M106: A Spiral Galaxy with a Strange Center
17.03.2019

What's happening at the center of spiral galaxy M106? A swirling disk of stars and gas, M106's appearance is dominated by blue spiral arms and red dust lanes near the nucleus, as shown in the featured image.

Perihelion to Aphelion
9.01.2020

Perihelion for 2020, the point in Earth's elliptical orbit when it is closest to the Sun, occurred on January 5th. The distance from the Sun doesn't determine the seasons, though. Those...

APOD: 2025 July 24 Б Titan Shadow Transit
24.07.2025

Every 15 years or so, Saturn's rings are tilted edge-on to our line of sight. As the bright, beautiful ring system grows narrower and fainter it becomes increasingly difficult to see for denizens of planet Earth.

APOD: 2026 May 3 Б Trifid Pillars and Jets
3.05.2026

Dust pillars are like interstellar mountains. They survive because they are more dense than their surroundings, but they are slowly being eroded away by a hostile environment. Visible in the featured picture...

Comet LINEAR: Fade To Black
13.09.2000

Only last month the stage was set for Comet LINEAR (C/1999S4 LINEAR) to become the first "naked-eye" comet of Y2K. It didn't fill that role, of course, but it did turn in a very dramatic performance.

N44C: A Nebular Mystery
14.05.2002

Why is N44C glowing so strangely? The star that appears to powers the nebula, although young and bright, does not seem hot enough to create some of the colors observed. A search for a hidden hotter star in X-rays has come up empty.

Orion's Horsehead Nebula
25.09.1995

The black indentation to the red emission nebula seen just to the right of center of the above photograph is one of the most famous features in any nebulae on the sky. Because of its shape, it is known as the Horsehead Nebula.

Europa: Oceans of Life?
6.08.1996

Is there life beneath Europa's frozen surface? Some believe the oceans found there of carbon-enriched water are the best chance for life, outside the Earth, in our Solar System. Europa, the fourth largest moon of Jupiter, was recently discovered to have a thin oxygen atmosphere by scientists using the Hubble Space Telescope.

Seyfert's Sextet
24.01.2003

Known as Seyfert's Sextet, this intriguing group of galaxies lies in the head portion of the split constellation Serpens. The sextet actually contains only four interacting galaxies, though. Near the center of this...

Alpha Centauri: The Closest Star System
23.03.2003

The closest star system to the Sun is the Alpha Centauri system. Of the three stars in the system, the dimmest -- called Proxima Centauri -- is actually the nearest star. The bright stars Alpha Centauri...