Window Seat over Hudson Bay
22.09.2018

On the August 18 night flight from San Francisco to Zurich, a window seat offered this tantalizing view when curtains of light draped a colorful glow across the sky over Hudson Bay. Constructed...

A Leonid Meteor Explodes
23.11.1998

Click on the above image and watch a Leonid meteor explode. The tremendous heat generated by the collision of a small sand-bit moving at 70 kilometers/second with the Earth's upper atmosphere causes the rock-fragment to heat up, glow brightly, and disintegrate.

A Sonic Boom
4.05.2003

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.

Meteor and Moonbow over Wallaman Falls
12.11.2012

Which feature takes your breath away first in this encompassing panorama of land and sky? The competition is strong with a waterfall, meteor, starfield, and even a moonbow all vying for attention. It is interesting to first note, though, what can't be seen -- a rising moon on the other side of the camera.

New Eyes for the Hubble Space Telescope
21.02.1997

The Hubble Space Telescope's second servicing mission has been completed. Every few years, the telescope is visited by a Space Shuttle to allow astronauts to switch old instruments for new. This time...

A Green Flash from the Sun
4.06.2014

Many think it is just a myth. Others think it is true but its cause isn't known. Adventurers pride themselves on having seen it. It's a green flash from the Sun. The truth is the green flash does exist and its cause is well understood.

APOD: 2023 December 12 Б Aurora and Milky Way over Norway
12.12.2023

What are these two giant arches across the sky? Perhaps the more familiar one, on the left, is the central band of our Milky Way Galaxy. This grand disk of stars and nebulas here appears to encircle much of the southern sky.

Spiral Meteor through the Heart Nebula
5.09.2016

What is this meteor doing? Dynamically, the unusually short and asymmetric train may indicate that the sand-sized grain at the center of the glow is momentarily spinning as it ablates, causing its path to be slightly spiral.

Night Glows
18.04.2017

What glows in the night? This night, several unusual glows were evident -- some near, but some far. The foreground surf glimmers blue with the light of bioluminescent plankton. Next out, Earth's atmosphere dims the horizon and provides a few opaque clouds. Further out, the planet Venus glows bright near the image center.

Moonrise Through Mauna Keas Shadow
5.12.2010

How can the Moon rise through a mountain? It cannot -- what was photographed here is a moonrise through the shadow of a large volcano. The volcano is Mauna Kea, Hawai'i, USA, a frequent spot for spectacular photographs since it is arguably the premier observing location on planet Earth.