took place the year after Gemini 4, Eugene Cernan was tasked with a spacewalk that was supposed to test out a backpack to let him move independently of the spacecraft.
Cernan, however, faced a lack of handholds and physical supports as he clambered outside towards the backpack. Putting it on took almost all the strength out of him, as he had nowhere to hold on to counterbalance himself.
“Lord, I was tired. My heart was motoring at about 155 beats per minute, I was sweating like a pig, the pickle was a pest, and I had yet to begin any real work,” Cernan wrote in his memoir, Last Man on the Moon, about the experience.
The situation worsened as his visor fogged up and Cernan struggled unsuccessfully to use the backpack. Cernan was so exhausted that he could barely get inside the spacecraft. “I was as weary as I had ever been in my life,” he wrote.
The three-astronauts-outside one
Spacewalks traditionally (at least, in the shuttle and station era) happen in pairs, so that if one person runs into trouble there’s another to help him or her out. However, two astronauts working outside during STS-49 couldn’t get enough of a grip on the free-flying Intelsat VI satellite they were trying to fix. So NASA elected to do another spacewalk with a third man.
Pierre Thuot hung on the Canadarm while Richard Hieb and Thomas Akers attached their bodies to the payload bay. Having three men hanging on to the satellite provided enough purchase for the astronauts inside the shuttle to maneuver Endeavour to a spot where Intelsat VI could be attached to the payload bay.
The facing-electrical-shock one
In 2007, the astronauts of STS-120 unfolded a solar array on the International Space Station and saw — to everyone’s horror — that some panels were torn. Veteran spacewalker Scott Parazynski was dispatched to the rescue. He rode on the end of the Canadarm2, dangling above a live set of electrified panels, and carefully threaded in a repair.
In an interview with Parazynski that I did several years ago, I asked how he used his medical training while doing the repair. Parazynski quipped something along the lines of, “Well, the top thing in my mind was ‘First do no harm.’ ”
The International Space Station construction ones
Spacewalks used to be something extra-special, something that only happened every missions or, on long-duration ones, maybe once. Building the International Space Station was different. The astronauts brought the pieces up in the shuttle and installed them themselves.
The station made spacewalking routine, or as routine such a dangerous endeavour can be. For that reason, an honorary mention goes to every mission that built the ISS.
What are your favorite EVAs? Feel free to add yours to the comments.
According to a press release posted on SpaceRef and NASAWatch, Dennis Tito — the first-ever space tourist — is planning to send a human mission to Mars in January 2018 on a round-trip journey lasting 501 days. The trip would be timed to take advantage of the launch ‘window’ when Mars and Earth reach a position in their respective orbits that offers the best trajectory between the two planets.
Reportedly, Tito has created a new nonprofit company called the Inspiration Mars Foundation to facilitate the mission. The mission is intended to “generate new knowledge, experience and momentum for the next great era of space exploration.”
(2/21/13 13:00 UTC) We have an update on this news below:
Tito, along with several other notable people from the space community will provide more information in a press conference set for Wednesday, February 27th. Also at the press conference will be Taber MacCallum and Jane Poynter who were members of the Biosphere-2 project, and who are with the Paragon Space Development Corporation, which creates life-support systems, and Jonathan Clark, a medical researcher at the National Space Biomedical Research Institute, who may discuss the dangers from radiation to humans in deep space. The press conference will be moderated by journalist Miles O’Brien.
Tito paid about $20 million to visit the International Space Station in 2001.
Another endeavor, the Mars One project, wants to create a human settlement on Mars by 2023.
UPDATE: Spaceflight expert Jeff Foust did a some digging, and posted some insights about this story in his NewSpace Journal. Foust obtained a copy of a paper Tito plans to present at the IEEE Aerospace Conference in March, which discusses conference, a crewed free-return Mars mission that would fly by Mars – no going into orbit or landing. Such a 501-day mission would launch in January 2018, “using a modified SpaceX Dragon spacecraft launched on a Falcon Heavy rocket,” Foust writes. “According to the paper, existing environmental control and life support system (ECLSS) technologies would allow such a spacecraft to support two people for the mission, although in Spartan condition. ‘Crew comfort is limited to survival needs only. For example, sponge baths are acceptable, with no need for showers,’ the paper states.”
