[HN Gopher] Stellar Explosion in Earth's Proximity
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Stellar Explosion in Earth's Proximity
Author : dnetesn
Score : 206 points
Date : 2020-10-01 10:20 UTC (12 hours ago)
(HTM) web link (phys.org)
(TXT) w3m dump (phys.org)
| snapetom wrote:
| If anyone is not familiar with Anton Petrov, he churns out
| YouTube videos on new astronomy and astrophysics papers. He does
| a wonderful ELI5 job of explaining the evidence and what it all
| means in the grand scheme of things. He did one on this paper
| earlier this week.
|
| https://www.youtube.com/watch?v=7uF_W-W7h08
| qubex wrote:
| He's a truly wonderful person. ;)
| princekolt wrote:
| > When the brightness of the star Betelgeuse dropped dramatically
| a few months ago, some observers suspected an impending supernova
| --a stellar explosion that could also cause damage on Earth.
|
| Why do people keep fretting about Betelgeuse?? No, it's extremely
| unlikely it will harm earth when it goes nova:
| https://arxiv.org/pdf/1406.3143v2.pdf
| sillyquiet wrote:
| Heh remember the panic about CERN creating mini black holes?
|
| Science reporting is so very bad.
| beervirus wrote:
| It ain't just science reporting.
|
| > Briefly stated, the Gell-Mann Amnesia effect is as follows.
| You open the newspaper to an article on some subject you know
| well. In Murray's case, physics. In mine, show business. You
| read the article and see the journalist has absolutely no
| understanding of either the facts or the issues. Often, the
| article is so wrong it actually presents the story backward--
| reversing cause and effect. I call these the "wet streets
| cause rain" stories. Paper's full of them.
|
| > In any case, you read with exasperation or amusement the
| multiple errors in a story, and then turn the page to
| national or international affairs, and read as if the rest of
| the newspaper was somehow more accurate about Palestine than
| the baloney you just read. You turn the page, and forget what
| you know. - Michael Crichton (1942-2008)
|
| https://www.epsilontheory.com/gell-mann-amnesia/
| taneq wrote:
| I'm not saying the LHC _did_ create a mini black hole and
| suck the Earth into a parallel pocket universe on a dark
| dystopian timeline, but... _gestures vaguely at everything_
| rthomas6 wrote:
| In the good timeline, KitKat had a dash in its name, Fruit
| of the Loom had a cornucopia in its logo, Pikachu had black
| on the end of its tail, C3PO didn't have a silver leg, and
| you could go up in the torch of the Statue of Liberty.
| karatinversion wrote:
| And don't even get me started on Project Z!
| rob74 wrote:
| And since then we are all trapped in... _the Twilight
| Zone_! (cue spooky music)
| Loughla wrote:
| I mean, that's a good philosophical premise for a book, I
| think.
|
| Would we know if we were sucked into an alternate timeline
| via that kind of science? Would it matter to us? Could we
| change it?
|
| I'm sure there's a YA novel in there somewhere.
| taneq wrote:
| I'm pretty sure going through a micro black hole involves
| everything being spaghettified and... waaait a minute,
| now that you mention it I've been eating a LOT of
| spaghetti these last few months.
| dylan604 wrote:
| Every single SciFi show uses a shimmering effect when
| that happens, and I never saw that effect. So, it either
| happened when I was sleeping or otherwise wasn't looking,
| or it didn't happen. Or maybe it happened the night I
| took all of those mushrooms. Never can tell if I'm seeing
| something or just seeing something.
| jkinudsjknds wrote:
| It's cool. Some dude fixed it with a tv and a microwave.
| vorticalbox wrote:
| Side question do we know why it dipped in brightness?
| macintux wrote:
| Mass ejection.
|
| Updating with link: https://phys.org/news/2020-08-hubble-
| betelgeuse-mysterious-d...
| rob74 wrote:
| Another quote from later in the article:
|
| > _a very close supernova could inflict massive harm to life on
| Earth_
|
| ...but they fail to mention how close this "very close" is. I
| assume 700 light years (Betelgeuse) is a little bit far away to
| qualify? As a total amateur in astronomy/astrophysics, I would
| assume that if there were any "very close" stars that are
| massive enough to go supernova, they would already be known?!
