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

[gellenburg]

Area 51 is very visible from Google Earth, jus that there's not much to see except a very long runway and some hangars.

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

[value_added]

Ok, so we can easily find anomalies caused by nature, but how about anomalies caused by us?

Well, dunno if you'd consider any of this as an anomaly, but it's an equally topical use of Google's map technology (season premier is tomorrow, kids).

Maybe someone can find Jimmy Hoffa?

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

Re:CoralCached

[Maikel_NAI]

I don't think so, we have a dedicated server, and this is not the first time we appear in big-traffic sites, like digg. Just remember this: http://digg.com/science/The_most_famous_picture_in _the_history_of_science Our machine is ready for the "slashdot effect" ;-)

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

[Twanfox]

The problem with Google earth and Google maps for such a 'real time' analysis such as troops massing is that the photos presented and used are not current. They're not even close to current. I think the images taken for the area surrounding my home is at least a year or more old, based on new construction in the area that does not show in the satellite photos. That building started to go up early last year. Troops massing could be done far faster than those images refresh, if they refresh at all.

Besides, the military has earth-watching satellites for their own private use to watch for such things. They need not rely on a civilian tool for it.

Re:Historical views

[tyme]

mgkimsal2 wrote:

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).

In all probability we do have plenty of satalite imagery from pervious years (at least from the last 30 years or so), it's probably even fully indexed and available for download from some some U.S. government agency or another.

As for how long it would take to re-image the entire planet: a little more than a month, at minimum, but probably more like a year on average. The calculation is easy: it takes about 90 minutes to make one orbit of the Earth in low orbit. If we assume a conservative low orbit altitude of 100 miles and a conservative aperature for the orbital camera of 22 degrees, we get a ground track about 40 miles wide. The Earth's circumference is about 24,000 miles so it would take 600 orbits to get imagery strips covering the entire equator (assuming a polar or near-polar orbit). That would take at least 600*90 minutes = 5400 minutes / 60 minutes in an hour = 900 hours / 24 hours in a day = 37.5 days.

You can already get time-lapse movies and comaprison photos showing coastal erosion and human impact, the difference over only 10 years is quite noticable (heck, the difference from year to year for barrier islands is astonishing).

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...

"Optical Recgnition"?

[bigattichouse]

Anyone have photo recgnition software that might look for the "raised circle" in a ring foot print and then wander over the map looking for interesting locations. You could use that database as a great testbed.

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"?

[cluckshot]

Just remember that craters have many causes. What is more both of the "craters" in Africa are not impact craters as they are not "blasted out" like is supposed to happen on impact. If they are in fact craters, they are probably plasma discharge craters or volcanic structures. www.thunderbolts.info has a lot of data on this. See picture of the day for 3/10/2006 etc. See the Sedan crater

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.

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.

Re:"Optical Recgnition"?

[John Muir]

Worldwind is a great companion app to Google Earth. I find its interface more intuitive when looking for visuals instead of just using text searches, and having a choice of imagery is a big bonus.

Google Earth's eye for aerial detail is great, but Worldwind is definitely not to be overlooked.

Re:"Optical Recgnition"?

[Forbman]

Hmm... I remember watching a movie of a study done by NASA to see why impact craters always seem to be circular. They shot high-speed pellets at sintered silica sand blocks, and filmed the results. Didn't matter what they did w.r.t. velocity or angle of impact (short of the absurd, like 5 degrees elevation), they all came out circular. How many ellipsoid craters are found on the moon, for example?

This one will get nailed hard

[gcnaddict]

This one's definitely going to need caching by CoralCache and MirrorDot: it got dugg as well.

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

[VisceralLogic]

I found the pyramids at Giza. That's pretty cool.

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:How cool is that?

[NorbrookC]

The idea that amateurs don't (or can't) do good science or make important discoveries is a more recent addition to popular culture - and it's wrong.

Admittedly, there are fields where it's true - like particle physics, stem cell research, or transplant biology, since the "entry level" for equipment and training is something you're not going to be able to pick up on the cheap (unless you're Bill G).

That said, there are many fields where 'amateurs' not only make important discoveries, they're actually the predominant workers in those fields. Comet discoveries and near-earth astronomy, paleontology, archaeology, and geology among others all have large numbers of amateurs - even outnumbering the "professionals".

What's interesting and exciting about this is that it's given a new set of tools for everyone who's interested to use.

Free information means news information

[Scrameustache]

Let's see, we've had archeological sites found by google earth, asteroid impacts found by google earth... who knows what's next?