One of the paper’s co-authors is NASA Ames director Pete Worden, the paper outlines how NASA would also have a role in this mission in terms of supporting key life support and thermal protection systems, even though this is a private-sector effort. No estimates of what such a mission would cost are included in the paper, but it does say it would be financed privately. The paper adds that if they miss this favorable 2018 opportunity, the next chance to take advantage of this lower energy trajectory would be in 2031.
Emily Coren is an accomplished illustrator and scientist, and she’s figured out how to bring those two skills together to make science easier to understand: science illustrations.
Emily completed a series last year on how adaptive optics works. This is the technology that increases the resolution of both telescopes and microscopes, and she gave us permission to reprint the series here on Universe Today.
NASA has released the findings from a panel that investigated the 2011 crash of the Glory spacecraft after it failed to reach orbit on board an Orbital Sciences Taurus XL rocket, falling into the Pacific Ocean. Early on, the problem was traced to the fairing – the clamshell nosecone that encapsulates the satellite as it travels through the atmosphere — which did not separate from the rocket, weighing the satellite down, preventing its flight toward orbit.
However, the mishap investigation board was not able to identify the definitive cause for the fairing system failure. The rocket and satellite weren’t recovered, so there was no physical evidence to examine. In short, the board confirmed the Taurus launch vehicle’s fairing system failed to open fully and caused the mishap. And the board’s report does recommend ways to prevent future problems associated with the joint system that makes up the fairing.
But the board’s complete report is not available for public release because it contains information restricted by U.S. International Traffic in Arms Regulations (ITAR) and information proprietary to the companies involved.
A similar technical glitch occurred during the 2009 launch of the Orbiting Carbon Observatory (OCO). A replacement, OCO-2 is scheduled to launch in 2014. NASA had originally planned to fly OCO-2 on a Taurus rocket, but changed its plans after the loss of Glory. OCO-2 will now launch on a United Launch Alliance Delta-II. But NASA and Orbital are continuing to investigate the fairing system.
Glory was going to be a three-year mission designed to improve our understanding of Earth’s climate by collecting data on the properties of natural and human-caused aerosols in Earth’s atmosphere and how they might affect climate change, as well as determining the Sun’s affect on climate by measuring the total solar energy entering Earth’s atmosphere.
This footage was obtained by the AIA instrument on the Solar Dynamics Observatory on July 19, 2012. It provides a stunning display of solar activity and shows how wildly different events on the Sun can be. Some come just with a solar flare, some with an additional ejection of solar material called a coronal mass ejection (CME), and some with complex moving structures in association with changes in magnetic field lines that loop up into the Sun’s atmosphere, the corona.
This eruption produced all three.
A moderately powerful solar flare exploded on the Sun’s lower right hand limb, sending out light and radiation. Next came a CME, which shot off to the right out into space. And then, the Sun treated viewers to one of its dazzling magnetic displays — a phenomenon known as coronal rain.
Over the course of the next day, hot plasma in the corona cooled and condensed along strong magnetic fields in the region. Magnetic fields, themselves, are invisible, but the charged plasma is forced to move along the lines, showing up brightly in the extreme ultraviolet wavelength of 304 Angstroms, which highlights material at a temperature of about 50,000 Kelvin. This plasma acts as a tracer, helping scientists watch the dance of magnetic fields on the Sun, outlining the fields as it slowly falls back to the solar surface.
SDO collected one frame every 12 seconds, and the movie plays at 30 frames per second, so each second in this video corresponds to 6 minutes of real time. The video covers 12:30 a.m. EDT to 10:00 p.m. EDT on July 19, 2012.