| speakeron wrote:
| 50 light years is the generally accepted distance that would
| cause problems. There are no candidates this close that could
| cause a type II supernova (this is when a massive old star,
| like Betelgeuse, collapses), but there could be potential
| type I supernovae lurking closer. These are binary pairs of a
| white dwarf and another star where the white dwarf is
| accreting mass from the companion and reaches a limit (the
| Chandrasekhar mass) where runaway nuclear fusion
| spontaneously occurs.
| dredmorbius wrote:
| 1. Sensationalism sells advertising. Don't overlook media
| dynamics.
|
| 2. Reasonably solid understanding and low risk notwithstanding
| (Beteleuse, at 300 light years, is well outside the 50 l.y.
| danger zone), some people will harbour some uncertainty,
| warranted or not.
|
| 3. It'll still be the biggest pop in the neighbourhood for a
| while.
| SamBam wrote:
| Was the "could also cause damage on Earth" theory a widespread
| worry? I never heard that in any of the reporting of the issue.
|
| My "worry" was based only on losing one of the nicest stars in
| the Heavens, although a certain excitement of the idea at the
| same time.
| uCantCauseUCant wrote:
| Eh, the supernova if it is impending for us- has already
| happened in the lightcone
| marcosdumay wrote:
| But it will look amazing.
|
| > When this supernova explodes it will be closer than any known
| supernova observed to date, and about 19 times closer than
| Kepler's supernova. Assuming it explodes as an average Type II
| super-nova, the optical luminosity will be approximately -12.4,
| becoming brighter than the full moon.
| TacticalTable wrote:
| Do we have any idea how long that light would last, and how
| long it would take to get to full brightness?
| jandrese wrote:
| Typically 3-5 months I think. It's not like it just turns
| on and off either, it flares up then slowly fades over
| time.
| DrBazza wrote:
| Is this the cause of the Local Bubble? Phil Plait's Death From
| The Skies book mentions a 'smoking gun'.
| antonvs wrote:
| The Local Bubble is thought to have been caused my multiple
| supernovae. See e.g. this 2002 paper:
| https://arxiv.org/abs/astro-ph/0205128v2
| btilly wrote:
| It seems to line up well enough. And it is hard to imagine
| another explanation.
|
| The gas arrived here 2.5 million years ago. According to
| https://en.wikipedia.org/wiki/Local_Bubble it seems that the
| Local Bubble was created 10-20 million years ago by a
| supernova, and we've been traveling through an area currently
| occupied it for the last 5-10 million years.
|
| If we've been traveling through that region for 5 million
| years, and the bubble is expanding as fast as we are moving
| (and we are moving at a pretty good clip), then we would have
| encountered the edge of the bubble 2.5 million years ago. Which
| would be exactly right for that to be this.
|
| And it is hard to imagine that there has been another supernova
| near us that it could have been, without it having left obvious
| signs of its existence. So Occam's razor says that this has to
| be right. The supernova that we know from astronomy had to
| happen near where we are now is the one that dumped detectable
| amounts of material on us 2.5 million years ago.
| baxtr wrote:
| I wonder if the The Permian Extinction (250 mil years ago) was
| caused by something like that?
| [deleted]
| DarkmSparks wrote:
| Surely (even) if it was deposited here 2.5 million years ago, it
| would have taken an insanely long time to get here.
| snapetom wrote:
| There's thought that it was so close, we're still flying
| through the remnants.
| Ma8ee wrote:
| Considering that a supernova jettisons material 15,000 to
| 40,000 kilometers per second [0], it would only take a few
| decades for the material to reach earth from a star in earth's
| proximity, which I interpret as a few light years away.
|
| [0]
| https://www.nationalgeographic.com/science/space/universe/su...
| DrBazza wrote:
| Also, the material swept up from the supernova, by the Earth
| is of the order of hundreds of tons
| (https://en.wikipedia.org/wiki/Death_from_the_Skies!)
| dredmorbius wrote:
| That would be 400--1,000 years for a supernova 50 light years
| distant, and clearly less for a closer event.
|
| Astronomically and geologically an eyeblink.
| JKCalhoun wrote:
| Always fascinated by historical observations of super novae:
| https://en.wikipedia.org/wiki/History_of_supernova_observati...
| datenwolf wrote:
| They did it, they finally did it!