I love this! You free up information, allow the unwashed masses access to it, and people find hidden treasure. Think how much we'd never know if all this was DRMed, locked and restricted!

Google, don't ever change.

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 ;-)

Re:It's a neat idea, but...

[adavidw]

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 ;-)

I'm not sure what you mean by "geological map layer". However, just in case you didn't know, Google Earth (the stand alone program) does have topography, and renders all the maps in three dimensions. I personally have spent many hours staring at impact craters and volcanic craters that way, just 'cause I think it's so cool.

Re:It's a neat idea, but...

[Anonymous Coward]

Yes, there are lots of circular structures in that part of Africa, but whether or not they represent impact structures can not be easily determined without referring to a geological map or doing some ground study. However, there are clues that these particular ones are not impact structrures.

For one thing, notice that the example at 22 06 53 N, 17 55 15 Ehas a circular "mate" just to the south, at 22 deg 04' 24" N. The northern one appears to have an outer ring and an inner raised zone -- suggestive of a complex crater. The southern one, though, just looks like a raised blob, which is not typical. Both have a similar "pinkish brown" colour compared to the surrounding, slightly darker and greener outcrops to the east (the really light zones are desert sand, rather than bedrock, and aren't relevant except as an indication of the topography -- they are lower). The southern of these two looks an awful lot like an ordinary granitic or other igneous intrusion. Its similarity to the ringed one that you mentioned makes me suspicious that they are both the same type of feature.

There are also a bunch of definite volcanoes in the area (it is in Chad), such as at: 21 deg 02' 51" N 17 deg 39' 58" E
21 deg 02' 48" 16 deg 30' 22" E. The former is fairly eroded, the latter is pretty recent -- it has dark-coloured lava flows visible around it. The caldera slightly to the SE has a saline lake in it (produces the blue colour).

There are a few more detailed explanations at NASA's "Earth from Space" website of astronaut photography. Though the explanations are only for a few scattered locations over a vast area, they are a great baseline for attempting interpretations elsewhere in the world as you explore things with Google Earth or similar tools. I highly recommend it.

I suspect alot of the circular structures seen in this area are just volcanic centers in various stages of erosive degradation or even exposure of the former magma chambers beneath them.

To figure it out for sure would still take fieldwork, but what information is known (e.g., take a look at those "Earth from Space" examples) makes me pretty skeptical they are impacts. But don't let that opinion discourage you from looking and asking questions.

Thank you, Google for bringing the fun of geology to everyone!

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.

Dr. Strangelove

[Doomedsnowball]

I wonder how much the US millitary could have saved using Google Earth to search for WMD test craters in Iraq...

Re:Dr. Strangelove

[laura20]

Mustard gas also isn't a WMD (despite the hype.) Terror weapon, battlefield denial weapon, but if it's a WMD then gasoline is too.

OMG! Right here!

[Lizard Slayer]

In Smallville ... a plethora of planetoid parts.

Crater studies and Air Force DSP

[amightywind]

The US has had much of the world's surface under continuous large scale infrared observation for 25 years or more with the Air Force DSP program. It can easily detect the smallest asteroid or comet impacts. I don't know if a scientific survey of its data has ever been done.

*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.

Google Earth - one in each classroom.

[Rational]

I've been addicted to Google Earth ever since I came across it. Generally, I'm very skeptical about the use of computers in the classroom environment, I think they are help and hindrance in pretty much equal measure - but there should be a computer running Google Earth in every classroom. It's a fantastic tool for teaching geography and geology, and would even help with biology, history and politics.

I found some!

[SirBruce]

There's two very interesting structures in Namibia, and I'm almost certain one of them is a crater:

  2046'24.47"S
  1618'18.43"E

You can see the multiple rings and the raise central structure. Also, just north of it is a smaller structure which may be associated with the first impact (sometimes you get crater chains):

  2043'56.35"S
  1617'28.12"E

Finally, there's a very strange (to a layman) structure to the SW that would have to be a very oblique impact crater if it is one, but I've never seen a crater like that; it looks more like a natural circular feature:

  2049'8.00"S
  16 7'48.59"E

If any geologist can look into this, let me know. I'd bet money the first one is an impact structure, though!

Bruce

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.

Re:What about this one?

[laura20]

Huh. If you focus in on the eastern ring shape, it looks even more concentric. And they aren't in the database I looked at, nor does googling on Morson and crater note anything.

But it is hard to believe that no one has noticed, given there's a (small) town sitting on top of one of them!