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.

Barsoom
31.03.2001

"Yes, I have been to Barsoom again ..." begins John Carter in Edgar Rice Burroughs' 1913 science fiction classic "The Gods of Mars". In Burroughs' novels describing Carter's adventures on Mars, "Barsoom" is the local inhabitants' name for the Red Planet. Long after Burroughs' stories were published, Mars continues to inspire Earthdwellers' interests and imagination.

The Eagle Soars
21.07.1996

On July 21, 1969 Apollo 11 astronauts Neil A. Armstrong and Edwin E. "Buzz" Aldrin Jr. lifted off the lunar surface in the ascent stage of their lunar module dubbed "The Eagle" -- after becoming the first to walk on the moon.

Orion: The Big Picture
1.12.1997

Orion is big. Some of the stars that form the constellation of Orion are part of a giant gas cloud complex that stretches over 100 light years and appears more than 50 times the diameter of the Moon.

M13: The Great Globular Cluster in Hercules
19.08.1998

M13 is one of the most prominent and best known globular clusters. Visible with binoculars in the constellation of Hercules, M13 is frequently one of the first steps beyond the ordinary visible to the casual sky gazer.

Colorful Arcs over Buenos Aires
15.12.2015

What are those colorful arcs in the sky? Like rainbows that are caused by rain, arcs of sunlight broken up into component colors can also result when ice crystals floating in Earth's atmosphere act together as a gigantic prism.

APOD: 2023 November 7 Б A Martian Dust Devil Spins By
7.11.2023

It moved across the surface of Mars -- what was it? A dust devil. Such spinning columns of rising air are heated by the warm surface and are also common in warm and dry areas on planet Earth.

Astronaut Exploring: An Apollo 15 Panorama
11.11.2018

What would it be like to explore the Moon? NASA's Apollo missions gave humans just this chance in the late 1960s and early 1970s. In particular, the Apollo 15 mission was dedicated to better understanding the surface of the Moon by exploring mountains, valleys, maria, and highlands.

A Huge Impact Crater on Mars
3.02.1996

What hit Mars? The impact crater Schiparelli near the center of the above image was likely caused by a collision with an object the size of an asteroid. Also evident in this full face mosaic of Mars are numerous craters from many other impacts with smaller objects over billions of years.

Dawn s Endeavour
27.02.2010

On February 21st, the Space Shuttle Endeavour and the International Space Station (ISS) flew through the sky near dawn over Whitby, Ontario, Canada. Along with star trails, both were captured in this single time exposure. Glinting in sunlight 350 kilometers above the Earth, Endeavour slightly preceeded the ISS arcing over the horizon.