A Star Where Photons Orbit
4.01.1997

The above computer animated picture depicts how a very compact star would look to a nearby observer. The star pictured is actually more compact that any known except a black hole, so it is only hypothetical. The observer is situated at the photon sphere, where photons can orbit in a circle.

Odysseus on the Moon
2.03.2024

Methalox rocket engine firing, Odysseus' landing legs absorb first contact with the lunar surface in this wide-angle snapshot from a camera on board the robotic Intuitive Machines Nova-C moon lander. Following the landing on February 22, broken landing legs, visible in the image, ultimately left the lander at rest but tilted.

The Moon Eclipses Saturn
16.07.2014

What happened to half of Saturn? Nothing other than Earth's Moon getting in the way. As pictured above on the far right, Saturn is partly eclipsed by a dark edge of a Moon itself only partly illuminated by the Sun.

A Star Where Photons Orbit
26.11.1995

The above computer animated picture depicts how a very compact star would look to a nearby observer. The star pictured is actually more compact that any known except a black hole, so it is only hypothetical. The observer is situated at the photon sphere, where photons can orbit in a circle.

APOD: 2007 August 1- Unusual Cratering on Saturns Dione
1.08.2007

Why does one half of Dione have more craters than the other? Start with the fact that Saturn's moon Dione always has one side that faces Saturn, and always has one side that faces away. This is similar to Earth's Moon.

In Ganymede s Shadow
7.10.2022

At opposition, opposite the Sun in Earth's sky, late last month Jupiter is also approaching perihelion, the closest point to the Sun in its elliptical orbit, early next year. That makes Jupiter exceptionally close to our fair planet, currently resulting in excellent views of the Solar System's ruling gas giant.

Martian Chiaroscuro
29.08.2020

Deep shadows create dramatic contrasts between light and dark in this high-resolution close-up of the martian surface. Recorded on January 24, 2014 by the HiRISE camera on board the Mars Reconnaissance Orbiter, the scene spans about 1.5 kilometers.

APOD: 2025 August 9 Б Interstellar Interloper 3I/ATLAS from Hubble
9.08.2025

Discovered on July 1 with the NASA-funded ATLAS (Asteroid Terrestrial-impact Last Alert System) survey telescope in Rio Hurtado, Chile, 3I/ATLAS is so designated as the third known interstellar object to pass through our Solar System. It follows 1I/йOumuamua in 2017 and the comet 2I/Borisov in 2019.

Apogee Moon, Perigee Moon
21.10.2004

Why don't these pieces fit? This third quarter Moon (left) and first quarter Moon were both photographed during the last lunar cycle or lunation with the same telescope and camera. But, simply combining the pictures into one sharp, full surface view would clearly be a problem.

APOD: 2025 July 17 Б 3I/ATLAS
17.07.2025

Discovered on July 1 with the NASA-funded ATLAS (Asteroid Terrestrial-impact Last Alert, System) survey telescope in Rio Hurtado, Chile, 3I/ATLAS is so designated as the third known interstellar object to pass through our Solar System It follows 1I/йOumuamua in 2017 and the comet 2I/Borisov in 2019.