New View Of U.S. At Night – Could Someone Please Dim The Lights?

The U.S. on the night of Oct. 1, 2013 photographed by the Suomi-NPP satellite from 512 miles high. Light clouds cover the region from Minneapolis across northern Wisconsin. Click for a supersized version you can dig into and find your city. Credit:  Jesse Allen and Robert Simmon

On Oct. 1 this year – a rare, almost cloud-free night across the continental United States – NASA snapped a series of natural light photos of the country with the Suomi-NPP satellite. The satellite orbits 512 miles (824 km) high in a polar orbit and is named for the late Verner Suomi, a pioneer in satellite meteorology.

Suomi-NPP satellite views showing Earth at night – narrated

Unlike many communications satellites, which orbit around Earth’s equator, Suomi-NPP circles the planet from pole to pole. As Earth rotates beneath it, the satellite sees a different slice of the planet each orbit. Over time, all the slices add up to give Suomi a complete picture of the Earth below.

Click image to go to a scroll-able map comparing U.S. highways with their night appearance.

That night, not only was it mostly clear across the U.S. but the moon was three days before new. The little bit of light it cast was not enough to illuminated the ground or atmosphere, allowing for good contrast between lights and landscape.

The rapid growth of lighting in the Bakken oil fields in western North Dakota shows up clearly in this cropped version of the photo above. Credit: Jesse Allen and Robert Simmon

Cities large and small stand out while highways festoon the darkness like strings of holiday lights. I’m always intrigued by the latest images of Earth at night because they let us gauge how bright our planet is becoming. One of the most appalling examples of recent light pollution comes from oil drilling and exploration in the Bakken formation in western North Dakota. A dozen years ago it was one of the darkest places on the planet. Now lights spread across more than a 100 miles (160 km) of high prairie.

You may have noticed a change in lighting type in your own city. Most roads and byways are illuminated by pink-orange high pressure sodium lights. They work well when boxed in shielded housings that focus the light downward onto the streets where it’s needed. Unfortunately, many sodium lights are unshielded, sending light sideways and upward. Light in those directions not only creates unwanted glare but seriously brightens the night sky, robbing many of the joy of stargazing.

Comparison of lighting colors and intensity of the new LED streetlights (left) and the older high-pressure sodium vapor lamps. Both these lamps are shielded – the photos were taken from very similar angles to show the difference in intensity. Credit: Bob King

Recently, much more energy-efficient LED (light-emitting diode) lights are now being packaged in ornamental as well as standard streetlighting. I’ve seen the change in my own city of Duluth, Minn. While these lights have tremendous energy benefits, they are INTENSELY bright, much more so than the “old-fashioned” sodiums.

As long as they’re shielded, light spill and glare are relatively well-controlled (though light reflected off snow becomes a bigger problem), but I’m concerned that low-cost LEDs will proliferate in ornamental and building and parking lot illumination. Much of that lighting is unshielded and heavy on glare, making driving at night more difficult and preserving what dark sky is left more challenging.

I encourage you to learn all you can about the new lighting and work with you local city councils and town boards to explain how LED lighting can be used wisely to make everyone happy – stargazers, drivers and those who walk at night. For help and more information, drop by the International Dark-Sky Association website.

15 Responses

        1. astrobob

          They’d have to be retrofitted somehow with hoods. The builders used standard issue wallpack lights that blaze straight out into the night. The glare they produce is very unproductive and actually makes it easier for someone to not be seen if they wanted to commit and act of vandalism.

  1. Dominik

    Oh yes light pollution! Totally love this side of artificial light.
    How many stars could one see on a perfect dark sky? 5600? I can view about 200 to 400 :/
    I’m even having problems seeing the plejades. With luck I can see 5 of them.
    Makes me want to go live in New Zealand or Norway. Lovely countries with very good dark skies in my opinion ( And not all as cold as Iceland haha ).
    Sadly one person alone can’t do much against the governments and local politics.
    Even though it is simply logical how shielded light can save such a great amount of energy over time…
    But that doesn’t matter, does it? The taxpayers and hobby astronomers as well as professional astronomers have to pay the prize for it. Materialistic and metaphorically speaking.
    We need a revolution here 🙂

    1. astrobob

      That’s why education is so important. Most people – officials, architects, city planners, the public – simply don’t know what they’re losing with bad lighting. Matter of fact, they don’t even recognize what bad lighting is.

      1. Dominik


        indeed! And how can some of them know what they lose, if they have never seen a real dark sky before. I’m sure even those people who are not all so very interested in astronomy would see the night sky from a whole different perspective after seeing a dark sky once.
        But I have to admit, my interest in astronomy and sky watching has really grown about 5 years ago. I was around 15 then.
        I was very often out, watching the stars, but it took quite some time till I learned about light pollution and it’s drastic effects.
        What I’m saying is, even those interested in watching the night sky, might not know about light pollution. And all petitions by organizations like the IDA are especially unknown to those people.
        However I think that your blog for example is a good way to get people interested in the topic and the problems of light pollution.
        Let me use this opportunity to thank you for your passionate work on this site.
        I am happy that I found your blog about one and a half year ago. It always helped/helps me to learn the names/background/properties of the stars and your charts for finding certain celestial objects are very detailed and easy to use. Your blog got me even more interested in the night sky!
        So thank you very much for that Bob, and I hope all of us stargazers have some exciting years before us with comets, better-than-average meteor showers, solar eclipses, Apophis fly-by and maybe even a Supernova in our own galaxy!

        1. astrobob

          Thank you for your thoughts as well as your kind words about the blog. I agree, most people don’t know about light pollution, which is why education is so important. That’s something we can all do in many small ways when we’re showing the sky at a public outing or putting on a show at the local planetarium. As for the future – many good things are yet to come!

  2. Edward O'Reilly

    There is a whole generation of people who have never seen the Milky Way and don’t even know what they’re missing.I don’t understand why all lights aren’t shielded-it’s more economical to concentrate light downwards to the ground-and that’s where security is needed,not up in the sky.

    1. astrobob

      My guess is that it’s simply cheaper to use wallpack-style lights that shine out in every direction. That way no one need erect light poles – at extra expense – with shielded lighting to illuminate areas around buildings and small parking lots. Ditto for the proliferation of the vintage lampposts that put out tremendous amounts of unwanted glare. At least in Duluth, Minn., our tall standard lights that line main thoroughfares are nearly all shielded as are many of the parking lots at malls. No more of the “cobra-style” lamps. Still, the proliferation of “quaint” architectural or vintage-style lights found has transformed many cities’ downtown (and sometimes entire neighborhoods) into glare zones.

  3. Edward M. Boll

    I live in a small town in a rural area. But there are lights scattered around to the north, more than there used to be. Maybe that is why I am not seeing the Northern Lights that I used to.

    1. astrobob

      They sure don’t help. While Duluth spoils the sky to our southwest, the north is thankfully pristine.

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