The Earth and Moon Planetary System
15.10.2001

How similar in size are the Earth and the Moon? A dramatic visual answer to this question is found by combining photographs taken by the Mariner 10 spacecraft that headed out toward Venus and Mercury in 1973.

Water World
18.11.1995

Water (Dihydrogen Oxide, H2O) is a truly remarkable chemical compound and is fundamental to life on Earth. Earth is the only planet in the Solar System where the surface temperature and pressure allow the three forms of water, solid (ice), liquid (ocean), and gas (water vapor condensing in clouds) to exist simultaneously on its surface.

Volcano and Aurora in Iceland
21.01.2002

Sometimes both heaven and Earth erupt. In Iceland in 1991, the volcano Hekla erupted at the same time that auroras were visible overhead. Hekla, one of the most famous volcanoes in the world, has erupted at least 20 times over the past millennium, sometimes causing great destruction.

Jupiter, Io, and Ganymede's Shadow
13.10.1995

Jupiter, the solar system's largest planet, is seen here next to Io, its closest Galilean moon. On the cloud tops of Jupiter near the left edge of the picture can be seen a dark circular spot which is caused by the shadow of Jupiter's largest moon Ganymede.

Io: A Volcanic Moon
3.08.1995

In 1610, Galileo turned his telescope to the heavens and discovered that the planet Jupiter had four bright moons. The innermost of these Galilean moons, Io, turned out to be one of the most exotic objects in the solar system.

Introducing Comet Lee
27.04.1999

Another large snowball is falling toward the Sun. Comet Lee was discovered two weeks ago by Steve Lee (AAO) in Australia, and is expected to brighten as it approaches the inner Solar System. Comet...

Crescent Neptune and Triton
27.05.2023

Gliding through the outer Solar System, in 1989 the Voyager 2 spacecraft looked toward the Sun to find this view of most distant planet Neptune and its moon Triton together in a crescent phase. The elegant image of ice-giant planet and largest moon was taken from behind just after Voyager's closest approach.

A String Of Pearls
23.03.1997

Comet Shoemaker-Levy 9, named after its co-discoverers, was often referred to as the "string of pearls" comet. It is famous for its unusual appearance as well as its collision with the planet Jupiter!

Astro 1 In Orbit
20.02.1999

In December of 1990, the Space Shuttle Columbia carried an array of astronomical telescopes high above the Earth's obscuring atmosphere to observe the Universe at ultraviolet and x-ray wavelengths. The telescopes, known...

Volcano and Aurora in Iceland
29.01.2006

Sometimes both heaven and Earth erupt. In Iceland in 1991, the volcano Hekla erupted at the same time that auroras were visible overhead. Hekla, one of the most famous volcanoes in the world, has erupted at least 20 times over the past millennium, sometimes causing great destruction.