radiocarbon dating, for starters.
Only problem is how do you calibrate it? What do you have that is millions or billions of years old
for sure. Remember the Eratsothenes Experiment. He ASSUMED the Earth was round and got his "correct" answers.
Mt. St. Helens (MSH) explosion. I have a video where the is a wall of strata (100+ ft) that was created within 3 YEARS on 3 separate dates that we know precisely - fine and coarse strata (so tell me the Grand Canyon couldn't have formed rapidly if there was a world-wide flood). One geologist said if he didn't know it was MSH, he would say that wall formed over millions of years. Furthermore, there is a mini-Grand Canyon with a stream running in the middle of it (gravity puts it there). Again, without knowing the MSH explosion, geologists would say the water eroded the canyon over millions of years. There are also trees on Spirit Lake that got deposited on the bottom, some standing upright. They don't have roots, just the lower part of the trees was heavier than the top. There are other areas around the world where geologists and botanists claim forests existed for millions of years. After this event, the roots were checked. Sure enough something similar. So it doesn't take millions of years for things to happen. These are measured/observed FACTS in our lifetimes - proof that these events do NOT take millions of years against THEORIES that these events take a long time.
(
http://www.mandley.com/advdemo/mod05/adv5430.htm)
In Australia they were digging a shaft. They found a forest sandwiched between rock. When they used radiometric dating, the forests came back ~45 THOUSAND years +/- a few and the rocks ~45 MILLION years +/- a few. Notice the +/- ACCURACY of these measurements. So how can forests that are thousands of years old be sandwiched between rocks millions of years old? (
https://answersingenesis.org/geology/radiometric-dating/radioactive-dating-in-conflict/)
Another strata failure is the recovery of a WWII squadron of aircraft from Greenland. They took off from Greenland to Britain but had to return because of weather. They landed on a glacier. People BELIEVING the radiocarbon dating (core samples tell us what the weather was like THOUSANDS of years ago) decided to go out there, shake off 50 years of snow and have pristine WWII aircraft. That didn't happen because the dating isn't true.
(
http://creation.com/the-lost-squadron)
Also, in the past, stalagmite and stalactite creation was thought to be a VERY slow process. Depending on several variables, it can be VERY rapid. Man has left "artifacts" recently in caves that these grow on/over quite rapidly. So it doesn't take millions of years, just the right conditions.
So, are there variables and conditions that change radiometric assumed values? The current values are based on a certain set of conditions (laboratory not environment). Did these same (laboratory) conditions exist unchanging for thousands, millions or billions of years (like the amount of carbon for the dating)?
From math, interpolation is usually accurate. Extrapolation is notoriously inaccurate (inaccuracy grows VERY rapidly - confidence limits), especially the farther out you go. At some point, statistical confidence is zero. So to estimate HUNDREDS or THOUSANDS of years, it might be good, but MILLIONS and BILLIONS - totally NOT scientific (statistically speaking).
These are some ACTUAL events that we KNOW happened and have actual dates or locations. Against this, how DO you know something is ACTUALLY millions or billions of years old?