Slideshow: The World at Night 2013

Andreas Max Baeckle

The winners of the 2013 "Earth and Sky" photo contest show off the beauties of the night sky and demonstrate the effects of light pollution.

Launch slideshow

Are the images featured in The World at Night's annual "Earth and Sky" photography contest meant to celebrate the wonders of the night sky, or draw attention to the worries about the night sky? They're meant to do both, says astrophotographer Babak Tafreshi.

For example, consider "Stars Over Salzburg," one of this year's top-rated images. Your first impulse is to marvel at the golden glow of the Austrian city, as seen from an Alpine vantage point high above.

"But then you realize the photographer has moved away from the city to the mountaintops in order to separate himself from the light pollution," Tafreshi, founder of The World at Night, told NBC News in an email. "Inside the yellow light cast by the city, people are no longer able to see this beauty."

That's the tragedy of the modern world, right? Studies suggest that as much as 80 percent of the world's population can no longer see the Milky Way, due to the lights that illuminate our cities and roadways. But it doesn't have to be that way, and the picture of Salzburg proves it. Tafreshi pointed out that the direct, unshielded glow of city lights can be seen even from a mountaintop.

"That shows that the lights are shining upward," he said. "Light pollution is not the lights we need for our modern world. It's the unnecessary, wrong-directed and excessive light that scatters to the sky instead of illuminating the ground. It isn't just an astronomer's problem. It's a major waste of energy, it disrupts ecosystems and has adverse health effects."

The International Dark-Sky Association estimates that $1 billion is spent in the United States every year to generate artificial light that goes to waste. And as other countries become more urbanized, the stars disappear from wider swaths of the world.

"Our images try to show how the night sky is an essential part of our environment, and not just an astronomer's laboratory," Tafreshi said. "They display how the night sky is becoming a forgotten part of nature for many people in urban, light-polluted areas. A major goal for us in TWAN imaging is to reclaim the beauties of the night sky and make people aware of this."

The World at Night isn't just about the dark side of the disappearing sky. The winning photos include views that reveal cosmic glories in all their purity. "A good example in this year's contest is 'Crossed Destiny' by Luc Perrot, from Reunion Island near Madagascar," Tafreshi said. "The stunning view of the Milky Way above the Indian Ocean has no touch of our modern world. The galactic band is merged with the horizon of our planet."

Click through our slideshow of images from this year's "Earth and Sky" contest, and check out The World at Night's website for still more cosmic glories and cautionary tales.

More beauties of the world at night:

• The World at Night 2012: Darkness and light
• Slideshow: The World at Night 2011
• All-time top 10 astronomy pictures
• The Month in Space Pictures: April 2013

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the NBC News Science Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with NBCNews.com's stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

Slideshow: The World at Night 2012

Christoph Otawa / The World at Night

Experience the wonders of the night sky in a slideshow that features the winners of the 2012 "Earth & Sky" contest, presented by The World at Night.

Launch slideshow

Light pollution never looked so good: The World at Night's annual photography contest highlights the beauties of the night sky, but it also highlights the challenges posed by humanity's efforts to light up the night.

This year's winners reveal how artificial lighting can add another dimension to the natural wonders of the stars and planets — or spoil the view forever. Hundreds of pictures were sent in from about 50 countries, including exotic locales such as the sub-Antarctic island of South Georgia, the national parks of Reunion Island and the savannas of South Africa, said Babak Tafreshi, the founder and leader of The World at Night. "We received a lot of submissions from Asian countries this year, especially China, India, Iran and Indonesia," the Iranian-born astrophotographer said in an email exchange.

He said the message of The World at Night is definitely getting out: "In general, it looks as if TWAN's aim of reclaiming the natural beauty of the night sky and promoting nightscape photography is reaching a growing audience worldwide, while the activities by amateur and professional astronomers and environmentalists to increase awareness on the light pollution issue is truly getting a lot of public attention."

This year's contest is limited to images taken since the beginning of 2011, but that leaves a lot to choose from — including pictures of Comet Lovejoy, the spectacular "Christmas Comet" that wowed skywatchers in the southern hemisphere, as well as the stunning auroral images that have cropped up over the past few months. Both those phenomena are represented in today's top-10 roundup from TWAN.

Tafreshi drew attention to two potential perils facing astrophotographers nowadays: light pollution and photo fakery. He noted that the increasing glare of city lights was "not just an astronomer's problem," but also "a major waste of energy, and like any other form of pollution, it disrupts ecosystems and has adverse health effects."

"Today, most city skies are virtually empty of stars," he said in his email. "About two-thirds of the human population today lives under light-polluted skies, not dark enough to see the Milky Way. Seeing a real dark sky is a must-see experience in the life of each of us, moments that you will not forget in your entire life."

Tafreshi also said there's a fast-rising concern about images that may not be telling the truth about the earth and sky.

"Unfortunately, a majority of photographers who are interested in nightscape photography are less familiar with astronomy, and the natural look and color of the night sky," he said. "So many landscape astrophotos today are intensely saturated, unnaturally contrasted, and sometimes with totally wrong colors of the sky. We had stunning compositions and amazing landscapes at night, some made by famous photographers, which were ruled out of the contest simply because they were 'overcooked' in processing."

You can rely on TWAN's prize-winning pictures to show the true glories of the night sky, along with the glow of the world below. Check out our slideshow, and read more of Tafreshi's observations in the comment space below.

More astronomy slideshows:

• The World at Night 2011
• Cosmic Log archive of auroral imagery
• All-time top 10 astronomy pictures from APOD
• Month in Space Pictures | Year in Space Pictures 2011

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.