It’s crazy to try to imagine how long humans have been wandering this world in one form or another. It’s hard to imagine, too, how different the world then looked from the way it does now.

Thanks to a set of fossilized footprints, though, imagining when humans first walked across North America is now a little bit easier.

The footprints were found in the gypsum-rich White Sands in New Mexico, and radiocarbon dating confirms there were humans in North America 23,000 years ago. This answers a question that has been debated for a long time due to the controversial fossil dating technologies, with most saying that humans can’t be confirmed to have been in North America before 10,000 years ago.

This finding suggests humans arrived before the last Ice Age, but there are those who still insist the seeds and pollen found in the nearby soil are unreliable dating markers. This is because Ruppia is known to take up carbon from water that contains dissolved carbon from ancient sources. This skews the results, making the plant seem older than it actually is.

Pollens, meanwhile, are lightweight and could be easily deposited next to much younger footprints.

So, the researchers used carbon dating to test the actual mud encasing the footprints. The analysis showed the mud is between 20,700 and 22,400 years old. 55 independent radiocarbon tests on all three materials yielded similar results that prove, as far as this team is concerned, that humans were in the Americas before 13,000 years ago.

Lead author, Vance Holliday, made a statement on the findings.

“It’s a remarkably consistent record. You get to the point where it’s really hard to explain all this away. As I say in the paper, it would be serendipity in the extreme to have all these dates giving you a consistent picture that’s in error.”

Questions, remain, however, like why there are no artifacts or other signs of life near the footprints. Holliday and his team suggest there could be an explanation for that as well.

“These people live by their artifacts, and they were far away from where they can get replacement material. They’re not just randomly dropping artifacts. It’s not logical to me that you’re going to see a debris field.”

Whether or not this study answers every question, it does answer many of them.

And that will have to be enough for now.

If you thought that was interesting, you might like to read about 50 amazing finds on Google Earth.