|
| Context: I did my diploma thesis work at that lab, and shared the
| office with those guys. This is a result almost 10 years in the
| making.
|
| Congrats!
| nomoreusernames wrote:
| yaaay i dont know anything about the subject but its something
| about science and somebody made progress so i will be happy
| just like a golden retriever is anytime you start dancing out
| of joy! im happy because you are happy!
| foota wrote:
| So stupid question, what was the slow part of this? Was the
| spectrometry process developed just for this?
| datenwolf wrote:
| They were using a so called accelerator mass spectrometer
| (AMS). The main challenge, as I understood it from talking
| with them, was in the chemistry required to prepare the
| samples for injection into the AMS. Specifically ensuring
| that there's no background signal created from the
| preparation itself. So there was a lot of work done just to
| get the process right (the less steps to prepare the sample,
| the less steps that might contaminate it). Then a lot of
| verification, calibration on the AMS and optimizing the beam
| transport to reduce losses as far as possible.
|
| EDIT: The AMS was built and used in a lot of experiments
| before that. Among other things done with that instrument was
| measuring the neutron flux of the nuclear blast at various
| locations in Hiroshima, by determining the isotopic
| composition of the copper on building facade elements.
| Neutron capture produces some radioactive as well as
| "unnatural" stable isotopes and by determining their ratio,
| one can determine the neutron flux and energies.
|
| https://www.researchgate.net/publication/6012967_Neutron-
| ind...
|
| It saddens me, that the accelerator they (and I for that
| matter) used for their research, has been decommissioned as
| of last year and is being dismantled right now :( - I could
| start a major rant about it, that would touch the subjects of
| funding, some people's personal pride and good science vs.
| fashionable science.
| codezero wrote:
| I left academia not long after our satellite got de-funded
| (it's still in orbit, operating and sending telemetry, just
| the Navy's side of the satellite that is.)
|
| Recessions will also hit even harder - when the next grant
| cycle hits in the winter/fall, a lot of good teams are
| going to get screwed. I really hate the inconsistency and
| the waxing and waning - fwiw, there were times my team just
| grabbed grant money and spun wheels on old research, so
| it's not just that the money dries up easily, I don't think
| there's good accountability when the money is flowing
| either.
| cmpb wrote:
| Please, rant away! I'm interested in your opinion and the
| context of the decommissioned machine
| btilly wrote:
| https://news.ycombinator.com/item?id=24650325 asks whether this
| was caused by the same supernova that created the Local Bubble.
|
| As someone with inside knowledge, can you review my reasoning
| that it fits, and it probably was?
| datenwolf wrote:
| > As someone with inside knowledge, can you review my
| reasoning that it fits, and it probably was?
|
| No idea. I left that particular lab a few months after I
| graduated which was 8 years ago.
| ivoras wrote:
| Astrophysics just seems soooo speculative. Even with margins of
| error in the millions of years and light years, it just seems
| that most of it is assumptions supported not by evidence (because
| we can't get direct evidence) but by previous assumtions which
| have over time fossilised into accepted theories.
|
| Not saying this paper isn't good or anything, just that
| extrapolating a supernova from a few atoms of an isotope of a
| metal seems... a long fetch. Though probably better than nothing.
| simonh wrote:
| Well, they have to come from somewhere and supernovae are the
| only process that makes them. If you find them consistently in
| a layer of a certain age all over the Earth, that points to a
| single source. Two different isotopes too, but only created by
| the same process so far as we know. It's pretty decent
| evidence.
|
| As for direct evidence, I know what you mean. There so way to
| observe the supernova, but how often do the jury get to watch a
| murder happen on film? Yet we still convict murderers.
| dgellow wrote:
| Given how flawed jury based systems are I'm not sure that's a
| good analogy :p
| Cederfjard wrote:
| How do you define evidence?
| 7373737373 wrote:
| Should have added a [2.5 million years ago], I was worried for a
| second there
| [deleted]
| thysultan wrote:
| Here let me fix it: "...in 2.5 million year cycles"
| vagab0nd wrote:
| Me too. But thinking about it more, the good thing about
| astronomy is that everything is in slow motion. We'd probably
| have a long time to react.
| neuronic wrote:
| We would probably cause our own mini stellar explosion on
| Earth before anything hit us from somewhere else.
