Earth is Younger Than First Thought

antijoke

antijoke

antijoke

Caporegime
Joined
28 Jan 2003
Posts
39,981
Location
England
A new geological study has set a more accurate age for planet Earth, according to scientists.

Researchers say their investigation shows the Earth is 70 million years younger than the 4.537 billion-year-old planet "we had previously imagined".

To confirm Earth's age, the team compared elements in its mantle to those in meteorites that are the same age as the Solar System.

The group reports its findings in the journal Nature Geosciences.

The crux of its conclusion was that the formation of the planet took much longer than previously thought.

The scientists studied this timescale by looking at how long Earth took to "accrete", or grow, as smaller "planetary embryos" smashed together to form it.

"The collisions caused part of the planet to melt, and allow metal to segregate to the centre of the Earth to form the core," explained Dr John Rudge, from Cambridge University, UK, who led the research.

"So [during this process], the planet differentiated into its molten metal core and outer-lying mantle."

The longer this process took, the later the Earth was "born" in its current size and geological form.
Planetary clock

To shed light on this, the scientists looked at two "isotopes" - chemical elements in the Earth's mantle called 182-hafnium and 182-tungsten. Over a set period of several million years, hafnium decays to become tungsten. And tungsten "loves" metal, so while the planet's core was still forming, it became incorporated into that.

This left a "signature" in the mantle that revealed how long the Earth took to differentiate.

By comparing the amount of 182-tungsten in the mantle to the amount found in meteorites, the researchers could work out how long it took for Earth to fully differentiate into mantle and core.

The team compared the results from this technique with a similar method using two different isotopes. And instead of assuming that one method was more accurate than the other, and that the Earth formed at a steady rate, they modelled all of the different ways that the process could have happened.

Dr Rudge explained that, for these two methods to agree, the formation of the Earth would have had to have been a "rapid early on, then there was some hiatus and more gradual accretion".

This meant, he said, that instead of Earth forming over 30 million years, it took closer to 100 million years.

He explained that the end of the "hiatus" could have been the giant impact that is believed to have formed the Moon.

"If correct, that would mean the Earth was about 100 million years in the making altogether," Dr. Rudge said. "We estimate that makes it about 4.467 billion years old - a mere youngster compared with the 4.537 billion-year-old planet we had previously imagined."
Click to expand...

Bloomin' 'eck! 4.467 billion years old.
 
Well when you think the Earth has been going for 4.467 billion years, and what has come and gone in the last few million years, you could start to wonder what has gone before!

Also how long has man been around? A mere blink of an eye compared to 4.467 billion years. Just shows how insignificant we are.
 
"To confirm Earth's age, the team compared elements in its mantle to those in meteorites that are the same age as the Solar System."

How did they know they were the same age as the solar system?

There must be so much guess work that goes into this lol.
 
Nick1881 said:
"To confirm Earth's age, the team compared elements in its mantle to those in meteorites that are the same age as the Solar System."

How did they know they were the same age as the solar system?

There must be so much guess work that goes into this lol.
Click to expand...

I imagine they look at various isotopes of various elements and compounds, how quick their half lives are and things like that.
 
Thought this was appropriate. Read Bryson's book if you get a chance.

"If you imagine the 4,500-bilion-odd years of Earth's history compressed into a normal earthly day, then life begins very early, about 4 A.M., with the rise of the first simple, single-celled organisms, but then advances no further for the next sixteen hours. Not until almost 8:30 in the evening, with the day five-sixths over, has Earth anything to show the universe but a restless skin of microbes. Then, finally, the first sea plants appear, followed twenty minutes later by the first jellyfish and the enigmatic Ediacaran fauna first seen by Reginald Sprigg in Australia. At 9:04 P.M. trilobites swim onto the scene, followed more or less immediately by the shapely creatures of the Burgess Shale. Just before 10 P.M. plants begin to pop up on the land. Soon after, with less than two hours left in the day, the first land creatures follow.

Thanks to ten minutes or so of balmy weather, by 10:24 the Earth is covered in the great carboniferous forests whose residues give us all our coal, and the first winged insects are evident. Dinosaurs plod onto the scene just before 11 P.M. and hold sway for about three-quarters of an hour. At twenty-one minutes to midnight they vanish and the age of mammals begins. Humans emerge one minute and seventeen seconds before midnight. The whole of our recorded history, on this scale, would be no more than a few seconds, a single human lifetime barely an instant. Throughout this greatly speeded-up day continents slide about and bang together at a clip that seems positively reckless. Mountains rise and melt away, ocean basins come and go, ice sheets advance and withdraw. And throughout the whole, about three times every minute, somewhere on the planet there is a flash-bulb pop of light marking the impact of a Manson-sized meteor or one even larger. It's a wonder that anything at all can survive in such a pummeled and unsettled environment. In fact, not many things do for long."
— Bill Bryson (A Short History of Nearly Everything)
 
You must log in or register to reply here.
Back
Top Bottom