[HN Gopher] 70% of meteorites from 3 collisions in asteroid belt...
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70% of meteorites from 3 collisions in asteroid belt within past
40M years
Author : bookofjoe
Score : 62 points
Date : 2024-10-24 18:56 UTC (4 days ago)
(HTM) web link (skyandtelescope.org)
(TXT) w3m dump (skyandtelescope.org)
| luckystarr wrote:
| Its baffling how they can reconstruct such an ancient event that
| happened so far away.
| Teever wrote:
| It makes me think of this:
| https://www.youtube.com/watch?v=p08_KlTKP50
| ithkuil wrote:
| Funny. My first thought was: what? 40Mya? That's recent history
| by astronomical standards!
| tracerbulletx wrote:
| Yeah that's recent enough some early primordial primates
| would have seen it.
| ForOldHack wrote:
| Give it another 80M years, and perhaps a fine dust could make
| some fine sunrises on Jupiter.
| Gigachad wrote:
| I guess there are just so few interactions in space that it's
| pretty easy. Bunch of rocks that have been on the same course
| for millions of years, and aren't impacted by air resistance or
| anything to slow them down.
| dark-star wrote:
| This pretty much means that there were only 3 large collisions in
| the asteroid belt in the past 40M years... Which is astonishing
| considering how busy the belt is...
| ryandrake wrote:
| It's not that "busy" though, is it? My understanding is that
| asteroids are pretty damn small and very far away from each
| other. It's always funny to see an "Asteroid Belt" in Sci Fi
| movies and TV, where it looks like they're flying their
| spaceships through a raging river of rocks dodging one every
| second. In reality: if you were standing on any asteroid in the
| belt, would you even be able to see any other one with the
| naked eye?
| dylan604 wrote:
| So you have a gripe about sci-fi for not being realistic
| about asteroid fields, but the ability to fly a space craft
| with the agility of a fighter jet on Earth is okay? I love
| the arbitrary nature every single sci-fi person has in their
| application of suspension of disbelief. There's a lot of
| times I end up thinking, "oh I didn't think about that" after
| someone mentions a hang up they have, and there's other times
| where I'm laughing at the ridiculous nature while someone
| else thought it was much more acceptable.
| ARandumGuy wrote:
| I think it's less "this asteroid belt is unrealistic," and
| more "I assumed asteroid belts were dense because that's
| what it's like in movies."
|
| For a lot of people, they know that super nimble spaceships
| aren't real, but they may have never thought about asteroid
| belt density. People often see something in media that
| seems plausible, and assume that's what it's like in
| reality, even if the media portrayal was way off. I can
| guarantee it's happened to you at some point.
| dylan604 wrote:
| The asteroid belt around Sol might be sparse, but what
| about other solar systems, other galaxies far far away?
| dotancohen wrote:
| Then gravity would condense it all down into a planet in
| very short order, geologically speaking.
|
| For an example in our own system, see Saturn's rings.
| gus_massa wrote:
| If the density of the asteroid belt is too high, I guess
| it (slowly) collapses and you get a planet.
| kadoban wrote:
| A belt like shown in many movies would become a damn
| black hole with how dense and large they are. They're not
| just unlike Sol's, they're completely ridiculous.
| jiggawatts wrote:
| To be fair, in at least some movies they only say
| "asteroids" instead of "asteroid belt".
|
| The aftermath of a recent collision between large bodies
| might be attractive to future spacefarers because it
| could expose the differentiated insides of planetoids in
| a convenient high-density but accessible form for mining.
| So I wouldn't be entirely unrealistic for "future
| stories" to be playing out in these rich and dense
| regions instead of the space equivalent of the middle of
| a barren desert.
|
| A statistically representative locale for a story on
| Earth would be in the middle of an ocean, _but that's not
| where most stories come from_.
| andrewflnr wrote:
| True, but that's not what they usually depict on screen.
| We see lots of "normal looking", i.e. rounded, well-aged,
| thoroughly cratered asteroids, neither the fresh shards
| or glowing/molten material we would expect from a
| collision.
|
| I do like the idea of prospectors diving into the debris
| of a recent asteroid collision to gather halfway pre-
| refined resources. With the rarity of asteroid collisions
| relative to human lifespans, I imagine the response the
| way deep sea creatures respond to a whale fall, sudden
| massive availability of resources. I might try to write
| that someday.
| ForOldHack wrote:
| You should ask them.
| buran77 wrote:
| > the arbitrary nature
|
| "Sci-fi" already tells you what's the fictional part of the
| story: the science/tech, and maybe some fundamental rules
| around those. Fantasy is where you get to rewrite the basic
| rules of the universe.
|
| In the span of a few decades we went from no planes to
| flying at almost Mach 10 in air (X-43) and 600.000km/h in
| space (Parker probe), and from AM radio to a super-computer
| in everyone's pocket. So you can bet any person can
| _reasonably_ imagine that in a few centuries we could be
| advanced enough to build today 's sci-fi. That's because
| they have a few real anchor points in the history of human
| civilization or even their own lifetime and an easy
| assessment of the progress of science between them.
|
| Most people also actually think asteroid belts are that
| dense. But that's because even basic concepts about gravity
| aren't immediately apparent from day to day experience.
| Basic grasp of gravity will never allow you to believe it
| naturally "wears off" in an asteroid field so the chunks
| stay close enough to even collide but magically never clump
| together, or that 1000 years "in the future" will change
| what was constant for billions of years.
|
| It only seems arbitrary if you don't bother to think about
| it.
| andrewflnr wrote:
| > but the ability to fly a space craft with the agility of
| a fighter jet on Earth is okay?
|
| What makes you think that GP thinks that? The mere fact
| that they didn't mention that, among all extant silliness
| in scifi media, in the context of a discussion about
| asteroids?
| bongodongobob wrote:
| The asteroid belt isn't like in Star Wars/Trek. The distances
| are huge. Average distance, from a quick Google says about 1
| million kilometers apart.
| blackeyeblitzar wrote:
| Does that mean the asteroid belt is some kind of ancient Kessler
| Syndrome but for the solar system?
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