When was the last time you looked at the starry sky?

Take care and do it!

The stars shine more and more faintly in the night sky.

This is shown by a new study based on so-called citizen research.

More than 50,000 volunteers worldwide have over eleven years estimated how well they see individual stars in the Big Dipper and Orion's belt.

It turned out that the average night sky gets almost ten percent brighter with each passing year.

The researchers calculated that this means that the night sky can completely change shape during a person's childhood.

If a child was born 18 years ago and his parents could then count 250 bright stars in the night sky behind their house, only 100 stars remain for the newly 18-year-old to look at - even though he is in the exact same place and time at night.

Five thousand stars in the sky

In the dawn of the human race when there was no artificial light, during moonless nights you could see up to 5000 stars in the sky.

But it is difficult to experience today.

- If you stand in the center of Stockholm, you might be able to see five stars, says Johan Eklöf, who is a bat researcher and author.

The increasingly bright nights are a direct effect of increased light pollution from growing cities.

The world's population is increasing and the availability of cheap LED lights has increased sharply in the last ten years.

Animals get tricked

This lighting trend affects many animal species.

Johan Eklöf has researched what happens when night lighting is installed on church towers where many bats live.

 - Bats are photosensitive.

They catch their prey under cover of darkness to avoid being discovered by birds of prey.

But if it's lit, the bats think it's day and they don't go out and hunt, says Johan Eklöf.

Other animals that are affected are insects that are fooled by the artificial light and lose their ability to navigate.