Scientists have discovered a new planet orbiting a Sun-like star, and the exoplanet is the smallest yet found in data from the Kepler mission. The planet, Kepler-37b, is smaller than Mercury, but slightly larger than Earth’s Moon. The planet’s discovery came from a collaboration between Kepler scientists and a consortium of international researchers who employ asteroseismology — measuring oscillations in the star’s brightness caused by continuous star-quakes, and turning those tiny variations in the star’s light into sounds.
“That’s basically listening to the star by measuring sound waves,” said Steve Kawaler, from Iowa State University in the US, and a member of the research team. “The bigger the star, the lower the frequency, or ‘pitch’ of its song.”
The measurements made by the astroseismologists allowed the Kepler research team to more accurately measure the tiny Kepler-37b, as well as revealing two other planets in the same planetary system: one slightly smaller than Earth and one twice as large.
While Kepler 37b is likely a rocky planet, this would not be a great place for humans to live. It’s likely very hot — with a smoldering surface and no atmosphere.
“Owing to its extremely small size, similar to that of the Earth’s moon, and highly irradiated surface, Kepler-37b is very likely a rocky planet with no atmosphere or water, similar to Mercury,” the team wrote in their paper, which was published this week in Nature. “The detection of such a small planet shows for the first time that stellar systems host planets much smaller as well as much larger than anything we see in our own Solar System.”
The host star, Kepler-37, is about 210 light-years from Earth in the constellation Lyra. All three planets orbit the star at less than the distance Mercury is to the Sun, suggesting they are very hot, inhospitable worlds. Kepler-37b orbits every 13 days at less than one-third Mercury’s distance from the Sun. The estimated surface temperature of this smoldering planet, at more than 800 degrees Fahrenheit (700 Kelvin), would be hot enough to melt the zinc in a penny. Kepler-37c and Kepler-37d, orbit every 21 days and 40 days, respectively.
The size of the star must be known in order to measure the planet’s size accurately. To learn more about the properties of the star Kepler-37, scientists examined sound waves generated by the boiling motion beneath the surface of the star.
“The technique for stellar seismology is analogous to how geologists use seismic waves generated by earthquakes to probe the interior structure of Earth,” said Travis Metcalfe, who is part of the Kepler Asteroseismic Science Consortium.
The sound waves travel into the star and bring information back up to the surface. The waves cause oscillations that Kepler observes as a rapid flickering of the star’s brightness. The barely discernible, high-frequency oscillations in the brightness of small stars are the most difficult to measure. This is why most objects previously subjected to asteroseismic analysis are larger than the Sun.
“Studying these oscillations been done for a long time with our own Sun,” Metcalfe told Universe Today, “but the Kepler mission expanded that to hundreds of Sun-like stars. Kepler-37 is the coolest star, as well as the smallest star that has been measured with asterosiesmology.”
Kepler-37 has a radius just three-quarters of the Sun. Metcalfe said the radius of the star is known to 3 percent accuracy, which translates to exceptional accuracy in the planet’s size.
Metcalfe launched a non-profit organization to help raise research funds for the Kepler Asteroseismic Science Consortium. The Pale Blue Dot Project allows people to adopt a star to support asteroseismology, since there is no NASA funding for asteroseismology.
“Much of the expertise for this exists in Europe and not in the US, so as a cost saving measure NASA outsourced this particular research for the Kepler mission,” said Metcalfe, “and NASA can’t fund researchers in other countries.”
The Kepler spacecraft carries a photometer, or light meter, to measure changes in the brightness of the stars it is focusing on in the Cygnus region in the sky.
Metcalfe said this discovery took a long time to verify, as the signature of this very small exoplanet was hard to confirm, to make sure the signature wasn’t coming from other sources such as an eclipsing binary star.
Kawaler said Kepler is sending astronomers photometry data that’s “probably the best we’ll see in our lifetimes,” he said, adding that this latest discovery shows “we have a proven technology for finding small planets around other stars.”
