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You entered: apod

5.11.2023
It was Halloween and the sky looked like a creature. Exactly which creature, the astrophotographer was unsure (but possibly you can suggest one). Exactly what caused this eerie apparition in 2013 was sure: one of the best auroral displays that year. This spectacular aurora had an unusually high degree of detail.

14.07.2024
The galaxy was never in danger. For one thing, the Triangulum galaxy (M33), pictured, is much bigger than the tiny grain of rock at the head of the meteor. For another, the galaxy is much farther away -- in this instance 3 million light years as opposed to only about 0.0003 light seconds.

24.08.2020
How come the crescent Moon doesn't look like this? For one reason, because your eyes can't simultaneously discern bright and dark regions like this. Called earthshine or the da Vinci glow...

28.02.2023
Why is a thin crescent moon never seen far from a horizon? Because the only geometry that gives a thin crescent lunar phase occurs when the Moon appears close to the Sun in the sky.

22.09.2024
Chicago, in a way, is like a modern Stonehenge. The way is east to west, and the time is today. Today, and every equinox, the Sun will set exactly to the west, everywhere on Earth.

29.11.2023
Could there be a tornado inside another tornado? In general, no. OK, but could there be a tornado inside a wider dust devil? No again, for one reason because tornados comes down from the sky, but dust devils rise up from the ground.

16.06.2000
Welcome to the sixth year of Astronomy Picture of the Day (APOD)! Above are the industrious Robert Nemiroff (left) and persistent Jerry Bonnell (right), still engaged in creating the APOD web pages. As suggested...

30.05.2024
Why does a cloudy moon sometimes appear colorful? The effect, called a lunar corona, is created by the quantum mechanical diffraction of light around individual, similarly-sized water droplets in an intervening but mostly-transparent cloud. Since light of different colors has different wavelengths, each color diffracts differently.

14.10.2024
Go outside at sunset tonight and see a comet! C/2023 A3 (TsuchinshanБATLAS) has become visible in the early evening sky in northern locations to the unaided eye. To see the comet, look west through a sky with a low horizon.

11.07.2025
Transfusing sunlight as the sky grew darker, this exceptional display of noctilucent clouds was captured on July 10, reflected in the calm waters of Vallentuna Lake near Stockholm, Sweden. From the edge of space...
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