[HN Gopher] Record-breaking gamma-ray burst possibly most powerf...
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Record-breaking gamma-ray burst possibly most powerful explosion
ever recorded
Author : Brajeshwar
Score : 75 points
Date : 2022-10-15 15:18 UTC (7 hours ago)
(HTM) web link (phys.org)
(TXT) w3m dump (phys.org)
| throwaway81523 wrote:
| Wonder if any of the space telescopes including JWST have swung
| around to observe this burst.
| ahelwer wrote:
| Many good sci-fi novels deal with GRBs and their threat to life?
| I know of Diaspora, what others?
| lapcat wrote:
| Supernova Era by Liu Cixin is basically that IIRC.
| HyperSane wrote:
| Larry Niven Known Space series.
| kelsolaar wrote:
| It would have been useful to put it on a scale to compare it
| against other measured GRB. It is hard to get a sense from the
| article on how much more powerful it was.
| kelsolaar wrote:
| GRB 221009A is detected by LHAASO-WCDA at energy above 500 GeV,
| centered at RA = 288.3, Dec = 19.7 within 2000 seconds after
| T0, with the significance above 100 s.d., and is observed as
| well by LHAASO-KM2A with the significance about 10 s.d., where
| the energy of the highest photon reaches 18 TeV.
|
| https://gcn.gsfc.nasa.gov/gcn3/32677.gcn3
| [deleted]
| ianai wrote:
| I wonder how big an accelerator would need to be to produce such
| energies?
| maxnoe wrote:
| LHC has a center of mass energy of 14 TeV, pretty close to the
| mentioned 18 TeV. That's however for protons, not photons. You
| really can only accelerate charged particles, as we use
| magnetic and electric fields for that. You need roughly a
| factor of ten higher energy of the charged particle to produce
| a certain energy gamma ray.
|
| Proton collisions are messy, and not the best way to get
| photons at certain energies. There is a new up to 1 TeV
| electron collider planned in Japan [1].
|
| Note however that these 18 TeV are only the highest energy
| Photon _from a GRB_. LHAASO observed gamma rays up to 1.4 PeV
| from other sources (mostly galactic super nova remnants) [2].
|
| - [1]
| https://en.m.wikipedia.org/wiki/International_Linear_Collide...
| - [2] https://www.nature.com/articles/s41586-021-03498-z
| chasd00 wrote:
| I like how no matter how awesome we think we are we're one grb
| away from extinction of all life. Reminds of of the smashing
| pumpkins lyric "despite all my rage, I'm still just a rat in a
| cage".
| blueprint wrote:
| meanwhile humanity continues not to most highly prioritize
| establishing colonies and stations that are not, you know, on
| earth. i don't get it.
| awestroke wrote:
| Economic growth is more important than survival. Didn't you
| get the memo?
| picsao wrote:
| checkyoursudo wrote:
| From a philosophical point of view, what difference does it
| make if life on earth ends?
|
| I am all for colonizing the galaxy, but just because I think
| it would be cool. It doesn't really matter whether or not it
| actually happens, does it? Why I personally think it is not
| widely a high priority is because establishing off-world
| colonies is just one of a really long list of things we could
| spend our time and money on, and most people themselves would
| not directly benefit.
|
| _I_ would prioritize it to some extent (maybe not highest
| priority) but I certainly understand why it is not a general
| priority.
| aardvark179 wrote:
| So in order to survive the colonies would need to be entirely
| self sustaining, and would only save humanity from an event
| that wiped out earth but left the colonies unharmed.
|
| Given the huge efforts that would be needed to create such
| colonies I think the work on spotting potentially dangerous
| asteroids and working out how to affect their orbits is
| probably a much better option.
| michaelmrose wrote:
| A post apocalyptic earth after every nation on earth
| detonated all their nukes on each others population centers
| or a post dinosaur killer event would both leave the earth
| substantially more survivable than Mars at present. The world
| faces unlikely total destruction from space. More likely
| species extinction, and inevitable economic failure.
|
| In the foreseeable future of the coming decades even
| inevitable economic failure is likely to doom any colony we
| establish whereas such colonies are not going to be enough to
| save the species from any species extinction scenario.
