The Lunar X
10.12.2016

The striking X appearing in this lunarscape is easily visible in binoculars or a small telescope. Yet, not too many have seen it. The catch is this lunar X is fleeting, only apparent in the hours before the Moon's first quarter phase.

NGC 3621: Far Beyond the Local Group
24.02.2017

Far beyond the local group of galaxies lies NGC 3621, some 22 million light-years away. Found in the multi-headed southern constellation Hydra, the winding spiral arms of this gorgeous island universe are loaded with luminous blue star clusters, pinkish starforming regions, and dark dust lanes.

The Horsehead Nebula
27.12.2017

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.

APOD: 2024 October 1 Б Porphyrion: The Longest Known Black Hole Jets
1.10.2024

How far can black hole jets extend? A new record was found just recently with the discovery of a 23-million light-year long jet pair from a black hole active billions of years ago. Dubbed...

Jupiter s Brain
1.02.2001

Gas giant Jupiter is the solar system's largest world with about 320 times the mass of planet Earth. Famous for its Great Red Spot, Jupiter is also known for its regular, equatorial cloud bands, visible in very modest sized telescopes.

Andromeda Island Universe
8.09.2000

How far can you see? The most distant object easily visible to the unaided eye is M31, the great Andromeda Galaxy some two million light-years away. Without a telescope, even this immense spiral galaxy appears as an unremarkable, faint, nebulous cloud in the constellation Andromeda

The Planet, the White Dwarf, and the Neutron Star
18.07.2003

A planet, a white dwarf, and a neutron star orbit each other in the giant globular star cluster M4, some 5,600 light-years away. The most visible member of the trio is the white...

How to Search for Aliens
17.05.1999

"Mom, can I use our computer to search for aliens?" Last week, the SETI@home project released free software that enables many home computers to search for signals from intelligent extra-terrestrials. These signals may have already been detected by the huge Arecibo radio telescope

Andromeda Island Universe
22.12.2005

The most distant object easily visible to the unaided eye is M31, the great Andromeda Galaxy some two million light-years away. But without a telescope, even this immense spiral galaxy - spanning over 200,000 light years - appears as a faint, nebulous cloud in the constellation Andromeda.

HD 189733b: Hot Jupiter
12.05.2007

HD 189733b is a Jupiter-sized planet known to orbit a star some 63 light-years away. But while the distant world is approximately the size of Jupiter, its close-in orbit makes it much hotter than our solar system's ruling gas giant.