How old is the Earth?

The earth is approximately 4.6 Gy (billion years old). How do we know this we date rocks. We believe that the surface of the earth was molten through the first few million years, so we date radioactive elements in asteroids which we believe formed at the same time. If you are looking for the oldest things on the earth the oldest zircon (type of crystal) is 4.4 Gy and would have had to form on a continent. The oldest rock is the Acastce Gniess in Canada which is 3.96 Gy. There is also 3.8 Gy old rocks in Montana, the Midwest US, and Greenland. Lastly the oldest fossils (stromatolites) are between 3.3 and 3.5 Gy. But the oldest chemical signature of life is 3.85 Gy. As you can see there is a lot of evidences. The earth is really, really old.

4.5 billion yrs old that's science based. bible....they try to squeeze it in and make it fit their story.. but we have civilizations nearly 6 k yrs old.. don't believe them for a second. we know this from various dating techniques using radioactive half lifes comparison of differing geologic events seeing how long things take to weather and then caculating inferences based on that reletive and absolute dating 4.5 billion yrs old 6 thousand yrs is nothing.. most rocks take 50 thousand yrs to erode and turn into soils and such......how come we have saprolite... type of clay resembling its parent rock.. if we were only here for 6 k yrs geologically speaking 6 thousand yrs isn't even a drop in the bucket.. how do you expain continental drift.. at a know rate.. and account for how far the continents have drifted... how do you account for orgeny ... mountain building or eperigeny.. continental plate building ice ages that have come and gone.. are cyclical about every 15 thousand yrs.. how does a 6 thousand yr old earth fit that model the bible time line goes against everything we have facts for... 4.5 billion is more reasonalbe hasn't been proven wrong yet

The Earth being 6,000 years old is an estimation based on the part in the Old Testament where it has a geneaology forward from Adam: "Adam was the father of so-and-so who was the father of so-and-so, who was the father of so-and-so...." Supposedly this can be traced in that chapter and throughout the rest of the Bible all the way to Jesus and then to us, giving a total of 6,000 years. It is a very literal, fundamental belief that assumes the Earth really was created only a few days before man. There are some things cited as scientific evidence for the 6,000 years, such as a smaller than expected amount of dust on the moon... but it is debatable if these things are "good science." The age of the Earth being around 4.6 billion years comes from radioactive isotope dating. Some people say that this type of dating is also debatable as to it's reliability... I am inclined to agree when it comes to Carbon-14 but that is not what is used to date the Earth. The isotopes used are, in my opinion, "good science" and we can firmly say that the Earth has been here for 4.6 billion years. I have also heard an argument for the 6,000 years saying that God must have created the Earth in a mature state, so it only appears like it's been here for 4.6 billion years when really it hasn't. To me that is grasping at straws to make science fit your beliefs which I don't agree with. If you go into something with an agenda, such as proving that the Bible is true (or not true), I don't think that's good science. In the end, we can't know for sure how old the Earth is (or anything else about the past) without a time machine. Each of us has to decide what we feel is most reliable/true to base our beliefs on.

That's a very complex (and highly debated) question, so I'm going to need to give you a long answer. Currently, the Earth is believed to be have been formed 4.6 billion years ago. This has been determined based on a number of scientific tests, including stratigraphy, index fossils, and radiometric dating. The Earth was initially molten. As the Earth cooled, the crust was formed 4.2-4.1 bya--which has been determined by carbon dating. Meteors and comets would continue to bombarded the Earth from 4.5 to 3.8 bya--also determined by carbon dating. As long as the Earth remained hot, all volatile compounds, such as water vapours, remained in the atmosphere. Once the Earth cooled to less than 100°C, the water in the atmosphere condensed and formed the oceans, and it has been determined that the Earth had liquid water on its surface by 3.8 bya, as has been shown from fossil evidence and sedimentary rocks. In fact, the first fossils of organic matter were found in quartz crystals and date to 3.85 b.y.a, and the first fully-formed bacteria-like fossils date to 3.7 b.y.a. Now, some of the dating methods. Fossils are found at different stratigraphic layers. Charles Lyell came up with the principle of uniformitarianism, which states that rocks on top are younger than rocks on the bottom, and thus the different fossil layers correspond to different periods in the fossil record. In short, we know the age of a fossil by the kind of rock that they come from and the depth at which they are found. Index fossils are the idea that there are some fossils that are extremely abundant. Thus, we can build an overlapping chronological sequence longer than is represented in any single site by matching rocks from different exposed localities. This basically means that, if you go to locality A, and you find a great abundance of fossilized organism 1 at a certain level in the rock, organism 1 now becomes an index for the next site, so that when you visit locality B and you find another abundance of organism 1, you know that this level of rock, even though it is a different level than at locality A corresponds to the same time period. The last two methods are based only on relative time (ie: how old is an animal relative to another; which is older). To get absolute time (ie: how old things actually are), radiometric dating is used. Radiometric dating is a technique that uses the natural transformation over time of an unstable elemental isotope to a more stable form or product. The amount of time this process requires is known as a half-life, and by measure the amount of unstable and stable isotopes in the rock and comparing it to that element's half-life, we can determine how long it has been around.

the earth is 4.6 billion years old the nly way to really find out is with new technology you can look at rocks and see there age and the oldest rock is 3billion yeRS OLD AND WIth calculations on how long it took for that rock to be made we come to a conclusion that earth is between 3.5 and 5 billion years old

Those that use the Bible to answer this type of question are completely missing the point of the creation stories (there are two in Genesis). I think they're missing the point on purpose. They think it's a science report, rather than a statement of who we are or are capable of becoming. Personally, I think they prefer a God they can control. I've met many people who are serious about developing their faith, who don't take these creationists seriously at all. The earth is considered to be slightly older than the moon, and prevailing theory is that the moon broke off from the earth after collision with a Mars-sized object. The other answers here are consistent with what I've learned - about 4.5 billion years. The moon landings, BTW, did a nice job of finding some ancient rocks for dating.

What a hot topic! Holy cow! But, anyway, no offence to anyone, just to put this out there, how much, really, does it matter? The only things humans can now control is the future, and yet people in general get so worked up over these little nick-picky things that they miss the whole point -- people came to be. And here we are, arguing over the internet about how old the earth is. I face this sort of thing everyday, and it drives me nuts! Believe what you will believe, and don't try to shove it down other people's throats for one minute and think. What are you accomplishing?

I would advise you to research 2 different things, Religion, and the big boom/stephen hawking. then you decide (i personally would go with science because it's more logical, but whatever floats your ark)

Pretty, pretty, pretty, pretty old. About 4-5 billion years old. I don't really know.