A late-night disco in the forest reveals tree performance

In 2017, the group from the Optics of Photosynthesis Lab (OPL) developed a new method to measure a small but important signal produced by all plants, and in this case trees. This signal is called chlorophyll fluorescence ...

What is pepper spray?

Whether it's walking down a dark street at night or fighting off grizzly bears on the trail, pepper spray is an effective tool to fend off an attacker and get safely away. But have you ever thought about what gives this personal-defense-in-a-can ...

Satellite data and AI help fight Sweden's forest fires

According to Swedish authorities, there is a high risk of forest and grass fires this week and some communities, such as Upplands Bro (northwest of Stockholm), have taken the step of banning the traditional bonfires that ...

Dung beetles navigate better under a full moon

Of all nocturnal animals, only dung beetles can hold their course using polarized moonlight. Researchers at Lund University in Sweden have now shown that beetles can use polarized light when its signal strength is weak, which ...

Winter solstice: The astronomy of Christmas

From the Neolithic to present times, the amount of sunlight we see in a day has had a profound impact on human culture. We are fast approaching the winter solstice for the Northern hemisphere, which takes place on December ...

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Night

Night or nighttime is the period of time when the sun is below the horizon. This occurs after dusk. The opposite of night is day (or "daytime" to distinguish it from "day" as used for a 24-hour period). The start and end times of night vary based on factors such as season, latitude, longitude and timezone.

At any given time, one side of the planet Earth is bathed in light from the Sun (the daytime) and the other side of the Earth is in the shadow caused by the Earth blocking the light of the sun. This shadow is what we call the darkness of night.

This text uses material from Wikipedia, licensed under CC BY-SA