[HN Gopher] Brightest-Ever Space Explosion Reveals Possible Hint...
___________________________________________________________________
Brightest-Ever Space Explosion Reveals Possible Hints of Dark
Matter
Author : rbanffy
Score : 146 points
Date : 2022-10-28 13:12 UTC (9 hours ago)
(HTM) web link (nautil.us)
(TXT) w3m dump (nautil.us)
| valarauko wrote:
| Q: do gamma rays undergo red shifting as they travel across the
| universe? If so, did they start out as gamma rays or get shifted
| into gamma rays?
| simcop2387 wrote:
| They absolutely do get red shifted (or blue shifted). In this
| regard they are no more special than any other electromagnetic
| wave. That said I don't believe we've got any kind of
| classification for higher energy EM waves than "gamma rays" so
| anything that red-shifted to gamma rays would be gamma rays
| originally anyway.
| hinkley wrote:
| However if you travel at relativistic speeds it's possible
| and likely for particles in the ligh cone ahead of you to be
| blue shifted to gamma. It's a major thing we seem to leave of
| when talking about interstellar travel.
|
| It's one of the lovely things about the Alcubierre drive, if
| anyone ever figures out how to make it work that is. You're
| traveling in a bubble that is moving at slower speeds, so the
| light cone is hitting you with fairly mild blue shifting
| instead of both barrels.
| roywiggins wrote:
| Maybe rather bad for your destination though:
|
| "were an Alcubierre-driven ship to decelerate from
| superluminal speed, the particles that its bubble had
| gathered in transit would be released in energetic
| outbursts akin to the infinitely-blueshifted radiation
| hypothesized to occur at the inner event horizon of a Kerr
| black hole; forward-facing particles would thereby be
| energetic enough to destroy anything at the destination
| directly in front of the ship"
|
| https://en.wikipedia.org/wiki/Alcubierre_drive#Damaging_eff
| e...
| hinkley wrote:
| Oh my. So 'back-in parking only' unless you want to end
| up in whatever the interstellar equivalent of The Hague
| ends up being.
| lazide wrote:
| Decelerating at sub-light speeds will also require
| massive high energy exhaust plumes if we're using any
| traditional drives for that, which if a 'warp' drive is
| possible, we'd likely still need.
|
| So death from both ends, basically.
|
| Probably best to wait for us to land to say hi, or nuke
| us from far enough away the mess doesn't get in their
| hair.
| quadcore wrote:
| I've an unrelated beginner physic question that make me lose
| sleep.
|
| Say Im on earth with a clock and a photon - with a clock - is
| emitted from the sun towards me.
|
| Is the following correct: when the photon reach me, my clock
| ticked for say 1 hour and I see photon's clock ticked for say 1
| min. But the photon sees its clock at 1 hour and mine at 1min?
| [deleted]
| TheCraiggers wrote:
| It should be noted that math sort of breaks down when you
| actually hit _c_. As I understand it, the math is a bit
| undefined as you 're effectively past the asymptote.
| Technically, I've always read that light has no reference
| frame.
|
| Basically, light doesn't experience _time_ as such, so your
| question kinda doesn 't make sense as written.
|
| I'm glossing over details here, but if I'm wrong I would love
| to learn why from somebody with more knowledge!
| Ancalagon wrote:
| What I think you're asking:
|
| "The photon has a watch, and I have a watch. Both read 12:00.00
| when the photon is emitted from the sun. What do the watches
| read when the photon reaches me?"
|
| Photons take ~8 min to travel from the sun to the earth.
| Therefore MY watch reads 12:08.00.
|
| The photon's frame of reference is at the speed of light
| though. So because of time dilation, the photon's watch reads
| 12:00.00.
|
| The photon traveled all that distance without experiencing any
| time at all. In fact, if you, a human being, could travel at
| the speed of light (spoiler: you can't) without running into
| anything, you would live forever in reference to the universe.
| quadcore wrote:
| _The photon 's frame of reference is at the speed of ligh_
|
| Thats the part I dont understand. From earth point of view
| the photon (or the spaceship) goes at speed of light (or
| close to it). But from the photon point of view, the earth is
| going at speed of light. If thats not the case, then speed
| isnt relative its absolute: photon goes at speed of light,
| earth does not.
