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According to the video 9 Shocking Facts from the Quran!

Iron is not natural to the Earth. It did not form on the Earth but came down to Earth from outer space. This may sound strange but it is true. Scientists have found that billions of years ago the Earth was stuck (sic) by meteorites. These meteorites were carrying iron from distant stars which has exploded.

The presenter then relates this fact with a verse from the Quran.

We sent down Iron with it's great inherent strength and its many benefits for humankind.

Did iron form on Earth? Did it come from outer space? Was all iron on Earth added after the Earth formed?

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    One of the claims is that all iron on Earth comes from meteorites (as opposed to be present when the Earth was formed. That is addressed/clarified on Geology.SE. It then goes on to suggest that the Quran said iron was "sent down". The obvious interpretation is that they authors meant sent down from Heaven, not sent down from outer space, but that isn't something we can resolve with evidence. – Oddthinking May 9 '18 at 2:35
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    If you take a broad enough view, all matter on Earth cam from outer space. In fact, an even broader view could claim that all matter on Earth is still in outer space. – Kamil Drakari May 9 '18 at 16:27
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    I don't think the Quran verse helps. It is a separate claim. – Oddthinking May 10 '18 at 1:08
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    There is some basis to this claim. Almost all of the iron and steel artifacts dating roughly before 1200 BC were meteoric iron. While peoples of that time and before didn't know how to smelt iron ore, they did know how to make a fire hot enough to be able to work steel that had fallen from the sky. The iron age, where peoples finally had learned how to smelt (primordial) iron ore, came later. The iron we use now is almost entirely primordial. If you want to call that too as having fallen from the skies, well it did, but it did so before the planet existed as a planet. – David Hammen May 14 '18 at 3:13
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    The claim "Iron is not natural to the Earth." is wrong. Iron is a primordial element that was present in the material from which our planet was formed. In that respect it is no different from many other chemical elements. It is true that some more iron has arrived to Earth from falling meteorites during the entire "lifetime" of the Earth. It is also true that natural spontaneous fission of uranium (and possibly other nuclides) will have produced a bit of iron. But the contribution from such "later" sources is negligible in comparison of the enormous amounts of primordial iron. – Jeppe Stig Nielsen Sep 21 '18 at 11:37
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The mass of the Earth is approximately 5.98×10²⁴ kg. In bulk, by mass, it is composed mostly of iron (32.1%), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8%), calcium (1.5%), and aluminium (1.4%); with the remaining 1.2% consisting of trace amounts of other elements.

Source: Abundance of the chemical elements

The proto-Earth grew by accretion until its interior was hot enough to melt the heavy, siderophile metals. Having higher densities than the silicates, these metals sank. This so-called iron catastrophe resulted in the separation of a primitive mantle and a (metallic) core only 10 million years after the Earth began to form, producing the layered structure of Earth and setting up the formation of Earth's magnetic field.

Source: History of Earth

So: no, not all iron on Earth came from outer space. Iron was part of the planet already from the beginning.

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    Is this a yes or no answer? – Oddthinking Sep 12 '18 at 7:55
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    Given that all the material in the proto-earth came from outer space, it didn't after all spontaneously come into being at some point, the iron on the proto-earth also came from outer space :) – jwenting May 27 at 6:07
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Nuclear fusion is the mechanism by which most atom nucleii have been formed from the original plasma present after the Big Bang. It requires incredibly hot temperatures not found in outer space. Since the Big Bang, nucleii have been formed in stars and then ejected in outer space at the end of the life of those stars.

See for instance: Nasa's Cosmicopia

Since Earth was formed by the aggregation of material in our solar system (like the other planets), there has not been enough energy to produce fusion (i.e. the temperature was much too low. Most of the iron present on our planet (and the core of the planet is mainly composed of iron & nickel) has thus been produced in stars that have disappeared before the Solar system was formed.

More details on phys.org

There might be iron produced on Earth by the radioactive decay of e.g. uranium, but this should be a very small quantity compared to the amount present when Earth was formed.

See this page from the Berkeley Lab

So, the formal answer to your question, is NO, not all the iron present on Earth came from outer space, but most of it did.

