A Full Circle Rainbow over Australia
30.09.2014

Have you ever seen an entire rainbow? From the ground, typically, only the top portion of a rainbow is visible because directions toward the ground have fewer raindrops. From the air, though, the entire 360 degree circle of a rainbow is more commonly visible.

Mars in the Clouds
8.09.2016

Wandering through this stunning field of view, Mars really is in front of these colorful cosmic clouds. The mosaic contructed from telescopic images is about 5 degrees (10 full moons) across. It captures...

NGC 2170: Angel Nebula Still Life
26.08.2019

Is this a painting or a photograph? In this classic celestial still life composed with a cosmic brush, dusty nebula NGC 2170, also known as the Angel Nebula, shines near the image center. Reflecting...

NGC 3717: A Nearly Sideways Spiral Galaxy
12.11.2019

Some spiral galaxies are seen nearly sideways. Most bright stars in spiral galaxies swirl around the center in a disk, and seen from the side, this disk can be appear quite thin. Some spiral galaxies appear even thinner than NGC 3717, which is actually seen tilted just a bit.

Millions of Stars in Omega Centauri
16.03.2023

Globular star cluster Omega Centauri, also known as NGC 5139, is 15,000 light-years away. The cluster is packed with about 10 million stars much older than the Sun within a volume about 150 light-years in diameter.

APOD: 2023 June 26 Б The Belt of Venus over Mount Everest
26.06.2023

You've surely seen it, but you might not have noticed it. During a cloudless twilight, just before sunrise or after sunset, part of the atmosphere above the horizon appears slightly dark and off-color.

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.

Gangly Spiral Galaxy NGC 3184
20.09.2000

NGC 3184 is a large spiral galaxy with a small nucleus and long sprawling spiral arms. Although NGC 3184 contains hundreds of billions of stars, the blue color of its spiral arms comes mostly from relatively few bright young blue stars.

Hydrogen, Helium, and the Stars of M10
30.06.2001

Stars like the Sun use hydrogen for fuel, "burning" hydrogen into helium at their cores through nuclear fusion. But what happens when that hydrogen runs out? For a while, hydrogen burns in a shell surrounding the stellar core and the star expands to become a red giant.

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.