| codethief wrote:
| The velocity of objects moving through spacetime is
| relative but there are certain quantities that aren't. The
| fact whether or not an object is traveling at the speed of
| light is one such quantity (called the interior product of
| the 4-velocity vector). That is, it is independent of the
| observer. So in all frames of reference Earth is traveling
| at sub-lightspeed velocities and the photon is moving at,
| well, the speed of light.
|
| Second, a photon doesn't have an inertial frame of
| reference. There is no "photon point of view". The
| equations that relate the velocities of the same object as
| seen from different reference frames break down when you
| plug in the speed of light as relative velocity between the
| two frames. Put differently, all frames of references have
| relative velocities that are lower than the speed of light.
|
| Hope this answers your question!
| quadcore wrote:
| Nice. Thanks.
|
| Not quite tbh. What if we are taking a fast spaceship
| instead of a photon. Spaceship starts from sun toward me.
| When it reaches me, I see my watch has ticked for an hour
| and I see the spaceship watch has ticked for 15 min. But
| from the spaceship point of view, earth was going toward
| it. From spaceship point of view, its watch must have
| ticked for an hour and it sees mine has ticked for 15min.
|
| If things are relative why isnt it the case?
| aardvark179 wrote:
| Right. So you see the ship taking an hour to travel from
| the Sun to the Earth, and the ship's clock only counts
| fifteen minutes. But you turned this round and ask how
| much time the ship would see our clock tick during its
| journey? Now if everything is symmetrical then it would
| see our clock tick 3.75 minutes.
|
| So, the thing the observers disagree in their different
| reference frames is what "now" means.
| quadcore wrote:
| I thought A goes toward B at C is undistinguishible from
| B going toward A at C. So if A sees A:60min and B:15min,
| therefore B should see B:60min and A:15min. Anything
| other than that means something was absolute.
|
| Damn its frustrating. Month I ask questions about that.
| Every time I get: velocity is absolute. Maybe it is,
| maybe thats the answer to my question, velocity is
| absolute, meaning the ship is going toward earth in
| "absolute". But then one could be at rest in the universe
| and then there is an absolute frame in the universe thats
| motionless. Therefore we could elect a center.
| aaroninsf wrote:
| Thank you for this framing. I haven't thought about this
| particular corner before!
|
| Also, if it is the case that from the POV time is not
| passing _at all,_ all time passes in no time, which would
| mean perceiving the entirety of time in one static
| juxtaposition,
|
| but... can information reach a thing traveling at light
| speed? Does it matter the angle of incidence? (Nothing can
| catch up, but information-carrying particles like other
| photons could intersect or approach head on... but with
| their own relative velocity capped...?)
|
| Time to fire up the Wikipedia...
| Ancalagon wrote:
| Nothing can travel faster than light, so no, nothing can
| catch up to something traveling at the speed of light.
|
| Really though the physics says nothing can _attain_ the
| speed of light, so light (or some other photon) could
| still intercept something with mass traveling at
| 99.9999999% the speed of light. And that thing with mass
| will never reach 100% the speed of light.
|
| If you want to look deeper I suggest checking out the
| accelerating expansion rate of the universe, and what
| that means for information traveling throughout the
| universe over the next billions of years. Humanity is
| actually extremely lucky to have been born at a time when
| the universe was young enough to still be mostly visible.
| Civilizations that come about in the next 10s of billions
| of years might actually assume their galactic clusters
| are the only ones in existence (much like we thought
| initially until Hubble found another galaxy).
| cdelsolar wrote:
| From the photon's perspective, the entire universe is
| compressed to a line of infinitesimal length, from the
| place it was emitted to the place it is ultimately
| absorbed, if any. In its perspective, it takes 0 time to
| travel through that line (really more of a dot).
| karmakaze wrote:
| Do photons have to slow down to change? Change requires time
| to pass doesn't it? So how does a photon change polarization
| (without slowing down)?
