It had never occurred to me to think about geostationary satellites in Mars orbit before reading a new paper by Juan Silva and Pilar Romero. The paper shows that it takes a lot more work to maintain a stationary orbit at an arbitrary longitude at Mars than it does at Earth.
I'm absolutely floored when I stop to think that our beautiful blue ocean is only one of perhaps a half dozen or more oceans on other worlds in our solar system, and only one of probably millions (or more) oceans on other Earth-like planets in our galaxy. Oceans abound!
With the Landsat Data Continuity Mission scheduled to launch on Monday, there's been a lot of Tweeting about Landsat, and through one such Tweet I learned about a resource that I hadn't known existed before: the LandsatLook Viewer. This is a graphical interface to more than a decade worth of Landsat data, a tremendous resource for anyone interested in Earth's changing surface, natural or manmade.
This is a very large (19000 pixels square) mosaic of the fjords and glaciers of southern Greenland. I had been interested for a long time in experimenting with the processing of Earth satellite imagery just to get a comparison to the other planets.
Today hurricane Sandy is a major threat to life and property across the west coast of the northern Atlantic ocean. I just want to give thanks in advance to all the people who have devoted their careers to making sure that Americans have sufficient warning of devastating, unstoppable weather events like this one.
Evaporites form on planetary surfaces when dissolved chemical solids precipitate out of saturated solution as their liquid solvent evaporates and, until recently, were known to exist only on Earth and Mars. This article from the IAG Planetary Geomorphology Working Group describes the third planetary instance of evaporite, discovered on Saturn's moon Titan.