Night Skies

 

Star trails over Grand Canyon as seen from the South Rim.

NPS Photo by Dan Pawlak

 

“Why did not somebody teach me the constellations, and make me at home in the starry heavens,
which are always overhead, and which I don't half know to this day?” – Thomas Carlyle

 

Imagine gazing up at the sky on a moonless summer night and having the center of the Milky Way Galaxy cast your shadow upon the earth. The jeweled planets Jupiter, Mars, and Saturn wander along the ecliptic plane, nestled in the ancient constellations of the zodiac, which has inspired art, science, and religion for millennia. You stand humbled by the brilliance of thousands of stars and become connected to countless civilizations through the stories written in the night sky.

 

Imagine the psychological differences this would make in our lives if we could commune with nights like these whenever we needed. Unfortunately, for nearly 80% of Americans today, the Milky Way is no longer visible. Light pollution, created by the inefficient use of outdoor lighting, will block the view of the Milky Way for 4 out 5 children born today if this trend continues. Thankfully, there is hope to preserve the last sanctuaries of our night skies and to return to an unimpaired view of the cosmos that our ancestors experienced.

 

What is a natural lightscape?

A natural lightscape is a sky that is unimpaired by artificial lighting. In 2001, John E. Bortle created a useful 9 class scale, called the Bortle Scale that gives us a foundation for what a pristine night sky should look like versus a severely light polluted night sky. Class 1 night skies are the most natural skies and Class 9 are affected urban areas in large cities. The majority of populated areas in the United States have lost pristine views of the night sky that have been inspiring us since the dawn of civilization. At most, we see a couple prominent stars that make up a fragmented constellation. Perhaps we see a planet. But within light polluted areas, the full glory of the night sky is mostly lost.

 

The Milky Way over Grand Canyon. A pristine night sky reveals these regions of the Milky Way. NPS/Ty Karlovetz

Yet our precious natural lightscapes are filled with thousands of visible stars. The Milky Way is bright enough to silhouette the clouds of gas and dust running through the center of our galaxy, creating a field of detailed structure, called the galactic interstellar medium.

Here we see with our naked eye parts of the galaxy once familiar to our ancestors: the Cygnus Dark Rift, the Northern Coal Sack, and Prancing Horse.The Scutum Star Cloud and Sagittarius Star Cloud illuminate the center of the galaxy.

Other abstract sources of celestial light like the gegenschein and the zodiacal band are visible.

An abundance of star clusters, nebulae, galaxies, and unimpaired views of seasonal meteor showers are what define natural lightscapes. Yet these celestial objects are becoming increasingly unfamiliar to us simply because they are disappearing from our evening experience.

 

What is light pollution?

Light pollution is defined as excessive, misdirected, or obtrusive artificial light. This definition applies to unwanted light in your own community as well as the night sky. Light that obtrusively shines upon an area, such as your property, is known as light trespass. The primary cause of light pollution is inefficient use of outdoor lighting.

 

Typical light fixtures can waste 60% of their emitted light. Photo: Tyler Nordgren, University of Redlands

Many lights are arranged in a way that wastes up to 60% of their emitted light. About 50% of emitted light shines directly in to the atmosphere and scatters off molecules and aerosols, a large percentage bouncing back down to Earth, creating the dome of light over cities called skyglow.

We can see these domes from many miles away and they have a profoundly negative effect on our view of the cosmos. The remaining 10% of that wasted light shines directly in to our line of sight producing glare which destroys our ability to see safely at night.

Not only does light pollution dissolve our cultural connections and hinder our scientific explorations of the night sky, it also has a negative impact on wildlife. Many nocturnal animals that rely on the natural darkness of the night to hunt or to navigate become confused from the obtrusive skyglow of artificial light. Their instinctive pursuit of this false light leads them on an unnatural course which often leads to death.

 

Light pollution also takes a toll on our finite resources. It is estimated that up to 35% of our total outdoor lighting in the United States is completely wasted in to the atmosphere. This means that 35% of the resources we use to create that electricity is completely wasted. This translates to about 3 billion dollars a year in resources that are wasted creating skyglow and light pollution.

We have seen a dramatic increase in light pollution over the last few decades. Many people have watched the Milky Way disappear over their homes as growing domes of unwanted light trespass over the sky like persistent, incoming tides. Thankfully, unlike many other forms of irreparable pollution, light pollution is 100% fixable. It cleans up at literally the speed of light!

 

Bright areas on this map show sky glow from artificial light scattering into the atmosphere from North America. To view an interactive version of the new global atlas, click/touch the photo above, or the use this link: https://cires.colorado.edu/artificial-sky

Graphic credit: Falchi et al., Science Advances, including Dan Duriscoe/NPS; Bob Meadows/NPS; Jakob Grothe/NPS contractor, and Matthew Price/CIRES and CU-Boulder

 

What can we do about light pollution?

