how old is the earth?

Answer 1

Around 4 billion years old.

Answer 2

old.

Geologists now think the Earth is about four and a half billion years old.

This is known from radiometric dating of rocks. In radiometric dating, scientists measure the amounts of different isotopes of certain elements in a rock sample. Since radioactive isotopes are known to decay at a certain constant rate, the amounts remaining in the rock will tell how old it is. For igneous rocks this is the time when it solidified from molten magma.

The oldest rocks ever found on Earth are actually slightly younger than this, about 3.8 billion years old. Most rock found on the Earth's surface is much younger because Earth's crust is "recycled" by plate tectonics. The radioactive "clock" in the rock is reset when it is melted or heated to high temperature.

So if the oldest rocks ever found on Earth are 3.8 billion years old, how do we know that the Earth is older than that?

Because we have some rocks that are not from the Earth!

Moon rocks and meteorites are older than any Earth rocks we know of. The Moon rocks collected on the Apollo missions and most meteorites that have hit the Earth are about 4.5 billion years old. The Moon doesn't have plate tectonics, so its crust is not recycled. The rock now on the Moon's surface was formed when the Moon was formed. Meteorites also would have been made when the solar system was formed, and of course the Earth would have been made at the same time as the rest of the solar system.

By the way, the search for the world's oldest rock still continues. Every decade or two someone finds a rock that is a little older and sets a new record. I think the current record is a rock from Canada found by Sam Bowring. Who knows? Maybe someday you could find a little remnant chunk of the Earth's original crust hidden away in some remote wilderness! Good luck hunting!

Answer 3

Modern geologists, based on extensive and detailed scientific evidence, consider the age of the Earth to be around 4.567 billion years (4.567×109 years). This age represents a compromise between the oldest-known terrestrial minerals – small crystals of zircon from the Jack Hills of Western Australia – and astronomers' and planetologists' determinations of the age of the solar system based in part on radiometric age dating of meteorite material and lunar samples.

The radiometric age dating evidence from the zircons further confirms that the Earth is at least 4.404 billion years old. Comparing the mass and luminosity of the Sun to the multitudes of other stars, it appears that the solar system cannot be much older than those rocks. Ca-Al-rich inclusions (inclusions rich in calcium and aluminium) – the oldest known solid constituents within meteorites which are formed within the solar system – are 4.567 billion years old, giving an age for the solar system and an upper limit for the age of the Earth. It is assumed that the accretion of the Earth began soon after the formation of the Ca-Al-rich inclusions and the meteorites. Since the accretion time of the Earth is not exactly known yet, and the predictions from different accretion models vary between several millions up to about 100 million years, the exact age of the Earth is difficult to define.

In the centuries preceding the scientific revolution, the age of the Earth was determined from the accounts of creation by religious authority. Today some religious groups continue to accept only theological accounts regarding the age of the earth, rejecting scientific evidence which contradicts their beliefs.

Answer 4

Earth's age is based on several things:

1) dating meteorites. When we find a meteorite from this solar system that has a similar composition to earth, you get many young ages, but the oldest and most common date to 4.6 Ga (billion years).

2) isotope trends. When you look at certain radiogenic isotope ratios that change with time, like Rb/Sr or U/Pb, you find that many rocks with differnt ratios of many ages form a line, and the line traces back to an origin of 4.6 Ga as well.

The oldest life is 3 1/2 Ga, the oldest rock is about 4 Ga, and the oldest date ever found is on the highly durable mineral Zircon from Australia, it's date is 4.2 Ga. So, there is no direct method, it is based on inferences. However, many different inferences lead to the same number 4.559 Ga (to be specific).

You would have to throw out everything we know and love about Geology to accept a young earth view. When you look at the Grand Canyon, how can you say that only took 6000 years to form?

Answer 5

Thousands of years old.
Contrary to what the contributors above are regurgitating, most evidence indicates a young earth (not billions of years).
For example:
Measurement of salt (and many other minerals)in the sea. We can measure/estimate the salt going in and salt going out. At current rates the oceans are just thousands of years old.
Decay of earth's magnetic field - backwards extrapolation indicates youth.
Distribution of helium - wouldn't still be in rocks if they were v old.
Existence of comets - they don't last long so solar system must be young (Oort cloud invented as 'explanation')
See link below for many others.

The principle 'proof' of great age is radiometric dating. This is seriously flawed - see link below for tech details, but how can anyone take it seriously when it ages volcanic rock known to be hundreds of years old - as millions of years old!

Another 'proof' of great age is the sedimentary rock which was allegedly laid down slowly over millions of years. However there is much evidence to indicate it was laid down catastrophically. Howhere do we observe the formation of vast areas of sedimentary rock. The presence of fossils, for example, indicates very rapid burial. Even a whale is eaten in days when it dies, and there are even fossils of fish giving birth.

For an accurate account of early earth history read Genesis 1-10.

But check the evidence for *yourself*.

PS to QFL 24/7 - The Grand Canyon can be readily explained by a creationist approach.
http://www.answersingenesis.org/creation/v18/i2/grand_canyon.asp
Rather than 'a little water and a lot of time' think 'a lot of water and a little time'

Answer 6

well older then u
probably 4 billion years what i remember so far but i wouldn't call u stupid if u would check out it's answer in an informative site as that information is much more authentic then what u get in here

Answer 7

Around 4.5 billion years.

I saw this question and I thought "Some half -wit is bound to say look in the bible.... 6000 years old" I was wrong. (up to now )

Answer 8

About 10 years younger than Esther Rantzen.

Answer 9

4570 million years

Answer 10

4.5 Billion years