Meet Deimos (Again)

The Smaller of Mars’s Two Moons

A February 21, 2009 image of Deimos, as seen by the HiRISE Camera on Mars Reconnaisance Orbiter. (Click to emibiggen.)

The folks from the Mars Reconnaissance Orbiter HiRISE team at the University of Arizona just released a very cool pic of Deimos. The scale of this view is 20 meters per pixel, so that means that anything about 60 meters or larger can be seen clearly.

You can see very subtle variations in the surface color — red in the smoothest areas and less red near areas where the impact craters are fresh. These color variations are probably caused when surface materials are exposed to the environment of space (UV radiation, etc.). That typically leads to darkening and reddening. Brighter and less-red surface materials haven’t been exposed to space nearly as long, since they were likely recently uncovered by impacts or downslope movements of surface “dirt” called regolith. I think this is a pretty marvelous view, considering that both the camera and Deimos were moving with respect to each other.

Are Your Skies Dark?

Tell the World What You See

Postcard for GLOBE at Night. (Click to embiggen.)

I know I’ve mentioned this before, but now that the time for GLOBE at Night is getting closer, it’s worth bringing it up again for your consideration.  GLOBE at Night 2009 is a week-long activity running from March 16-28  that anybody can participate in to measure the darkness of their local skies. You don’t need fancy equipment, just the ability to walk outside and compare what stars are visible to you with a chart that you can get online. Then, you report what you find to the GLOBE at Night folks and they do the rest. The result will be a global “chart” of what light pollution is doing to our night skies.

The capstone of the event will be an event called Earth Hour, where cities around the world turn off as many lights as possible for one hour. Nearly a thousand cities have committed to turning off the lights so their citizens can see something they haven’t seen for a long time: the night sky in all its glory.  I see that a few dozen cities and towns in the U.S. (my home country) are participating. That needs to change, folks.  Work on your city’s officials to commit an hour to the sky.

You might think to yourself “So what if there’s some light pollution?”  And, for a long time, people did. That is, until we started finding out that we are losing our night skies. In the process, we’re affecting nocturnal animals,the environment, and possibly even affecting human health in ways that we are still measuring.

We’re also radiating a lot of light upwards, wasting energy doing so. It costs money to light up the skies, and I’m not sure why we do it. Someone once wrote that civilizations that can afford to waste money sending unused light upwards must be very wealthy indeed. Is that true?  Are we on this planet so wealthy we can afford to do that? Are all of our people fed?  Does everybody have a safe drinking water supply?  A dignified place to live?  I think you know the answer to that. And yet, we waste money on brightly lit car lots and buildings and other places that don’t need to be lit up bright as day each night.  We’re spending money to drown out the vision of the night sky. And the stars.

We don’t have to be doing that.

To understand the magnitude of the problem, programs like GLOBE at Night and Earth Hour  illustrate for people in a first-hand way just what we’re blotting out with our energy waste, and what we’re doing to our environment.   You don’t have to be a tree-hugger or of one political party or another to appreciate the beauty we’re washing away with light pollution. You just have to be someone who appreciates the beauty of the sky and also someone who appreciates not wasting tax dollars and advertising money on lighting up the sky.  Shine the lights where we need them, not where they aren’t needed or wanted. And, in the process, help save tax dollars and public monies in a time when the economy is having a rough go of it.

Light pollution on a freeway causes glare and wastes energy. It can be done better. Courtesy IDA.

To that end, I also recommend you take a look at the International Dark-sky Association’s web page. This is a group of citizens and experts from all walks of life, all political persuasions and outlooks, who have banded together to find ways to use energy resources wisely when it comes to light use. They have an incredibly useful set of handouts and position papers that people can give to their local officials to point out how best to light our public spaces safely but with respect for the night sky AND taxpayer pocketbooks.  Check it out!  And, be sure and participate in GLOBE at Night and Earth Hour.  You’ll be glad you did.