This stencil of a graceful, outstretched hand was discovered in a cave on an Indonesian island. And now we know that it's more than 39,900 years old. That makes it the oldest painting in the world, at least so far, and shows that humans in Asia developed symbolic expression at the same time as humans in Europe.

Photo by Kinez Riza

Though the discovery of these paintings isn't new, the method that scientists used to date them are. Bethany Hubbard reports in Discover:

Maxime Aubert and colleagues dated the creations by analyzing mineral deposits found on top of the paintings. These minerals formed calcite nodules called coralloid speleothems, also known as "cave popcorn" due to their bulbous shape. The cave popcorn contains trace amounts of the chemical element uranium.

Using a small electric saw the researchers collected 19 samples from 14 individual motifs, comprised of 12 hand stencils and two figurative drawings. By measuring the radioactive decay of uranium in the calcite above and below the paint layer, scientists were able to determine the minimum and maximum ages of the art.

And what's truly brilliant is that this finding shows that art was emerging all over the world, in distant communities, at roughly the same time. Previously, the oldest known paintings were in Europe, which had given rise to the idea that perhaps art was born in that area. But we now have evidence that this idea is untrue.

Write Aubert and colleagues in their paper, published this week in Nature:

We show that rock art traditions on this Indonesian island are at least compatible in age with the oldest European art. The earliest dated image from Maros, with a minimum age of 39.9 kyr, is now the oldest known hand stencil in the world. In addition, a painting of a babirusa ('pig-deer') made at least 35.4 kyr ago is among the earliest dated figurative depictions worldwide, if not the earliest one. Among the implications, it can now be demonstrated that humans were producing rock art by ~40 kyr ago at opposite ends of the Pleistocene Eurasian world.

Something happened to humans roughly 40 thousand years ago, some evolutionary and cultural development, that allowed us to start expressing ourselves symbolically. It's extraordinary to imagine it arising in disconnected human communities throughout the world.

Read the full scientific paper in Nature