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Ancient crystals suggest Earth's core is 4 billion years younger than the planet

Ancient crystals suggest Earth...
A new study dates the Earth's inner core to just 565 million years old – much younger than the 4.5-billion year old planet
A new study dates the Earth's inner core to just 565 million years old – much younger than the 4.5-billion year old planet
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(Left) The Earth's core and magnetic field 565 million years ago, at its weakest point. (Right) The Earth's current core and magnetic field
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(Left) The Earth's core and magnetic field 565 million years ago, at its weakest point. (Right) The Earth's current core and magnetic field
A new study dates the Earth's inner core to just 565 million years old – much younger than the 4.5-billion year old planet
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A new study dates the Earth's inner core to just 565 million years old – much younger than the 4.5-billion year old planet

The Earth is almost 4.5 billion years old, but it's young at heart – literally. Researchers from the University of Rochester have now dated the solid inner core of the planet to just 565 million years, making it a relative toddler compared to the rest of Earth.

Since Earth started life as a growing clump of rock, it's easy to assume that the core is the oldest part of the planet, but that's not quite the case. Today, it's divided into two regions: a solid ball of iron in the inner core, which is surrounded by a swirling pool of liquid iron. When exactly that inner core solidified has long been up for debate, with conventional thinking placing it somewhere between half a billion and 2.5 billion years.

But now the Rochester researchers have narrowed it down to the lower end of that scale. The key to the discovery is the magnetic field that surrounds and protects Earth, and measuring how that's changed over time.

To do so, the team collected samples of ancient crystals from the Sept-Îles Complex in Quebec. Inside these crystals are tiny magnetic needles that preserve a record of the magnetic field at the time they were first locked away in the mineral. The researchers found that about 565 million years ago, the Earth's magnetic field was the weakest it's ever been – about a tenth of its current strength – and was on the verge of collapse.

Since life is still here today and we're able to go outside without being bombarded with deadly cosmic radiation, the magnetic field obviously bounced back from that low point. But how? The Rochester team says that a newly-formed solid inner core could be responsible.

The Earth's magnetic field is generated by the flowing fluid iron, in a process called a geodynamo. The team says Earth has probably had a weak geodynamo for billions of years, created by a core that was mostly molten iron. But this process slowed down over time, until that turning point 565 million years ago when it was stabilized, possibly by the arrival of the solid inner core we know today.

(Left) The Earth's core and magnetic field 565 million years ago, at its weakest point. (Right) The Earth's current core and magnetic field
(Left) The Earth's core and magnetic field 565 million years ago, at its weakest point. (Right) The Earth's current core and magnetic field

"This is a critical point in the evolution of the planet," says John Tarduno, corresponding author of the study. "The field did not collapse because the inner core started to grow and provided a new energy source for the formation of the geodynamo."

The team says the idea is backed up by other data sets and simulations, but at will need more work to confirm it. The study doesn't just help us understand our own planet a bit better – it could aid in the search for exoplanets that are capable of supporting life.

"The same factors that drive dynamos on Earth might affect the magnetic shielding on exoplanets," says Tarduno. "It could be the case that some planets don't have long-lived dynamos and those planets would not have the magnetic shielding we have, meaning that their atmosphere and water might be removed."

The research was published in the journal Nature Geosciences.

