APOD: 2026 April Б Caught in the Web
3.04.2026

How can we see what is invisible? Black holes are not easy to see in the dark cosmic night, but astronomers can find them by analyzing their gravitational effects on matter, light and spacetime.

APOD: 2026 July 24 Б RCW 86: Historical Supernova Remnant
24.07.2026

In 185 AD, Chinese astronomers recorded the appearance of a new star in the Nanmen asterism. That part of the sky is identified with part of the southern constellation Centaurus on modern star charts.

X Ray Moon
2.09.2000

This x-ray image of the Moon was made by the orbiting ROSAT (Röntgensatellit) Observatory in 1990. In this digital picture, pixel brightness corresponds to x-ray intensity. Consider the image in three parts: the bright hemisphere of the x-ray moon, the darker half of the moon, and the x-ray sky background.

Comet NEAT Passes an Erupting Sun
24.02.2003

As Comet NEAT flared last week, the Sun roared. Just as the comet swooped inside the orbit of Mercury and developed a long and flowing tail of gas and dust, the Sun emitted a huge Coronal Mass Ejection (CME).

Shells in the Egg Nebula
20.05.1997

The Egg Nebula is taking a beating. Like a baby chick pecking its way out of an egg, the star in the center of the Egg Nebula is casting away shells of gas and dust as it slowly transforms itself into a white dwarf star.

Spicules: Jets on the Sun
2.11.2008

Imagine a pipe as wide as a state and as long as half the Earth. Now imagine that this pipe is filled with hot gas moving 50,000 kilometers per hour. Further imagine that this pipe is not made of metal but a transparent magnetic field.

A Triple Sunrise Over Gdansk Bay
4.08.2009

How can the same Sun rise three times? Last month on Friday, 2009 July 10, a spectacular triple sunrise was photographed at about 4:30 am over Gdansk Bay in Gdansk, Poland. Clearly, our Sun rises only once. Some optical effect is creating at least two mirages of the Sun -- but which effect?

Exploring the Antennae
11.02.2015

Some 60 million light-years away in the southerly constellation Corvus, two large galaxies are colliding. The stars in the two galaxies, cataloged as NGC 4038 and NGC 4039, very rarely collide in the course of the ponderous cataclysm, lasting hundreds of millions of years.

NGC 6357: Cathedral to Massive Stars
27.03.2016

How massive can a normal star be? Estimates made from distance, brightness and standard solar models had given one star in the open cluster Pismis 24 over 200 times the mass of our Sun, making it one of the most massive stars known.

Giant Storms and High Clouds on Jupiter
29.12.2021

What and where are these large ovals? They are rotating storm clouds on Jupiter imaged last month by NASA's Juno spacecraft. In general, higher clouds are lighter in color, and the lightest clouds visible are the relatively small clouds that dot the lower oval.