| jjslocum3 wrote:
| Also what I think is being asked:
|
| ...if the photon comes to rest on earth, and we compare
| clocks...
|
| IIRC, the deceleration of the photon relative to me (as it
| comes to rest on earth as would a returning space traveler)
| would "reverse" the time dilation relative to me, so both our
| clocks would read 12:08.
|
| Please, correct me if I'm wrong. I read this many years ago
| but never dove all the way into the math.
| Ancalagon wrote:
| No. This difference in the clocks will remain even if you
| could somehow slow down the photon without it being
| absorbed. This is why if you sync two atomic clocks, bring
| one atomic clock up to orbiting speed (such as on a gps
| satellite), then decelerate it and return it to earth the
| clocks will still read different numbers.
|
| Which is why if you could accelerate yourself to say 90%
| the speed of light, then decelerate and return to earth,
| you would have essentially traveled into the future and
| outlived everyone you ever knew.
| MikeDelta wrote:
| The photon actually experienced only one minute* and you one
| hour, that is what the clocks would show. The photon sees you
| one hour older and you see the photon one minute older.
|
| It is like the waterplanet in the movie Interstellar (I think
| it was that planet), where they spent a short while on the
| surface and the person in space aged decades.
|
| It is called time dilation [0] and there was a rather
| interesting experiment done by Hafel Keating [1].
|
| * Interesting to know: time slows down to a halt at the speed
| of light, and the one second time lapse of the photon goes to
| zero no matter how long you wait on earth.
|
| [0] https://en.m.wikipedia.org/wiki/Time_dilation
|
| [1]
| https://en.wikipedia.org/wiki/Hafele%E2%80%93Keating_experim...
| Victerius wrote:
| Ancient intergalactic war between two alien civilizations. Facing
| imminent defeat, Emperor Glurkz resolved to take his foe down
| with him, and detonated his ultimate weapon.
| pavlov wrote:
| Could also be noise from the construction site of the Goe D.
| Glurkz Intergalactic Tunnel. A notice about this unfortunate
| disturbance was posted 7,700 years ago in our local
| municipality Galaxy Hall in downtown Mu Cephei.
| daveslash wrote:
| Posted?!? I eventually had to go down to the cellar to find
| them. With a flashlight. And the stairs were gone! It was on
| display in the bottom of a locked filing cabinet stuck in a
| disused lavatory with a sign on the door saying 'Beware of
| the Leopard'.
| pmontra wrote:
| We never got to know if there was really a leopard in that
| room.
| ly3xqhl8g9 wrote:
| No way. It was clearly some intern testing in production the
| fancy new framework for handling remote total obliteration with
| no side-effects. Naturally, the side-effects were plenty and
| extremely local.
| muxxa wrote:
| Is there any estimation of the angular width of the cone for
| these sorts of gamma ray bursts?
| anentropic wrote:
| I love how we're able to debate the origins and life story of a
| single photon from 2.4 billion light-years away
| yummybear wrote:
| It's the ultimate counterargument to "my actions don't matter".
| Nevermark wrote:
| Distance:
|
| 2.4 billion light years = (2.4 * 10^9) * (6 * 10^15) meters = 15
| * 10^24 meters away! (approximately)
|
| Area of emission sphere at contact with Earth:
|
| 4 * pi * (15 * 10^24 meters)^2 = 2 * 10^50 meters^2 sized sphere
| when passing Earth (approximately)
|
| The amount of energy that must have been spread out over that
| sphere shaped wave, so any discernible signal reached Earth, much
| less interacted noticeably with our atmosphere ... simply
| incredible.
| [deleted]
| zasdffaa wrote:
| Err, looks like we were hit by a polar jet
| https://en.wikipedia.org/wiki/Astrophysical_jet so the energy
| doesn't radiate equidirectionally. But still mindblowing, and
| thanks for doing the maths.
| pmontra wrote:
| In fiction: the solar flare of Inconstant Moon [1] and, very
| appropriately, the gamma ray burst of Diaspora [2]
|
| [1] https://en.wikipedia.org/wiki/Inconstant_Moon
|
| [2] https://en.wikipedia.org/wiki/Diaspora_(novel)
| zh3 wrote:
| I remember reading [1] and enjoying the hard science (e.g.
