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‘Hypatia’ Stone Contains Compounds Not Found in the Solar System (popularmechanics.com)
215 points by curtis 12 days ago | hide | past | web | favorite | 67 comments

> A new study led by geologists at the University of Johannesburg found that compounds in the Hypatia stone are distinct from anything discovered in the solar system. The researchers therefore conclude that parts of the rock formed before the solar system, and if these compounds are not presolar, the prevailing idea that the solar system formed from a nebula of homogenous gas is called into question.

Couldn't it have come from outside our solar system, in which case it is pretty much irrelevant whether it is presolar or not? Granted, that would also make it pretty exciting :-)

It seems a bit premature to question the formation theory of the solar system, based on a single rock from which we don't know if it even formed inside the solar system.

Read the text 'russdill linked in another comment:

"Most (99 percent) of the meteorite inventory on Earth comes from the main asteroid belt, between the orbits of Mars and Jupiter. A small fraction of meteorites come from Mars (about 180) and the Moon (about 275). Some meteorites have been suspected to come from comets. Famous astronomer Carl Sagan once said, “It is unlikely that a single meteorite of extrasolar origin has ever reached the surface of the Earth.” Numerical calculations suggest that the possibility of exchange of meteoritic fragments between stellar systems is highly unlikely. Indeed, extrasolar meteorites have not been identified in our meteorite collections."

So it's still highly probable that it's still from the stuff of our solar system, it's just the question how homogeneous the stuff was and did the stuff coalesce before or after the Sun was formed. But we know that stuff formed in the cold, from the University of Johannesburg press release:


"What we do know is that Hypatia was formed in a cold environment, probably at temperatures below that of liquid nitrogen on Earth (-196 Celsius). In our solar system it would have been way further out than the asteroid belt between Mars and Jupiter, where most meteorites come from. Comets come mainly from the Kuiper Belt, beyond the orbit of Neptune and about 40 times as far away from the sun as we are. Some come from the Oort Cloud, even further out. We know very little about the chemical compositions of space objects out there. So our next question will dig further into where Hypatia came from."

I would have loved to hear Sagan reconsider his statement when he learned that a large oblong extra-solar object (Oumuamua) passed through.

> a large oblong extra-solar object (Oumuamua) passed through

Just the one. What are the odds that another passes through our solar system, and another, and what are the odds that any of those lands on earth? Close to 0.

We've just seen the one, but we've only had the capability to detect something like that for ~5 years. So in the absence of further data, it's reasonable to conclude that `Oumuamua-like objects pass through the solar system once every 10 years.

Of course smaller and larger interstellar objects will also pass through the solar system. Objects half the size -- which presently we'd be quite lucky to detect -- should pass through with ~5 times the frequency, assuming a size/frequency distribution similar to asteroids. Objects with a quarter the size (currently almost impossible to detect) should be ~25 times as frequent, etc. There is presumably a lower bound to this: at some minimum size, interstellar objects will be repelled by light pressure and the solar wind. I have no idea what this size might be, but for argument's sake let's say that is 1/8th the size of `Oumuamua.

So for any given year, the probability of interstellar objects passing through the solar system, should be as follows, (where `Oumuamua is size=1):

    Size | Annual probability
   0.125 | 12.5
   0.25  |  2.5
   0.5   |  0.5
   1     |  0.1
   2     |  0.02
   4     |  0.004
   8     |  0.0008
...there's not really an upper bound, but I can make my point without one. My point is, in any given year, based on current observations, there should be roughly 16 interstellar objects passing through the inner solar system.

Multiplying that by the ~4 billion years that the Earth has been around to run into, and you get a very large number. It seems certain that some small fraction of that large number would have run into Earth. So based on this back-of-the-envelope analysis, either the actual probabilities are MUCH lower -- as in thousands of times lower -- and we were unbelievably lucky to see `Oumuamua when we did, or Carl Sagan was wrong.

> We've just seen the one, but we've only had the capability to detect something like that for ~5 years. So in the absence of further data, it's reasonable to conclude that `Oumuamua-like objects pass through the solar system once every 10 years

No it's not. It's impossible to deduce anything from a sample size of 1. (And yes I realise that this invalidates my point as well.)