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    But then again, virtually all the elements that comprise the earth's crust (and atmosphere) "came from outer space". – Daniel R Hicks Sep 11 '18 at 11:52
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    Welcome to skeptics. We don't allow unreferenced answers on this site. Please correct yours. – Sklivvz Sep 11 '18 at 21:17
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    That should be a big NO to the question as the majority of iron on earth arrives as part of the formation of the planet and not later from meteoric impacts after the original planet settled down. But then, the claim itself is confused about this when stating "iron is not natural to the earth" which is clearly wrong in any meaningful sense. – matt_black Sep 21 '18 at 15:14
  • I'm curious, do you have evidence that any decay pathways of any significant elements in Earth's crust eventual lead to iron? – HDE 226868 Jun 27 at 17:51
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    Technically, the entire earth came from outer space - it is nothing else than a big ball of clumped star-matter, afteral. – T. Sar - Reinstate Monica Jul 1 at 11:58
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TL;DR

The majority of the Earth's iron was around when the planet formed. Calculations of the mass deposited by subsequent impacts show that these impacts were comparatively insignificant in changing Earth's iron levels, making the claim false. Additionally, those impacts came from bodies originating within the Solar System - not around other stars.


In the early Solar System, over several tens of millions of years, planetesimals collided and aggregated, forming protoplanets, which subsequently accreted even more matter (Wood et al. 2006). Many of these planetesimals formed iron cores; when they impacted the young Earth, which was molten and conducive to metal segregation, that iron sank to the center, forming a core of that was ~85% iron. This segregation ended only when silicate perovskite in the mantle crystallized. This iron core remains today, and while you can argue that the iron indeed came from outer space, it was on Earth essentially since the planet was formed, which makes the claim quite false.

To see if any large amount of iron on Earth came from space later in the planet's history, we can ask how much iron was deposited on Earth in subsequent impacts. According to the Giant Impact Hypothesis, the last major impact Earth suffered was with a protoplanet named Theia; matter thrown off by the collision subsequently formed the Moon. Assuming a reasonable value for the mass of Theia's core, and an appropriate composition, it should have deposited an insignificant amount of iron onto Earth, on the order of 1021 - 1022 kg, a couple orders of magnitude less than the iron already on Earth (Sleep 2016) (compare to Earth's mass, 5.97*1024 kg).

We could generously suggest that the originator of the YouTube video is referring to the Late Heavy Bombardment, a series of asteroid impacts that occurred about 3.9 billion years ago (Bottke & Norman 2017). A leading theory behind the LHB holds that it arose from the migration of the giant planets in what is known as the Nice model (Gomes et al. 2005), perturbing a relic population of asteroids. This, too, could not have deposited much iron on Earth (Ryder 2002), judging by impact rates on the Moon.

Interstellar interlopers are likely not a significant source of iron, given the local density of 'Oumuamua-like objects (Do et al. 2018). With only 4 Earth masses worth of interstellar minor planets per cubic parsec (according to Do et al.; Engelhardt et al. 2017 give a value three orders of magnitude lower), it's unlikely that Earth has experienced any collisions with any over the course of its existence, which should put to rest the claim that iron came from meteorites from other stars.

The above show that impacts were not significant sources of terrestrial iron - although at any rate, this point is moot, since we've already shown that there was iron when Earth formed, and any amount of iron on the planet would invalidate the claim.

As an aside, I'd like to specifically address something mentioned in Vincent's answer:

There might be iron produced on Earth by the radioactive decay of e.g. uranium, but this should be a very small quantity compared to the amount present when Earth was formed.

The main contributors to radiogenic heat inside Earth are uranium-238, uranium-235, thorium-232, and potassium-40 (Korenaga 2011); most models of radiogenic heat assume that all radiogenic heat on Earth comes from those four isotopes. As the latter has an atomic mass less than iron, it clearly cannot decay to iron. We can look at the decay chains of the other three elements (uranium-238, uranium-235, thorium-235) and see that none of them produce iron. Therefore, as there are no major natural fusion pathways operating on Earth to form iron from lighter elements, it seems that Earth is not producing a significant amount of iron from any nuclear process, including fission.

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As Kamil Drakari said, technically everything is from outer space. After all Earth was created from a result of big bang and gasses.

See related answer about it here: https://earthscience.stackexchange.com/a/2325

About the Quranic part, "sent down" is used as a term to describe creation of something. There are many verses using the term "sent down" See here: list of verses with sent down term

One example is:

Who has made the earth your couch, and the heavens your canopy; and sent down rain from the heavens; and brought forth therewith Fruits for your sustenance; then set not up rivals unto Allah when ye know (the truth). (Surah Al-Baqara, 22)

This doesnt mean that rain is "sent down" from outer space. Quran states itself as written in clear language but you are not supposed to take words literally which is odd.

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