Accretion Disk Binary System
26.12.1995

Our Sun is unusual in that it is alone - most stars occur in multiple or binary systems. In a binary system, the higher mass star will evolve faster and will eventually become a compact object - either a white dwarf star, a neutron star, or black hole.

The Double Nucleus of M31
11.10.1996

The center of M31 is twice as unusual as previously thought. In 1991 the Planetary Camera then onboard the Hubble Space Telescope pointed toward the center of our Milky Way's closest major galactic neighbor: Andromeda (M31). To everyone's surprise, M31's nucleus showed a double structure.

Contemplating Mars
2.09.2003

Is that really another world? Thousands of people the world over lined up last week to see Mars through a telescope as the red planet and Earth passed unusually close together in their orbits around the Sun. Reviews of Mars were mixed, with some people disappointed that Mars still appeared somewhat blurry.

The Missing Craters of Asteroid Itokawa
21.11.2005

Where are the craters on asteroid Itokawa? No one knows. The Japanese robot probe Hayabusa recently approached the Earth-crossing asteroid and is returning pictures showing a surface unlike any other Solar System body yet photographed -- a surface possibly devoid of craters.

The Eskimo Nebula from Hubble
3.05.2009

In 1787, astronomer William Herschel discovered the Eskimo Nebula. From the ground, NGC 2392 resembles a person's head surrounded by a parka hood. In 2000, the Hubble Space Telescope imaged the Eskimo Nebula. From space, the nebula displays gas clouds so complex they are not fully understood.

South Polar Vortex Discovered on Titan
24.07.2012

What's happening over the south pole of Titan? A vortex of haze appears to be forming, although no one is sure why. The above natural-color image shows the light-colored feature. The vortex was found on images taken last month when the robotic Cassini spacecraft flew by the unusual atmosphere-shrouded moon of Saturn.

Milky Way over the Pinnacles in Australia
17.02.2016

What strange world is this? Earth. In the foreground of the featured image are the Pinnacles, unusual rock spires in Nambung National Park in Western Australia. Made of ancient sea shells (limestone), how these human-sized picturesque spires formed remains unknown.

Supernumerary Rainbows over New Jersey
27.11.2022

Yes, but can your rainbow do this? After the remnants of Hurricane Florence passed over the Jersey Shore, New Jersey, USA in 2018, the Sun came out in one direction but something quite unusual appeared in the opposite direction: a hall of rainbows.

APOD: 2023 August 22 Б The Pistachio Nebula
22.08.2023

This nebula had never been noted before. Newly discovered nebulas are usually angularly small and found by professionals using large telescopes. In contrast, the Pistachio Nebula was discovered by dedicated amateurs and, although faint, is nearly the size of the full Moon.

APOD: 2023 November 27 Б LBN 86: The Eagle Ray Nebula
27.11.2023

This eagle ray glides across a cosmic sea. Officially cataloged as SH2-63 and LBN 86, the dark nebula is composed of gas and dust that just happens to appear shaped like a common ocean fish. The interstellar dust nebula appears light brown as it blocks and reddens visible light emitted behind it.