“We uncovered a planet smaller than any in our solar system orbiting one of the few stars that is both bright and quiet, where signal detection was possible,” said Thomas Barclay, lead author of Nature paper. “This discovery shows close-in planets can be smaller, as well as much larger, than planets orbiting our sun.”
And are there more small planets like this out there, just waiting to be found?
As the team wrote in their paper, “While a sample of only one planet is too small to use for determination of occurrence rates it does lend weight to the belief that planet occurrence increases exponentially with decreasing planet size.”
We’ll be the first to admit that the 1983 movie The Right Stuff takes artistic license when it talks about the Mercury program and other events. It exaggerates problems between the astronauts, portrays the journalists as unthinking buffoons and misrepresents historical events such as breaking the speed of sound.
Late in the three-hour film, the movie turns to astronaut John Glenn‘s first flight in space, which took place on this day in 1962. Glenn was the first American to make an orbital flight of the Earth. He returned a national hero.
Below we’ll highlight a few points of similarity and difference between the movie and John Glenn’s own account of the flight of Friendship 7, which he detailed in his 1999 biography John Glenn: A Memoir. And yes, the rest of this post does contain spoilers for those who haven’t seen the film.
– Visit from Lyndon Johnson. During an aborted launch attempt, the movie shows Lyndon Johnson parked nearby the Glenns’ house in a limousine, ordering an aide to let him inside. Glenn’s wife Annie (through a fellow astronaut wife) keeps informing the hapless assistant that there’s no way Johnson (and the TV cameras he wants to include) can come in. While Glenn’s actual account doesn’t specify where the vice-president of the United States was at that time, he does talk about the request and refusal. “She said she was tired, she had a headache, and she just wasn’t going to allow all those people in her house … I told her whatever she wanted to do, I would back her up 100 percent.”
– Threat to remove Glenn from the flight. In The Right Stuff, Glenn then gets into a shouting argument with a NASA official nearby, who orders him to get on the phone and tell Annie to let the vice-president in. The NASA official threatens to replace Glenn with another astronaut, at which point Glenn’s colleagues surround him and the official backs down. Glenn confirms the incident, but does not mention other astronauts: “I saw red. I said that if they wanted to do that, they’d have a press conference to announce their decision and I’d have one to announce mine, and if they wanted to talk about it anymore, they’d have to wait until I took a shower. When I came back, they were gone and I never heard any more about it.”
– Fireflies. An extended sequence in The Right Stuff shows Glenn exclaiming as he sees “fireflies” outside of the spacecraft. The movie doesn’t really explain why they happen, but yes, they actually were there. “I saw around the capsule a huge field of particles that looked like tiny yellow stars,” Glenn wrote in his memoir. “They seemed to travel with the capsule, but more slowly. There were thousands of them, like swirling fireflies.” Glenn added: “They were droplets of frozen water vapor from the capsule’s heat exchanger system, but their fireflylike glow remains a mystery.” However, fellow astronaut Scott Carpenter noted frost flakes from his spacecraft, Aurora 7 on the next Mercury flight after Glenn’s, and floating nearby. They shone when the Sun illuminated the flakes. He also noticed more flakes coming off the side of his spacecraft when he banged the inside.
– Activities in orbit. While allowing that The Right Stuff probably had other priorities in mind, the movie does not show Glenn doing much in orbit besides gazing out the window and talking about the aforementioned fireflies. Glenn’s book shows him doing more than that: taking his blood pressure, snapping pictures of the Canaries and Sahara Desert, testing his vision, and doing exercises with a bungee cord to compare his readings to previous ones taken on the ground.
– Lights on in Perth and Rockingham, Australia. Glenn and a ground station in Australia chat about the residents of Rockingham and Perth turning on their lights for him. This actually did happen (and it happened again when Glenn returned to space in 1998.)
– Decision to bring Glenn down after three orbits. The movie accurately says Glenn was go for at least seven orbits, but then shows Glenn being confused when he’s told to come down after only three. Glenn contradicts that directly in his account: “The mission was planned for three orbits, but it meant that I could go for at least seven if I had to.”
