Exposed ice on steep slopes can also help reveal the Red Planet’s climate history
Hmmm, not sure I understand the bolded part of the above. I realize that Earth's "magnetic north" flip-flops periodically, and I know that Earth wobbles on its axis of rotation, but I thought the latter was a small effect and due to changes in distribution of water on Earth's surface.
What could cause Mars' axis to change so dramatically?
Science News said:Martian ice has a thin skin. The newly discovered exposure of ice on steep banks suggests that the Red Planet’s ice sheets are buried by just a meter or two of soil, researchers report in Science January 12.
“What’s new and exciting here is that these ice sheets start quite shallowly,” says planetary scientist Colin Dundas of the U.S. Geological Survey in Flagstaff, Ariz. That could be good news for future astronauts hoping to use that water to drink, or to create oxygen to breathe or make fuel for returning spacecraft (SN: 1/20/18, p. 22).
Dundas and his colleagues used the Mars Reconnaissance Orbiter satellite to observe eight regions where steep slopes called scarps seem to reveal ice. In 2008, the Phoenix Mars lander revealed ice in regions close to the planet’s north pole (SN Online: 6/20/08). But these scarps were closer to the equator, at latitudes of about 55° north or south.
High-resolution images showed that the ice is organized into thin layers. Dundas says these layers probably originated as snowfall millions of years ago, when the north pole pointed in a different direction.
“It’s essentially giving a cross section through recent history,” Dundas says.
...
Hmmm, not sure I understand the bolded part of the above. I realize that Earth's "magnetic north" flip-flops periodically, and I know that Earth wobbles on its axis of rotation, but I thought the latter was a small effect and due to changes in distribution of water on Earth's surface.
What could cause Mars' axis to change so dramatically?