Several observations have been conducted since last September till March of this year, 1997 when Mars was at its closest point to Earth in the past two years. Further observations are scheduled for late 1998 since Mars is now nearing and will pass behind the Sun making observations by the Hubble Space Telescope impractical and dangerous to instrumentation.
Phil James (University of Toledo), Todd Clancy (Space Science Inst.,Boulder,CO), Steve Lee (University of Colorado) and NASA.
Planetary Evolution; Meteorology
Hubble's Sharpest View Of Mars
Predicting weather conditions here on Earth is a challenge, and everyone complains about the weather; but trying to predict the unpredictable weather conditions on Mars is another matter. For Mars, changes can sweep over the entire planet every week. Mars' weather conditions appear to be on a roller coaster-like ride; making conditions more chaotic than scientist first thought. Observations by the Hubble Space Telescope together with the National Radio Astronomy Observatory (NRAO) at Kitt Peak,Arizona, show that the atmosphere of Mars is more complex and variable than the picture revealed by the Viking and Mariner 9 orbits.
|Instrument used:||Hubble Space Telescope Wide Field and Planetary Camera 2 (WFPC2).|
|Date of Observations:||A series of observations taken in October,1996 and in January and March of 1997.|
The Hubble Space Telescope is being used to monitor the weather conditions on Mars to support the Mars Pathfinder and Mars Global Surveyor Orbiter Missions, which are currently en route to Mars. Hubble's "weather report" from these images is invaluable for Mars Pathfinder, which is scheduled for a July 4 landing. At this time the images show no large-scale dust storm activity, which plagued a previous Mars mission in the early 1970's.
Ground based observations of the planet Mars have provided a rich if not often inaccurate picture of the Red Planet. Most famous of Martian observers was Percival Lowell who supported the idea that life existed on Mars; perhaps intelligent life as indicated by the complex system of canals Percival Lowell was so famous for mapping. It was known that Mars experienced seasonal change not unlike that here on Earth. Mars has polar ice caps that appear to grow and shrink with the seasonal change. Thin cloud cover often forms around mountains, and if observed while Mars is in perihelion--the closest point in its orbit to the Sun--planet-wide dust storms will obscure almost all features for weeks.
The information collected during the 1970's orbiters gave a fairly one-dimensional picture of the Martian climate, but information captured by the Hubble Space Telescope and NRAO show that Mars is more often cloudy than dusty, experiencing abrupt planet-wide swings between dusty/hot and cloudy/cold. A state of emergency would be declared on Earth if such an ice or dust storm blanketed the entire planet.
These shifts in climate are driven by three important factors: