Ocean sediment sample holds iron believed to be from a supernova

Supernova
Credit: NASA

A team of researchers from several institutions in Germany and Austria has found possible evidence of iron from a supernova in sediment cores taken from the floor of the Pacific Ocean. In their paper published in Proceedings of the National Academy of Sciences, the team describes how they analyzed the core samples and why they believe they hold evidence of an ancient supernova.

The study began, the researchers report, when team members came across information regarding during internet searches. It is a type of bacteria that lives in ocean sediments and absorbs tiny amounts of iron. As sediment builds, the bacteria die leaving behind bits of iron in the layers of sediment. And because they have been at it for millions of years, these sediment layers may contain a type of iron that came from space millions of years ago—iron-60, which prior research has shown is spewed into space when supergiant stars explode.

Iron-60, the researchers note, is extremely rare on this planet, with a half-life of just over two and a half million years; thus, any iron-60 present when our planet formed would have disappeared long ago. And since there is no known natural means to produce it, that leaves arrival from space as the logical origin. Prior research has shown that there are two likely sources, micrometeorites and possibly material sent millions of miles across space due to a supernova.

To learn more, they obtained core samples taken from the Pacific Ocean by researchers working on other projects. To look for iron-60 among the much more common iron-56 and other material, they used accelerator mass spectrometry—which is capable of isolating single atoms.

The team reports that they found concentration levels of iron-60 from single atoms to small clusters of atoms. The greatest concentrations, they also report, were from a time approximately 2.2 million years ago, which just happens to coincide with a massive marine die-off.

The researchers believe it is more likely that the iron-60 came from a supernova rather than micrometeorites because magnetotactic bacteria absorb iron from hydroxides—micrometeorites tend to harbor in magnetite or silicate.


Explore further

Supernovae showered Earth with radioactive debris

More information: Peter Ludwig et al. Time-resolved 2-million-year-old supernova activity discovered in Earth's microfossil record, Proceedings of the National Academy of Sciences (2016). DOI: 10.1073/pnas.1601040113

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Aug 09, 2016
The team reports that they found concentration levels of iron-60 from single atoms to small clusters of atoms. The greatest concentrations, they also report, were from a time approximately 2.2 million years ago, which just happens to coincide with a massive marine die-off.

I would imagine for measurable quantities of iron-60 to be found this nova must have happened relatively close to Earth. Further evidence for a binary system?

Aug 09, 2016
More likely from Mars.

A fact which mainstream science has yet to engage is the color of sand. Sand is of course made of quartz -- which exhibits a whitish appearance. In recent years, microscopy of sand has revealed a huge surprise: Sand's color comes from a thin varnish of iron-oxide glued to the quartz with clay.

The problem with this is that iron is not involved in the process of forming or transporting sand. If it was observed in just one instance, this would be a riddle demanding an explanation. The fact that this seems to be the rule for all sands, rather than just the exception, is a very serious problem for sand.

Aug 09, 2016
So what, right?

Well, if you look into the textbook theories for how all of the largest deserts of the world formed, you will find that they mostly have mysterious, problematic origin theories. The Sahara and Arabian deserts appear to have suddenly appeared 5,000 years ago.

The only surface reservoir of sufficient size of iron-painted sand is in fact Mars.

Aug 10, 2016
The crab nebula is expanding at 0.5% of the speed of light.
If the 60FE has reached Earth at this speed then the SN can have occurred at no more than 11000 lightyears.

I didn't read the study, but I find it hard to believe there would be sufficient amounts of 60FE from a nova that occurred so far away.

Aug 10, 2016
but I find it hard to believe there would be sufficient amounts of 60FE from a nova that occurred so far away.


For shits and giggles I just did a back-of-the-envelope calc (someone check the math, please):

assumption:
- supernova about 10k lightyears away
- ejected mass (from what I google this can range between lower than 1 and 100 solar masses..so I'll take a conservative 10 solar masses)
- isotropic mass ejection (which is an iffy proposition but good enough for a lower bound)

1) R = 10k (roughly 10^13km)
2) M = 10 solar masses (roughly 10^31kg)
3) effective dispersion area (4*Pi*R^2) is 4*Pi*10^26km^2
4) effective capture area of Earth (Pi * r^2) is roughly 4*Pi*10^7km^2

Which gives me roughly 100 million tons of material impacting Earth (only a small fraction of which is Iron 60...But still that's a lot of stuff)

Aug 10, 2016
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Aug 11, 2016
Phys/AAP, you also have to consider any other celestial object that could've been in the way to capture or deflect the ejected matter, especially the gas giants in our own system. Just sayin

Aug 11, 2016
Phys/AAP, you also have to consider any other celestial object that could've been in the way to capture or deflect the ejected matter, especially the gas giants in our own system.

Their effects average out, so they can be safely omitted.

Aug 11, 2016
Well, if you look into the textbook theories for how all of the largest deserts of the world formed, you will find that they mostly have mysterious, problematic origin theories. The Sahara and Arabian deserts appear to have suddenly appeared 5,000 years ago. -HannesChristianAlfven
No. You are either lying or uninformed. The Sahara is 7 million years old. The "5,0000 years" is an apparent reference to the Neolithic Subpluvial, a.k.a. Holocene Wet Phase. The dessert has been drier before and since. During wet phases vast sand dunes simply stop moving and become covered with vegetation, like the Sandhills of Nebraska.

Aug 11, 2016
Their effects average out, so they can be safely omitted.

Umm, feel free to explain that one...

If Jupiter is in the direct line from nova to Earth, how does that average out?

Aug 11, 2016
In recent years, microscopy of sand has revealed a huge surprise: Sand's color comes from a thin varnish of iron-oxide glued to the quartz with clay.

The problem with this is that iron is not involved in the process of forming or transporting sand. If it was observed in just one instance, this would be a riddle demanding an explanation. The fact that this seems to be the rule for all sands, rather than just the exception, is a very serious problem for sand. -HannesChristianAlfven
Clay and iron oxide are both created when water breaks down the minerals found in basalt and other volcanic products. All it takes to form such layers on sand is ash from a nearby volcano and a little rain or dew. If you look at satellite photos of the Sahara, you can see red streaks downwind from volcanic provinces. https://www.googl...2.884206

Aug 11, 2016
That's just a lazy ass approach. You must fit in well with the rest of the science community.

The question isn't IF it's here, because duh, we found it here, it's where did it come from.

Aug 11, 2016
Umm, feel free to explain that one...

I'm taking this from simulations done on how Jupiter supposedly deflects incoming rocks (which was an argument that was made a long time for life on earththat Jupiter protects us from too many impacts). Turns out when you do the simulations Jupiter deflects as many rocks into our path as it kicks out of our path.

If Jupiter is in the direct line from nova to Earth, how does that average out?

The material from a nova arrives over years and years (as it's not all at exactly the same speed). Jupiter would be in a blocking position for only a few minutes of that. And it must also be in the same plane as earth and Jupiter (which is incredibly unlikely). In that case Jupiter would only block a tiiiiny blip of that...and add some stuff taht curves inward as it barely misses jupiter so as to hit us) . That effect is utterly negligible.

You need to get a sense for orders of magnitude, sizes and lengths of time.

Aug 11, 2016
You need to get a sense for orders of magnitude

Like one nova 10 light years away, travelling the vastness of space, encountering stars/planets/heliospheres, depositing enough material that we can measure...

Perhaps repetition can get this into your skull?

Na, garbage doesn't stay long

Aug 11, 2016
You're a tool Phwyz, adios

Aug 11, 2016
Like one nova 10 light years away, travelling the vastness of space, encountering stars/planets/heliospheres

You would not believe how empty space is. A nova 10ly from here would encounter absolutely nothing (there's no star within 10ly that in direct line with another star closer). Even for 10k light years the amount of solar systems that line up are very few. And the argument that goes for Jupiter and rocks gooes for nova material and stars just as well. You get as much deflected towards us as gets blocked.

You really need to stop looking at star trek and actually go out and look at the stars more often. Space is a pretty big (and pretty empty) place.

Aug 11, 2016
and actually go out and look at the stars more often.
Tonight, in particular, if you like to see shooting stars (Persieds)...

Aug 11, 2016
Space is a pretty big (and pretty empty) place.

Ya, which is why the stars are small. If photons reach us as only a tiny point in the sky it's unlikely the matter blown from one will reach us any more.

You also forget that the resulting plasma from a nova would be subject to the interstellar magnetic field (and magnetic fields in general), which depending on where the nova occurred could help or hinder a large blob of plasma on its course to or from Earth.

Aug 11, 2016
Ya, which is why the stars are small. If photons reach us as only a tiny point in the sky it's unlikely the matter blown from one will reach us any more.
Wow. Compared to the reality-based formulation and calculations of Antialias, your use of the words "small," "tiny," and "unlikely" makes all the difference. [/sarc]

Aug 11, 2016
Haha those random numbers give you a warm and fuzzy? Random estimate of star, area of a sphere, area of a circle, equals random calculation with no physical bearing on reality. Why is the "effective capture area" of the Earth only the area of a circle? Do we have a flat Earther here? Let's not even get into the dispersion pattern of the material over light years which isn't accounted for.

Think of bird shot fired from a shotgun, it only has a limited effective distance before the bbs are too far apart to hit anything...

Aug 12, 2016
Why is the "effective capture area" of the Earth only the area of a circle? Do we have a flat Earther here?
Wow again, Scroofy. It's referred to as a cross section:

"Any cross section through a sphere is a circle... The size of the circle is maximized when the plane defining the cross section passes through a diameter." See MathWorld > Sphere

Going by the EEG alpha wave output commensurate with those questions, I think we have a flat-Liner. Wait, the methane detector is flashing too, pretty good indication of where you actually pulled the questions from.

Aug 12, 2016
Wow Proto, you missed the point, again.

Why would we call the capture area of the earth a circle, while the nova's dispersion a sphere? Doesn't the entire sphere of the earth capture material? BTW, only half of the material from a nova would be in our direction, so there's another miscalculation...

Aug 12, 2016
Doesn't the entire sphere of the earth capture material?

Capturea area is always cross section. That goes for nuclear interactions as well as celestial bodies. c'mon, man. That's stuff you must have heard about in high school.

BTW, only half of the material from a nova would be in our direction, so there's another miscalculation...

Seriously? You didn't even bother to try and understand the calcs?
OK, here's for dummies. Take the shell of ejected material at distance to the Earth. Take the effective capture area of the Earth. Divide the two and you get the ratio of material that impacts the Earth. It's not rocket science.

Aug 12, 2016
The SN emits matter in all directions, so this can be thought of as an expanding sphere

Sure, an expanding sphere of decreasing density, np. But you can't assume that the whole sphere is going to hit the earth.
Earth receives matter only from 1 direction, that of the SN.

Still with ya, the location of the SN is not changing.
that is a circular disk, is used

For any given moment. But if you are looking over time, you would have to integrate the deposited material (of decreasing density) over the surface area of the earth for the time that earth would be in the SN debris field.

Like AAP said:
The material from a nova arrives over years and years (as it's not all at exactly the same speed)

This is why such a simple calculation has no bearing on the reality of it.

Aug 12, 2016
Of course the density decreases like the inverse of the surface of the expanding sphere

Then where is the calculation for it? In you and AAPs simple calculation there's only 4pi*r^2/pi*r^2 times the mass of the ENTIRE star. Not representative of reality and far too many assumptions of "empty space"...

Aug 12, 2016
I didn't read the study, but I find it hard to believe there would be sufficient amounts of 60FE from a nova that occurred so far away.
The paper talks about the measuring technique at page 89. enjoy http://www.gams.p...esis.pdf

Aug 12, 2016
@Scroofy
Your questions are getting more and more stupid.


That couldn't be more true in this case. Good lord man.

Aug 12, 2016
The paper talks about the measuring technique at page 89. enjoy

Thanks dude, I am. I've never read a thesis before and this one is really good. The GAMS is a pretty sweet machine and the data shows it to be accurate for 60FE. That's not the part of I've been arguing about.

The question has been how far away would a SN have to be to have enough matter deposited. Basically there's two theories, either a CCSN deposited it from around 10 pc away (with 8 pc being the range "kill" range for the ozone layer), or a conglomeration of cosmic dust from numerous SNs. End conclusion seems to be one or multiple SNs from about 2Ma-1Ma years ago.

A typical SN star's 60FE core has the radius of Earth, and total dust from a SN is about .1-1 Msolar. Since the core of a star is about 34% of the total mass, that brings the total possible to .034-.34 Msolar total 60FE ejected. Nowhere close to the assumed 10Msolar in the earlier calculations.

Aug 12, 2016
Don't lecture professionals when you don't even have a minimum of understanding and skill yourself.

Ok Phwyz, when I find a professional I'll make sure to take that advice.

Aug 12, 2016
Nowhere close to the assumed 10Msolar in the earlier calculations.
Wow #3, how did you miss the "back-of-the-envelope" disclaimer and the accompanying list of assumptions? It only took you three tries to finally honor the request, "check the math, please." So, finally a 5-star from me and a sincere thanks for keeping it reality-based instead of just a "small, tiny, unlikely" opinion.

Aug 12, 2016
Well Phwyzard unless you and AAP are the authors of the paper then I'm not lecturing them. If you think I don't understand a simple non-representative calculation then you are the blind fool, and can't see that you are the ones belittling the professionals by reducing their work to a 10k light year sphere and a circle and a bunch of lazy assumptions...

Aug 12, 2016
So, finally a 5-star from me and a sincere thanks for keeping it reality-based instead of just a "small, tiny, unlikely" opinion

Thanks Proto and feel free to color me lazy for not looking for Ludwig's thesis. I guess I'll have to start looking for those more often.

Aug 12, 2016
The material from a nova arrives over years and years (as it's not all at exactly the same speed)


This is why such a simple calculation has no bearing on the reality of it.

The capture ratio is independent of whether all arrives at once or it arrives over billions of years. You can verify this yourself by just going from one shell with density x to n shells with density x/n and doing a limit calculation for n->infinite. That way you get the sumtotal of continuous impact on Earth which comes out exactly the same.

Of course the density decreases like the inverse of the surface of the expanding sphere


Then where is the calculation for it?

The calculation is in the part where we take a shell at distance star->Earth. That automatically gets you the inverse square law (because a shell surface is dependent on the radius squared). Duh.

Aug 12, 2016
The calculation is in the part where we take a shell at distance star->Earth

Ok this is the part that is throwing me off, maybe I am dumber than I think. How does the surface area of a shell account for the density of the matter, since density is a function of volume?

Aug 13, 2016
Our Sun is quite capable of creating such iron during a mega-CME, and such events likely occur every few thousand years.

Aug 14, 2016
Technically, all the iron on this planet and everywhere in the universe is from supernova's. :P

Aug 19, 2016
HannesAlfven/Chris_Reeve, I take your silence as signifying that your desert-sand-is-from-Mars hypothesis is dead. Let me add one more nail in that coffin. Mars has an oxygen isotope fingerprint (specifically 17O/18O ratio) that is different from Earth's. http://wiki.chemp...tios.PNG
The Mars oxygen isotope signature has not been found in the oxgyen in the iron oxide of Earth sand.

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