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Moving ripples on Mars

Using Mars Reconnaissance Orbiter (MRO) high resolution images, scientists have now determined that the giant ripples seen from space are actually moving, albeit very slowly.

Megaripples are found in deserts on Earth, often between dunes. Waves in the sand spaced up to tens of meters apart, they’re a larger version of ripples that undulate every 10 centimeters or so on many sand dunes. But unlike dunes, megaripples are made up of two sizes of sand grains. Coarser, heavier grains cap the crests of megaripples, making it harder for wind to move these features around, says Simone Silvestro, a planetary scientist at Italy’s National Institute of Astrophysics in Naples.

Since the early 2000s, Mars rovers and orbiters have repeatedly spotted megaripples on the Red Planet. But they didn’t seem to change in any measurable way, which led some scientists to think they were relics from Mars’s past, when its thicker atmosphere permitted stronger winds.

Now, using images captured by NASA’s Mars Reconnaissance Orbiter, Silvestro and his colleagues have shown that some megaripples do creep along—just very slowly.

They found that the ripples shift position about four inches per year, which astonished them since they had not believed the winds of Mars were strong enough to move them at all.

Pioneer cover

From the press release: From the moment he is handed a possibility of making the first alien contact, Saunders Maxwell decides he will do it, even if doing so takes him through hell and back.

 
Unfortunately, that is exactly where that journey takes him.

The vision that Zimmerman paints of vibrant human colonies on the Moon, Mars, the asteroids, and beyond, indomitably fighting the harsh lifeless environment of space to build new societies, captures perfectly the emerging space race we see today.

He also captures in Pioneer the heart of the human spirit, willing to push forward no matter the odds, no matter the cost. It is that spirit that will make the exploration of the heavens possible, forever, into the never-ending future.

Available everywhere for $3.99 (before discount) at amazon, Barnes & Noble, all ebook vendors, or direct from the ebook publisher, ebookit. And if you buy it from ebookit you don't support the big tech companies and I get a bigger cut much sooner.

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