As the weather warms up, more wildlife is returning to Canada from down south. But as cities continue to grow, the sky is becoming less dark in many areas due to artificial light at night. On this edition of Ask an Astronomer, Dr. Phil Langill with the Rothney Astrophysical Observatory explains how urban light pollution is putting our wildlife at risk. “The overuse of light at night is making the whole Earth at night brighter, and what is really suffering the most is just the natural world: plants and animals and bugs and insects who need to work at night,” said Langill. “There are many types of animals and critters who look for food in darkness, who look for a mate in darkness; all these fundamental, just survival things rely on darkness.” We’ll show some simple ways you can safely minimize your light usage at night to keep the sky dark. Plus, we head to the moon for one of our viewer questions! Kimmy was curious how planned nuclear fission reactors on the moon could impact Earth if something were to go wrong. Space science educator Don Hladiuk says modern-day reactors are incredibly safe. “I don’t believe there are any worries about destroying Earth or causing any harm to Earth,” Hladiuk said. “The technology is well-known, and being on the moon is about 400,000 kilometres away. We’re a safe distance away, so I wouldn’t worry about any problems back here on Earth.” Here’s a breakdown of what’s covered in this episode by timecode: If you have a question you would like to ask an astronomer, you can email us at yourmorningcalgary@ctv.ca, text us at 10-400 or leave a question in the comments section on YouTube. You can also watch full episodes of Ask an Astronomer on our CTV Calgary website and on our CTV News YouTube page.