"You're really only left with two possibilities," Renne said. "One is that they are really old hominids - shockingly old - or they're not footprints."
...or maybe a third possibility - that there was a flaw or error in the testing. Scientists must always include that possibility.
Time for a new calibration curve. Until then let me look at the pictures and I will decide for myself.
"You're really only left with two possibilities," Renne said. "One is that they are really old hominids - shockingly old - or they're not footprints."Sure, but they cited two separate lines of evidence that it couldn't be 40,000 years old: Argon-argon dating, and the paleomagnetic signature....or maybe a third possibility - that there was a flaw or error in the testing. Scientists must always include that possibility.
And as they mention, argon/argon "reliably dates rock as young as 2,000 years or as old as 4 billion years", while the initial 40,000 year old figure came from carbon-14 dating of a different layer above the "footprints".
I'm disappointed that they didn't mention any evidence regarding the footprints themselves, especially since "the British team claims to have found 250 footprints - mostly human, but also dog, cat and cloven-hoofed animal prints." Surely with such a variety of prints, they should be able to decide if at least some of them are legitimate. (But I guess that's not that team's specialty, so they left that up to someone else to examine.)
Another question: Does volcanic ash really have to be hot in order for a footprint to get impressed in it? How long does it take for ash to solidify? I'd expect the ash to take a footprint long after it's cooled down enough to walk on, especially if it was a shallow layer of ash.