Evidence of Ancient Lakes and Seas on Mars Announced
NASA advanced the date of a press conference previously scheduled for Thursday to this afternoon today after a news embargo was broken regarding an article that will appear in the 8 December issue of Science magazine. The topic was the discovery of features on Mars indiciative of ancient lakes and seas. Participating in the press conference were:
- Dr. Michael Malin, principal investigator, Mars Orbiter Camera
on NASA’s Mars Global Surveyor spacecraft, at Malin Space Science
Systems (MSSS), San Diego, CA
- Dr. Ken Edgett, Malin’s collaborator and staff scientist at MSSS
- Dr. Jim Garvin, Mars Exploration Program Scientist at NASA
Headquarters.
According to Michael Malin “The story that we are presenting today began for the Mars Global Surveyor (MGS) 3 years ago. While it was still in its aerobraking orbit it was making observations that began to show that the surface and subsurface of Mars had many layers. It was not until the spacecraft was able to enter and maintain a close, circular, polar mapping orbit in March 1999 that we began to make observations that brought into focus what we were seeing.”
Ken Edgett continued saying that “the layering was starling to us – it was hard to create this under the conditions we expected at Mars.” Referring back to observations of Mars made as early as 1972, Edgett noted that layered terrain had been seen in a variety of locations. “We were seeing layers that are repeated and of almost the same thickness – and there are hundreds of them – We’re not sure how to do this without water.”
The locations where these layered deposits we sighted were spread out across the surface of Mars. According to Edgett “one feature in western Arabia looks like a Zebra pattern that stair steps up hills. What we saw was unlike the seepage gullies we described here last summer. ”
According to Malin these sedimentary features are found most frequently near the equator. Tectonic and fracturing activity has cracked crust to reveal layers. Malin said “we expect that most of Mars has this layering but are only able to see it where cracks in its surface occur.”
The best examples of these features have been found on Mars in places where erosion has occurred – similar to how locations on Earth, such as the Grand Canyon, reveal many layers that reach deep into Earth’s past. On Mars the regions of western Arabia, northern Hellas and Valles Marineris have the most locations found thus far.
One example is Crater Gale which is 170 km across and 3-4 km deep. A large mound with peak is located in center of crater – the peak is almost as high as the crater’s outer rim. Detailed high resolution imagery shows a series of layers extending right up the slope of the mound.
According to Malin “to geologists layering is like the holy grail – it tells us that the planet has recorded a history of change. What we see on Mars today is very different from what we expected to find based on Viking and Mariner 9. These areas record a complex story – one that can be addressed with tools used to understand Earth. This planet is more than just impact craters and dust.” Edgett added that “this story tantalizes and begs us to come back.”
Jim Garvin, Mars program scientist at NASA Heaquarters noted that these photographs “give us an idea of where we should look next for the elusive record on Mars. This layering has been known since Mariner 9 – but linking this all together now as a story is what is exciting. We have a Mars program that is now unfolding. The next step is the Mars Odyssey which we will launch in 5 months. That mission will help put these observations in context and try to understand the composition of the structure by use of a high resolution middle infrared spectrometer (MIS).
Garvin went on to characterize these discoveries as being akin to the “great archaeological discoveries” wherien the secrets of Earth’s past were revealed. Garvin felt that these photos do much the same for Mars.
Malin closed the conference by addressing an issue on many people’s minds – the implications of these findings for the possibility of life – past and/or present on Mars. He said ” if there was life on Mars that was similar to terrestrial life then these are exactly the locations where you’d want to go. These sort of rocks have been sought for astrobiologists for decades.”
Related Links
° Mars Global Surveyor, NASA JPL
° NASA’s Mars Exploration Program, NASA JPL
° 4 December 2000: Evidence of Martian Land of Lakes Discovered, NASA PAO
° 4 December 2000: Science report: sedimentary rocks on Mars may suggest an ancient land of lakes, Science Magazine
° 4 December 2000: IMAGES from Science report: sedimentary rocks on Mars may suggest an ancient land of lakes, Science Magazine
° 4 December 2000: Major Mars Discovery to be Announced Today in Press Briefing, NASA PAO
° 4 December 2000: Layered Material in West Arabia Terra Crater, MSSS/NASA JPL
° 4 December 2000: Layered Outcrops of Far West Candor Chasma, MSSS/NASA JPL
° 4 December 2000: Sediment History Preserved in Gale Crater Central Mound, MSSS/NASA JPL
° 4 December 2000: Alternating Light- and Dark-toned Layers in Holden Crater, MSSS/NASA JPL
° 4 December 2000: Light-toned Layered Outcrops in Valles Marineris Walls, MSSS/NASA JPL
° 4 December 2000: “White Rock” of Pollack Crater, MSSS/NASA JPL
° 4 December 2000: Illustrations Regarding Early Mars Sedimentary Rocks from the NASA Space Science Update, December 4, 2000, MSSS/NASA JPL
Earlier Links
° 2 December 2000: Another “Major” Mars Discovery to be Announced by NASA, SpaceRef
° 2 December 2000: Dried-up sea beds found on Mars, Sunday Times, London
° 1 December 2000: Major Mars Discovery to be Announced at Dec 7 Briefing, NASA PAO
Background Information – Mars News from the past year
° A Year of Mars News: It was the worst of times; it was the best of times, SpaceRef
° 19 October 2000: NASA Outlines Mars Exploration Program for the Next Two Decades , NASA
° 19 October 2000: Bacterial Species 2-9-3 Resurrected after a Quarter of a Billion Years, SpaceRef
° 20 August 2000: Arctic and Antarctic Analogs for Liquid Water on Mars, SpaceRef
° 27 June 2000: British Researchers Try to Challenge Evidence of Mars Meteorite Fossils – But Don’t Make Their
Case, SpaceRef
° 27 June 2000: NASA Makes Mars 2003 Mission Selection, SpaceRef
° 25 June 2000: Mars Once Had Salty Oceans – Just Like Earth. , SpaceRef
° 22 June 2000: Mars May Be Even Wetter Than It Was Last Week, SpaceRef
° 22 June 2000: Mars, Like Earth, is not a Simple Planet to Understand, SpaceRef
° 12 May 2000: NASA Will Either Land or Orbit Mars in 2003 – But Not Both, SpaceRef
° 12 April 2000: NASA Advisors Explain Mars Mission Failures to a Concerned Congress, SpaceRef
° 28 March 2000: NASA Reveals Probable Cause of Mars Polar Lander and Deep Space-2 Mission Failures, SpaceRef
° 13 March 2000: Testimony of Thomas Young, Chairman of the Mars Program Independent Assessment Team before the House Science Committee, NASA
° 13 March 2000: Two Mars Mission Reports Delivered to NASA; A Third to Follow, SpaceRef
° 20 February 2000: Mars Exploration: AAAS Ponders: “Where do we go from here?”, SpaceRef
° 17 January 2000: NASA Concludes All Attempts to Communicate with Lander, NASA
° 7 January 2000: Mars Program Independent Assessment Team Begins Work, NASA
° 4 December 1999: Mars Polar Lander Mission Status, NASA JPL
° 30 November 1999: Mars Polar Lander Mission Status, NASA JPL
° 10 November 1999: Mars Climate Orbiter Failure Board Releases Report, Numerous NASA Actions Underway in Response
° 30 September 1999: Mars Climate Orbiter Team Finds Likely Cause of Loss, NASA
° 20 September 1999: Mars Climate Orbiter to Arrive at Mars This Week, NASA