|
| In the near term space exploration is about developing our
| potential not preserving it from destruction. Indeed this
| argument is both more palatable and potentially effective
| than doom and gloom.
| doctor_eval wrote:
| A GRB close enough to fry Earth would also fry all the other
| planets in the solar system. Mars won't help.
| computator wrote:
| Some very insightful and thought-provoking comments are under
| the above _downvoted_ parent comment. I wonder what the
| Hacker News algorithm does with threads that have a downvoted
| parent but with highly upvoted replies? Does it push the
| thread down or keep it high? In either case, I 've often
| thought that this was small flaw with threaded discussions
| (though I don't know a solution): There should be a way to
| maintain visibility or priority for great comments that are
| buried in downvoted threads.
| andrewflnr wrote:
| My read on downvotes is that they exist for managing
| signal/noise, basically for avoiding comments that are
| better off not read or engaged with. If a reader has to get
| through a noisy comment to get to a good comment that only
| exists because of the noise, is it worth it for the
| platform to try to lead them to it? And that's a pretty
| rare case anyway. So yeah, pretty hard to even specify a
| solution.
| giantrobot wrote:
| The Earth is the only habitable place in the solar system.
| Everywhere else requires humans to bring along their own life
| support systems, fresh water, and means to produce food.
| Human occupation of any body in the solar system or
| artificial bodies like a space station will always be limited
| by the amount of high tech infrastructure that can be built
| there. Even on Mars there's no guarantee there's enough _in
| situ_ resources for humans to be self-sufficient.
|
| So the _only_ was an extinction event on Earth would be
| survived by off-world colonies is if they were 100% self
| sufficient. Even a broken toilet could kill everyone in a
| space vehicle, human lungs don 't appreciate aerosolized shit
| in them.
|
| Building a permanent off-world base is a huge undertaking.
| Building an actual colony is an order of magnitude more
| difficult. And building a completely self sufficient colony
| is several orders of magnitude more difficult than that.
|
| In any sort of near term setting an extinction level event on
| Earth is going to lead to the extinction of all off-world
| colonies/bases. They stand even chances of completely dying
| out even _with_ unlimited support from an intact Earth.
|
| A solar flare could wipe out a space station or Mars base. A
| GRB capable of wiping out life on Earth will wipe out life
| pretty much everywhere in the solar system.
| lapcat wrote:
| Because an extinction level gamma ray burst directed at Earth
| is an extremely unlikely event compared to many other
| possibilities, such as humanity trashing our own ecosystem,
| which is pretty close to a certainty at this point.
|
| Also, outer space is really incredibly hostile to life. The
| likelihood of dying in space, on the Moon, on Mars, is vastly
| higher than the likelihood of the aforementioned GRB.
|
| Let me put it this way: the Earth, in the aftermath of
| getting hit by the dinosaur-killing asteroid 66 million years
| ago, was still infinitely more habitable to life than Mars is
| today. The grass is not greener on the other side.
|
| It would be so much easier to build underground or underwater
| shelters on Earth than it would be to build permanent
| shelters on other planets.
| sgt101 wrote:
| So something 2.4bn light years away created a detectable impact
| on Earths atmosphere? Holy holy holy holy something.
| antiquark wrote:
| Cow?
| empiricus wrote:
| Actually, closer gamma-ray bursts would be extinction events.
| RobertoG wrote:
| Sounds like a Fermi paradox related fact. Specially in the
| center of the galaxy, I suppose.
| Archelaos wrote:
| This is why there exists the concept of a galactic
| habitable zone. See:
| https://en.wikipedia.org/wiki/Galactic_habitable_zone
| analog31 wrote:
| It would be interesting to hang a number on that, like how
| far away you could be and receive a dangerous dose.
| anthropodie wrote:
| Can someone ELI5 what are implications of this? AFAIK GRBs are
| threatening if directed at Earth. And now they are detecting it?
| watersb wrote:
| If you're reading this, then this Gamma Ray Burst is not going
| to hurt you.
|
| Gamma ray bursts were first detected by satellites that had
| been designed to watch for nuclear weapons on Earth. They kept
| reporting super high energy radiation events-- bursts -- but
| there were no other signs of nuclear explosions. They were
| seeing light from outer space.