Toss a coin (known to be non-evenly-weighted) five times. It comes up heads once. Can you now estimate the probability of the coin coming up heads? Of course you can. What you can't do is put error-bars on that estimate: you might have just seen the only "heads" that you'll see in the next ten thousand tosses. So the error bars are essentially infinite, but you can make a first-order estimate.

Analogously, we've had the capability to to detect `Oumuamua-like objects for ~5 years, and after searching for 5 years, have found one such object. That's good enough to start making first-order estimates of probabilities. Such estimates will obviously change, possibly significantly, as more observation time goes by.

Absent error bars, you can't be certain of that first-order estimate is even approximately correct. But if it's not even vaguely correct, then that means your initial "heads" observation was very, very, unlikely. Hence my conclusion is valid: either we got extraordinarily lucky in detecting `Oumuamua when we did, or Carl Sagan is wrong.

remember though, it's "just 1" in the past few years we've had the capability of detecting them.

I would guess that he would have loved it, too! But in fairness, while it is 'passing through' Oumuamua isn't leaving any minerals on the surface of the Earth, either.

Was that quote from Sagan basically saying "panspermia is very unlikely"?

Universes are very unlikely. Life is very unlikely.

Applying statistical analysis to single instances of things always seems like a major flaw to me - it being unlikely means that if we have a million earths few will have extra-solar matter on them. It doesn't really help when you have one Earth.

Well, this is about establishing priors. If something seems unlikely, maybe our understanding of it is wrong? Concepts like Anthropic principle have been introduced to deal with the fact that we exist, however unlikely it may seem.

I'm not very knowledgeable about all of this but :

>> A small fraction of meteorites come from Mars (about 180) and the Moon (about 275).

How come that the moon being closer to earth, we have just 50% more meteorites Mars ? And how come we have so many more from the asteroid belt ?

You have to leave Mars's surface at 6300 m/s to get to Earth, ignoring slowing down at the end which is accomplished by the atmosphere. To get to Earth from the Moon takes 5670 ms/s. The Moon is much closer in Cartesian space, but that just means that the delay from an object leaving the Moon's surface to getting to the Earth's is much smaller, it affects latency but not throughput and on geologic timescales both latencies are small.

EDIT: See this map of the solar system in delta-v terms:


EDIT2: Argh, I messed up my calculations and the distance from the moon is just 2410 m/s. You have to factor in how often Mars gets hit by stuff and the speed at which stuff is going given Mars's gravity well.

It seems like your comment ignores the relevance of proximity in the likelihood that an ejected object with the necessary velocity ends up at Earth. Wouldn't the probability of such an object hitting Earth from Mars would be many orders of magnitude smaller than one from the Moon (like trying to hit a target from 100x further away)?

I always understood the large numbers of meteorites from Mars to be related to the fact that Mars is closer to the asteroid belt and therefore has had a lot more impacts historically...

The levels of delta-v we're talking about here aren't nearly enough to knock these objects out of the solar system. When they leave the Moon or Mars they're still in orbit and will remain in orbit until they collide with something. In the case of a moon rock that means either hitting the Earth or returning to the Moon in what is likely a single orbit so 2 weeks. In the case of Mars it will either hit Mars again or the Earth. Or possibly the Moon, one Mars's moons, or an asteroid but probably the first two. The odds of this collision taking place on any given orbit around the Sun are low but the object isn't going anywhere and eventually, possibly millions of orbits later, it will end up hitting something. So no, the probability that it will eventually hit the Earth doesn't really go down with the distance in this case since we're only talking millions of years for a collision to occur rather than billions.

Mars is about 10 times the mass of the moon, so maybe that helps. Though the Kuiper Belt is about the same mass as Mars, so not sure if that's the answer

The energy required for a transfer orbit from Mars is only a bit more than the Moon. Energy matters more than distance or time.

Mars is much bigger than the Moon, so it's hit more often by stuff that could send rocks our way. In terms of delta-v, Mars is not so much farther away than the Moon.

I wonder if two comets (within our solar system) colliding at high speed could have created some of the substances found in this.

It might be an issue of travel time.

I originally read this as "It might be an issue of time travel," which would be another very fun possibility to consider. ;)

Probably not. Oumuamua, the first extrasolar object we've tracked through the solar system, has a hyperbolic excess velocity of ~30km/s, or 1/10,000 of light speed.

So in a billion years, such an object could travel 100k light years, or the diameter of the entire galaxy.

