Composite image of the Earth at night (NASA)
Help researchers monitor and understand light pollution with a simple smartphone app
Guest post by Christopher Kyba How many stars can you see when you look up at the night sky? The answer depends a bit on your vision and a lot on where you live. The bright sky over cities reduces the contrast between the stars and the spaces between them, making them difficult or impossible to see. It’s similar to how the noise from traffic makes it hard to hear singing birds. This phenomenon is known as light pollution and is of concern for both ecological and human health reasons. For example, the croaking of frogs and toads is a nighttime breeding ritual and artificial right disrupts this activity, reducing populations. Similarly, birds that migrate or hunt at night can have their navigation severely affected by artificial light. One way ...
