Presenter: Hello and welcome back! Today we continue the discussion of the environmental problems. Our today’s topic is light pollution. The guest of our program is Dr. Donald Matthews. Good morning, Dr. Matthews! What exactly is light pollution? And why is it a problem?

Dr. Matthews: Good morning! Well, let me answer your first question by asking one: when was the last time you were somewhere dark enough to see the Milky Way, or just the stars for that matter? I’m afraid, for people who live in big cities stargazing has already become a luxury. Our planet is so thickly covered by artificial light that we are rapidly losing night’s natural darkness and many good things that come with it. We have completely forgotten how valuable darkness is.

Presenter: I have to admit that apart from being able to see the stars, I cannot really think of any advantages of natural darkness.

Dr. Matthews: Exactly! Very few people actually think about the value of darkness. While in reality, all life on earth evolved to the steady rhythm of bright days and dark nights. The good health of plants, animals and people is dependent on this rhythm. Take our bodies, for example. They need darkness to sleep. Without it, people get sleep disorders which lead to such common problems as depression and obesity.

Presenter: You have also mentioned animals. Are they hurt by light pollution as well?

Dr. Matthews: Absolutely! Especially those that are active at night, like bats, moths and fireflies. Light easily confuses them and their bodies cannot function the way they are supposed to. Or take sea turtles! They usually come ashore to lay their eggs at night to avoid humans and other animals that can attack them, and their little babies hatch at night as well. It is a lot less dangerous for the baby sea turtles to find their way to the sea in total darkness.

Presenter: I would never have thought of that! Are there any economic implications of light pollution as well?

Dr. Matthews: Well, putting it simply, much of this light is just wasted energy. Which means wasted natural resources. In my opinion, without darkness and with so much energy wasted for nothing, Earth’s ecology would collapse.

Presenter: Now that you’ve put it this way, I can see that it is a big problem. Are there no solutions to it?

Dr. Matthews: The good news is, such solutions are easily available. First of all, using new lighting technologies helps. Many cities and towns across North America and Europe are changing to LED streetlights which offer great possibilities for controlling wasted light. But simply turning off portions of public lighting after midnight also helps. Even Paris, the famous "city of light", turns off its monument lighting after 1am, and requires its shops, offices and public buildings to turn off lights after 2am.

Presenter: That’s good to know! Is there anything ordinary people like you and me can do in their everyday life?

Dr. Matthews: This is a very good question, because we will never truly address the problem of light pollution until we become aware of the value and beauty of the darkness we are losing. There are many International Dark Sky Parks and Reserves that provide dark sky programs for visitors. Many of them are located around astronomical observatories. People can hike in these parks and enjoy starry skies. But just realizing that it’s a bad idea to take your smartphone or tablet or laptop to bed is already a big step forward and will help you preserve your own health.

Presenter: You have mentioned the beauty of the dark skies.

Dr. Matthews: But of course! The vision of night sky has always inspired writers and artists, think of Van Gogh’s "Starry night"! We should not deprive our children and grandchildren of such an inspiration!