How to Discover Impact Craters with Google Earth

Maikel_NAI writes "Believe it or not, Emilio Gonzalez, a Spaniard amateur began his crater search at home after reading an article about the discovery of Kebira, the biggest one found in the Sahara. After a couple of minutes he located two craters. After checking the records, he realized these were completely new, and now two geologists confirm his findings. And there is more, these craters may be part of a chain studied by NASA geologist Adriana Ocampo, so if it's confirmed that these new ones are part of the same episode, it could mean the definitive evidence for her theory of an asteroid broken into pieces fallen in that area."

Comments

Google Earth

[gcnaddict]

Ok, so we can easily find anomalies caused by nature, but how about anomalies caused by us? I mean things like Area 51 and nuclear bomb test sites... I wouldn't mind seeing a few of those.

Re:Google Earth

[Altima(BoB)]

Both of those are visible in Google Earth quite easily. Try checking the menu on the left and activating the Google community tabs, especially "military." Enthusiasts point out things like military bases, notable vehicles or facilities and, yes, nuclear test sites. There's an area where you can clearly see many of them in the American west.

Speaking of other manmade items found on google, last september a man found ruins of a roman villa near his house via Google Earth. It is proving itself to be a very fun and useful tool indeed.

Re:Google Earth

[mordors9]

Obviously Google knows to only allow that to be seen. How long would they survive if they allowed everyone to see evidence of the alien government conspiracy.

Re:Google Earth

[radtea]

Try checking the menu on the left and activating the Google community tabs, especially "military." Enthusiasts point out things like military bases, notable vehicles or facilities and, yes, nuclear test sites.

Zoom in on the coastline of southern Cuba and you'll see a narrow bay cutting deeply into the shore. With a little imagination you can almost see the IVth, Vth and VIth ammendments of the Constitution of the United States of America being violated.

I don't know if these sorts of out-of-date images of military installations have any practical value, but they do give a certain valuable sense of reality regarding the existence of places that many people would like us to ignore, or forget. It's hard to think of the prison camp where innocent people are being incarcerated without trial[*] as being "out of sight, out of mind" when you can fire up Google Earth and see it plain as day.

[*] Do the math: there are 500+ people there, mostly captured in battlefield conditions in villages and farms. We know the cops, in the best of circumstances, sometimes get the wrong guy. We know the courts, in even better circumstances, sometimes convict the wrong person. So we no with what would be ordinarily called certainty that a non-trivial number of innocent people are being held, indefinitely, without trial, without legal recourse. Even with the most generous assumptions the number comes out to 25 or so. The only question is: are the goals being pursued so valuable and the means being used to pursue them so valuable as to justify the certain incarceration of innocents? "Is life so dear, and peace so sweet..?"

So would the lawyer for these people...

[AnonymousPrick]

Area 51 workers suing Gov.

From the TV specials that I've seen about this, it looks like area 51 was an R&D facility for rockets, planes, and other weapons. Unfortunatley, that requires a lot of toxic chemicals. Also, the workers would burn a lot of the failed projects so that they wouldn't be discovered. Like many areas of the US, one of the biggest polluters is the US Government.

CoralCached

[VisceralLogic]

Just in case Coral Cache version

Historical views

[mgkimsal2]

I know we don't have the previous satellite images from years gone by, but would it be practical to use some sort of image diffing program to look for changes in satellite imagery in the future? Yes, you'd get all the new building activity and whatnot, but we should also be able to tell when new craters hit (or other bigger changes happen) automatically. 'course, I've no idea how often global satellite images are updated, or how long it takes, so it might not be practical any time soon... Hundred years or so from now, it would be fun (if nothing else) to watch movies of how areas changed, both from direct human changes (buildings, etc) and from natural forces (coastal erosion and so on).

Re:Historical views

[Anonymous Coward]

The short answer: Yes, we've had that for a looong time. Google Earth is neat, and it's great that home-users now how access to this kind of data, but this field (called remote sensing) is well established with some amazing capabilities.

What you're talking about is called change detection. It's most commonly used for biodiversity inventory and urbanization growth measurements. The successfullness of change detection is dependent on a lot of variables, but can work very well. I used a sort of change detection to help delineate the transient snow altitude- a common elevation at which glaciers change from predominately ice-covered to predominately snow-covered.

There are lots of different systems that take these images. Some can reshoot an area in a days, some once a month, a year, maybe never again. Again, there a lots and lots of factors involved. Do a search for remote sensing basics and you'll probably find lots of cool stuff about it. If you're into this kind of thing...

Google Earth tourism

[FuzzyBad-Mofo]

You can find many interesting sights on Google Earth (and Maps). Some of the ones I've found interesting are:

Australia's Great Barrier Reef
The USS Arizona memorial at Pearl Harbor
China's Three Gorges dam
The Golden Gate Bridge

Re:Google Earth tourism

[Ford Prefect]

The Register had a fun black helicopters competition - looking for covert military stuff with Google Earth. They've had plenty of weird Google Earth things featured, including an incredible, um, giant profanity. Wahey.

Re:Google Earth tourism

[toxcspdrmn]

For more interesting sights see Google Sightseeing.

How cool is that?

[blueZ3]

It's easy to get caught up in the idea that either everything cool that's discoverable by amateurs has already been discovered, or that it takes years of experience or expensive tools to do "new" work in science. This discovery, by someone whose interest was piqued a few days ago by a translated article, should serve as a reminder that there are still things out there that people without a formal science degree can discover.

Re:"Optical Recgnition"?

[Astroseti]

Hi, I'm Emilio, the "discoverer"

The main problem is that circularity is not a proof by itself, because it can be caused by other natural processes.

