The 220 Mirrors of CRTF
4.10.1999

Even the largest of modern optical telescopes are small when compared with the light gathering power of the Central Receiver Test Facility (CRTF) located in New Mexico, USA. CRTF has 220 mirrors each over 7-meters in diameter all focused on a single tower.

Blue Flash
9.01.2002

Difficult to observe, the momentary green flash above the rising or setting sun has been documented as a phenomenon caused by the atmospheric bending or refraction of sunlight. Like a weak prism, the Earth's atmosphere breaks white sunlight into colors, bending red colors slightly and green and blue colors through increasingly larger angles.

Flying Over the Earth at Night
5.03.2012

Many wonders are visible when flying over the Earth at night. A compilation of such visual spectacles was captured recently from the International Space Station (ISS) and set to rousing music. Passing below are white clouds, orange city lights, lightning flashes in thunderstorms, and dark blue seas.

Aurora Shimmer Meteor Flash
6.12.2014

Northern Lights, or aurora borealis, haunted skies over the island of Kvaløya, near Tromsø Norway on 2009 December 13. This 30 second long exposure records their shimmering glow gently lighting the wintery coastal scene.

Sun Pillar with Upper Tangent Arc
17.02.2021

This was not a typical sun pillar. Just after sunrise two weeks ago in Providence, Rhode Island, USA, a photographer, looking out his window, was suddenly awestruck. The astonishment was caused by a sun pillar that fanned out at the top.

Colorful Airglow Bands Surround Milky Way
13.03.2022

Why would the sky glow like a giant repeating rainbow? Airglow. Now air glows all of the time, but it is usually hard to see. A disturbance however -- like an approaching storm -- may cause noticeable rippling in the Earth's atmosphere.

Night of the Long Leonid
22.11.2012

A cosmic grain of sand left the long and colorful trail across this all-sky view. Its grazing impact with planet Earth's atmosphere began at 71 kilometers per second. With the Milky Way stretching...

A Sonic Boom
21.02.2001

Many people have heard a sonic boom, but few have seen one. When an airplane travels at a speed faster than sound, density waves of sound emitted by the plane cannot precede the plane, and so accumulate in a cone behind the plane.

Time Lapse Auroras Over Norway
29.12.2013

Sometimes, after your eyes adapt to the dark, a spectacular sky appears. Such was the case in 2011 March when one of the largest auroral displays in recent years appeared over northern locations like the border between Norway and Russia.

Titan: Moon over Saturn
9.01.2021

Like Earth's moon, Saturn's largest moon Titan is locked in synchronous rotation. This mosaic of images recorded by the Cassini spacecraft in May of 2012 shows its anti-Saturn side, the side always facing away from the ringed gas giant.