Sub-relativistic interstellar travel is very slow on human timescales, but fast on geologic ones.

I went to read the paper and I am wrong, they looked at the minerals and the physical conditions to form them, and they are consistent with a place and a phase of the creation of the solar system.

Yes, I'd also go with the "Alien spaceship crashed in Africa 28 million years ago" theory. :-)

Outside our solar system does not equate to the grandparent going "IT'S ALIENS!"; that's all you.

Funny coming from cthulhu... :)

I wouldn't laugh.

What Cthulhu_ meant is that the real explanation is something no human can even attempt to understand without immediately going insane. Calling it "aliens" is just our naïve, simplistic way of wishing away the cosmos.

"Cthulhu" is the name of a character (well, Great Old One) from writer H. P. Lovecraft who is an other worldly being aka an alien.

I have a feeling TeMPOraL knows this, since their post is rife with Lovecraftian cosmicism :)

It's a shame this comment was down-voted. It's awesome.

> are distinct from anything discovered in the solar system.

Well, they just discovered it so that should be 'discovered so far'.

And how much do we know about the solar system to begin with, if it took this long to analyze a rock that was on the planet to begin with it stands to reason there will be many rocks like it and possibly others entirely unlike it in the rest of the solar system.

This should answer a lot of questions people have about the article: http://www.astronomy.com/magazine/ask-astro/2017/10/meteorit...

Title should have been "ratios of compounds"

Yes. As a chemist, this was a very frustrating read. However, I found a concise summary in the abstract to the original article:

A lack of silicate matter sets the stone apart from interplanetary dust particles and known cometary material. This, along with the dual intermingled matrices internal to it, could indicate a high degree of heterogeneity in the early solar nebula.


> There are also grains of a compound consisting of mainly nickel and phosphorus, with very little iron, a mineral composition never observed before on Earth or in meteorites

The title is correct.

Then I am just not familiar with this use of the term "compound". I was thinking synonymous with "mineral", as in


"Minerals are chemical compounds, and as such they can be described by fixed or a variable formula."

But now I think it means like: http://www.scienceclarified.com/everyday/Real-Life-Earth-Sci...

"COMPOUND: A substance made up of atoms of more than one element, chemically bonded to one another"

No, not at all, it's ratios of elements that form a compound.

Some of the compounds found are predominantly composed of elements that are expected to be minor constituents, particularly carbon, which is an element.

That wouldn't have attracted nearly as many clicks.

I do not see how they can categorically state the compounds are not from our solar system. We've barely begun to explore our solar system. Seems arrogant to assume such things.

Take a chill pill. They're not assuming anything, they're making a hypothesis based on the available evidence. The paper title even includes the words "A contribution to the debate on it's origin". That hardly looks like a final pronouncement.

I understand what the article is trying to say but the title is kinda funny.

Compounds not found in the solar system. By the race that has not even left its little corner of the solar system yet.

Sure we have spectral analysis but fact remains there are parts of the solar system we can't investigate. So the title is a bit amusing and click-baitey.

It's like saying "I haven't found my keys yet and I've only looked around my desk".

Nitpicking of this sort is incredibly annoying, it's obvious they mean the presence of the compounds does not match current theories of the origin of the solar system.

Things can only be found in places you can look.

> The mysterious Egyptian rock contains micro-mineral compounds not found on Earth

And apparently, Egypt is not located on Earth.

And doesn't everything in the solar system ultimately have extrasolar origins?

now did it crash to earth or did it land?

> Named for Hypatia of Alexandria, the first prominent Western woman astronomer

How is a middle-eastern woman who lived circa ~400AD "western"? "The west" didn't take the lead in science until much, much later.

Hypatia was a Neoplatonist who lived in Alexandria in the late Roman Empire. Egypt had been integrated into the Roman sphere for centuries at that time. If "Western" implies a connection with the Greco-Roman tradition, which it often does, then Hypatia certainly seems to fit that. The modern notion of the "Middle East" being distinct from "the West" was less strong at that time because the Western world was more of a Mediterranean world; cultures in north Africa and the Levant were more integrated with Europe during the Roman period and even for centuries afterward. It was the rise of the Islamic Empire and its disruption of trade routes with Europe that more strongly created that distinction.