| Jupiter taking its time to light up). Then the dawn...
| zh3 wrote:
| >The burst even appears to have caused Earth's ionosphere, the
| upper layer of Earth's atmosphere, to swell in size for several
| hours.
|
| For a gamma ray burst from an object that's 2.4 billion light
| years away, that seems pretty worrying. If it had been in our
| galaxy (50k light years across, so about 50,000 times closer) I'd
| assume the consequences would be serious indeed.
| lostmsu wrote:
| The object is likely an active galactic core, so couldn't have
| been in our galaxy.
| zasdffaa wrote:
| 2.4 x 10^9 light years away, so not in our galaxy by a very
| large measure.
| actionfromafar wrote:
| I think the meaning was more, that our galaxy can't produce
| such events, so that's one thing we don't have to worry
| about in our galaxy.
|
| Edit: a (to me) random site [0] says the Milky Way does not
| have an active galactic nucleus.
|
| 0: https://socratic.org/questions/does-the-milky-way-have-
| an-ac...
| zasdffaa wrote:
| Okay, missed that.
| https://en.wikipedia.org/wiki/Active_galactic_nucleus
| says
|
| "An active galactic nucleus (AGN) is a compact region at
| the center of a galaxy that has a much-higher-than-normal
| luminosity over at least some portion of the
| electromagnetic spectrum with characteristics indicating
| that the luminosity is not produced by stars. Such excess
| non-stellar emission has been observed in the radio,
| microwave, infrared, optical, ultra-violet, X-ray and
| gamma ray wavebands. A galaxy hosting an AGN is called an
| "active galaxy". The non-stellar radiation from an AGN is
| theorized to result from the accretion of matter by a
| supermassive black hole at the center of its host
| galaxy."
|
| Do we? https://en.wikipedia.org/wiki/Sagittarius_A\* says
|
| "Sagittarius A*, abbreviated Sgr A* is the supermassive
| black hole[4][5][6] at the Galactic Center of the Milky
| Way"
|
| Front row seat! Get in!
| codethief wrote:
| Sgr A* isn't a very active black hole (meaning that it's
| accreting only very little matter), compared to black
| holes at the center of AGNs.
| voorwerpjes wrote:
| These types of GRBs are caused by the death of massive stars
| with low metallicity, not active galactic nuclei. There
| absolutely could be a GRB inside of the milky way galaxy
| pointed at us, but it is very unlikely.
| LargoLasskhyfv wrote:
| Is that so? There is the theory that our galaxy could be a
| Seyfert Galaxy, we just haven't witnessed it so far.
|
| https://link.springer.com/article/10.1007/BF00717870
|
| https://earthsky.org/space/explosion-milky-way-center-
| seyfer...
|
| https://www.bbc.com/news/science-environment-49955468
|
| Edit: I meant to say that our galaxy could, and has had such
| fits of rage, not that _this_ event could have come from it.
| zasdffaa wrote:
| From the article
|
| "It's also likely that the BOAT's powerful jet was pointed
| toward us"
|
| The energy given out is(?) very non-isotropic. A random shot
| got 'lucky' and hit us.
| zycon wrote:
| There's a hypothesis that Ordovician-Silurian extinction cca
| 450 milion years ago, one of the big five mass extinctions, was
| caused by a GRB.
| nicksrose7224 wrote:
| Is there any data to back this up? (not attacking, just
| genuinely curious, i love learning about mass extinctions)
| jfengel wrote:
| Only extremely circumstantial evidence. Some guesses about
| which species died off vs being protected, some climate
| change signatures that are consistent with a high UV burst.
|
| About the best you can say for it is "you can't prove it
| didn't happen". Which, given that it was half a billion
| years ago, may be the best you can get. There isn't a real
| smoking gun.
|
| The leading hypothesis is more that a long-term climate
| change caused secondary effects in a vicious cycle. We know
| the climate change was happening; there's very strong
| evidence. But it's not clear exactly what caused it or
| exactly how it led to mass extinction.
