The Winds of Mars

changing martian dunes
Images taken 1363 days apart.

In two different papers published in two different journals in the past month, scientists have concluded that — despite the thinness of the planet’s atmosphere — the dunes and sands of Mars are being continually shaped and changed by its winds. In both papers the data from which this conclusion was drawn came from high resolution images taken by the HiRISE camera on Mars Reconnaissance Orbiter.

What is especially interesting about this conclusion is that the climate models that had been developed for the Martian atmosphere, combined with wind measurements gathered by the various Martian landers, had all suggested that the kind of strong winds necessary to move sand were rare. To quote the abstract of the paper published on Monday in the journal Geology, Bridges, et al,

Prior to Mars Reconnaissance Orbiter data, images of Mars showed no direct evidence for dune and ripple motion. This was consistent with climate models and lander measurements indicating that winds of sufficient intensity to mobilize sand were rare in the low-density atmosphere.

Similarly, the second paper, Silvestro, et al, published on October 22 in Geophysical Research Letters, stated that

results from wind tunnel simulations and atmospheric models show that such strong wind events should be rare in the current Martian atmospheric setting.

Yet, both studies found significant evidence that such winds do occur on Mars, and are moving sand in many different places.
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Obama: “You’ve got a governor whose state is on fire denying climate change.”

Obama on Sunday at a fundraiser, attacking Rick Perry: “You’ve got a governor whose state is on fire denying climate change.”

Here is another example of a politician making a fool of himself. The wildfires in Texas have nothing to do with climate change. And if Obama thinks they do, he immediately shows himself to be completely ignorant of the science behind the Earth’s climate.

Private Japanese weather company to launch satellite to track Arctic Ice

A private Japanese weather company plans to launch a satellite to track Arctic ice for use by shipping.

The satellite will transmit images and information about sea ice in the Arctic Ocean. Weathernews will combine the information with available data on sea currents, weather and wave height to provide consumers with a finished product enabling safe navigation along the northern route.

Though I know most people are skeptical of this idea, I think that all weather information should be gathered and sold by private companies, as Weathernews is doing above. For example, the Weather Channel makes its money providing weather information to the public. If they didn’t get the satellite data free from NOAA weather satellites, they would have every reason to launch their own satellites.

Ethane lakes in a red haze: Titan’s uncanny moonscape

Titan’s ethane lakes in a red haze.

So far, there are no recognisable signs of organic life. That’s not surprising: by terrestrial standards, Titan is a deep freeze with surface temperatures at a chilly -180°C. Yet Titan is very much alive in the sense that its atmosphere and surface are changing before our eyes. Clouds drift through the haze and rain falls from them to erode stream-like channels draining into shallow lakes. Vast dune fields that look as if they were lifted from the Sahara sprawl along Titan’s equator, yet the dark grains resemble ground asphalt rather than sand. It is a bizarrely different world that looks eerily like home. Or as planetary scientist Ralph Lorenz puts it: “our prototype weird-world exoplanet”.

Snowbound England

Images of a snowbound England.

I know it’s weather and not climate, but Europe is experiencing its second cold winter in a row, despite predictions by many in the global warming community that such things would never happen again. My point here is that their claims in the late 1990s that hot streaks and big storms were proof of global warming were patently dishonest, and it is worthwhile to remind ourselves of this fact.

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