I say this as someone not particularly emotionally invested in the idea of "claiming" Hypatia for the West or anything like that. To tell the truth, the story of Hypatia has turned into a modern myth in various ways -- like the story of Galileo -- in which we end up coloring it with our own narratives.

If anyone is interested in details about Hypatia's life, I recommend reading this post which responds to the typical modern narrative about Hypatia: http://tofspot.blogspot.com/2017/10/the-herstory-of-hypatia....

I also recommend the more detailed series of posts by the same author, which gets into the political/social issues of the day, which is more interesting than you might think: https://tofspot.blogspot.com/2015/02/hypatia-part-i-mean-str...

Alexandria was founded as a Greek city and stayed Hellenistic until the Islamic Invasion 600 something.

Wikipedia lists Hypatia as "Greek", Greek and Roman culture is usually counted as "western".

It could also be meant in contrast to "eastern" as in Chinese and Indian astronomy.

In any case Egypt is certainly not in the "middle east"

It is: https://en.wikipedia.org/wiki/Middle_East (the Near East then being the Balkan).

In other languages (e.g. in German) one calls this part "Near East", "Middle East" is Iran -> India, "Far East" is South-East Asia, China, etc.

Huh, never heard it used in such a way as to include Egypt. I've always heard Egypt included in MENA (Middle East/North Africa). There you go.

MENA includes Morocco, Tunisia, et cetera.

Surely Greco-Roman culture was pre "Western". So it's like calling Boudica an Anglo-Saxon.

Better would surely be the "Hellenic astronomer", or just "Alexandrian astronomer" which places things reasonable well in geo-historical context. Would you call pharoahs "Western rulers"?

If you say Western I'd assume it's after the downfall of the Roman Empire.

Worth noting that Hypatia precedes the Qin dynasty by 200 years so there was no "Far East"/China in civilisation terms as such.

I think this just highlights how much "Western" is a movable feast. The Byzantine empire is typically counted as part of the west. So "Constantinople" is part of the West, but "Istanbul" is not. The qualification here mostly means "not Chinese".

I'm confused by all the confusion about "western" here. It refers to a family of civilizations, cultures, and nations. Despite the geographic specifier, it is primarily about people and traditions, not a location.

Pick up any book about "Western Civilization" and it always refers to the thing that nucleated with Greece and Rome, and then all the things that descended from it. Byzantium is absolutely part of this lineage.

> The qualification here mostly means "not Chinese".

Well, and not Islamic. The West is 'European,' so Roman North Africa & Roman Anatolia were Western. 'Near East' or 'Middle East' mean the now-Islamic world (much of it was Western pre-conquest). 'Far East' mean Chinese or Japanese. At one point I think 'Oriental' (a word just meaning 'Eastern') could also apply to folks from the Indian subcontinent, but that's pretty rare to nonexistent nowadays.

Alexandria was a greek city more or less at that time. It was first part of the ptolemaic egypt[0], and after Roman conquest a province[1]. The middle eastern influence came en masse only after the muslim conquest.

[0] https://en.wikipedia.org/wiki/Ptolemaic_Kingdom

[1] https://en.wikipedia.org/wiki/Egypt_(Roman_province)

It was found, along with all of the compounds that it contains, in western Egypt. Which, last I checked, is in the Solar System.

The idiom used in the title has a commonly well understood meaning in English. It basically means ‘here is a thing found in this context that is usually not found in that context and therefore probably came from somewhere else’. I can see that technically it’s incorrect, but pretty much any native English speaker would understand what is meant.

The contention is that the stone is not composed of material from the cloud of dust and gas which formed our solar system, and therefore does not share that common origin with the other material in our solar system we are familiar with.

It's been interesting watching the score on my original comment, which was (I thought) pretty clearly tongue-in-cheek. It first got quite a few upvotes, and now is well on its way to being buried - I'm not sure if that's just noise, or if it indicates changing demographics (with different attitudes towards flippancy) reading HN at different times of day.

Anyway, yeah, it's not hard to figure out what the title meant.

Usually jokes don't get better by explaining, but this was an exception.

It's incorrect everywhere, except for click-bait purposes.

A compound in Egypt clearly places it in the solar system.

Interestingly, everything found in the solar system is simulatneously both from the solar system AND is ultimately of extrasolar origins, since the solar system can from gas and dust from elsewhere when it was created.

You need to start thinking in 4D

Not according to Dan Quayle...

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