New Mars Crater Spotted In Before-and-After Pictures 41
The Bad Astronomer (563217) writes "The Mars Reconnaissance Orbiter spotted a new crater on the surface of Mars, and, using before-and-after pictures, the impact date has been nailed down to less than a day — it happened on or about March 27, 2012. The crater is 50 meters or so in size, and surrounded by smaller craters that may have been caused by smaller impacts due to the incoming meteoroid breaking up. Several landslides were spotted in the area as well, possibly due to the shock wave of the impact."
Being picky ; photographed != "spotted" (Score:5, Informative)
It was photographed at less than a day old, but since it's only being reported now, there was probably a period of some days or even weeks between the photos being taken, downloaded to Earth, decoded, and analysed with a before/ after filter. Then follow-up photos with other orbiters, preparing reports etc ... I'd guess that it wasn't much more than a week between the photography and realisation (the actual "spotting") ; but I won't go into philosophical pickiness over whether the "spotting" was done by the before-after comparison algorithm or the human reviewing the list of before-after differences.
It would be informative (if The Bad Astronomer is reading) to know how many false before-after differences turn up each day or orbit? Tens, hundreds? The origins would be informative too - weather, cosmic ray hits, transient glints off Tripods?