Venus on the Horizon
19.06.1999

Venus can appear as a brilliant evening star. Besides the sun and moon, Venus is the brightest object visible in Earth's sky. Because it is closer to the sun than Earth, Venus never...

Earth and Moon from Saturn
22.07.2013

You are here. Everyone you've ever known is here. Every human who has ever lived -- is here. Pictured above is the Earth-Moon system as captured by the Cassini mission orbiting Saturn in the outer Solar System.

Iridium Flare
2.04.1998

Have you seen an Iridium flare? Satellites in low Earth orbit reflect sunlight and are often visible gliding across early evening and predawn skies. But sun glints from Iridium commercial digital communications satellites are providing the most spectacular sightings.

Venus On The Horizon
14.10.1997

The month of October features a sky full of planets, including Venus as the brilliant evening star. Besides the sun and moon, Venus is the brightest object visible in Earth's sky. This month, Venus appears in early evening near the red planet Mars and Mars' red giant rival Antares above the southwestern horizon.

Saturn Behind the Moon
14.08.2019

What's that next to the Moon? Saturn. In its monthly trip around the Earth -- and hence Earth's sky -- our Moon passed nearly in front of Sun-orbiting Saturn earlier this week. Actually the Moon passed directly in front of Saturn from the viewpoints of a wide swath of Earth's Southern Hemisphere.

The Secret of the Black Aurora
1.01.2002

What causes black aurora? These gaps in normal bright aurora are frequently recorded but rarely questioned. Recent research using data from four Cluster spacecraft orbiting the Earth has now likely found the secret: black auroras are actually anti-auroras.

Sunrise from the Surface of Gliese 581c
2.05.2007

How might a sunrise appear on Gliese 581c? One artistic guess is shown above. Gliese 581c is the most Earth-like planet yet discovered and lies a mere 20 light-years distant. The central red dwarf...

Artistic Impression: The Surface of TRAPPIST 1f
26.06.2017

If you could stand on the surface of the newly discovered Earth-sized exoplanet TRAPPIST-1f, what would you see? Presently, no Earthling knows for sure, but the featured illustration depicts a reasoned guess based on observational data taken by NASA's Sun-orbiting Spitzer Space Telescope.

Orbits of Potentially Hazardous Asteroids
29.08.2021

Are asteroids dangerous? Some are, but the likelihood of a dangerous asteroid striking the Earth during any given year is low. Because some past mass extinction events have been linked to asteroid impacts, however, humanity has made it a priority to find and catalog those asteroids that may one day affect life on Earth.

Green and Black Auroras Over Norway
29.03.2006

What causes gaps between aurora curtains? These unusual gaps can make Research using data from four Cluster spacecraft orbiting the Earth has likely found the secret: auroral gaps, sometimes knows as black auroras, are actually anti-auroras. In normal auroras, electrons and/or predominantly negatively charged particles fall toward Earth along surfaces of constant magnetic field.