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.

Geometers Playground Over Wyoming
6.06.2011

If you travel several kilometers off a main highway through Wyoming, you may see an unusual sight. In particular, near Buford, Wyoming, USA, you could run across the geometric Ames Monument, visible on the right, built to commemorate the financiers of a historic transcontinental railroad across North America.

The Sombrero Galaxy from Hubble
26.07.2015

Why does the Sombrero Galaxy look like a hat? Reasons include the Sombrero's unusually large and extended central bulge of stars, and dark prominent dust lanes that appear in a disk that we see nearly edge-on. Billions of old stars cause the diffuse glow of the extended central bulge.

Geminid Meteors over Xinglong Observatory
23.12.2015

Where do Geminid meteors come from? In terms of location on the sky, as the featured image composite beautifully demonstrates, the sand-sized bits of rock that create the streaks of the Geminid Meteor Shower appear to flow out from the constellation of Gemini.