-
Perspective view of Mars' north polar ice cap.European Space Agency
-
Perspective view of Chasma Boreale. The giant trough is thought to have been present before the iconic spiraling ice cap formed.European Space Agency
-
Color mosaic of Mars' north polar ice cap. The position of the north pole is marked.European Space Agency
-
Mars' north polar ice cap in context.European Space Agency
-
An earlier mission, the Mars Global Surveyor, acquired this image of the Martian north polar cap in early northern summer. The north polar cap is about 1,100km across.NASA/JPL/Malin Space Science Systems
NASA and other space agencies have been observing the Martian poles in some detail for the better part of five decades, beginning with the Mariner 9 spacecraft. Since then, augmented by increasingly high-resolution photos and better data, scientists have successfully teased out details of the ice-covered poles. And now, finally, we can come to a singular conclusion: the north pole of Mars looks delicious.
Seriously, the polar caps are pretty interesting features. And now we can see the north pole for the first time in a "perspective view," a three-dimensional image that better showcases their depth and detail. These arresting new images were created from elevation data and 32 orbital passes, made between 2004 and 2010, by the European Space Agency's Mars Express spacecraft. The space agency released the mosaic earlier this month.
Unlike the pure water ice caps on Earth, the ice at the Martian caps is part water and part carbon dioxide. When water warms, of course, it melts from ice to water, until finally becoming water vapor. Carbon dioxide is different—it sublimates directly from "dry ice" into a gas at a temperature of -78.5 degrees Celsius. And so, during the Mars summer, it is warm enough for the carbon dioxide at the poles to sublimate into the atmosphere before it freezes again in the fall or winter.
This probably helps to explain why the poles look like a Cinnabon. Over time, a vast number of sand dunes have formed at the poles, likely spiraling out due to winds originating from the elevated pole and flowing toward the equator, governed by the same Coriolis force that produces swirling hurricanes on Earth. As the dunes thaw out in the spring, the sublimating carbon dioxide reveals dark spots and highlights the Martian dunes.
One of the most dramatic features is the Chasma Boreale, which is about 500km long, 100km wide, and 2km deep. Scientists believe this chasm predates the existence of the modern polar ice cap and has likely grown deeper as new ice deposits have grown up around it.
Listing image by European Space Agency
reader comments
46