Noctilucent Clouds
19.06.2005

Sometimes it's night on the ground but day in the air. As the Earth rotates to eclipse the Sun, sunset rises up from the ground. Therefore, at sunset on the ground, sunlight still shines on clouds above.

The Red Rectangle Nebula from Hubble
8.05.2018

How was the unusual Red Rectangle nebula created? At the nebula's center is an aging binary star system that surely powers the nebula but does not, as yet, explain its colors. The unusual...

APOD: 2026 March 30 Б Peculiar Elliptical Galaxy Centaurus A
29.03.2026

What's happened to the center of this galaxy? Dramatic dust lanes run across the center of unusual elliptical galaxy Centaurus A. These dust lanes are so thick they almost completely obscure the galaxy's center in visible light.

The Red Rectangle Nebula from Hubble
14.06.2010

How was the unusual Red Rectangle nebula created? At the nebula's center is a young binary star system that surely powers the nebula but does not, as yet, explain its colors. The unusual...

A Crescent Sunrise
17.08.1999

Normally, the Moon shows phases, but the Sun does not. The reason is founded in the fact that the Moon shines only by reflected sunlight. When the Moon is closer to the Sun than the Earth, only part of it appears to be lit - resulting in a familiar crescent-shaped phase.

APOD: 2026 January 5 Б The Red Rectangle Nebula from Hubble
4.01.2026

How was the unusual Red Rectangle nebula created? At the nebula's center is an aging binary star system that surely powers the nebula but does not, as yet, explain its colors. The unusual...

Infrared Uranus
20.10.1998

The Sun's third largest planet usually looks quite dull. Uranus typically appears as a featureless small spot in a small telescope or a featureless large orb in a large telescope. Last August, however...

An Energetic Radio Galaxy
29.09.1995

The radio and optical emission seen in the above superposed images of the radio galaxy 3C368 indicate that energetic processes are at work. A radio galaxy is a galaxy that is visible to radio telescopes. A large radio signal usually indicates very powerful phenomena.

A Floral Aurora Corona
28.07.2009

Few auroras show this level of detail. Above, a standard digital camera captured a particularly active and colorful auroral corona that occurred last week above Alberta, Canada. With a shape reminiscent of a flower, the spectacular aurora had an unusually high degree of detail.

Supermoon Over Paris
7.05.2012

Did you see that full Moon Saturday night? Dubbed a supermoon, the latest fully illuminated moon appeared slightly larger than usual because it occurred unusually near the closest point in its orbit to Earth. Pictured above, the supermoon was captured Saturday night rising behind the top of the Eiffel Tower in Paris, France.