– Heat shield threat. The movie shows Mission Control grappling with a signal indication that the landing bag deployed, which implies that the heat shield might have cut loose prematurely. They recommend Glenn refrain from removing a retrorocket package that usually was jettisoned after the rockets fire for re-entry, and keep it on the spacecraft to hold the heat shield on. Glenn talks at length about the situation in his book, and expresses frustration that he didn’t receive information quickly: “I was irritated by the cat-and-mouse game they were playing with the information.” It turned out to be a false alarm.
– Humming. Glenn hums a lot in the movie during the re-entry, especially as the gravity forces build up on him. The astronaut makes no mention of doing so in his book. Long-standing New York Times spacejournalist John Noble Wilford unequivocally stated the movie was wrong: “Mr. Glenn did not hum ”The Battle Hymn of the Republic” during re-entry,” he wrote in a 1983 review of the movie.
With all the various space rocks flying by and into Earth last Friday, perhaps you’ve been wondering about the correct terminology, since a rock from space has different names depending on what it is made of and where it is.
Infographics artist Tim Lillis has put together a primer of sorts, in the form of an infographic, describing the different between a comet, asteroid, meteoroid, meteor and meteorite.
Asteroids are generally larger chunks of rock that come from the asteroid belt located between the orbits of Mars and Jupiter. Sometimes their orbits get perturbed or altered and some asteroids end up coming closer to the Sun, and therefore closer to Earth.
Comets are much like asteroids, but might have a more ice, methane, ammonia, and other compounds that develop a fuzzy, cloud-like shell called a coma – as well as a tail — when it gets closer to the Sun. Comets are thought to originate from two different sources: Long-period comets (those which take more than 200 years to complete an orbit around the Sun) originate from the Oort Cloud. Short-period comets (those which take less than 200 years to complete an orbit around the Sun) originate from the Kuiper Belt.
Space debris smaller than an asteroid are called meteoroids. A meteoroid is a piece of interplanetary matter that is smaller than a kilometer and frequently only millimeters in size. Most meteoroids that enter the Earth’s atmosphere are so small that they vaporize completely and never reach the planet’s surface. And when they do enter Earth’s atmosphere, they gain a different name:
Meteors. Another name commonly used for a meteor is a shooting star. A meteor is the flash of light that we see in the night sky when a small chunk of interplanetary debris burns up as it passes through our atmosphere. “Meteor” refers to the flash of light caused by the debris, not the debris itself.
If any part of a meteoroid survives the fall through the atmosphere and lands on Earth, it is called a meteorite. Although the vast majority of meteorites are very small, their size can range from about a fraction of a gram (the size of a pebble) to 100 kilograms (220 lbs) or more (the size of a huge, life-destroying boulder).
Thanks again to Tim Lillis for sharing his infographic with Universe Today. For more info about Tim’s work, see his Behance page, Flickr site, Twitter, or his website.
A good majority of modern Americans have never seen truly dark skies. I was fortunate to grow up in northern Maine in the 1970s with skies dark enough to see the summer Milky Way right from my doorstep. For most of the Eastern Seaboard of the United States, this is no longer the case. During the blackout brought on by Hurricane Sandy over the tri-state area in 2012 and after Hurricane Andrew hit Miami in 1992, many urbanites got to see an unfamiliar sight first hand; a dark night sky. There were even calls to 9/11 reporting fires on the horizon, which were in fact the Milky Way!
In just over two weeks time on March 10th, most of North America will “spring forward” once again to daylight savings time; three weeks afterwards on March 31st, the European Union will follow suit.
For astronomers, this means waiting until the later evening hours for total darkness and late start times for star parties. If it seems like we spend more of the year on daylight savings time, we in fact do; the Energy Policy Act of 2005 mandates that daylight savings for most of the U.S. (a majority of Arizona is a staunch hold out) now starts on the second Sunday of March and runs until the first Sunday of November, or about 65% of the year. But discussions of DST’s utility or anachronism aside, it puts just one more hurdle between astronomers and what they love: dark skies.
