And how do we know If something is millions of years old other than carbon dating and what is carbon dating
In: Chemistry
Amber is the fossilized form of tree sap. Tree sap is sticky, similar to honey, and insects can get stuck in it and die. Then, over time, the tree sap can become hardened into amber.
Radio carbon dating is a way of testing the age of an artifact or fossil by testing the radioactive isotopes of carbon in it. However, despite popular belief, radiocarbon dating cannot be used on anything over 50,000 years old. So, it would be good for dating a Neolithic basket, the bones of a human from the Iron Age, or a copy of the Dead Sea Scrolls, but it’s useless for a dinosaur bone. By it’s very nature, radiocarbon dating can also only test objects with carbon in them, like, say, wood, a wool cloak, or bones.
If you want to test a dinosaur bone or an insect who was possibly alive during the Jurassic, you’ll need to choose a different form of Radiometric dating. The most popular form of Radiometric dating for something that’s possibly millions of years old is Uranium-Lead dating, which was a maximum range of 4.5 billion years. Uranium-Lead dating, however, usually involves not testing dinosaur bones directly, but the rock they were found in, because bones generally contain insufficient amounts of uranium for testing.
Insect lands on a tree with sap seeping out. Sap is really sticky, and occasionally the insect becomes stuck there and dies. Sap encases the insect and eventually solidifies into amber with insect trapped inside.
Radiometric dating is the process where scientists observe isotopes of a particular atom in a substance. If scientists know what the original distribution of the isotope is compared to when the substance first formed and if they know the half-life of the atom, they can mathematically calculate how old the thing is. Carbon dating is a form of this using a carbon isotope that builds up to a certain level when an organic thing is alive but then decays once that thing dies. By measuring the ratio of carbon isotopes, scientists can calculate about when the thing died. Carbon dating is reliable up to around 50,000 years. For older things, other types of radiometric dating are more often used.
Other types of dating often involve examining the geology around a sample. If a sample is found at a particular layer in the crust, its age is likely to be the same as other things found in the same layer. So if a particular sample is difficult to test for whatever reason, using geology can help place it with other samples that are more reliably testable.
Amber is petrified tree sap. So a bug gets stuck in sap, eventually enveloped in it as more sap runs down the tree and over millions of years it hardens into amber
They land on a tree, it is sticky with sap, they get stuck, more sap comes out of the tree from the same spot and eventually buries them. It is probably a slow and uncomfortable death, given the speed of sap.
Carbon slowly degrades over time. We know how fast it degrades. So, carbon dating involves looking at how degraded the carbon is in order to see how old it is. This isn’t the case for pure carbon, But there are certain types of molecule that do degrade at a set speed. A half life is the amount of time it takes for 50% of something to degrade or change.
> what is carbon dating
Carbon dating rests on Carbon’s existence in (at least) two forms — a radioactive one (C14) and a stable one (C12). C14 experiences radioactive decay, resulting in losing its 2 extra neutrons and becoming C12 over 5730 years. The initial ratio of the two isotopes is known and it is also known that over 5730 years (+/- 50) that half of the C14 will lose its extra neutrons and become chemically indistinguishable from C12.
Carbon dating is only accurate for up to 60,000 years though. For longer periods, there are other radioactive isotopes for other elements that are used. For example, half the concentration of Uranium 238 will decay into Plutonium in 4.3 billion years.
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