Mysterious Green Patches on the Sky
30.09.2013

What is it? Some surely natural phenomenon has appeared in a video that, so far, has defied clear identification. The above time-lapse video was made to record Perseid meteors above Hopewell Rocks in New Brunswick, Canada late this summer.

Coronal Holes on the Sun
18.03.2003

The ominous, dark shapes haunting the left side of the Sun are coronal holes -- low density regions extending above the surface where the solar magnetic field opens freely into interplanetary space. Studied extensively from...

X Ray Stars in the Orion Nebula
19.05.2005

When our middle-aged Sun was just a few million years old it was thousands of times brighter in x-rays. In fact, it was likely similar to some of the stars found in this false-color x-ray composite of the Orion Nebula region from the Chandra Observatory.

The Nucleus of Comet Tempel 1
15.09.2005

Approaching the nucleus of comet Tempel 1 at ten kilometers per second, the Deep Impact probe's targeting camera recorded a truly dramatic series of images. Successive pictures improve in resolution and have been...

A Filament Leaps from the Sun
8.11.2021

Why, sometimes, does part of the Sun's atmosphere leap into space? The reason lies in changing magnetic fields that thread through the Sun's surface. Regions of strong surface magnetism, known as active regions, are usually marked by dark sunspots.

APOD: 2023 July 11 Б Sunspots on an Active Sun
11.07.2023

Why is our Sun so active now? No one is sure. An increase in surface activity was expected because our Sun is approaching solar maximum in 2025. However, last month our Sun sprouted more sunspots than in any month during the entire previous 11-year solar cycle -- and even dating back to 2002.

Large Sunspots Now Crossing the Sun
10.07.2013

One of the largest sunspot regions in recent years is now crossing the Sun. This region of convoluted magnetic fields may well produce a solar flare that releases a cloud of energetic particles into the Solar System.

A Flight over Jupiter Near the Great Red Spot
19.10.2020

Are you willing to wait to see the largest and oldest known storm system in the Solar System? In the featured video, Jupiter's Great Red Spot finally makes its appearance 2 minutes and 12 seconds into the 5-minute video.

The Light of Stars
8.05.2012

What's moving? Time lapse videos of the sky can be quite spectacular when they last long enough for stars, planets, aurora, and clouds to appear to move in just a few seconds. Pictured...

Sunspot Group AR 2339 Crosses the Sun
29.06.2015

How do sunspots evolve? Large dark sunspots -- and the active regions that contain them -- may last for weeks, but all during that time they are constantly changing. Such variations were particularly apparent...