Click for full image.
The image above, cropped, reduced, and annotated to post here, was released this week by the Mars Reconnaissance Orbiter (MRO) team. It shows the changes that have occurred at one location at the Martian south polar cap in the past decade. As planetary geologist Alfred McEwen wrote,
The south polar residual cap of carbon dioxide ice rapidly changes. This image was planned as an almost exact match to the illumination and viewing angles of a previous one we took in August 2009.
The pits have all expanded and merged, and we can just barely see the patterns in the 2009 image compared to this January 2019 picture. The 2009 image is also brighter and bluer, with more seasonal frost and/or less dust over the surface. These images were both taken in late southern summer, but our 2019 picture is slightly later in the Martian season by about two weeks.
You can get a better idea how much is changed by seeing the full image from which the above small area was cropped.
Click for original image.
Click for original image.
To the right is the 2009 image, reduced, rotated, and annotated by me. The red box indicates the small area covered by the above image. South is to the right. The many circular features probably indicate craters buried below the cap.
Below and to the right is the full 2019 image, rotated and cropped by me to match the 2009 image. The widespread differences are obvious. All of the white smooth areas have shrunk. New spots have appeared in those white areas, also suggesting the existence of buried craters.
The mystery here is that these images were both taken at almost the same moment in the late southern summer, though about five Martian years apart. Why should the white areas have shrunk? We would expect a reduction from winter to summer, but these were both taken in summer. While it would make sense to see changes, with some areas growing and others shrinking, we should expect to see about the same amount of white area.
Instead we see shrinkage only. Why? The only simple solution I can come up with that maybe these images simply don’t cover enough territory to provide us the full picture. The white areas, which are probably either frost or dry ice, have shrunk here, but grown in adjacent areas beyond this image.
Or maybe Mars has too many SUVs, and is now experiencing global warming! Yeah, that’s the answer! Nothing else make sense! The science is now settled. And if you disagree with me you must be a homophobic, white supremacist fascist, racist!
I must unfortunately ask you for your financial support because I do not depend on ads and rely entirely on the generosity of readers to keep Behind the Black running. You can either make a one time donation for whatever amount you wish, or you sign up for a monthly subscription ranging from $2 to $15 through Paypal or $3 to $50 through Patreon.
Your support will allow me to continue covering science and culture as I have for the past twenty years, independent and free from any outside influence.
Your support is even more essential to me because I not only keep this site free from advertisements, I do not use the corrupt social media companies like Google, Twitter, and Facebook to promote my work. I depend wholly on the direct support of my readers.
You can provide that support to Behind The Black with a contribution via Patreon or PayPal. To use Patreon, go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation. For PayPal click one of the following buttons:
If Patreon or Paypal don't work for you, you can support Behind The Black directly by sending your donation by check, payable to Robert Zimmerman, to
Behind The Black
c/o Robert Zimmerman
Cortaro, AZ 85652
Or you can donate by using Zelle through your bank. You will need to give my name and email address (found at the bottom of the "About" page). The best part of this electronic option is that no fees will be deducted! What you donate will be what I receive.