From APOD...What are those red filaments in the sky? They are a rarely seen form of lightning confirmed only about 30 years ago: red sprites. Recent research has shown that following a powerful positive cloud-to-ground lightning strike, red sprites may start as 100-meter balls of ionized air that shoot down from about 80-km high at 10 percent the speed of light. They are quickly followed by a group of upward streaking ionized balls. The featured image was taken earlier this year from Las Campanas observatory in Chile over the Andes Mountains in Argentina. Red sprites take only a fraction of a second to occur and are best seen when powerful thunderstorms are visible from the side.
The Sun sets beneath two horizons...
Taken from the Paranal mountain, home to the ESO Paranal site that houses the Very Large Telescope (VLT), this spectacular view points out over the South Pacific Ocean at sunset. The water itself is hidden beneath a second sea of very thin clouds — so thin that the Sun shines up through them, revealing the line of the true water horizon. This gives the odd illusion that the Sun is sinking into the sea.