Hi Damian79. Welcome to PF!
Before we begin this discussion (which appears to have already started while I was typing this), I'd like to make it clear that ALL discussion should take place in the context of known science. This means that if someone tells you that X is true or Y is the way that something works, we are talking about those things as currently understood by the mainstream scientific community. There is no discussion of "absolute truth" here. I say this because I want to avoid many of the issues that often plague these conversations where criticism is given of the scientific view for not "truly" knowing what happened in the past or at large distances. We fully know and admit that we can't know any absolute truth and any statements or facts given here should always be understood as being part of a theory or model that is always being tested and verified to the best of our abilities. And rather than being a weakness of science, it's actually a strength in that it allows us to constantly ensure that our body of knowledge is as accurate as possible
Damian79 said:
So how do we know when the Earth was formed by the particles of the big bang that the particles from the big bang haven't aged on the way to the creation of the Earth assuming the particles from the big bang are "day zero" particles?
For starters, this is not how cosmologists and other scientists model and understand the formation of the Earth or anything within the universe. It would be beyond the scope of this post and probably this thread to give you the entire history of the universe as given in the standard model of cosmology (you can find a decent explanation on wikipedia), but we can talk about a few key points. Note that this is a very brief and general overview and is not intended to be an extremely accurate description.
1. The big bang and subsequent evolution of the universe resulted in the formation of mostly hydrogen and helium, with a tiny smattering of lithium and a few other light elements (we're going to mostly ignore dark matter here, as it's not well understood yet and doesn't do much except provide extra gravity help form galaxies and galaxy clusters).
2. These atoms eventually coalesced under gravity to form the galaxies and then the first stars.
3. The fusion of light elements inside these stars created heavier elements like carbon, oxygen, nitrogen, etc. These first stars were very, very massive and eventually underwent supernova, spreading their heavier elements out into the universe to mix with the hydrogen and helium gas still out there. Galaxy and star formation continued, pumping out larger quantities of heavier elements over time.
4. During subsequent star formation, the heavier elements formed what we call "dust". Now, dust is a very different thing that hydrogen and helium gas and has a profound impact on the events of star formation. With only hydrogen and helium (and perhaps trace quantities of lithium), the collapsing gas cloud tends to just get blown away once the proto-star becomes hot enough to emit lots of radiation and solar wind. There is no formation of rocky planets at this time because there are no heavier elements. However, once you add carbon, oxygen, nitrogen, iron, and the dozens of other heavier elements (including uranium) to the collapsing cloud of dust and gas, things change.
Heavy elements are much denser than either hydrogen or helium and when the collapsing cloud of dust and gas forms a large, rotating disk surrounding the proto-star they tend to "stick together" to form molecules, dust grains, and small rocks that aren't simply blown away when the proto-star heats up. Over time, these rocks collide and merge with other rocks to form larger bodies, which then collide with more material, building up what are called "planetesimals". Further merging of these planetesimals results in the formation of proto-planets which eventually become full-fledged planets as they finally merge with the remaining material.
5. Now, this is where a crucial part of dating the ages of rocks comes into play. At first, the proto-planets and newborn planets are very, very hot. So hot that they are essentially completely molten. Over time they cool down and the different elements are able to form solid rock. The particular composition of this rock is extremely important. We know that certain elements only bond in certain ways with other elements. For example, a particular type of rock is formed by silicon, oxygen, and zirconium and is known as Zircon. Zircon has the property that it readily incorporates uranium into itself, but it strongly rejects lead during its formation. So as the Earth cooled, zircon formed wherever there was sufficient quantities of oxygen, silicon, zirconium, and uranium.
However, uranium is radioactive and has a half-life of about 4-billion years (experiments have verified this to a very high precision). Over time, part of the uranium that was taken up into zircon decays into various other elements, which themselves also decay into lighter elements. This chain of decay eventually stops at lead. As I said above, lead is strongly rejected by zircon when zircon is initially forming. So we can say with good confidence that any lead present inside zircon is the result of the decay of uranium. By looking at the ratio of lead to uranium, and knowing the decay rate of uranium and its decay products, we can reliably date the age of a sample of rock. Obviously things are more complicated than I've described them, but that's the general idea behind radiometric dating.
Now, the reason I explained all of this was to give a very basic overview of how we date
rocks and to show that much of the atoms making up the Earth were
not formed directly via the big bang, but inside of massive stars and supernovae. When it comes to dating the age of the universe things get a bit more complicated and we have to use multiple methods that are very difficult to explain if you know very little about astrophysics. For example, I could tell you that we can date the age of a star cluster by looking at the type of stars remaining in the cluster (the ones that haven't undergone supernova yet), but you'd need to know about the details of how stars work to understand why that particular type of dating method works. And things only get more complicated from there.
Damian79 said:
Could being in the proximity of antimatter age or reverse age matter? So many questions regarding this but I'll stat here.
No. Antimatter is understood pretty well. It does not have any "mystical" properties that normal matter lacks. Antimatter works just like matter in all respects except that the sign of certain properties change (charge goes from positive to negative or vice versa as an example).
