Just like the Italian economy, since it’s very founding Venice has always sort of headed in the wrong direction–underwater. Not that the inhabitants needed any more proof of sinking. But, according to this article on BusinessInsider, a polar low earth orbiting satellite zipping 319 miles around the Earth called TerraSAR-X, is documenting Venice’s neighborhoods downward trends.
What you’re seeing is not an image, even if the picture in the article looks like one. What makes it different from a RapidEye or DigitalGlobe imagery satellite is how it was taken with the payload on TerraSAR-X: it’s actively pinging the Earth’s surface with radar (SAR typically=synthetic aperture RADAR). So that “picture” is actually radiowaves bounced back to it from the Earth, and the data from those bounces is used to form something more familiar to us. The resolution of SAR is so good, it can help determine something as subtle as the small shifts in the buildings in Venice as they settle further downwards. And, unlike picture-taking payloads, clouds will not bother radar very much.
- Venice’s Gradual Sinking Charted by Satellites (livescience.com)
- ScienceShot: Can We Save Venice? (news.sciencemag.org)