Research: Mars' present in Earth's future

April 30, 1999
by Paul Hoversten

Mars is more like Earth than expected, scientists said Thursday, and evidence from the Red Planet's history might give a glimpse into Earth's future.

Mars: From Surveyor

New data from the orbiting Mars Global Surveyor probe indicate that Mars once had a global magnetic field as well as a tectonic process in which molten rock oozed from a heated interior and shifted giant plates of crust under what might have been an ocean.

That geological process was believed unique to Earth.

Both planets were formed about the same time, 4.5 billion years ago. But because Mars is only half the size of Earth, it cooled faster and became a geologically dead planet within a few hundred million years.

The larger Earth began cooling about 2 billion years ago, and scientists estimate it could lose all its heat in another few billion years and turn into a cold, barren rock.

	?What similarities do scientists find between ancient Mars and ancient Earth? What evidence supports their theories? ?Based on information in the story, what other theories would you propose about Mars, ancient or modern? Invite another students to question or critique your theories. ? Use both your imagination and information in the story to explain how ancient Mars, complete with crustal plates, continental drift and oceans, became Mars today, the Red Planet of endless deserts, rocks, and lifeless valleys.

"Someday Earth will be like Mars, because as our planet cools off we'll go through the same changes," says Steve Maran, assistant chief of space sciences at NASA's Goddard Space Flight Center in Greenbelt, Md.

The findings also could provide a boost for the search for life elsewhere in the solar system.

"Geologic activity favors diversity of environment, and that in turn favors the origin of life," says Goddard's Jack Connerney, a co-investigator with the Mars Global Surveyor program.

Scientists say that as Mars cooled, its magnetic field was "frozen" into the crust and provided a fossil-like record of surface changes.

The evidence, seen as magnetic "stripes," was found in the oldest regions of Mars' heavily cratered southern highlands.

Mars' magnetic stripes are similar to those found in Earth's ocean floors but 10 times as strong. On Earth, scientists believe, the stripes were created when the continental plates spread, allowing molten rock to ooze through the crust and form ridges. When the iron in the rock cooled and magnetized, the magnetic stripes were left behind.