| igor47 wrote:
| seriously, my heart was pounding for a sec. the subject line
| should really be changed.
| mckirk wrote:
| It's 2020, my first instinct was to look at the sky to try and
| spot the impending supernova.
| mtgx wrote:
| 2020: Stellar Explosion for president!
| 1_player wrote:
| How good is our supernova detection technology?
|
| Would we be able to predict one with reasonable precision [1]
| before it wipes off the face of the Earth, or would we fry
| with gamma rays before we knew what was going on?
|
| 1: "by this time next year we'll all be dead with 99%
| certainty"
| spaetzleesser wrote:
| I think right now "reasonable precision" means "within the
| next few ten thousand years".
| BurningFrog wrote:
| After Betelgeuze blows, we should know more about what to
| look for.
| spaetzleesser wrote:
| I think that's the real problem. We have no first hand
| observations of the processes around a supernova before
| it blows up. It may take a very long time until we will
| get these observations.
| freehunter wrote:
| Ultimately I'm not sure it matters if we detect a supernova
| that will kill us within a year. That's not enough time to
| do anything about it, but enough time for worldwide panic
| and massive suffering before we all die anyway.
|
| We'd really need to know at least 10-20 years out. Enough
| time to rally the world to find a solution but not enough
| time that it ceases to be a concern (like thousands of
| years).
| jaynetics wrote:
| That's an interesting thought. Severe consequences of
| climate change can be expected within decades, but
| apparently that is still to far off and hard to imagine
| for many people, and hard to sell for politicians. This
| leaves me wondering if people would accept decades of
| worsening quality of life (moving into caves etc.) even
| if the alternative was certain death by gamma rays.
| qubex wrote:
| I presume that if the astronomers did spot an imminent
| supernova that threatens to extinguish life on earth, we'd
| collectively respond by lowering interest rates to
| stimulate the economy...
| zaarn wrote:
| Betelgeuse, the only star that I know of within the range
| to produce a supernova dangerous to us, has scientists
| looking at it closely. Mostly because it's a closeby giant
| and those are interesting.
|
| I think most estimates range between 40'000 and 140'000
| years until core hydrogen is exhausted. It's ejecta are
| unlikely to reach earth or cause harm (either radiation or
| otherwise). So while it lasts, you can enjoy reading a book
| under the light of a dying star at night for a few days.
|
| Eta Carinae is another candidate but it's too far away and
| unlikely to outshine Venus significantly. It's also not due
| for some due. There is also the possibility it'll just
| collapse into a black hole with no fanfare or extra light
| emission, it'll just be gone one day.
|
| Supernovae usually come from very bright stars, those are
| easily detectable and visible. From what I remember, there
| aren't any candidates even close to us that are about to
| expire minus Betelgeuse, which isn't aiming it's poles at
| us and won't do much harm.
|
| I would like to add that in the even we could predict that
| a supernova is about to wipe us out, there isn't anything
| we could do. Any nearby object we could use as shelter,
| such as Venus, Mars, the Jupiter Moons etc would likely be
| just as affected if not more (Jupiter's magnetic field will
| likely make a Supernova hit more deadly IMO). It would be
| over within the span of a few days and nobody will survive.
| Just lean back and enjoy the show, tbh.
| sokoloff wrote:
| I am irrationally frustrated that I won't live to
| experience this. I mean there are so many more important
| things to live for, but...
| echelon wrote:
| > Jupiter's magnetic field will likely make a Supernova
| hit more deadly IMO
|
| Why is that?
| Aperocky wrote:
| Core hydrogen is already gone in Betelgeuse case.
|
| It's a matter of when it gets to Fe56 and exceed
| Chandrasakhar limit
| TaupeRanger wrote:
| I wonder if there are any sci-fi books with a doomed
| planet along these lines. Pick up 10 years before the
| planet gets destroyed. People of the past lived with the
| futility of trying to escape, doing almost nothing, and
| now people are desperate and taking insane scientific
| risks to try to save the species.
| narag wrote:
| In Ring World there is a massive burst in the galaxy
| center and there is a race that, instead, puts its
| planets in formation and moves them to the edge of the
| galaxy.
| paul_f wrote:
| Neal Stephenson's Seveneves is a great read kinda along
| these lines.
