IC 1805: The Heart Nebula
11.09.2019

What energizes the Heart Nebula? First, the large emission nebula dubbed IC 1805 looks, in whole, like a human heart. The nebula glows brightly in red light emitted by its most prominent element: hydrogen. The red glow and the larger shape are all powered by a small group of stars near the nebula's center.

Halley s Nucleus: An Orbiting Iceberg
5.08.2000

What does a comet nucleus look like? Formed from the primordial stuff of the solar system, it is thought to resemble a very dirty iceberg. But for active comets, telescopic images only reveal the surrounding cloud of gas and dust, the comet's coma, and the characteristic cometary tails.

A Northern Winter Sky Panorama
24.12.2019

What stars shine in Earth's northern hemisphere during winter? The featured image highlights a number of bright stars visible earlier this month. The image is a 360-degree horizontal-composite panorama of 66 vertical frames taken consecutively with the same camera and from the same location at about 2:30 am.

APOD: 2025 April 13 Б An Unusual Hole in Mars
13.04.2025

What created this unusual hole in Mars? Actually, there are numerous holes pictured in this Swiss cheese-like landscape, with all-but-one of them showing a dusty, dark, Martian terrain beneath evaporating, light, carbon dioxide ice.

Comet Halley's Nucleus
10.12.1996

Here is what a comet nucleus really looks like. For all active comets except Halley, it was only possible to see the surrounding opaque gas cloud called the coma. During Comet Halley's most...

Young Suns of NGC 7129
11.08.2005

Young suns still lie within dusty NGC 7129, some 3,000 light-years away toward the royal constellation Cepheus. While these stars are at a relatively tender age, only about a million years old, it is likely that our own Sun formed in a similar stellar nursery some five billion years ago.

The Starry Night of Alamut
25.06.2010

A meteor's streak and the arc of the Milky Way hang over the imposing mountain fortress of Alamut in this starry scene. Found in the central Alborz Mountains of Iran, Alamut Castle was built into the rock in the 9th century. The name means Eagle's Nest.

Rosetta s Target Comet
23.05.2014

The Rosetta spacecraft captured this remarkable series of 9 frames between March 27 and May 4, as it closed from 5 million to 2 million kilometers of its target comet. Cruising along...

Noctilucent Clouds over London
10.07.2014

This scene from the early morning hours of July 3 looks out across the River Thames from the Westminster Bridge. Part of a luminous timelapse video (vimeo), the frame captures a sight familiar in London, the nighttime glow of the London Eye.

Chilean Skyscape
29.11.2008

Night skies over Chilean mountain top observatories can be dark and clear, with glorious cosmic vistas. In this recent example, the plane of our Milky Way galaxy stretches parallel to the horizon, the galactic center's star clusters, dark dust clouds, and glowing nebulae hovering in the west.