• Be inspired. Go outside tonight and try to identify a constellation, a planet, and a star. Pursue a question you have always wanted to know about the universe.
• Become a citizen scientist. Follow these easy steps to figure out how dark your night sky is in your community and submit that data in to an international database known as Globe at Night. Your data contributes to a global inventory of light pollution.
• Educate yourself on the negative impacts of light pollution.
• Attend free ranger evening programs, constellation tours, and star party events.
• Use efficient lighting at your house. Find ways to reorient your light fixtures to meet your safety needs and reduce the amount of excess light scattered in to the atmosphere. Doing this is cost and energy effective.
• Pass on your knowledge and inspiration to your community. Your city can apply to become an International Dark Sky Community.

 

The best type of outdoor lighting reduces light pollution and glare. It also saves money and energy.

 

What is an International Dark Sky Park?

National Parks are some of the last remaining sanctuaries for pristine night skies. The International Dark Sky Association certifies a park as an International Dark Sky Park if the park retrofits the lights within its boundaries to be night sky friendly, educates visitors about the values of the night sky, and inspires the world to address the problem of light pollution within their own communities.

 

The Milky Way over Desert View Watchtower of Grand Canyon. Photo/Tyler Nordgren, University of Redlands

In 1999, The National Park Service assembled the Night Sky Team. This small group of NPS scientists has been steadily collecting data on the darkness of night skies in National Parks around the country.

The methods used by the Night Sky Team to measure light pollution around National Parks have been effective in understanding the threats that our natural lightscapes face.

The data collected by the Night Sky Team within a given National Park is important for the determination of International Dark Sky Park status.

Download the 2007 Night Sky Team Report of Grand Canyon National Park (868 kb PDF)

Download the January 2016 International Dark Sky Park Nomination Package - Grand Canyon National Park (6 MB PDF)

CBS Report: "Grand Canyon offers starry views free of light pollution (YouTube)"

 

Grand Canyon National Park Dark Skies Program

 

Half the park is after dark! Photo/Tyler Nordgren, University of Redlands

Grand Canyon National Park continues to build a robust Dark Skies Program, which includes improvements to the park's lighting and a diverse range of educational outreach.

Grand Canyon National Park's certification as an International Dark Sky Park.

Grand Canyon Star Party

Free Park Ranger Night Sky Programs

Astronomer in Residence Program

Astronomy Volunteers Program

Night Spoken Video Series

Learn how you can help Grand Canyon night skies by visiting our non-profit partner Grand Canyon Conservancy.

For more information about night skies and light pollution:

NPS Natural Sounds and Night Skies Division

International Dark Sky Association

 

How to Stargaze at the Grand Canyon

Because of the park's efforts to reduce its light pollution, practically anywhere in the park is a great place to stargaze. That said, there are tips you can follow to maximize your stargazing experience:

• Ask a park ranger at the Grand Canyon Visitor Center about any formal stargazing events that might be occuring during your trip. You can also check our park ranger program page. If there are no events, you are welcome to stargaze on your own!
• The park is open 24 hours a day. Visitors may stargaze anytime of night in the park.
• Stargazing is best at least 1.5 hours after sunset and 1.5 hours before sunrise.
• Plan your visit around the Moon phase. The brighter the Moon, the less stars you see! Avoid dates around the First Quarter Moon and the Full Moon. Plan your trip around Third Quarter and New Moon phases.
• Mather Point, behind the Grand Canyon Visitor Center, is a fantastic place to stargaze in the South Rim Village.
• Desert View, Moran,and Lipan Points are amazing places to stargaze along east Desert View Drive.
• Cape Royal is the best place to stargaze on the North Rim. However, Bright Angel Point, next to the Grand Canyon Lodge, is incredible as well.
• Temperatures swing wildly from day to night. Dress warm, even for summer nights.
• Use RED instead! Bring a light source to help you navigate safely in the dark (it is REALLY dark). However, in order to get the most of out of your stargazing experience, try to use a RED headlamp or flashlight. Red light will preserve your night vision, allowing you to see the delicate celestial phenomena in the sky. If you must use a white light, keep the light source low and out of yours and others' direct vision.
• Allow for your eyes to dark-adapt for at least 30 minutes. Once fully adapted, you will be able to see thousands of more stars.
• Bring a camp chair, a blanket, a beverage, and perhaps a starmap.
• For photographers: In order to get the core of the Milky Way in the background and the Canyon in the foreground, you may consider planning a trip to the North Rim. The core of the Milky Way is south, so it can be challenging to get good shots of the Canyon in the foreground and the Milky Way in the background from the South Rim. That said, Desert View Watchtower provides an excellent foreground object to the Milky Way core from the South Rim. Always consider the Moon phase and the time of year before planning a night sky photography trip.
  

 

Duration:

10 minutes, 4 seconds

Experience the mystery and wonder of Grand Canyon National Park's night sky with Astronomer Tyler Nordgren and Park Ranger Rader Lane. Explore the beauty of the night sky and learn what you can do to help preserve it.