A Zodiacal Sky over Horseshoe Bend
22.05.2017

What's causing the unusual ray of white light extending upward from the central horizon? Dust orbiting the Sun. At certain times of the year, a band of sun-reflecting dust from the inner Solar System rises prominently before sunrise and is called zodiacal light.

The Galaxy Above
15.10.2019

Have you contemplated your home galaxy lately? If your sky looked like this, perhaps you'd contemplate it more often! The featured picture is actually a composite of two images taken last month from the same location in south Brazil and with the same camera -- but a few hours apart.

Spiral Galaxy NGC 2403 from Subaru
5.07.2006

Sprawling spiral arms dotted with bright red emission nebulas highlight this new and detailed image of nearby spiral galaxy NGC 2403. Also visible in the photogenic spiral galaxy are blue open clusters, dark dust lanes, and a bright but relatively small central nucleus.

Milky Way over French Alp Hoodoos
16.05.2022

Real castles aren't this old. And the background galaxy is even older. Looking a bit like an alien castle, the pictured rock spires are called hoodoos and are likely millions of years old. Rare, but found around the world, hoodoos form when dense rocks slow the erosion of softer rock underneath.

APOD: 2025 May 12 Б Gaia Reconstructs a Side View of our Galaxy
12.05.2025

What does our Milky Way Galaxy look like from the side? Because we are on the inside, humanity canБt get an actual picture. Recently, however, just such a map has been made using location data for over a billion stars from ESAБs Gaia mission.

Nebulosity in Sagittarius
18.07.1996

What causes the colors in this beautiful nebulosity in Sagittarius? Dubbed NGC 6589 and NGC 6590, the colors of this nebulosity, are caused by gas and dust. The blue color of the nebula nearest the bright stars is caused by reflection off interstellar dust.

APOD: 2023 December 13 Б Deep Field: The Heart Nebula
13.12.2023

What excites the Heart Nebula? First, the large emission nebula on the left, catalogued as IC 1805, looks somewhat like a human heart. The nebula glows brightly in red light emitted by its most prominent element, hydrogen, but this long-exposure image was also blended with light emitted by silicon (yellow) and oxygen (blue).

Meteors over Four Girl Mountains
13.12.2016

On some nights it rains meteors. Peaking over the next two nights, asteroid dust is expected to rain down on Earth during the annual Geminids meteor shower. This year, unfortunately, fainter Geminids will be harder to see because of the brightness of the Long Nights Full Moon, which occurs Wednesday.

NGC 5189: An Unusually Complex Planetary Nebula
19.12.2012

Why is this nebula so complex? When a star like our Sun is dying, it will cast off its outer layers, usually into a simple overall shape. Sometimes this shape is a sphere, sometimes a double lobe, and sometimes a ring or a helix.

Composite Crab
4.09.2003

The Crab Pulsar, a city-sized, magnetized neutron star spinning 30 times a second, lies at the center of this composite image of the inner region of the well-known Crab Nebula. The spectacular picture combines...