Images: Google Earth finds Atlantis? Nah

A recent post by CNET News' Caroline McCarthy about Google's denial that its Google Earth ocean-floor mapping software had unearthed the mythical city of Atlantis piqued the interest of quite a few of our readers.

A subsequent post on Google's explanation didn't quite quell the swell of theories about the street grid-like patterns on the ocean floor off the coast of Africa.

Andy Smith, at our sister site ZDNet, has put together a slide show of some of the images on Google Earth at the center of it all.

Last week, a grid was discovered on Google Earth at coordinates 31 15'15.53N, 24 15'30.53W on the ocean floor 600 miles off the coast of Africa, sparking rumors that spread over the Internet that the ruins of the lost city of Atlantis were found. Or maybe they were plow marks from aliens?

Google was quick to discredit the rumor, saying that these lines couldn't have been from the lost city and were created by "ship tracks."

Google was swamped by even more conspiracy-theory feedback, and ultimately it pulled in Walter Smith of the National Oceanic and Atmospheric Administration (NOAA) and David Sandwell of UC San Diego's Scripps Institution of Oceanography, two scientists who helped gather some of the ocean-floor data in Google Earth, to clear it all up in a post on the company's official blog.

First, Google says the image is way too big to be a city. If you use Google Earth's ruler, the grid is about 104 miles wide.

This defined "city block" is about 11 miles wide according to the Google Earth measurement tool.

Google has an explanation of the "ship tracks":

"By measuring the time it takes for sound to travel from a ship to the sea floor and back, you can get an idea of how far away the sea floor is. Since this process--known as echosounding--only maps a strip of the sea floor under the ship, the maps it produces often show the path the ship took, hence the ship tracks."

The dots indicate the soundings produced in this area.

Shown here is a higher resolution ship track off Hawaii.

There's still a chance of finding Atlantis. Much of the ocean floor has not been mapped. Google estimates the cost would be around $2 billion.

Since Ocean in Google Earth was released, searchers have been surprised by discoveries such as an emerging volcanic island off Hawaii called the Loihi Seamount.

Another discovery is the Mid-Atlantic Ridge, which forms a nearly continuous mountain range that is more than 3,600 miles long.