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.

Crescent Enceladus
16.12.2023

Peering from the shadows, the Saturn-facing hemisphere of tantalizing inner moon Enceladus poses in this Cassini spacecraft image. North is up in the dramatic scene captured during November 2016 as Cassini's camera was pointed in a nearly sunward direction about 130,000 kilometers from the moon's bright crescent.

Crescent Enceladus
7.02.2026

Peering from the shadows, the Saturn-facing hemisphere of tantalizing inner moon Enceladus poses in this Cassini spacecraft image. North is up in the dramatic scene captured during November 2016 as Cassini's camera was pointed in a nearly sunward direction about 130,000 kilometers from the moon's bright crescent.

Ganymede Enhanced
20.09.2009

What does the largest moon in the Solar System look like? Ganymede, larger than even Mercury and Pluto, has a surface speckled with bright young craters overlying a mixture of older, darker, more cratered terrain laced with grooves and ridges.

Stereo Helene
1.06.2024

Get out your red/blue glasses and float next to Helene, small, icy moon of Saturn. Appropriately named, Helene is a Trojan moon, so called because it orbits at a Lagrange point. A Lagrange point is a gravitationally stable position near two massive bodies, in this case Saturn and larger moon Dione.

Stereo Helene
29.03.2025

Get out your red/blue glasses and float next to Helene, small, icy moon of Saturn. Appropriately named, Helene is a Trojan moon, so called because it orbits at a Lagrange point. A Lagrange point is a gravitationally stable position near two massive bodies, in this case Saturn and larger moon Dione.

NGC 3621: Far Beyond the Local Group
19.07.2003

Far beyond the local group of galaxies lies NGC 3621, some 22 million light-years away. Found in the serpentine southern constellation Hydra, the loose spiral arms of this gorgeous island universe are loaded with luminous young star clusters and dark dust lanes.

A Mercury Transit Sequence
4.05.2016

This coming Monday, Mercury will cross the face of the Sun, as seen from Earth. Called a transit, the last time this happened was in 2006. 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.

Galaxies in the River
11.12.2025

Large galaxies grow by eating small ones. Even our own galaxy engages in a sort of galactic cannibalism, absorbing small galaxies that are too close and are captured by the Milky Way's gravity.

Galaxies in the River
17.07.2010

Large galaxies grow by eating small ones. Even our own galaxy practices galactic cannibalism, absorbing small galaxies that get too close and are captured by the Milky Way's gravity. In fact, the practice...