Animation: Perseid Meteor Shower
8.08.2018

Where do Perseid meteors come from? Mostly small bits of stony grit, Perseid meteoroids were once expelled from Comet Swift-Tuttle and continue to follow this comet's orbit as they slowly disperse. The featured animation depicts the entire meteoroid stream as it orbits our Sun.

Shells of Stars in Elliptical Galaxy PGC 42871
29.10.2018

How do galaxies grow? To help find out, the Hubble Space Telescope was deployed to image the unusual elliptical galaxy PGC 42871. How this galaxy came to be surrounded by numerous shells of stars may give clues about how it evolved.

A Sunset Night Sky over the Grand Canyon
4.02.2020

Seeing mountain peaks glow red from inside the Grand Canyon was one of the most incredible sunset experiences of this amateur photographer's life. They appeared even more incredible later, when digitally combined with an exposure of the night sky -- taken by the same camera and from the same location -- an hour later.

Comet Leonard Before Star Cluster M3
12.12.2021

Comet Leonard is now visible to the unaided eye -- but just barely. Passing nearest to the Earth today, the comet is best seen this week soon after sunset, toward the west, low on the horizon.

APOD: 2024 November 17 Б LDN 1471: A Windblown Star Cavity
17.11.2024

What is the cause of this unusual parabolic structure? This illuminated cavity, known as LDN 1471, was created by a newly forming star, seen as the bright source at the peak of the parabola.

Anticrepuscular Rays Over Colorado
30.10.2001

What's happening over the horizon? Although the scene may appear somehow supernatural, nothing more unusual is occurring than a setting Sun and some well placed clouds. Pictured above are anticrepuscular rays. To understand them, start by picturing common crepuscular rays that are seen any time that sunlight pours though scattered clouds.

A New Constellation Takes Hold
1.04.2003

A new constellation has taken hold of the sky, much to the surprise of many sky gazers. The constellation of Ollie the Owl has suddenly started dominating the southern hemisphere, as shown above. The constellation is taking the place of Wrinkles the Rhinoceros, who was unexpectedly voted off they sky by the other constellations.

Accretion Disk Binary System
19.12.1999

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.

Jupiter Eclipsing Ganymede
6.01.2009

How hazy is Jupiter's upper atmosphere? To help find out, astronomers deployed the Hubble Space Telescope to watch Jupiter eclipse its moon Ganymede. Although Ganymede circles Jupiter once a week, it usually passes above or below the planet, so that a good eclipse occurs more rarely.

An Extraordinary Spiral from LL Pegasi
14.09.2010

What created the strange spiral structure on the left? No one is sure, although it is likely related to a star in a binary star system entering the planetary nebula phase, when its outer atmosphere is ejected.