Pluto s P4
22.07.2011

Nix and Hydra were first introduced to human eyes in Hubble Space Telescope images from May 2005, as Pluto's second and third known moons. Now Hubble images have revealed a fourth satellite for the icy, dwarf planet. Provisionally designated P4, it completes an orbit of Pluto in about 31 days.

Aerosol Earth
1.09.2018

On August 23, 2018 the identification and distribution of aerosols in the Earth's atmosphere is shown in this dramatic, planet-wide visualization. Produced in real time, the Goddard Earth Observing System Forward Processing (GEOS...

The Small Cloud of Magellan
17.06.2005

Portuguese navigator Ferdinand Magellan and his crew had plenty of time to study the southern sky during the first circumnavigation of planet Earth. As a result, two celestial wonders easily visible for southern hemisphere skygazers are known as the Clouds of Magellan.

XMM Launched
21.12.1999

X-ray astronomy entered a golden age earlier this month with the successful launch of the X-ray Multi-Mirror (XMM) satellite. XMM's three huge telescope barrels each hold 58 concentric cylindrical mirrors, together totaling a surface area rivaling a tennis court.

Io: Moon over Jupiter
7.08.2016

How big is Jupiter's moon Io? The most volcanic body in the Solar System, Io (usually pronounced "EYE-oh") is 3,600 kilometers in diameter, about the size of planet Earth's single large natural satellite.

Saturn and Six Moons
6.07.2021

How many moons does Saturn have? So far 82 have been confirmed, the smallest being only a fraction of a kilometer across. Six of its largest satellites can be seen here in a composite...

APOD: 2025 October 26 Б Halloween and the Ghost Head Nebula
26.10.2025

Halloween's origin is ancient and astronomical. Since the fifth century BC, Halloween has been celebrated as a cross-quarter day, a day halfway between an equinox (equal day / equal night) and a solstice (minimum day / maximum night in the northern hemisphere).

Rocket Streak and Star Trails
30.01.2014

Fixed to a tripod and looking east across the Kennedy Space Center's Turn Basin, a camera captured these star trails as a series of short exposures over a three hour period on the evening of January 23rd.

Moons of Saturn
17.10.2019

On July 29, 2011 the Cassini spacecraft's narrow-angle camera took this snapshot and captured 5 of Saturn's moons, from just above the ringplane. Left to right are small moons Janus and Pandora respectively 179 and 81 kilometers across, shiny 504 kilometer diameter Enceladus, and Mimas, 396 kilometers across, seen just next to Rhea.

Islands of Four Mountains from Above
22.06.2010

Our Earth is covered by volcanoes. Volcanoes are breaks in the Earth's cool surface where hot liquid rock from the interior comes out -- sometimes suddenly. In the above image from the ASTER camera...