APOD: 2024 September 18 Б The Mermaid Nebula Supernova Remnant
18.09.2024

New stars are born from the remnants of dead stars. The gaseous remnant of the gravitational collapse and subsequent death of a very massive star in our Milky Way created the G296.5+10.0 supernova remnant, of which the featured Mermaid Nebula is part.

The Regolith of Asteroid Eros
3.03.2002

From fifty kilometers above asteroid Eros, the surface inside one of its largest craters appears covered with an unusual substance: regolith. The thickness and composition of the surface dust that is regolith remains a topic of much research.

Zodiacal Light and the False Dawn
25.09.2007

An unusual triangle of light will be particularly bright near the eastern horizon before sunrise during the next two months for observers in Earth's northern hemisphere. Once considered a false dawn, this triangle of light is actually Zodiacal Light, light reflected from interplanetary dust particles.

Comet Holmes Coma Expands
30.10.2007

Go outside tonight and see Comet Holmes. No binoculars or telescopes are needed -- just curiosity and a sky map. Last week, Comet 17P/Holmes underwent an unusual outburst that vaulted it unexpectedly from obscurity into one of the brightest comets in recent years.

M57: The Ring Nebula
15.11.2009

It looks like a ring on the sky. Hundreds of years ago astronomers noticed a nebula with a most unusual shape. Now known as M57 or NGC 6720, the gas cloud became popularly known as the Ring Nebula.

Iridescent Clouds from the Top of the World Highway
8.02.2011

Why would a cloud appear to be different colors? A relatively rare phenomenon known as iridescent clouds can show unusual colors vividly or a whole spectrum of colors simultaneously. These clouds are formed of small water droplets of nearly uniform size.

The Unexpected Tails of Asteroid P5
12.11.2013

What is happening to asteroid P/2013 P5? No one is sure. For reasons unknown, the asteroid is now sporting not one but six discernible tails. The above images were taken two months ago by the orbiting Hubble Space Telescope and show the rapidly changing dust streams.

Comet McNaught Over New Zealand
19.10.2014

Comet McNaught was perhaps the most photogenic comet of modern times -- from Earth. After making quite a show in the northern hemisphere in early January of 2007, the comet moved south and developed a long and unusual dust tail that dazzled southern hemisphere observers.

A Mercury Transit Sequence
10.11.2019

Tomorrow -- Monday -- Mercury will cross the face of the Sun, as seen from Earth. Called a transit, the last time this happened was in 2016. Because the plane of Mercury's orbit is not exactly coincident with the plane of Earth's orbit, Mercury usually appears to pass over or under the Sun.

APOD: 2024 July 7 Б Iridescent Clouds over Sweden
7.07.2024

Why are these clouds multi-colored? A relatively rare phenomenon in clouds known as iridescence can bring up unusual colors vividly -- or even a whole spectrum of colors simultaneously. These polar stratospheric clouds also, known as nacreous and mother-of-pearl clouds, are formed of small water droplets of nearly uniform size.