How do scientists know for certain, how old the Earth is?

Question

How can they be certain that their measuring devices are acurate? I've read some articles that say that man walked the Earth at the same time as dinosaurs, and that some civilizations are older than they had previosly been dated.

Answer 1

We must first understand something about atoms.

Every atom has a small nucleus surrounded by a cloud of particles called electrons (with a negative electrical charge). In the nucleus there are protons (with a positive charge) and neutrons (with no electrical charge).

Some atoms are unstable and decay by emitting a certain kind of particle. As they decay, they change from being an atom of one element into an atom either of another element or of the same element with a lighter nucleus. An element that exists in more than one form is called an isotope, and an unstable isotope is called a radioisotope.

The time taken for one half the atoms of a radioactive substance to decay into its daughter element is called its half-life. In simple terms, radioisotope dating works by measuring the ratio of parent to daughter in a rock and calculating how long it took for the one to decay into the other. It can be applied only to rocks that formed directly out of magma (igneous rocks). The age of sedimentary rocks is worked out indirectly by dating the igneous rocks associated with them.

There are 3 main types of rocks:
Igneous – formed from molten magma which crystallises within the earth or is erupted onto the earth’s surface

Sedimentary – composed of material like sand and mud which has come from the wearing down of older rocks.

Metamorphic – igneous or sedimentary rocks which have been transformed by high pressures, high temperatures, or both.

Crystalline rocks usually give very old radioisotope dates, within a broadly consistent sequence from older to younger. There is also other evidence that a substantial amount of radioactive decay has gone on in the past:

The right amount of decay products – just what we would expect from millions of years of decay at today’s rates.
Short-lived radioisotopes are absent – suggesting that long ages have passed to allow them to all decay away.
Visible scars (radiohalos) left by decay – direct evidence for hundreds of millions of years’ worth of decay at today’s rates.
Crystal damage (fission tracks) left by splitting atoms – indicating millions of years of decay at today’s rates.
The expected heat in rocks near the Earth’s surface – left by millions of years of decay at today’s rates.

Evidence such as this proves that the Earth is billions of years old.

Answer 2

Hi Bunny! We use isotopes to date rocks.

Carbon dating is used primarily for Anthropological and Archaeological studies because carbon's half-life (5,730 years) is much, much too short for dating across the geologic time scale (say, 145 million years to the Jurassic period).

We use other isotope pairs like uranium and thorium (238U/230Th, half-life=4.47 billion years), and potassium and argon(40K/40Ar, half-life=1.25 billion years) to date rocks (nothing existed in the surface back then other than rocks and lava). The elements are often found trapped within crystals; uranium, for example, can be trapped in a zircon as the rock cools from magma.

How old is the Earth?
The Earth was formed at around the same time with the other members of the Solar System, planets and meteorites including. These meteorites are what we like to call "pristine Solar System stuff" because they're pretty much made of the same material as when they were formed.

Dating these meteorites that have fallen and were preserved here on Earth gives us a good idea how old the Solar System, and therefore the Earth, is.


As for your question about men and dinosaurs: Yes, man and dinosaur have walked and are still walking this planet together... because birds are descendants of dinosaurs. XP

Kidding aside, the first primate appeared some 60 million years ago, well after the Age of the Dinosaurs or the Mesozoic Era (65-250 million years ago). Paleontologists have yet to find a primate fossil from that time.

Answer 3

It depends on what you mean "know for certain".
Nothing in science is exact. Today there are many pieces of evidence that are consistent with an earth that is a few Billion years old. Radioactive decay provides one scale that is used. Layers of material like the rings in the wood of a tree are also a scale that is used. The existence of fosils in the ground of animals and plants that currently do not exist is another scale. All these scales and others besides are used to measure the age of the Earth. Different scales do a good job of measuring different ages. A ruler might be a good thing to measure the distance between two points on a piece of paper but would be very inaccurate at measuring the distance from the grocery store to home. In a similar manner the various scales result in different estimates of how old the Earth is. Most seem to say that Earth is a few Billion years old.

200 years ago people knew that Newton's description of time space and gravity were correct. After all, all the evidence they had was consistent with the predictions made by his way of describing the workings of the universe. Then in the mid to late 1800's there were some experiments performed that had results that were not consistent with Newton's equations. In the early 1900's Einstein discovered a different way of describing time, space and gravity that was not only consistent with the earlier results but also predicted the results that were inconsistent with Newtonian physics. I would not be surprised if people in the future didn't look back on Einsteinian physics as an approximation of the truth but that they knew something we currently don't that shows that some aspect of the way the Universe works is inconsistent with Einsteinian Physics. I would be very surprised if the difference affected anything we are able to measure today.

Answer 4

Science is not certain of anything, that's why it works so well. What they do is gather all the information they can, then find the explanation that fits it best. If new information comes in, they modify the theories to take it into account if they need to.

With that in mind, the estimates for the age of the Earth fits a wide variety of the information we have and hasn't had to be changed greatly for some time to fit the new information coming in faster than ever.

Be careful where you get your information. The information you have seen about men walking the Earth with dinosaurs comes from people who have no conflict with repeating known lies to get you to believe them. Usually a little research into their claims shows their evidence is interpreted completely wrong, missing, or even completely faked. But that won't keep them from making the same claims well after it is pointed out to them that they are spreading stories which are untrue.

Answer 5

They use carbon-dating. They use the half-life of the object and determine how much it has broken down. They know that it is accurate by testing it on objects that they know are a certain age.