| xixixao wrote:
| Would the Earth shield one side of itself? If yes by how
| much?
| usefulcat wrote:
| Seems like that would only help if the duration of the
| blast was less than 24 hours
| jiminymcmoogley wrote:
| doesn't this depend on the blast's origin relative to the
| Earth's axis?
| phyzome wrote:
| Or perhaps more like 12 hours, as half of the Earth would
| be exposed instantly.
|
| But even then it depends on whether it's the direct
| radiation that's the issue or something more indirect
| (atmospheric changes, etc.)
| IAmGraydon wrote:
| The longest gamma ray bursts only last a few minutes.
| thfuran wrote:
| Just how many nines reduction from peak intensity after a
| few minutes are we talking? Because I'd imagine 0.01% of
| a nearby gamma ray burst would still be bad news.
| DavidSJ wrote:
| Rotation around the axis doesn't expose the northern
| hemisphere to the southern sky, nor vice versa.
| causality0 wrote:
| That depends on the orientation with regard to the poles.
| If the source were directly over a pole, only fifty
| percent of the planet would be directly exposed. If it
| were over the equator, however, the whole planet would
| be, if it were a magic GRB that lasted way longer than
| usual.
| ivalm wrote:
| It will affect atmospheric chemistry. It will produce a ton
| of NO2 and make atmosphere unbreathable without equipment.
| bawolff wrote:
| I imagine that killing half the planet is enough to send
| the "lucky" half into chaos and collapse.
| Avshalom wrote:
| So the upside is that anything that can get through 10k km
| of rock is very unlikely to interact with anything on the
| other side (eg neutrinos)
| elorant wrote:
| And this answers the Fermi Paradox. The universe is an
| extremely hostile environment for life to evolve.
| Jweb_Guru wrote:
| This does not really answer anything. As far as we can tell
| (modulo the precision of our instruments), it's likely there
| are many, many stars like our sun and planets like Earth,
| even if they are not in the majority. It also seems like life
| sprang up almost immediately after the Earth cooled enough
| for it to be feasible.
| elorant wrote:
| If the universe is filled with violent incidents then it
| doesn't really matter how probable life is. It will take an
| extreme amount of luck to manage to survive through all
| those events. The Fermi Paradox doesn't exclude life, just
| the frequency of it. You could still have plenty of alien
| civilizations out there, but at a frequency of one every a
| thousand galaxies or so because everything else gets wiped
| out every so often.
| suggestion wrote:
| If I'm not mistaken, gamma ray bursts properly directed from a
| close enough entity are a realistic "wipe out all life on
| Earth" event, though extremely improbable.
| Moodles wrote:
| Indeed, I think a supervolcano like Yellowstone erupting is
| much more likely.
| actionfromafar wrote:
| That would not even kill all humans. It would possibly
| destroy all of civilization though. But even then, the
| coming generations would have artefacts to study and be
| inspired by.
| brtkdotse wrote:
| Sure, but since we've used up all easily accessible oil
| and gas they'd have a hard time to find the energy
| required to level up a society.
| gibspaulding wrote:
| That's an interesting thought. ACOUP did a blog post a
| while back [1] outlining the very specific circumstances
| that led to the Industrial Revolution and arguing that
| it's hard to imagine another way it could have happened.
| I suppose a rebuild would have to find a completely new
| route. Perhaps fields of Don Quixote esque wind mills
| connected to giant led-acid batteries rather than coal!
| With a couple hundred years gap between Armageddon and a
| substantial human population making progress, at least
| there would hopefully be decent timber reserves to work
| through the early phases.
|
| [1] https://acoup.blog/2022/08/26/collections-why-no-
| roman-indus...
| pchristensen wrote:
| In a rebuilding event, we'd have the advantage of knowing
| it was possible and desirable. This book, for instance,
| would be worth kingdoms in such a situation -
| https://www.amazon.com/Knowledge-Rebuild-Civilization-
| Afterm...
| hinkley wrote:
| Using recycled copper from scavenged wiring, because
| there's no high grade copper ore anymore.
