[HN Gopher] Meteorite Self-test check-list
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Meteorite Self-test check-list
Author : accrual
Score : 57 points
Date : 2024-03-21 21:02 UTC (1 days ago)
(HTM) web link (sites.wustl.edu)
(TXT) w3m dump (sites.wustl.edu)
| Titan2189 wrote:
| Why is the "Did someone see it fall?" included? Sounds like that
| question is irrelevant
| CommitSyn wrote:
| Because identifying meteorites is very difficult and almost
| always requires taking them to a university for analysis.
| jumploops wrote:
| This meteorite fell last Thursday, tracked with cameras[0].
|
| [0]https://www.reddit.com/r/meteorites/s/pPlwNsizEE
| snitch182 wrote:
| There are 365 degree cameras in every larger populated area.
| The people operating them report to a central database. I once
| saw a fireball going to the supermarket at night. It was in the
| database a couple hours later. It is like winning the powerball
| lottery if you would find a meteor not seen by anyone.
| lupire wrote:
| Those are impressive cameras!
|
| But that's not what we're talking about here.
| https://news.ycombinator.com/item?id=39790272
| extraduder_ire wrote:
| If you see a meteorite "fall" or something that looks like a
| shooting star, you aren't going to find it.
|
| If it's moving fast enough to be a glowing streak, it's going
| to land hundreds of miles away from you. If it's near enough
| that you found it, you have no chance of seeing it land (sort
| of like seeing a bullet whizzing past your head).
|
| Keep in mind that this flowchart is to cut down the number of
| people who contact this person wondering if their rock is a
| meteorite, which it almost always is not. I first learned about
| this chart from this: https://xkcd.com/1723/
| lupire wrote:
| Commenters didn't look at the chart to understand your
| question.
|
| It's just a mistake in the chart.
|
| "No" should point somewhere else to continue classifying. Also
| "someone" is ambiguous -- it could mean "someone nearby" (not
| meteorite) or "someone far away" (possibly meteorite).
|
| https://sites.wustl.edu/meteoritesite/items/some-meteorite-r...
| anamexis wrote:
| I don't think it's a mistake - just a cheeky note that if you
| "saw it fall," you probably didn't. Your own link supports
| this.
|
| > If you saw a meteor and later found a stone, then the stone
| is not a meteorite
|
| > Meteorite fragments land far from where you last saw the
| meteor and there is no way that observers at a single point
| on the Earth's surface are going to find fragments of the
| meteorite. It requires triangulation from several viewpoints,
| usually with cameras.
| dang wrote:
| We changed the URL from
| https://sites.wustl.edu/meteoritesite/items/self-test-check-...
| ("Do this first - Self-test check-list") to the more informative
| related page, but both are worth taking a look at!
| extraduder_ire wrote:
| The title should probably also be changed to "Meteorite fusion
| crust" or something like it.
| dang wrote:
| Ah yes, I forgot that earlier. Thanks!
| toss1 wrote:
| I read another article which asked strongly that people NOT use
| rare earth, neodimium or other strong magnets on meteorites, so
| this should perhaps be emphasized more strongly.
|
| >>You say that your rock attracts a magnet or a compass. Most
| (>95%) of meteorites (irons and ordinary chondrites) attract
| cheap magnets because they contain iron-nickel metal. Many
| terrestrial rocks, however, contain the mineral magnetite, which
| also attracts a cheap magnet. (Do not use a rare-earth magnet; a
| cheap "refrigerator magnet" will attract a meteorite.)
|
| The reason is that the strong magnets can re-orient the magnetic
| properties of the meteorite, ruining it for some aspects of tests
| or research. Seems polite to not ruin the thing for research for
| only a few seconds of 'that's cool' sensation.
| kibitzor wrote:
| To add: there's ongoing research to "reverse-engineer" the
| magnetic properties of certain meteorites that contain
| tetrataenite [0], which is as strong as a rare-earth magnet,
| but requires no rare-earths, but takes millions of years to
| make[1]. I studied techniques to speed this process up in the
| lab over a decade ago when this was new, and got to handle
| meteorites in the process.
|
| A less "magnetically invasive" way to check if a material has
| magnetic material would be to put a compass nearby (as
| recommended by the site). Also, one could put a rare earth
| magnet on a string, watch it align to the earth's field away
| from the rock in question, then bring it carefully close to the
| meteorite seeing if it settles to a newer direction. This would
| still expose the meteorite to a magnet, but a very small field
| vs checking if something sticks.
|
| [0]https://www.cam.ac.uk/research/news/new-approach-to-
| cosmic-m... [1]https://en.wikipedia.org/wiki/Tetrataenite
| toss1 wrote:
| Great extra detail -thx!
|
| Sounds like fun research and a quick skim seems to indicate
| success in fabrication - congrats! Did you get to the point
| of making magnets and if so, how strong did they get?
| baxtr wrote:
| Nice check-list. I wished it had also some "it's not a meteorite
| but this instead" pathways included.
| Simon_ORourke wrote:
| 1. Are you in the Antarctic?
|
| 2. Is that a stone on top of all the snow and ice?
|
| 3. That's a meteorite
| adonovan wrote:
| A friend (whom I shall not name) with the British Antarctic
| Survey once told me that the mornings after a meteor shower,
| they would take a Twin Otter plane out low, looking for dark
| rocks against the snow, land, gather, repeat, and finally sell
| the rocks on eBay.
|
| Your tax pounds at work. :)
| xandrius wrote:
| Unexpected bread: loved it.
| pugworthy wrote:
| R/Arrowheads could use something like this. "JAR" (for Just A
| Rock) is not an uncommon reference for things that are in fact,
| just a rock.
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