A Meteor Wind over Tunisia
15.08.2022

Does the Earth ever pass through a wind of meteors? Yes, and they are frequently visible as meteor showers. Almost all meteors are sand-sized debris that escaped from a Sun-orbiting comet or asteroid, debris that continues in an elongated orbit around the Sun.

Pleiades Deep Field
21.09.2011

Have you ever seen the Pleiades star cluster? Even if you have, you probably have never seen it like this: all dusty. Perhaps the most famous star cluster on the sky, the bright stars of the Pleiades can be seen without binoculars from even the depths of a light-polluted city.

Orionids Meteors over Inner Mongolia
29.10.2018

Meteors have been shooting out from the constellation of Orion. This was expected, as October is the time of year for the Orionids Meteor Shower. Pictured here, over two dozen meteors were caught in successively added exposures last October over Wulan Hada volcano in Inner Mongolia, China.

Two Tails of Comet Lulin
24.02.2009

Go outside tonight and see Comet Lulin. From a dark location, you should need only a good star map and admirable perseverance -- although wide-field binoculars might help. Yesterday, Comet Lulin passed its closest to Earth, so that the comet will remain near its brightest over the next few days.

The Ecliptic Plane
29.05.1999

The Plane of the Ecliptic is illustrated in this Clementine star tracker camera image which reveals (from right to left) the Moon lit by Earthshine, the Sun's corona rising over the Moon's dark limb, and the planets Saturn, Mars, and Mercury.

The Ecliptic Plane
14.10.2000

The Plane of the Ecliptic is well illustrated in this picture from the 1994 lunar prospecting Clementine spacecraft. Clementine's star tracker camera image reveals (from right to left) the Moon lit by Earthshine, the Sun's corona rising over the Moon's dark limb, and the planets Saturn, Mars, and Mercury.

Perseids from Perseus
9.08.2020

Where are all these meteors coming from? In terms of direction on the sky, the pointed answer is the constellation of Perseus. That is why the meteor shower that peaks tomorrow night is known as the Perseids -- the meteors all appear to came from a radiant toward Perseus.

Colorful Airglow Bands Surround Milky Way
12.03.2022

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.

Colorful Airglow Bands Surround Milky Way
5.03.2018

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.

Satellites Behind Pinnacles
13.06.2022

What are all those streaks across the background? Satellite trails. First, the foreground features picturesque rock mounds known as Pinnacles. Found in the Nambung National Park in Western Australia, these human-sized spires are made by unknown processes from ancient sea shells (limestone). Perhaps more eye-catching, though, is the sky behind.