Someone recently applied paint AND it was thought the fossil was 280m years old.
It does rather carry a pall over the idea we can accurately date anything, doesn't it?
It does rather carry a pall over the idea we can accurately date anything, doesn't it?
And carbon dating.
And decay of uranium into lead.
They usually have multiple techniques that can be used together.
But yeah there's all kinds of decay chains and geology techniques used to date these things. It's a really cool mix of logical deduction and chemistry and cleverness.
Specific decay chains are effective clocks for differing lengths of time. Radiocarbon dating is often used on recent human or organic artefacts or remains, within the past 50,000 years or so as noted. It was uranium-lead decay which first demonstratively showed that the Earth was not "young", whether the few thousand years of theological textual analysis or the 30--300 million years that various geological estimates had suggested, but at least 1 billion years old, established by Ernest Rutherford in the early 20th centuries.
The present value of 4.54 +/- 0.05 billion years was arrived at by the 1950s, based on the ratios of lead to uranium within zircon crystals, the latter of which cannot form in the presence of lead, and hence, any lead present necessarily being the result of radioactive decay. The measurement process also demonstrated the extent to which modern industrial activity was creating pervasive lead contamination virtually everywhere, largely the result of leaded gasoline, one of Thomas Midgley's lethal legacies.
More generally, geochronology is based on numerous methods of which radiometric dating is but one, though a quite powerful one.
<https://en.wikipedia.org/wiki/Radiometric_dating>
> How could scientists have presumed the dark outline was carbonized soft tissue for so many decades? "This fossil was discovered in 1931 and back then fossils were treated very differently than today," said Rossi. "Application of paints, consolidates and lacquers on fossil bones was the norm, because that was the only way to protect the specimens from further deterioration. It was also sometimes to embellish specimens by making them sleek and shiny. Unfortunately, in the case of Tridentinosaurus, the mechanical preparation did most of the damage and then the application of a black paint created the illusion of a lizard-like animal impression on the surface of the rock."
If anything, I am constantly blown away by how accurately we actually can date things. For example, thanks to dendrochronology[0] we can now often accurately date the exact year prehistoric wooden constructions like buildings or bridges were made, up to almost 14,000 years into the past! And that range will only increase.
There’s no need to cast broad suspicion on scientific methods.
Rocks on earth are rarely that old, as they’re composed from sedimentation (aka they get weathered then deposited), metamorphosed (compacted and modified by heat and pressure), cool from a lava flow (basalt, etc). [https://en.m.wikipedia.org/wiki/List_of_rock_types]
Each of those forms/types changes fundamental properties of the rocks which allows for dating.
Some rocks are literally only tens of years old, or even formed yesterday. Like basalt formed from lava from active volcanos.
> On Earth, it is relatively rare—5.2 ppm by volume in the atmosphere. Most terrestrial helium present today is created by the natural radioactive decay of heavy radioactive elements (thorium and uranium, although there are other examples), as the alpha particles emitted by such decays consist of helium-4 nuclei. This radiogenic helium is trapped with natural gas in concentrations as great as 7% by volume, from which it is extracted commercially by a low-temperature separation process called fractional distillation. Terrestrial helium is a non-renewable resource because once released into the atmosphere, it promptly escapes into space. Its supply is thought to be rapidly diminishing. However, some studies suggest that helium produced deep in the Earth by radioactive decay can collect in natural gas reserves in larger-than-expected quantities, in some cases having been released by volcanic activity.