[HN Gopher] Two Grand Canyon-size valleys on far side of the moo...
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Two Grand Canyon-size valleys on far side of the moon formed within
10 minutes
Author : pseudolus
Score : 84 points
Date : 2025-02-07 16:10 UTC (3 days ago)
(HTM) web link (www.cnn.com)
(TXT) w3m dump (www.cnn.com)
| polotics wrote:
| less clickbait title would begin with: "millions of years ago..."
| simonebrunozzi wrote:
| Billions
| thunkingdeep wrote:
| Billions is technically also millions... not the parent
| commenter, just thought I'd be a nit
| kamikazeturtles wrote:
| By that logic, you can also say seconds ago...
| gcanyon wrote:
| "10^17 seconds ago..."
| IanCal wrote:
| This is why my go-to estimate for many things where the
| result is outlandishly large is "at least six".
| rob74 wrote:
| > _"Nearly four billion years ago, an asteroid or comet flew over
| the lunar south pole, brushed by the mountain summits of Malapert
| and Mouton, and hit the lunar surface," Kring said. "The impact
| ejected high-energy streams of rock that carved two canyons ...
| in less than 10 minutes."
|
| For comparison, it took 5 million to 6 million years for water to
| erode the landscape of Arizona to create the Grand Canyon._
|
| Well yeah, it sounds perfectly reasonable that two _wildly
| different_ mechanisms of producing a crack in the surface of a
| celestial body would also work on _wildly different_ timescales.
| I mean, the crater itself (which is even bigger than the
| "canyons") also formed within 10 minutes or less, but that
| doesn't sound so spectacular, because all impact craters are
| formed this way.
| opello wrote:
| From the Nature article[1], despite being prominent in the
| abstract it's almost a throwaway in the body:
|
| > ... Moon's Vallis Schrodinger and Vallis Planck were carved
| by streams of impacting rock in less than 10 min.
|
| and earlier in the same article:
|
| > Flight times of debris producing the 270 km-long main canyon
| are 4.9 to 15.0 min for Vallis Schrodinger over the entire
| range of potential ejection angles, with canyon-forming
| secondary impacts occurring within a 5 min interval. Flight
| times of debris producing the 280 km-long main canyon are 5.2
| to 15.4 min for Vallis Planck over the entire range of
| potential ejection angles, with canyon-forming secondary
| impacts occurring within a 5 min interval.
|
| I didn't dig all the way into how we get 10 minutes from 4.9-15
| minutes. I was very interested in how this time was so
| confidently bounded. I'm guessing it's the graph that charts
| impact sizes, distances, and energies to assume flight travel
| time from a point of impact.
|
| I'm also annoyed at the shift from "min" to "minutes" during
| the article. That just seems like really bad editing.
|
| [1] https://www.nature.com/articles/s41467-024-55675-z
| chr wrote:
| Then, the ejected debris that created the canyons likely soared
| over the lunar surface and then collided with it at speeds of
| about 2,237 miles per hour (3,600 kilometers per hour).
|
| Oddly adding a veil of precision to an estimate of a kilometre
| per second.
| bena wrote:
| Yeah, they just did the conversion and slapped it on there.
| Should have said "about 2200 mph".
| JoshTriplett wrote:
| It's unfortunate that the only written mechanism we have for
| expressing a lack of precision is scientific notation, which
| tends to be obfuscating for numbers at this scale: if you
| write "3.6e3 kph (2.2e3 mph)", you make it clear
| approximately how much precision you do and don't have, but
| it's less obvious-at-a-glance for the target audience of an
| article like this.
| carlmr wrote:
| Or use kps and not lose additional precision every time you
| translate units?
| bena wrote:
| In an ideal world.
| floxy wrote:
| m/s
| kingds wrote:
| 2200 would improperly add an extra significant figure, "about
| 2000" would be okay.
| bena wrote:
| I had figured since km/h was NN00, the same would be good
| for mph.
| olddustytrail wrote:
| Naw, it's already been false precisioned to hell.
|
| The original would have been "about 1000 metres/second".
| That got translated to 3600 km/h etc.
|
| Check how much it charges if it was really 800 m/s. Or
| 1200 m/s.
| hansvm wrote:
| That's only a problem if your favorite method of representing
| uncertainty is in-band signalling via a technique like
| significant figures.
| justonceokay wrote:
| You could translate the units and then also translate
| separately the error bands (assuming +/- 100 km). But "2237
| mi/hr +- 62 mph" sounds pretty silly.
| floatrock wrote:
| Use the error bands to find a close-enough round number:
| 2200 or 2300 mph or "almost 3 times the speed of sound on
| earth"
|
| Anyone pedantic enough to notice the conversion mismatch
| should be smart enough to understand the concept of "error
| bars".