Source: University of Rochester

10 comments
Chris Coles
And let me guess, they have never read up on the concept that the crust of the planet has moved; regularly! if they had read the likes of Earth's Shifting Crust by Charles Hapgood, they would have had to consider that their crystals magnetic properties were in fact created when the crystals were not in line with the earth's magnetism; instead at the time being located where the magnetism is always less than where they are today located. Then add that their model of the properties of the core do not reflect new demonstrations of how the gravitational field of the planet cannot pass the central point of equilibrium of the forces; that the force of gravity is towards the surface at the centre of the core and represents the full force of gravity across the full outer surface of the planet. The core is solid because of the immense forces within its structure, emanating from the centre towards the surface.
Nik
This seems like rubbish! It is known that 600 million years ago, the Earth exited from the condition referred to as ''Snowball Earth'' and all present life evolved from bacteria and algae that existed at that point. If a massive chunk of iron had ''arrived'' its arrival would be visible in the geological record. It isn't! It would seem that the ''data sets and simulations,'' may need some adjusting, before it resembles reality.
Edward Vix
Nik,although not explicitly stated in the article, it would seem that the solid core didn't "arrive", but formed at the center of the liquid one responding to forces not identified.
Thinker
Does it not make sense that the core of the earth is cooing? If not, what’s keeping it hot? Since the core is cooling, it is reasonable that the earth is also shrinking. Thus we experience the movement of th tectonic plates, and the eruptions of volcanoes. It’s not as complicated as some would have you believe.
AbsolutJohn
Sooo... how did it get here just 500 million years ago without causing another planetary “reset” level event like what happened to Mars - or like when our moon was formed?! Just realizing the other comments here that are also casting doubt - but to summarize, this clearly needs further proof, there are too many unanswered questions, and this conflicts with current theories - like plate tectonics! Did the research prove what the earth’s magnetic field was like BEFORE it was weak? Was it stronger, then weak, then suddenly stronger?? OR - did it gradually gain momentum from slowly increasing iron deposits working their way down from the crust into the core - bit by bit - until what was once a somewhat homogeneous planet slowly segregated itself into the various layers that we now know exist today, with the core spinning ever faster due to the gravitational mass of the earth concentrating itself more and more at the core - just like what happens when a spinning ice skater pulls in their arms... They spin faster. This would explain the greater magnetic field, but I highly doubt that there was a stronger one before it was weak.
piperTom
So, the liquid center of the earth solidified "about 565 million years ago"... Also, about that time, we have "Snowball Earth" recovering its warmth. Coincidence? Maybe, but it's surely worth considering that the two events are causally related.
flyerfly
Of course there are many assumptions that can't be proven that make all this aging very suspect. I love it when with great confidence these scientists declare somethings age with great gusto...then a few years later someone comes along and change that age by MILLIONS of years...makes me think of the Bible text that says "science falsely so called"...true science does not try to prove something based on an agenda but based on real facts...but you can't convince evolutionists because that is their religion as well...Oh the irony.
mark56984985165
If this is true, isn't it an interesting coincidence for it to be roughly simultaneous with the Cambrian Explosion?
Nik
A number of scientists seem to view the Earth as a closed system. It isn't, as the Dinosaurs found out. The Earth orbits the sun, but the sun orbits the galaxy, independently of the rotation of the galaxy, in a sinusoidal path through the plane of the galaxy. [Which would tend to suggest the the solar system was captured by the milky-way] During that orbit, the solar system passes through the various arms of the galaxy. During those passes, the Earth will experience a number of gravitational effects, and Birkeland Currents. This may cause an increase in both volcanic, and earthquake events, and also ice ages, due to attenuation of the suns radiation by interstellar dust. It may also experience an increase in meteors, and comets. My information's gave the length of the orbit as approximately 600 million years, and the passage through the arms of the galaxy occurs at approximately 150 million year intervals. The end of the ''snowball earth'' event may well be due to the solar system exiting from one of the arms of the galaxy. It is known that the 11 year sunspot cycle is due to periodic alignments of the larger planets in the solar system. So changes in the earths core is also likely to be due to external effects from space.
amazed W1
I wonder just like "absolutejohn". Arguably local veins of metals and ores, and other elements, rather than complete mixing of all the elements almost to a molecular level, has to be explained by formation in particular shells, due to nuclear fusion generated by pressure and temperature presumably. Then the movement of the shells caused by any of the effects various people have suggested would account for the current more local concentrations. the randomising effects a.k.a. entropy describe what is happening. Sub question, what happens if all the iron solidifies, is the gravitational effect too strong temporarily or always so because pressure rules in the solid/liquid transformation?