Astronomy Picture of the Day

Discover the cosmos! Each day we feature a different image or photograph of our fascinating universe, along with a brief explanation written by a professional astronomer.

October 21, 1995
See Explanation.  Clicking on the picture will download 
 the highest resolution version available.
A Glimpse of Titan's Surface
Credit: NASA, HST, Peter H. Smith UA Lunar and Planetary Laboratory.

Explanation: The surface of Titan, Saturn's largest moon, is normally hidden from view by its thick, hazy atmosphere. However, for the first time astronomers have been able to see surface features in images like the one above, made at near-infrared wavelengths with the Hubble Space Telescope. At these wavelengths (longer than visible light) Titan's smog like atmosphere begins to be transparent enough to allow glimpses of it's surface. The bright feature seen above is about 2,500 miles across, similar in size to Australia. Astronomers are still trying to work out what the bright and dark areas represent - oceans, continents, craters, or other features. The images represent important information for planning the Cassini mission, scheduled for launch in 1997. The Cassini spacecraft will explore the Saturn system and parachute a probe to Titan's surface.

Tomorrow's picture: A Quasar-Galaxy Collision?

| Archive | Glossary | Education | About APOD |
Top 5 logo Best pick logo Cool NASA site logo

Authors & editors: Robert Nemiroff (GMU) & Jerry Bonnell (USRA).
NASA Technical Rep.: Sherri Calvo. Specific rights apply.
A service of: LHEA at NASA/ GSFC