(10-23-2023, 02:25 PM)mikesez Wrote:

(10-23-2023, 09:43 AM)homebiscuit Wrote: Red shift. Similar to the Doppler effect for sound, light shifts towards the longer red wavelengths the longer it travels. By studying the shift on a spectrum, astronomers can determine how far, and thus how long, light has traveled. 

Paleontologists determine how long ago dinosaurs became extinct by studying fossil beds within geologic strata with known ages. At a certain point dinosaurs bones suddenly stopped appearing in these geologic layers, which coincides with the K-T Boundary, a layer of iridium rich ash deposited around the globe from an asteroid strike.

I read a lot of science stuff.

Aging by the red shift is only possible when the source emission spectra is known and the cosmological principle is assumed.  So you can be precise within a common set of assumptions but what if those assumptions are wrong?