| rzzzt wrote:
| 10 m/s = 36 km/h, I believe they started from a round number.
| robin_reala wrote:
| US people typically want numbers translated into American
| football fields it seems. So around 39,000 football fields an
| hour might be more obvious.
| dandelany wrote:
| Please be complete if you're gonna translate to American
| units. That's 117,000 football fields per football game, or
| 325 per commercial.
| smallmancontrov wrote:
| Does the hour include or exclude ad breaks?
| dmurray wrote:
| That's nothing! They determined that one valley formed 3.8
| billion years ago, and the other one, 3.8 billion years plus or
| minus 10 minutes.
| GaggiX wrote:
| (3.8 billion BC)
| mykowebhn wrote:
| Touche
| berkes wrote:
| BC? 3.8 billion + 2024 is still just 3.8 billion.
| GaggiX wrote:
| My comment is meant to be humorous (while still being
| informative) because the title is misleading.
| DougMerritt wrote:
| But 3.8 billion A.D. is far in the future.
| BurningFrog wrote:
| "BC" is shorter than "ago"
| EDEdDNEdDYFaN wrote:
| extremely misleading headline implies that it just happened.
| 52-6F-62 wrote:
| No it doesn't. English is as algorithmic as math.
|
| If there is a formula x = x^1 + y you wouldn't say ; no good it
| implies z is also the same. You would not because it says
| nothing about z.
| Al-Khwarizmi wrote:
| If you have a specification for a program saying "input:
| variables x and y, output: z holds x+y", you would probably
| be annoyed if someone coded "x=0; y=0; z=0", though.
|
| Just playing devil's advocate, I think the headline is not
| bad (could be less ambiguous, but sacrificing brevity)
| 52-6F-62 wrote:
| Figured someone would have to get specific. Lol.
|
| Have you read The Overstory? I recommend it, it's a great
| modern novel.
|
| "What they do?"
| yathern wrote:
| > English is as algorithmic as math
|
| Ain't no way!
|
| This "illogical" double negative shows how English is not at
| all like algebra. English is not a set of formal rules -
| there is no formal authority on the language. The rules that
| exist are derived from how English is commonly used -
| descriptive rather than prescriptive. This is why
| dictionaries are constantly adding new (sometimes annoying)
| words, and the Chicago Manual of Style is on its 18th
| version. For example, I was taught that "they" could never
| describe a singular person, and one should assume "he", "she"
| or "the suspect". Not so anymore [1]. The language, its
| constructs, and implicit rules are always changing,
| regardless (and irregardless[2]) of how you criticize those
| that speak it.
|
| [1] https://www.chicagomanualofstyle.org/help-tools/what-s-
| new.h... [2] https://dictionary.cambridge.org/us/dictionary/e
| nglish/irreg...
| andrewfromx wrote:
| Yeah I could say:
|
| "Wall Street Loses 14% Within 10 Minutes of Opening Bell" (1929
| Crash)
|
| "Radio Broadcast Causes Mass Panic Within 10 Minutes" (1938 War
| of the Worlds)
| oxygen_crisis wrote:
| You're somewhat exaggerating the effect, the headline uses
| past tense and your comparisons don't.
| berkes wrote:
| Misleading? Or just misintepretable? Misleading implies the
| author tries to lead you to a wrong conclusion. The article is
| very clear about what it really means.
|
| I immediately read the headline as "it happened in a time span
| of 10 minutes probably a gazillion years ago". So in any case,
| it's not misleading to everyone, and therefore certainly not
| "extremely misleading".
| autoexec wrote:
| > Misleading implies the author tries to lead you to a wrong
| conclusion.
|
| Why on earth would anyone assume that this clickbait title
| wasn't intended to be clickbait? What history of non-
| clickbait headlines would make anyone assume good faith on
| the part of CNN here?
| add-sub-mul-div wrote:
| Just because someone makes a wrong assumption about a headline
| doesn't mean they have to come here and tell everyone else
| about it.
| nashashmi wrote:
| It is missing a verb: "were" _formed_
| Fricken wrote:
| Reading is an act of guessing. I guessed that if the moon had
| recently been impacted that hard we would be hearing about it
| from more than CNN, and likely would have known about it in
| advance. I don't feel as though I have been mislead.
| panzagl wrote:
| Neal Stephenson fans are already heading to the salt mines.
| RandomBacon wrote:
| _Seveneves_ in case anyone wants to read it. I thought it was
| okay, certainly captivating enough for me to finish it.
| distrill wrote:
| I thought it was quite good, although maybe it should have
| been a series rather than a single book. That might have
| given Stephenson time to flesh out the end, which felt a
| bit rushed.
