1. Mars-2005

2. Two Reasons Why Mars is of Interest Now
It is prominent in the night sky (brightest on November 5)
There have been major new discoveries about Mars in the past 10 years.
Where is Mars in the solar system?

3. Mars is the fourth planet in the solar system

4. Mars is the most Earth-like of the other planets

5. But not too Earthlike

6. Reasons why scientists are interested in Mars
Mars is the best “test case” for the origin of life on another astronomical object.
Either life arose there in the early history of the solar system or it didn’t. The significance of a negative result depends on Martian conditions at that time.
The central issue is water on Mars.

8. For Mars, the main scientific question is the existence of water in the remote past
Mars Explorations Rovers (“Spirit” and “Opportunity” are extensively studying two regions on the surface of Mars, both chosen for possibility of water

9. We are on the way to the answer, thanks to robotic spacecraft

10. The MER (Mars Exploration Rover) Mission
Mobile, remote-controlled spacecraft
Have self-contained labs and instruments
Both have been on Mars since January, 2004
They are in 554 Martian day of operation, 464 MD past “warranty”

11. MER landing sites chosen to be places that seemed to be sites of water
“Spirit”: Gusev crater: crater with apparent ancient river flowing into it.
“Opportunity”: Meridiani Planum: site with signature of mineral hematite, mineral which forms in the presence of water on Earth

12. How the MER spacecraft (and others) have changed our view of Mars
From this

13. To This..

14. The View From “Spirit” (MER-1)

15. Aquatic past of Opportunity landing site from detailed analysis of rock outcropping

16. Scientific Conclusions from MER analysis
Landing site described as once being “soaking wet”
Deposits of hydrated sulfur salts
Presence of mineral jarosite (forms in presence of water on Earth)
Pockmarks in rocks believed due to mineral pockets dissolved…rocks were submerged
Ripple patterns in rocks indicating past lakes or oceans

17. What have we learned?
The Mars Exploration Rovers have strengthened evidence that there was extensive surface water on Mars billions of years ago. Future missions will further elucidate the geological and biological (?) history of Mars.

18. See Mars in the Sky this Summer and Fall!