Skyglow is when the night sky looks brighter than it should be because of lights from cities, buildings, and other places. Imagine that you and your friends are having a sleepover at your house. It's late at night, and all of you are trying to go to sleep. But then, your big sister comes in with a really bright flashlight and turns it on. Suddenly, the whole room is lit up so much that it's hard for you to sleep. That's kind of like what skyglow is like for people who live in cities or suburbs with lots of lights.
Because of all the lights that are turned on at night, the sky gets brighter than it should be. This can make it harder for people to see stars or planets in the sky because the light from the cities makes it too bright. It can also be bad for animals that are used to living in the dark. Some animals need to be in darkness at night to be able to do things like hunt for food or find their way back to their homes. Skyglow can make it harder for them to do that.
Scientists are also worried about skyglow because it can affect people's health. When there is too much light at night, it can mess up our sleep patterns and make it harder for us to get good rest. This can lead to all sorts of health problems, like being tired all the time or getting sick more often.
So, in summary, skyglow is when the night sky looks brighter than it should be because of all the lights from cities and other places. It can make it hard to see stars or planets, affect animals that need darkness, and even affect our health.