4 ms·
This is fascinating, especially whether the hole was created from a top impact or from the bottom such as volcanic eruption. On another note, why are we discov
by Rotor 14y ago
This is fascinating, especially whether the hole was created from a top impact or from the bottom such as volcanic eruption.
On another note, why are we discovering this just now? I was under the amateur impression that the entire surface of Mars was scanned and imaged by NASA at some point. But again, I may have interpreted that incorrectly.
- a1k0n 14y agoOne of the links goes to an earlier APOD from 2007 of other holes in Mars: http://apod.nasa.gov/apod/ap070528.html http://apod.nasa.gov/apod/ap070528.html
- Arelius 14y ago> why are we discovering this just now? I was under the amateur impression that the entire surface of Mars was scanned and imaged by NASA at some point. It's easy to forget just how large Mars is, as a comparison, if we scaled Mars up to the size of Earth, the hole would only end up being about 120 meters, or about %30 larger than an American football field. And when it's a feature that we pretty much need human eyes on to determine it's significance, it's easy to imagine how we've missed it. Just imagine trying to find a random football field sized thing in Google Earth, somewhere on the planet. And to make the comparison even more valid, Mars isn't covered in water, and has a very comparable amount of land surface area as Earth does. in that case, it makes the hole only about 36 meters when scaled up to the surface are of Earth, which is likely what you'd be searching for in Google Earth. Not to mention that I have no idea to what resolution Mars was scanned and imaged at, considering imagery I see of Earth often, the mentioned scans could easily have pixels larger then the entire size of that feature. Hence it's easy to imagine that many more interesting features of similar size exist on the martian surface, sitting there in plain view, waiting to be discovered.
- swombat 14y agoIt's pretty high-contrast, though. Presumably an algorithm could find interesting high-contrast, high-symmetry structures quite easily...
- ojilles 14y agoThis image is probably not the resolution all of Mars got imaged at, right?
- Arelius 14y agoI don't have the tools on this CPU to get good numbers, but if that hole is about 35 Meters, I'd estimate to resolution to be about 20 CM/Pixel. I know it's often difficult to find civilian access to Imagery at a better resolution than 5 M/Pixel for some places on Earth. It's probably safe to assume we don't have imagery this good for the entire surface of Mars. Edit: It seems likely that these new images are captured with this equipment: http://en.wikipedia.org/wiki/HiRISE http://en.wikipedia.org/wiki/HiRISE
- joshuahedlund 14y agoI wonder how far launch costs will have to drop before "Google Mars" (and/or someone else and/or other celestial bodies) is plausible...
- mcguire 14y agohttp://www.google.com/mars/ http://www.google.com/mars/ ? Or did you mean StreetView?
- _delirium 14y agoMacro-level features have been mapped for a while, but even from earth orbit (Hubble) it's not possible to resolve features at high resolution. I'm not sure what the precise limits are, but according to one photo (http://commons.wikimedia.org/wiki/File:Mars_HST_Mollweide_map_1999.png http://commons.wikimedia.org/wiki/File:Mars_HST_Mollweide_ma...), Hubble's imaging of Mars is at a resolution of approximately 20 km/pixel, which is several orders of magnitude too low to resolve the "hole" here, which is <100m. Since 2006, there's been a high-resolution camera platform orbiting Mars (http://en.wikipedia.org/wiki/HiRISE http://en.wikipedia.org/wiki/HiRISE), and it's doing this high-res imaging, at up to 30cm/pixel (!), for the first time. Though Wikipedia says that as of 2010, it's only mapped 1% of Mars's surface to that degree.