On the shortest day of the year — Dec. 21 — the shadow of one of the blocks disappears when the sun is directly above it.
"It is this block's alignment with the winter solstice that leads us to believe the site was once an astronomical observatory," said Mariana Petry Cabral, an archaeologist at the Amapa State Scientific and Technical Research Institute. "We may be also looking at the remnants of a sophisticated culture."
But then they say this:
Cabral has been studying the site, near the village of Calcoene, just north of the equator in Amapa state in far northern Brazil, since last year. She believes it was once inhabited by the ancestors of the Palikur Indians, and while the blocks have not yet been submitted to carbon dating, she says pottery shards near the site indicate they predate Columbus' voyages and may be much older — as much as 2,000 years old.
You can't have it both ways. Due to precession, any actual observatory that's 2,000 years old will no longer align with either soltice - as is the case with Stonehenge.
So methinks this is PC selective science on a par with global warming.
Precession of the equinox is apparently not commonly known. Thought everybody knew after the hit song "Age of Aquarius". How can an archaeologist function in the world without knowing these elementary facts?
Check out the photo in post 5. Hard to believe that the "no shadow" stone is still in exactly the same place they put it 2000 or so years back, when everything around it looks like rubble.