Impacts don't have to be circles necessarily, it depends on the path inclination. They could be ellipses too. (I'm learning a lot these days)

Another problem is that I found with Google Earth great portions of Africa are cloud covered. If would be great if they could make the mosaics showing only pictures without clouds.

I don't think, but maybe I'm wrong, that there are many structures missing with such clear structure. I was really lucky, but most structures should be very erosioned like the candidates close to Arorunga, that need radar images to show details.

I'm now also using NASA World Wind, and it has some interesting features shuch false colors that help to better distinguishing structures. Anyway Google Earth is great for sweeping big areas

Re:"Optical Recgnition"?

[Sporkinum]

Good job Emilio! I decided to try Worldwind as well, and your discoveries stick out like a sore thumb using Nasa's program. Yes, Google Earth scrolls faster, but I think Worldwind is better for seeing the detail.

It's a neat idea, but...

[Anonymous Coward]

As a geologist, I know that there are a great many processes that can form roughly circular geological structures besides impacts. For example, deformation associated with salt diapirs (AKA "salt domes") and plug-shaped igneous intrusions, among many others. So, although it is reasonable to identify impact *candidates* with aerial or satellite imagery, and many impact structures have been found that way initially, there are also many false positives. As the article mentions, it takes ground geological evidence to determine one way or the other.

Here's some examples:

a circular structure in Louisiana -- this is related to a salt structure beneath the surface. There are several in the area. It has been somewhat enhanced by artificial canals and other development.

volcanic cones in various stages of erosion in Mexico. Volcanic cones are usually fairly easy to distinguish from impacts, but if they are deeply eroded (e.g., after the eruptions have stopped, and the peak has been worn down to the igneous plug in the center), they could be confused with well-eroded craters.

salt domes and folding-related structures in the Zagros Mountains of southern Iran.

There is *alot* of awesome geology visible from space, especially in desert areas without much vegetation (I *love* Google Earth), but people should evaluate the possibilities skeptically. In the sum total of circular structures out there, probably only a fraction of a percent have anything to do with impacts.

For comparison, here are a few legitimate impact structures:

Clearwater Lakes in northern Quebec, Canada.

Lake Manicouagan, also in Quebec. The best places to look for craters is often these very old parts of the continents (called continental shields), where the surface has been exposed for a long, long time, even on geological scales.

In the same area you'll also notice round structures like these that relate to igneous intrusions (usually granites or other plutonic rocks) and which have nothing to do with impacts.

Meteor Crater, Arizona is a "simple" crater, which is bowl-shaped. Most of the bigger ones (like the ones above) are "complex craters" with one or more raised rings or central areas.

I guess if Google Earth ever adds a geological map layer, it might make hunting for impacts a little less hit-and-miss, but geological maps aren't usually how people navigate or locate a business, so I can't see that happening soon ;-)

Googlicious!

[Kittie Rose]

Man, all we need now is a Google Mars, and we won't have to bother with all this Orbiter crap.

Google Sight Seeing

[ntsucks]

If you just want to look at cool stuff with Google Maps/Earth, without the searching. This place www.googlesightseeing.com has tons of cool stuff found in Google Maps/Earth.

Re:"Optical Recgnition"?

[Sporkinum]

worldwind://goto/world=Earth&lat=21.74227&lon=19.3 4509&alt=58760
worldwind://goto/world=Earth&lat=21.28825&lon=19.3 4041&alt=58916
For his two features in worldwind.

*yawn* You mean this?

[AnswerIs42]

Mars will be included with the World Wind 1.3.4 release (Beta version should be out in a few weeks).

But here is a post about the imagery that is currently "ready" there will also be a full color imagery dataset by release time.

There is also an add-on to view Venus imagery in World Wind. Though that is not yet with a 3D texture yet.

Don't get me wrong.. GE is a nice image viewer, but you can't really expand it's boundries that far.

The visible craters are probably far too old

[jesterzog]

I know we don't have the previous satellite images from years gone by, but would it be practical to use some sort of image diffing program to look for changes in satellite imagery in the future? Yes, you'd get all the new building activity and whatnot, but we should also be able to tell when new craters hit (or other bigger changes happen) automatically.

If you mean to search for impact craters, then it's probably not at all practical for the types of craters that are discussed in this article. The initial crater mentioned is 195 kms in diameter. The article's not specific about the other two, but it seems that they're also on the order of many kilometres in diameter. Add to that that they'll be very very old, probably on the order of many tens of thousands to millions or hundreds of millions of years depending on the size and state. The erosion of them is part of the main reason they wouldn't have been discovered until now.

If any of these craters were created in modern times, we'd very definitely know about it, irrespective of where on the Earth it was. If the entire Earth's sky didn't turn red and light wasn't blocked for years and large populations weren't killed, the impact would show up quite obviously on geological equipment for detecting Earth tremors.

There are probably smaller impact craters forming on a more common basis if there were extremely high resolutions available, but they'd also be eroding much more quickly. Consequently you'd likely need very high resolutions, and need new ones frequently, and then some reliable algorithm for filtering out every farmer (or rabbit) who's dug a small hole for some reason.

I'm an amateur astronomer but I'm not an expert on meteorite impacts, so I'd be interested to hear the comments of someone who knew a bit more about satellite images and impact craters. It seems pretty unlikely to me from my own understanding that it'd be infeasible, though.

What about this one?

[slagheap]

Is this in a database somewhere? It's like a bulls-eye of small islands. I found this while looking around with Google Earth. It's near Lake of the Woods Minnesota USA / Canada.

http://maps.google.com/?ll=49.169583,-94.491348&sp n=0.249613,0.464859&t=k

There is a really obvious circular pattern in the center of that one, and a slightly less obvious one just off to the east.