Our Rotating Earth
1.07.2020

Has your world ever turned upside-down? It would happen every day if you stay fixed to the stars. Most time-lapse videos of the night sky show the stars and sky moving above a steady Earth.

Kepler s House in Linz
15.05.2018

Four hundred years ago today (May 15, 1618) Johannes Kepler discovered the simple mathematical rule governing the orbits of the solar system's planets, now recognized as Kepler's Third Law of planetary motion.

Twistin' by the Lagoon
23.01.1997

The awesome spectacle of starbirth produces extreme stellar winds and intense energetic starlight -- bombarding dusty molecular clouds inside the Lagoon Nebula (M8). At least two long funnel shaped clouds, each roughly half a light-year long, have apparently been formed by this activity.

Historic Optical Flash Fades
22.04.1997

The largest telescopes in the world have scrambled to point toward this faint, fading object. Why? Because it may well be the first active optical counterpart ever found for a gamma-ray burst, and could hold the clue to the distance scale to this most enigmatic class of astronomical objects.

Comet C 2001 Q4 (NEAT)
23.04.2004

Inbound from the distant solar system, comet C/2001 Q4 will soon pass just inside planet Earth's orbit and should be one of two bright, naked-eye comets visible in southern skies in May. First...

Binary Black Hole in 3C 75
12.04.2006

The two bright sources at the center of this composite x-ray (blue)/ radio (pink) image are co-orbiting supermassive black holes powering the giant radio source 3C 75. Surrounded by multimillion degree x-ray emitting gas, and blasting out jets of relativistic particles the supermassive black holes are separated by 25,000 light-years.

Jupiter Unpeeled
6.09.2003

Slice Jupiter from pole to pole, peel back its outer layers of clouds, stretch them onto a flat surface ... and for all your trouble you'd end up with something that looks a lot like this. Scrolling right will reveal the full picture, a color mosaic of Jupiter from the Cassini spacecraft.

Big Dipper over Pyramid Mountain
21.11.2017

When did you first learn to identify this group of stars? Although they are familiar to many people around the world, different cultures have associated this asterism with different icons and folklore. Known...

Saturn at Equinox
30.09.2009

How would Saturn look if its ring plane pointed right at the Sun? Before last month, nobody knew. Every 15 years, as seen from Earth, Saturn's rings point toward the Earth and appear to disappear.

Full Moon, Full Mars
18.01.2025

On January 13 a Full Moon and a Full Mars were close, both bright and opposite the Sun in planet Earth's sky. In fact Mars was occulted, passing behind the Moon, when viewed from some locations in North America and northwest Africa.