| nonameiguess wrote:
| I guess it depends on how long before the collapse
| happens, but I think there's enough accessible fossil
| fuels left to sustain a less than 10-figure human
| population for under a century while it figures out what
| else to do. They'd probably have to live with far more
| local supply and distribution networks, but global
| communication should still be fine.
| njarboe wrote:
| If you can jump right to electric power, then hydro power
| can give you all the power you need to get civilization
| going again. I don't think that tech knowledge would be
| likely lost if people survive at all.
| entropicgravity wrote:
| My guess is that all the required knowledge, including
| sufficient people, are squirreled away in the bottom of
| Cheyenne Mountain and probably a few similar locations
| around the world.
| Nevermark wrote:
| I think the level of scientific knowledge we have
| accumulated would be a tremendous short cut.
|
| Even without books, the myths and obvious ruins of
| previous technological success would be a huge cultural
| guidepost for recovery.
|
| Perhaps we would go through a 1000 year energy poor "dark
| age", and recovered populations wouldn't peak as high as
| ours, but I would expect that to be the worst case if an
| awareness of our history was not lost.
|
| And maybe 10,000 years, after a complete cultural
| breakdown to hunter gathering with little functional
| memory of the past.
|
| --
|
| Given rewrites of first versions are often much improved
| for having seen previous failure modes, it would be
| interesting to pop into the future of a recreated
| civilization and see how they might do things better!
| sixothree wrote:
| Even having this written knowledge available to us it
| might still be impossible to recreate the technologies;
| so much knowledge exists in an active state only.
|
| Like the F1 engines on Saturn V. We couldn't just
| "recreate them" because all of the know-how was lost.
| Moodles wrote:
| Call me selfish but I don't make much of a distinction
| since there's a good chance me and everyone I know are
| dead.
| actionfromafar wrote:
| Another question is, how selfish are your genes? _Half-_
| kidding. :)
|
| I suppose people in North America have very slim chances
| either way, though.
| thrown_22 wrote:
| Wait 80 years and you'll get the same effect.
| Plasmoid wrote:
| They are. Luckily the only GRB candidate close enough to do
| that is eta carinae and it's probably pointing in the wrong
| direction.
| dima_vm wrote:
| Sounds like it's a perfect case where "probably" is not
| enough.
| lallysingh wrote:
| Enough for what? Useless worry? I don't think there's
| much we could do about it.
| Beltalowda wrote:
| I mean, not much you can do about it, can you?
|
| Either way, it's not likely to produce a GRB in the first
| place, it's too far away to really affect the earth in
| dramatic sci-fi story ways, and it's pointed in the wrong
| way.
|
| It's a "GRB candidate" in the same way you're a "lottery
| winner candidate" if you buy a ticket.
| doctor_eval wrote:
| What does "pointed in the wrong direction" mean? Isn't it
| a sphere? Genuine question; I am ignorant of such things.
| Beltalowda wrote:
| Stars have a magnetic field and rotate along their axis,
| similar to planets. The burst is emitted along the axis
| of rotation (the geographic north and south pole).
|
| Many stellar objects rotate and/or have a magnetic field,
| and thus an "up", "down", and "side" in spite of being a
| sphere. Pulsars (extinguished stars that emit radio waves
| from their poles) are another famous example.
| JumpCrisscross wrote:
| > _What does "pointed in the wrong direction" mean?_
|
| Gamma-ray bursts [1] are a class of observations, not
| single event. (Like how we first saw pulsars, and then
| learned they're neutron stars.) Some GRBs may originate
| from relativistic jets [2] emitted by massive, spinning,
| charged objects colliding ( _e.g._ black holes) or
| collapsing (supernovae). Those jets ' intensity is not
| uniform, they emit from the poles. (See: spinning,
| charged.)
|
| There are other proposed mechanisms that columnate
| emissions [3][4]. These involve a star's rotation
| creating a radiating column along the star's axis. (I'm
| not sure if the atoms in that column radiate with a
| bias.)
