Forget about exploring other planets -- it looks like Earth has a few surprises left. How about a massive canyon buried underneath an ice sheet?
Researchers announced Thursday, in the journal Science, the discovery of a massive canyon below an ice sheet that covers Greenland. The canyon is at least 750 kilometers long and 800 meters deep, in some parts. Its scale is being compared to the Grand Canyon in Arizona.
Scientists believe the canyon predates the ice sheet that has kept it hidden from the world, which is estimated to be a few million years old. The researchers are in awe that a discovery of this scope can still be made on Earth.
"With Google Streetview available for many cities around the world and digital maps for everything from population density to happiness one might assume that the landscape of the Earth has been fully explored and mapped. Our research shows there's still a lot left to discover," Jonathan Bamber, professor at Bristol's School of Geographical Sciences and lead author of the study said in a press release.
The canyon cannot be seen with the naked eye. Scientists measured it using several decades' worth of airborne radar data, which was collected by NASA and researchers from the United Kingdom and Germany. The team analyzed data from radio waves that were bounced off the bedrock underneath the ice sheets -- on a frequency that does not detect ice.
Data from the research suggests the canyon's meandering structure served as a funnel for melt water to flow from the ice sheet interior to Greenland's coast. The well-organized structure of the melt water flow is believe to be an important discovery because it could help predict similar scenarios, in light of the warming climate producing more melt water.
"A discovery of this nature shows that the Earth has not yet given up all its secrets. A 750 kilometer canyon preserved under the ice for millions of years is a breathtaking find in itself, but this research is also important in furthering our understanding of Greenland's past. This area's ice sheet contributes to sea level rise and this work can help us put current changes in context," said David Vaughan, ice2sea coordinator at British Antarctic Survey in Cambridge.
This story originally appeared as "Massive canyon discovered under ice sheet in Greenland" on CBSNews.com.