| qubex wrote:
| I loved _Seveneves_ but I disagree that it provides an
| indication of how one would face this kind of emergency.
| For sure one would not venture into space if one fears an
| onslaught of harsh gamma-ray radiation. It's an entirely
| different kind of disaster.
|
| (SPOILER: Admittedly, the underground and underwater
| subplots might be more applicable but... they're side-
| shows at best.)
| abecedarius wrote:
| Seconded.
|
| There's a trilogy starting with The Last Policeman with a
| similar scenario: kilometer-scale asteroid projected to
| hit in about a year. To a first approximation everyone
| just says "Well, fuck, guess we're going to die."
| Thinking about the ways that seemed unrealistic and how I
| thought it would go instead, Seveneves turned out a lot
| more like it (though with exciting-story elements
| injected, and also in Seveneves they're starting from
| maybe a decade ahead of us in space tech). (The Last
| Policeman is still interesting in other ways.)
|
| Egan's _Diaspora_ is another good match, with an
| astrophysical cataclysm instead of a merely planetary
| one. It happens to a much more advanced future society,
| though.
| brandmeyer wrote:
| It was the plot of a Star Trek: The Next Generation
| episode, and a pretty good one.
|
| https://en.wikipedia.org/wiki/The_Inner_Light_%28Star_Tre
| k:_...
| sliken wrote:
| Larry Niven has a short inconstant moon where the main
| character looks up at the moon which brightens to 1000
| times normal brightness, what that means dawns on him
| shortly later.
| hvis wrote:
| Three Body Problem has this as one of the premises.
| cgriswald wrote:
| Years ago, and it might have stolen the story from
| somewhere else, there was a Twilight Zone/Outer
| Limits/Tales from the Darkside type show and in one
| episode space explorers are visiting the remains of a
| charred planet ~2,000 light years away. They learn the
| star that went supernovae and that it is the star the
| three wise men followed to Bethlehem.
| nobody9999 wrote:
| >Years ago, and it might have stolen the story from
| somewhere else,
|
| Yes they did. It was Arthur C. Clarke's "The Star"[0].
| And it was "The Twilight Zone" (1980s version).
|
| While the TV episode was interesting, the short story
| itself is _much_ better. I highly recommend it.
|
| The story was in the "The Nine Billion Names of God"
| collection[1]. The title story is also interesting in its
| religious focus.
|
| [0] https://web.archive.org/web/20080718084442/http://luc
| is.net/...
|
| [1] https://en.wikipedia.org/wiki/The_Nine_Billion_Names_
| of_God_...
| jandrese wrote:
| If you're talking about a massive gamma burst sterilizing
| life on the surface of the planet there are some
| continuation of the planet options with a 10 year
| timescale. Ark submarines full of embryos that are mass
| produced by a world that somehow puts aside their
| differences and comes together for the singular goal of
| saving life.
|
| Restarting the carbon cycle would require a massive
| effort, but with planning and lots of hard work it might
| be possible. The post apocalyptic world would be a
| strange place full of dead plants and animals that take a
| long time to start decaying because all of the microbiota
| that normally cause decay were also killed off. It would
| be interesting to see how fast they would spread
| afterward. It would give humanity a small buffer before
| they start releasing gigatons of CO2 into the atmosphere
| at least. It really depends on how well the oceans
| survive. If algae can come back reasonably quick the
| planet can be saved.
| ivalm wrote:
| I think there is also the issue that that level of gamma
| will mess up atmospheric chemistry. Something like
|
| N2+O2 -> dissociated N and O plasmas -> NO2
|
| Which means the air might become not breathable.
| dodobirdlord wrote:
| I don't think there would be much in the way of dead
| plants and animals lying around. In an oxygen atmosphere
| any organic material would ignite, and a sufficiently
| intense burst would melt anything on the surface of the
| crust that doesn't burn.
| hirundo wrote:
| See the classic Larry Niven short story Inconstant Moon,
| collected in All the Myriad Ways.
| waffle_ss wrote:
| Wild that this throwaway "haha 2020 amirite?" comment got at
| least 22 karma. HN comment SnR has really nosedived in the
| past year (yeah I know, I'm not supposed to say anything
| because guidelines, but it's true).
| blocked_again wrote:
| Well that would be against the anti click bait journalism
| ethics guidelines.
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