You can’t even see your hand in front of your face under truly dark skies. Such darkness is measured on what’s known as the Bortle Scale, with 1 being dark enough to notice air glow and phenomena like the Gegenschein, while 9 is a washed out inner-city night sky, with perhaps only the Moon and the brightest planets punching through the haze.
We once did a Bortle scale estimation while waiting for an airport shuttle on the Las Vegas strip; Vegas is arguably the most light-polluted locale on the planet. Jupiter, the Moon and the brightest stars of Orion could only be seen if you knew exactly where to look for them. In contrast, we’ve heard many service members remark about how splendid the sky looks from such deployed locations as Afghanistan.
The encroachment of civilization on wilderness areas also means that most school star parties and downtown observatories are restricted to bright targets, and serious deep sky observers must now drive several hours for a reasonably dark sky. Living just outside the Tampa/Saint Petersburg area in Florida, I can actually tell if it’s cloudy or clear at night just by how bright our bedroom appears with lights out. A cloudy sky reflects all the city lights back down, creating a “false dawn” that fills the room.
Dark sky sites are like secret fishing holes for backyard astronomers. Everyone knows of a few, some of which are even carefully hidden and discussed in hushed tones for fear of the light generating hordes which will descend upon them.
For dark skies in the Tampa Bay area, most observers head north to Chiefland along the Nature Coast about a two hour drive north. If you’ve got boat access, a truly dark sky locale can be had in the Dry Tortugas off of the Florida Keys to the south.
We recently visited such a hidden “dark sky island” in northern Georgia. Dunham Farms is a great old farmhouse Bed & Breakfast in Liberty County near Hinesville, Georgia. Despite how close as it is to Savanna, Dunham Farms sits in a “triangle of darkness,” a rarity along the Atlantic coast. We estimated the sky at a Bortle Scale of 2-3 while we were there doing nighttime astrophotography. Astronomy clubs in nearby Savanna also find dark sky requiem at nearby Tybee Pier, and further north, clubs such as the Midlands Astronomers based out of Melton Observatory in Columbia, South Carolina head to nearby Congaree Swamp.
And so it is along much of the U.S. East Coast, as observers must make to pilgrimage ever further inland in search of dark skies. Truth is, much of nighttime lighting is simply wasted energy headed skyward to illuminate the undersides of clouds and aircraft. Not only does this destroy our pristine night sky, but it’s also a threat to nocturnal wildlife and humans as well. Nigh-time lighting confuses migrating birds, often casuing them to fly into buildings. In 2009 the American Medical Association joined the fight against light pollution, citing it as a health risk. Light pollution effects our natural circadian rhythms, and studies show it may be linked to increased cancer rates as well. Turns out, our bodies need darkness.
But there is light (bad pun intended) at the end of the tunnel. Light pollution ordinances are now on the books in many municipalities. In 2001, the International Dark Sky Association recognized Flagstaff, Arizona as the first dark sky certified city. Increasingly, observatories around cities in Arizona such as Tucson and Flagstaff are being recognized as national scientific assets to be safeguarded.
Of course, legislation on the books is only as good as its enforcement. There are no “light pollution police” on the beat, and ordinances against “light trespass” are only put into practice when someone complains about it. We’ve found that frequently, inviting the neighbors over for a “backyard star party” can avoid having them install a World War II surplus anti-aircraft spotlight in their back yard to begin with… hey, that’s what your security light looks like to us!
And there’s nothing stopping hardware outlets from selling light fixtures that are illegal to install. A good fixture directs light downward where it’s needed. Lowes has recently launched its line of dark sky compliant outdoor lighting, and hey, if enough customers “vote with their wallets” more may follow suit. Its money saved in these cash strapped times, and a night sky gained!