| atrus wrote:
| A rushed ending seems to be a key Stephenson trait in my
| experience haha
| TeaBrain wrote:
| To call that ending a bit rushed might be a little
| generous.
| janalsncm wrote:
| It is impossible for a headline to give you all of the details
| of an article.
|
| If you feel "tricked" into reading an astrogeology article, I
| would suggest you might be one of the people who should be
| reading it.
| dotancohen wrote:
| > astrogeology
|
| English needs a better term for this field. I understand that
| Astrology is already taken, but astro- (stars) geo- (earth)
| logy (study) is just wrong.
|
| Maybe Exolithology? Or Lunology, if these processes are
| unique to smaller bodies. Actually, our moon does have a
| differentiated core (I think the only one in the solar
| system) so per that argument we're a double planet (also the
| fact that the moon never has retrograde motion relative to
| the sun, another unique feature of our moon in the solar
| system) and thus just Geology is a proper enough name.
| autoexec wrote:
| No one said they were "tricked" by the article, only that the
| found the headline to be misleading which is entirely fair
| because it is a clear example of clickbait.
| stronglikedan wrote:
| It didn't imply that. You inferred that. Big difference.
| ReptileMan wrote:
| >The energy unleashed that created the canyons was 1,200 to 2,200
| times more powerful than the nuclear explosion energy once
| planned to excavate a second Panama Canal, the study authors
| estimate.
|
| Sometimes I miss that crazy boldness of the beginning of the Cold
| war era - imagination, engineering prowess and just a sprinkle of
| pure insanity.
| jerf wrote:
| If it wasn't for the radioactive fallout, it wouldn't have been
| a bad idea. It took time to understand how bad the fallout was.
| And perhaps ultimately, we came to an overestimate of how bad
| it is for various reasons... people are generally unaware that
| about 500 surface nuclear bombs have been set off for testing,
| and I think a lot of people would think that that is already
| enough to render Earth uninhabitable or something. (Although
| over the course of decades, not all in one construction
| project.) From a strictly rational perspective it is probably
| something that could be done reasonably, but, the world is what
| it is.
| seanw444 wrote:
| The tests are very pretty to watch though. I'm very grateful
| they were recorded.
| jandrese wrote:
| Even without the fallout you're still looking at a nuclear
| winter just from blowing all of that rock dust into the
| atmosphere.
| ReptileMan wrote:
| I think that you don't have fallout. You dig charges deep,
| the goal is to make huge caverns that you collapse and are
| filled with water? This is how I would do it anyway.
| andrewflnr wrote:
| Rock is not very compressible. The cavities created by
| underground nuclear tests aren't that large: https://en.wik
| ipedia.org/wiki/Underground_nuclear_weapons_te... . They
| did get surface subsidence, but maxing out at a scale of
| "over half a mile", and not terribly deep. To create "huge
| caverns", that volume still has to go somewhere, and when
| you're talking about vaporized rock that mostly means
| atmosphere or nothing, more often the latter. But at least
| they didn't _always_ get fallout, that 's nice.
| bornfreddy wrote:
| Like Aral Sea? Thanks, I can live without.
| psunavy03 wrote:
| When men were men, and test pilots were dropping like flies . .
| .
| loeg wrote:
| These comparison units are crazy. Normal people don't know how
| much energy was proposed for the Panama Canal thing either.
| floatrock wrote:
| ha! True.
|
| Yeah, back then the insane ideas were pushing the limits on
| unbounded possibilities (including unbounded destruction).
|
| Now the insane ideas are on how to deal with our bounded
| resources and life support systems (or pretending such bounds
| don't exist...)
| pmontra wrote:
| Whatever, but that's the weirdest unit of measurement I ever
| read.
| andrewflnr wrote:
| It would be really cool if they explained why the erosion was so
| concentrated in those two particular directions, instead of
| generally peeling back the surface or even lots of smaller
| streams in all directions. Why the asymmetry?
| layer8 wrote:
| Large pieces of debris, I'd assume.
| abecedarius wrote:
| I guess a very shallow angle of impact was part of it:
|
| > brushed by the mountain summits of Malapert and Mouton
| sharpshadow wrote:
| "...giant backhoes that have dug up the lunar surface and exposed
| material from underneath..."
|
| That's indeed compelling to get rock samples from.
|
| Maybe it would be even possible to see different layers of moon
| inside those canyons, but afaik the whole moon is covered in dust
| isn't it?
| thenthenthen wrote:
| Schrodinger impact basin...mmmmm
| LightBug1 wrote:
| So what. I used to bullseye womp rats in my T-16 back home.
| They're not much bigger than two meters.
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