Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

4.4 billion-year-old crystal is oldest confirmed piece of Earth

cnn.com

Post reply on HN
Print view View original

11–20 of 39 posts

Re: 4.4 billion-year-old crystal is oldest confirmed piece of Earth

#11

Post by s0rce »

yeukhon wrote: post #6

I just search a bit about Jack Hills. http://en.wikipedia.org/wiki/Jack_Hills The last modified was last December. The actual paper http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo20... was received last July but published on Fed 23, 2014. So it took a while to confirm and accept by the reviewers using the new technique. And Jack Hills seems to have caught a lot of attention as early as 2006. http://earthob…

Correct, this paper demonstrated that the Pb doesn't move around too far that it would invalidate the previous measurements. This was done using atom probe tomography.

Source: I know John and also do atom probe work.

Also, It was accepted at the end of last year and took a bit to publish, not unusual.

Re: 4.4 billion-year-old crystal is oldest confirmed piece of Earth

#12

Post by [deleted] »

it_learnses wrote: post #10
yeukhon wrote: post #9

Earlier quoted context omitted.

See my edit https://news.ycombinator.com/item?id=7299294 It has been found a long time ago on Jack Hills. But you are right, somehow, someone, a long time ago, walked on Jack Hills and found a crystal pretty old and started calling for interest.

It seems like it's a pretty small crystal (largest dimension is about the width of 4 human hairs - if I understand correctly). I'm curious as to how they actually found it...

[deleted]

Re: 4.4 billion-year-old crystal is oldest confirmed piece of Earth

#14

Post by VLM »

Shivetya wrote: post #4

Dumb question, would finding this just be pot luck, or did they have an idea of what they were looking at before they decided to subject it to the battery of tests?

Zircons are industrially useful as the primary ore for zirconium metal. If you keep it reasonably cool, like under red hot, it makes a great nuclear fuel rod protective cladding, assuming you refine out the hafnium which does little good in a fuel rod. Its also good for high temp ceramics, although too expensive for your fireplace, probably. If you get the metal red hot and dip it in water it does a fair impersonation of sodium being dumped in water at room temp. Unfortunately, recently, an extremely large demonstration of this effect was performed in Japan with predictable outcome.

Anyway there's lots of profit involved, leading to lots of geological research, leading to interesting discoveries.

Re: 4.4 billion-year-old crystal is oldest confirmed piece of Earth

#15

Post by Groxx »

it_learnses wrote: post #10
yeukhon wrote: post #9

Earlier quoted context omitted.

See my edit https://news.ycombinator.com/item?id=7299294 It has been found a long time ago on Jack Hills. But you are right, somehow, someone, a long time ago, walked on Jack Hills and found a crystal pretty old and started calling for interest.

It seems like it's a pretty small crystal (largest dimension is about the width of 4 human hairs - if I understand correctly). I'm curious as to how they actually found it...

It would probably have been found by someone looking for the ages of rocks. In which case: probably sifted out of buckets of earth, looking for signs of extreme age. Seems like it's from a known-interesting area, which would attract that kind of crowd.

Re: 4.4 billion-year-old crystal is oldest confirmed piece of Earth

#17

Post by bcbrown »

Aardwolf wrote: post #16

Isn't everything on Earth as old? It's all the same material that was there when the Earth formed, except for a few meteoroids that dropped on it later during its lifetime.

The same atoms, but in different combinations and configurations. What's newsworthy here is that this chunk of atoms has been in the same configuration for 4.4 billion years, and that the configuration can tell us something about the history of earth.

Re: 4.4 billion-year-old crystal is oldest confirmed piece of Earth

#18

Post by InclinedPlane »

Aardwolf wrote: post #16

Isn't everything on Earth as old? It's all the same material that was there when the Earth formed, except for a few meteoroids that dropped on it later during its lifetime.

Atoms are actually of potentially different ages, but I'll get back to that. The important thing here is that it's a chunk of mineral, an arrangement of atoms, that can be confirmed to be 4.4 billion years old. There are atoms on Earth that are actually much older, as old as the Universe in fact. But there are atoms that are much younger too. For example, most commercial Helium comes from oil wells, where the alpha particles released by radioactive decay in rocks forms Helium and is trapped underground. This Helium is only a few million years old.

Re: 4.4 billion-year-old crystal is oldest confirmed piece of Earth

#20

Post by teddyh »

yeukhon wrote: post #6

I just search a bit about Jack Hills. http://en.wikipedia.org/wiki/Jack_Hills The last modified was last December. The actual paper http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo20... was received last July but published on Fed 23, 2014. So it took a while to confirm and accept by the reviewers using the new technique. And Jack Hills seems to have caught a lot of attention as early as 2006. http://earthob…

The almost incomprehensible age of the Earth was famously summarized thus:

“The reſult, therefore, of our preſent enquiry is, that we find no veſtige of a beginning,–no proſpect of an end.”

— Theory of the Earth, James Hutton, 1788

Post reply on HN