|
| [1] https://en.wikipedia.org/wiki/Gamma-ray_burst
|
| [2] https://en.wikipedia.org/wiki/Astrophysical_jet
|
| [3] https://arxiv.org/abs/astro-ph/9808355
|
| [4] https://www.plasma-universe.com/gamma-ray-bursts/
| mrshadowgoose wrote:
| Stars, like planets, rotate around an axis. GRBs that are
| emitted by collapsing stars are believed to be
| directionally aligned with the axis of rotation.
| echelon wrote:
| > I mean, not much you can do about it, can you?
|
| Work to shed our biology faster.
|
| We'll get to that sometime in the next hundred years or
| so.
| JohnJamesRambo wrote:
| Your comment helped my worrying about this a lot, thank
| you.
| [deleted]
| throwawaymaths wrote:
| Probably not? Half of the life on earth would probably
| survive the initial radiation burst, due to geography, and
| while there will be massive atmospheric chemistry changes
| that would be highly traumatic it seems like life would find
| a way, as they say.
| danbruc wrote:
| Anton Petrov discussed this [1] a bit, but the essence was that
| there still would not be any obviously noticeable immediate
| effects, but that it would kick off a chain of changes like
| changes in atmospheric composition that would unfold over a
| longer time span.
|
| [1] https://www.youtube.com/watch?v=4AWaqeUmQik
| throwaway81523 wrote:
| If I understand this right, they are hypothesizing that a super
| high energy photon encountering a magnetic field near its origin
| supernova got converted into a dark matter particle. That let it
| travel 2.4 billion light years to earth without interacting with
| stray photons during that intergalactic journey. Then somewhere
| near here, it hit another magnetic field and got converted back
| to a normal photon that set off all our detectors.
|
| Does that mean we get hit with unconverted dark matter particles
| all the time? Do they just sail through the earth, like neutrinos
| supposedly do most of the time? Could they be converted to
| regular photons using magnetic fields? Could we reproduce the
| conversion to and from dark matter in the LHC, which reaches
| comparable energy levels to this photon? This is big brain stuff,
| I guess.
| [deleted]
| 1970-01-01 wrote:
| TL;DR: Scientists think the 18TeV reading was an axion. I'm sure
| Wikipedia will update itself soon:
|
| https://en.wikipedia.org/wiki/Axion#Possible_detections
| AnimalMuppet wrote:
| _Some_ scientists think it was an axion. The articles says
| "one possibility". There is _far_ from being a consensus on
| that.
| Maursault wrote:
| Finally, we have _possible hints_ of Dark Matter! We may be able
| to silence skeptics once and for all with this data that may have
| a few percent chance of being defining proof of Dark Matter. Or
| maybe it 's axions! Either way, tens of thousands of physicists,
| astronomers and cosmologists will be relieved they may have not
| wasted their entire professional careers.
| Avshalom wrote:
| I know that a combination of second-option-bias and someone-is-
| wrong-on-the-internet might make it seem like dark matter is an
| all consuming concern in physics but in the real world even
| most astrophysics people don't give much of a shit or bump up
| against it in their work.
| Maursault wrote:
| The problem is Dark Matter, without any proof it exists, was
| elevated into the cosmological paradigm, taken for granted
| that it exists, _when it may very well not exist._ As part of
| the paradigm, it is incredibly difficult to remove. Someone
| could have figured out what the missing mass was 15 years
| ago, or that there was no missing mass - eliminating the need
| for Dark Matter - yet Dark Matter could continue remain part
| of the established paradigm for 50 more years or longer.
| Paradigmatic criteria should _at the very least_ include
| positive proof of existence, saving the effort wasted in
| teaching, discussing and testing for something that never
| existed, as proving it doesn 't exist is much more difficult
| if not impossible even if it doesn't exist, which I
| personally think is a pretty good bet at this point.
| layer8 wrote:
| Few cosmologists doubt that dark matter exists. It's quite well
| established that it does (multiple independent sources of
| evidence), we just don't know what exactly it consists of. What
| this gamma-ray burst _possibly_ hints at is that it _might_ be
| axions.
| DFHippie wrote:
| > Dark Matter. Or maybe it's axions!
|
| This would be proof that dark matter, or at least some of it,
| _is_ axions.
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