As for them discovering that civilizations are older than previsouly thought...they have found objects that can be dated back farther than any other objects previously found.

Personally I think that carbon dating is pretty accurate, they don't claim that it is exact, but nothing is. When they are dating back 100,000 years then give or take 1000 years is pretty good in my opinion. (The variation there is just an example, don't know how much variation there is.)

Answer 6

They use radioactive dating using elements that have half lives in the billion year range. Carbon dating is useless. No, men and dinosaurs were not around at the same time except in the movies.

Answer 7

They are estimating with the best tools they have available. Carbon dating is not proven past a certain time period (50,000 years ?). Drilling cores into the Arctic ice they can count seasons like the rings of a tree, but they can only drill so far. Levels of sedimentary rock is the same. The rest is science they can't prove beyond doubt, but on current knowledge it seems right.

Answer 8

So, what about radiometric dating methods; don’t they prove millions of years? Well, these are far from infallible—they are indirect methods based on quite a few assumptions, and evolutionary geologists themselves will often not accept a radiometric date unless they think it’s correct (i.e. it matches what they already believe). There are plenty of scientists who question their accuracy. For instance, the “RATE” project has discovered several striking examples of contradictions in these dating methods. If you want, you can get their book or movie called "Thousands...Not Billions" and learn about some of their remarkable results. If you do a bit of research, you will find that there is a lot of proof of radiometric dating not being accurate.

Since you mentioned dinosaurs, let me give you some evidence:

In 1981, scientists identified unfossilized dinosaur bones which had been found in Alaska 20 years earlier. Philip J. Currie (an evolutionist) wrote about this and some similar finds, “An even more spectacular example was found on the North Shore of Alaska, where many thousands of bones lack any significant degree of permineralization. The bones look and feel like old cow bones, and the discoverers of the site did not report it for twenty years because they assumed they were bison, not dinosaur, bones.” As Dr. Margaret Helder has said, “How these bones could have remained in fresh condition for 70 million years is a perplexing question. One thing is certain: they were not preserved by cold. Everyone recognizes that the climate in these regions was much warmer during the time when the dinosaurs lived.”

In 1990 a sample of various dinosaur bones were sent to the University of Arizona for a “blind” Carbon-14 dating procedure. “Blind” in the sense that they didn’t tell them what the bones were. The oldest date they got was 16 thousand years. That’s a far cry from the millions of years evolutionists suggest. If dinosaurs became extinct more than 65 million years ago, there should be no carbon-14 left in their bones. Evolutionist of course say the samples must have been contaminated.

In 1990, Scientists from the University of Montana found T. rex bones that were not totally fossilized and even found what appeared to be blood cells in them. Dr. Mary Schweitzer said, “It was exactly like looking at a slice of modern bone. But, of course, I couldn’t believe it. … The bones, after all, are 65 million years old. How could blood cells survive that long?” How indeed?

And then in 2005, they found an even greater discovery. Science Daily website said (March 25, 2005): “Dr. Mary Schweitzer . . . has succeeded in isolating soft tissue from the femur of a 68-million-year-old dinosaur. Not only is the tissue largely intact, it’s still transparent and pliable, and microscopic interior structures resembling blood vessels and even cells are still present.” As Dr. David Menton said, “It certainly taxes one’s imagination to believe that soft tissue and cells could remain so relatively fresh in appearance for the tens of millions of years of supposed evolutionary history.” Wouldn’t that be a hit for the meat industry if we could figure out how to preserve meat for so long?

An article in the January 1993 National Geographic boldly proclaimed: “No human being has ever seen a live dinosaur.” Now, does he know that, or does he think that? There is no way for anyone to know that unless they had at least talked to everyone who has ever lived.

If dinosaurs did live with man, you would expect to find legends of dinosaurs in history. Why don’t we read stories about men fighting dinosaurs or dinosaurs eating people’s cows and stuff like that? Well, most people are unaware that the word “dinosaur” was not coined until the 1840s by Sir. Richard Owen (who was a Creationist by the way). So, if these creatures lived alongside humans prior to that time, they were not called dinosaurs. So what were they called? Dragons. Most cultures throughout the world possess ancient stories about dragons and sea monsters that closely resemble what we today would call dinosaurs. Dragon stories have been handed down for generations in most civilizations.

No doubt many of these stories have been exaggerated through the years, but that doesn’t mean they didn’t have their original basis in fact. I believe many of the dragon legends are simply distorted versions of dinosaur encounters. As Paul Taylor has said, “Most of the dragon legends are full of exaggeration, magic and marvelous deeds. But this is not true of all of them. Many stories seem rather believable.”

It is true that many of them are mythical or legendary but it is also true that most legends are based on some truth. It cannot be an accident that so many separate peoples of the world tell such stories. The same can be deduced from the 250+ different flood stories from around the world. Flood legends in many cultures that have never even heard of the Bible, and yet many of them are very similar to the account in Genesis. Why? Because everyone is descended from Noah. Some of the details have been distorted from thousands of years of telling and retelling, but it is based in fact. I believe the same is true of the dragon legends.

World Book Encyclopedia says: “The dragons of legend are strangely like actual creatures that have lived in the past. They are much like the great reptiles [dinosaurs] which inhabited the earth long before man was supposed to have appeared on earth.” Evolutionists just say that it’s coincidence that many of the dragon legends sound like dinosaurs.

Answer 9

carbondating , i dont kno how it works .... something about how the deteriantion of differnt rocks and fossils

Answer 10

They don't.