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The history of Earth covers approximately 4 billion years (4,567,000,000 years), from Earth’s formation out of the solar nebula to the present.
Earth formed as part of the birth of the solar system: what eventually became the solar system initially existed as a large, rotating cloud of dust, rocks, and gas.

2007-02-16 16:28:10 · answer #1 · answered by neumor 2 · 0 1

There are several lines of evidence we can use to demonstrate, easily, that the world must be far older than 12,000 years. The simplest is our own species - there's two much genetic variation in the human population for it to be anything younger than several million years old.

But the dating of the age of the Earth is usually done through radiometric methods - not the familiar "carbon dating", which is only useful for living things and is only applicable for things less than 100,000 or so years old. The age of the Earth is calculated using isotope ratios; the most precise dating to date was performed with uranium-lead dating, in zircon crystals (formed of ZrSiO4). Zircon crystals can accommodate uranium in their crystal structure, but are unable to accommodate lead. However, uranium that decays to lead in the already-formed crystal will remain in place. So: we know that when the crystal formed, it must contain only uranium, which over time slowly decays to lead at a known rate (the radioactive "half-life"). By measuring precisely the current fraction of lead, we can determine how long the uranium in the crystal has been decaying, and thus date the age of the crystal. Samples on Earth have been dated to 4.55 billion years.

It's a bit difficult to say *exactly* when the Earth formed, of course - the current theory of planetary formation (developed from observation of star formation) says that planets form through a slow accretion process, gradually accumulating material from nebulae, etc., until they condense into planetary bodies. This process probably takes millions of years, so it's hard to give the Earth a precise "birth date". We can date it on the scale of billions, to ~4.6 billion years.

2007-02-16 02:02:09 · answer #2 · answered by astazangasta 5 · 2 0

The Earth was formed around 4.57 billion years ago and its natural satellite, the Moon, was orbiting it shortly thereafter, around 4.53 billion years ago.
Based on the available evidence, current scientists have been able to reconstruct detailed information about the planet's past. Earth formed 4.567 billion years ago out of the solar nebula, along with the Sun and the other planets. Initially molten, the outer layer of the planet cooled when water began accumulating in the atmosphere when the planet was about half its current radius, resulting in the solid crust. The moon formed soon afterwards, possibly as the result of the impact with a Mars-sized object known as Theia. Outgassing and volcanic activity produced the primordial atmosphere; condensing water vapor, augmented by ice delivered by comets, produced the oceans. The highly energetic chemistry is believed to have produced a self-replicating molecule around 4 billion years ago, and half a billion years later, the last common ancestor of all life lived.

The development of photosynthesis allowed the sun's energy to be harvested directly; the resultant oxygen accumulated in the atmosphere and gave rise to the ozone layer. The incorporation of smaller cells within larger ones resulted in the development of complex cells called eukaryotes. Cells within colonies became increasingly specialized, resulting in true multicellular organisms. Aided by the absorption of harmful ultraviolet radiation by the ozone layer, life colonized the surface of Earth.

Over hundreds of millions of years, continents formed and broke up as the surface of Earth continually reshaped itself. The continents have migrated across the surface of the Earth, occasionally combining to form a supercontinent. Then they seperated to form seven continents. Hope you understood.

2007-02-16 01:55:06 · answer #3 · answered by ♥ ΛDIƬΥΛ ♥ ııllllııllıı 6 · 3 1

Earth is a water Producing Planet for the Need of Universe's functioning to wipe soil and Dust on Magnetic surface, so that Rotations go accurate with Magentic power unaffected.
Humans are created to see that Earth shud not Tilt or Break from abundace water while Rotating, with their Lifes connected.
This is called and termed as '' Intelligent Design ''.

2007-02-16 02:11:52 · answer #4 · answered by kumar 2 · 0 3

it seems that it was created 4,567 billion years ago . some others believe it was created 20,000 years ago.Different people have different things. But the yeat told by scientists is 4,567 billion years .

2007-02-19 12:05:07 · answer #5 · answered by vignesh v 1 · 0 0

the Earth was a piece of planet that broke off in a cosmic colission

a cosmic collision also knocked Mars out of orbit ,and the people that seeded the earth came from there

2007-02-16 01:50:02 · answer #6 · answered by Anonymous · 0 4

About 4.567 billion years ago

2007-02-16 01:42:36 · answer #7 · answered by Wei H 2 · 3 1

according to Christian scholors the earth was created 8 to 12 thousand years ago.

According to Evolutionary scientists, the earth is approxamately 3 billion years old. Strange, since merely 10 years ago they beleived 5million years less, and 100 years ago it was a mere 1billion years old.

2007-02-16 01:45:54 · answer #8 · answered by Your mom goes to college 3 · 1 5

4.5 billion years ago

2007-02-19 22:04:15 · answer #9 · answered by phyteacher 2 · 0 0

4.5 billion years ago

2007-02-17 12:23:35 · answer #10 · answered by kate 2 · 0 0

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