Fireball over Lake Louise
12.10.2021

What makes a meteor a fireball? First of all, everyone agrees that a fireball is an exceptionally bright meteor. Past that, the International Astronomical Union defines a fireball as a meteor brighter than apparent magnitude -4, which corresponds (roughly) to being brighter than any planet -- as well as bright enough to cast a human-noticeable shadow.

Earth at Twilight
27.12.2007

No sudden, sharp boundary marks the passage of day into night in this gorgeous view of ocean and clouds over our fair planet Earth. Instead, the shadow line or terminator is diffuse and shows the gradual transition to darkness we experience as twilight.

Apollo 11 Landing Site Panorama
19.12.2014

Have you seen a panorama from another world lately? Assembled from high-resolution scans of the original film frames, this one sweeps across the magnificent desolation of the Apollo 11 landing site on the Moon's Sea of Tranquility.

Lunar Eclipse at the South Pole
5.11.2022

Last May 16 the Moon slid through Earth's shadow, completely immersed in the planet's dark umbra for about 1 hour and 25 minutes during a total lunar eclipse. In this composited timelapse...

Tonight: A Total Lunar Eclipse
26.09.1996

Tonight brings the last total lunar eclipse visible from North America until the year 2000 - with the Moon becoming completely immersed in Earth's shadow. The above time-lapse photograph shows a lunar eclipse that occurred in April 1993.

Apollo 11: East Crater Panorama
20.07.2007

On July 20, 1969, Apollo 11 astronauts Neil Armstrong and Edwin "Buzz" Aldrin became the first to walk on the Moon. This panorama of their landing site sweeps across the magnificent desolation of the Moon's Sea of Tranquility, with their Lunar Module, the Eagle, in the background at the far left.

APOD: 2023 February 5 Б Enceladus by Saturnshine
5.02.2023

This moon is shining by the light of its planet. Specifically, a large portion of Enceladus pictured here is illuminated primarily by sunlight first reflected from the planet Saturn. The result is that the normally snow-white moon appears in the gold color of Saturn's cloud tops.

Planet Earth at Twilight
27.12.2024

No sudden, sharp boundary marks the passage of day into night in this gorgeous view of ocean and clouds over our fair planet Earth. Instead, the shadow line or terminator is diffuse and shows the gradual transition to darkness we experience as twilight.

Ice at the Lunar South Pole
4.12.1996

Ice on the Moon? The prospecting Clementine spacecraft may well have discovered it. In 1994, Clementine spent 70 days in lunar orbit mapping the Moon's surface. Shown above is a dramatically detailed composite view centered on the Lunar South Pole - constructed from 1500 Clementine images.

The Horsehead Nebula
13.07.2003

One of the most identifiable nebulae in the sky, the Horsehead Nebula in Orion, is part of a large, dark, molecular cloud. Also known as Barnard 33, the unusual shape was first discovered on a photographic plate in the late 1800s.