Cassini Images The Moon
10.09.1999

On August 18, the Cassini spacecraft flew by the Earth and Moon, then continued on its way to the outer solar system. Near its closest approach to the Moon, a distance of about 377,000 kilometers, controllers tested Cassini's imaging systems on this most familiar celestial body.

Earth's Plasmasphere
31.01.2001

Our Earth is surrounded by plasma. The overall shape that this ionized gas plasmasphere takes was discovered last year by NASA's robot IMAGE spacecraft, and shown in the recently released above image in ultraviolet light.

Giant Storm Systems Battle on Jupiter
5.02.2002

Two of the largest storm systems on Jupiter are colliding, and nobody is sure what will result. The larger storm is the famous Great Red Spot, while the smaller is a large white oval. Both are swirling cloud systems that circulate on Jupiter.

A Martian Autumn Begins
23.09.1997

Today is the first day of Autumn in the Northern Hemisphere of Planet Earth. The Autumnal Equinox occured yesterday at 7:56 pm EDT as the Sun crossed the celestial equator from North to South.

Ice Fountains Discovered on Saturns Enceladus
5.12.2005

Fountains of ice shoot out from Saturn's moon Enceladus. Clear discovery images of the fountains were made using observations from the robot Cassini spacecraft currently orbiting Saturn. During a recent pass, Cassini was programmed to look back toward the Sun where Enceladus would appear as a thin crescent.

Thermal Mars
2.06.1999

It's 2 AM on Mars and surface temperatures range from -65C to -120C, as measured by the Thermal Emission Spectrometer (TES) onboard the Mars Global Surveyor spacecraft. TES data used...

Possible Methane Lakes on Titan
31.07.2006

Have methane lakes been discovered on Saturn's Titan? That exciting possibility was uncovered from analyses of radar images returned last week by the robotic Cassini spacecraft now orbiting Saturn. The above image is a radar reflection from terrain near Titan's North Pole and spans a region about 200 kilometers across.

Phoenix Lander Arrives at Mars
25.05.2008

Will Phoenix survive its landing today on Mars? Phoenix's landing sequence will ramp up starting at about 7:30 pm EDT (23:30 UTC) today and last just over an hour. If all goes well, one of Phoenix's first images from Mars will appear on APOD tomorrow.

The Regolith of Asteroid Eros
3.03.2002

From fifty kilometers above asteroid Eros, the surface inside one of its largest craters appears covered with an unusual substance: regolith. The thickness and composition of the surface dust that is regolith remains a topic of much research.

Detailing Hale-Bopp
8.05.1997

This enhanced composite image detailing structure in the coma and dust tail of Hale-Bopp was recorded May 5 - one day before the comet's passage from north to south across the plane of Earth's orbit.