This only works because the core is denser than the surface.
(hint: imagine the limit case where the earth were a hollow sphere)
The young centre of the Earth (2016)
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Re: The young centre of the Earth (2016)
#12How is it possible that the core is several years younger if the core and the surface have gone around the sun the same number of times?
General Relativity
That explains how it can be ...does the conversion... 75 megaseconds younger, but the whole of the earth modulo ejected material like spacecraft should be the same number of _years_ old.
Re: The young centre of the Earth (2016)
#13Here is a more accessible explanation for those (like me) who are unfamiliar with the maths: https://www.sciencealert.com/earth-s-core-is-2-5-years-young...
Re: The young centre of the Earth (2016)
#14What about the center of a black hole? Is it younger than the surface?
Re: The young centre of the Earth (2016)
#15This only works because the core is denser than the surface. (hint: imagine the limit case where the earth were a hollow sphere)
They calculated the 1.5 years assuming a homogenous Earth (equal density throughout), so this is not true. The 2.5 years is calculated using a more realistic density distribution for the Earth.
Re: The young centre of the Earth (2016)
#16What about the center of a black hole? Is it younger than the surface?
Black holes are a singularity. They have an even horizon but it's not really a surface of an object it's just a place in space where certain conditions occur. What happens underneath that horizon (and in the singularity) isn't solidly known.
Re: The young centre of the Earth (2016)
#17Does the same apply to the Sun? How old is the centre of the Sun compared to its surface?
Re: The young centre of the Earth (2016)
#18How is it possible that the core is several years younger if the core and the surface have gone around the sun the same number of times?
I found this helpful:
Re: The young centre of the Earth (2016)
#19What about the center of a black hole? Is it younger than the surface?
The question is slightly ill-formed. I understand why you'd ask it, but there are a couple of possible answers, none of which work directly.
- No, because a black hole has nothing underneath the event horizon. (This is true from the perspective of anyone outside it, at least to a first approximation. Gravity is affected by curvature, and whatever might be in the centre cannot be the cause of the event horizon, except historically, but the event horizon is stable in itself. It's a self-sustaining cascade of space-time.)
- Mu, because once you pass the event horizon the extreme warping of space-time turns "inwards" into "future", making the centre of the hole a point in time, not space. This makes it difficult to determine what the question is asking.
- Maybe, because singularities probably don't exist. There should be something in the centre, which might evolve over time. It might just be a faster-than-light cascade of space-time, though. We still can't answer your question, because we don't know how to accurately model the 'singularity'. (As anything other than a singularity, and that's essentially just the math giving up.)
Re: The young centre of the Earth (2016)
#20What's the deepest core sample; 10 km? I assume isotope dating is no where near accurate enough to see the difference.
12 km to be precise, of the earth’s 6000 odd km radius. That’s all we could accomplish in entire human history.
https://www.smithsonianmag.com/smithsonian-institution/ask-s...