Twilight is the time of day between daylight and darkness. Astronomers, the experts on nighttime, recognize three kinds of twilight.
Posts by EarthSky
The multiverse hypothesis – the idea that there are other universes – can be tested, scientists say.
If you’re a beginning stargazer or a veteran of thousands of starlit nights, binoculars can be your best friend. Here’s how to get started.
It’s said that once you’ve seen a green flash, you’ll never go wrong in matters of the heart. Here’s all you need to know … plus great pics.
Conditions must be just right to see beautiful, mysterious sunrays – also called crepuscular rays. They often appear after sunset or before sunrise.
Telstar was the first satellite able to relay television signals between Europe and North America. It launched on this date … and helped change the world.
2014 has been a great year for noctilucent, or night-shining, clouds, seen at high latitudes only from about mid-May to August. Wondrous, if you can catch them!
They’re about to become genetic models for astronauts, to help explore the long-term effects of space flight and deep space travel.
This week, Fred Espenak posted this wonderful photo, which shows the minor planets Ceres and Vesta, together on Earth’s sky dome in late June and early July 2014.
This short timelapse video of a microburst in the desert, with images every 30 seconds, makes you feel nature’s power.