APOD: 2006 January 1- The Largest Rock in the Solar System
1.01.2006

There, that faint dot in the center - that's the largest rock known in our Solar System. It is larger than every known asteroid, moon, and comet nucleus. It is larger than any other local rocky planet.

Happy Birthday Jules Verne
6.02.1998

Sunday marks the 170th anniversary of the birth of Jules Verne (born in Nantes, France on the 8th of February, 1828). Inspired by a lifelong fascination with machines, Verne wrote visionary works about "Extraordinary...

Solar Sail
8.03.2003

Nearly 400 years ago astronomer Johannes Kepler observed comet tails blown by a solar breeze and suggested that vessels might likewise navigate through space using appropriately fashioned sails. It is now widely recognized that...

Mysterious Spokes in Saturns Rings
27.11.2006

What causes the mysterious spokes in Saturn's rings? Visible on the left of the above image as ghostlike impressions, spokes were first discovered by the Voyager spacecraft that buzzed by Saturn in the early 1980s. Their existence was unexpected, and no genesis hypothesis has ever become accepted.

APOD: 2025 September 1 Б Callisto: Dirty Battered Iceball
1.09.2025

Its surface is the most densely cratered in the Solar System -- but what's inside? Jupiter's moon Callisto is a battered ball of dirty ice that is larger than the planet Mercury.

A Mysterious Hexagonal Cloud System on Saturn
3.04.2007

Why would clouds form a hexagon on Saturn? Nobody is yet sure. Originally discovered during the Voyager flybys of Saturn in the 1980s, nobody has ever seen anything like it anywhere else in the Solar System.

Happy Birthday Jules Verne
15.02.2003

One hundred seventy-five years ago (on February 8th), Jules Verne was born in Nantes, France. Inspired by a lifelong fascination with machines, Verne wrote visionary works about "Extraordinary Voyages" including such terrestrial travels as Around the World in 80 Days, Journey to the Centre of the Earth, and Twenty Thousand Leagues Under the Sea.

Galileo's First Color Image of Io
19.07.1996

Above is the first color image of Jupiter's volcanic moon Io released by the Galileo Project. (Io sounds like "eye-oh".) The image was made on June 25 when the Galileo spacecraft approached within 1.4 million miles.

Happy Birthday Jules Verne
17.02.2001

One hundred seventy-three years ago on February 8th, Jules Verne was born in Nantes, France. Inspired by a lifelong fascination with machines, Verne wrote visionary works about "Extraordinary Voyages" including such terrestrial travels as Around the World in 80 Days, Journey to the Centre of the Earth, and Twenty Thousand Leagues Under the Sea.

Spokes Reappear on Saturns Rings
2.06.2009

What causes the mysterious spokes in Saturn's rings? Visible in the above image as light ghostlike impressions, spokes were first discovered by the Voyager spacecraft that buzzed by Saturn in the early 1980s. Their existence was unexpected.