|
| The short duration of these bursts, along with the extreme
| energy level of the photons, impose constraints on the type of
| event that could emit such light.
|
| Light moves really fast, but it doesn't move infinitely fast,
| and nothing else can happen faster than light. Anything violent
| enough to shine mostly in gamma rays is going to be pretty much
| the only thing going on at the source: a big explosion. A burst
| two minutes long generally means that the source is two light-
| minutes wide. Something that would fit inside the orbit of
| planet Mercury. For example. It gives you an idea of limits
| that can be placed on the phenomena that might cause such a
| thing.
|
| NOT_IMPOSSIBLE + REALLY_UNUSUAL = SCIENCE!
| anthropodie wrote:
| Thank you
| kloch wrote:
| > If you're reading this, then this Gamma Ray Burst is not
| going to hurt you.
|
| This reminds me of something my dad would say when I was a
| little kid afraid of lightning.
|
| He would say "By the time you hear the thunder you have
| already survived"
| ryandrake wrote:
| If Gamma Ray Bursts have been detected by satellites, how
| come none of them have hit the Earth and cooked the
| atmosphere? I thought a GRB aimed in our general direction
| would be an extinction event.
| tehjoker wrote:
| iirc one of the major mass extinction events is
| hypothesized to be due to a GRB but it's only one of
| several possibilities
| SAI_Peregrinus wrote:
| If the burst were very close, it would be. Most are from
| other galaxies, so the intensity is much lower (fewer
| photons) even though those few photons are still very high
| energy.
| gilbetron wrote:
| Even though the beam of the gamma ray burst is incredibly
| focused, it still dissipates as it travels, like a
| searchlight beam (or even a laser). Nearly all GRBs that we
| detect are from really far away and so are not a threat. If
| one happens "nearby" and it was pointed at the earth, we'd
| be cooked! But they are extremely rare events.
| gus_massa wrote:
| > _we 'd be cooked!_
|
| Would it cook all the Earth or only the unlucky half that
| is in that direction?
| ianmcgowan wrote:
| I'm not sure the half sheltered from the direct burst
| would be considered lucky. There's a cool short story
| about the sun going nova, and one half of the planet is
| immediately destroyed. For me it always seemed like going
| quickly would be the better option..
| jrd259 wrote:
| Inconstant Moon by Larry Niven
| choeger wrote:
| How does the length of the burst depend on the size of the
| event?
| post-it wrote:
| Not an astrophysicist, but I think the assumption is that
| all of the photons are emitted at once in an explosion, and
| of course they all travel at the same speed. So if the
| burst is two minutes long, the near side of the explosion
| was two light-minutes closer than the far side of the
| explosion.
| keketi wrote:
| Imagine observing a lightning bolt strike the ground. The
| bolt travels through air almost instantly and emits sound
| in every direction throughout its path. First you will hear
| the sound waves emitted from the point that it touches the
| ground, because that is the closest. Then you will hear the
| sound waves from 1 cm off the ground, 2 cm, 3 cm and so on
| all the way up to the lightning bolt's point of origin in
| the sky. By measuring the duration of the noise you can
| tell the length of the lightning bolt (assuming it's
| perpendicular to the ground).
| denton-scratch wrote:
| Is that true? Can you cite? (I don't mean to question
| you, I'd just like a practical procedure)
| yaks_hairbrush wrote:
| The length of the burst tells us the maximum size of the
| event. Imagine the event takes place instantly at the
| source, and that the source has some size. If we observe
| the event over two minutes, then the event size was two
| light-minutes.
|
| In reality, these aren't completely instantaneous events.
| But any event duration at its source is going to decrease
| the event size. Take the extreme case: the event actually
| took place at its source over the course of two minutes.
| And we observed it over two minutes. We would have to
| conclude that the event had zero size.
|
| Of course, the reality is that we have no idea how long the
| event took place at its source. All we know is that we
| observed it over two minutes. But that's enough information
| to conclude that the event we're seeing certainly occurred
| within a two light-minute sphere. If it had occurred over a
| larger sphere, we would have observed it over a longer
| period of time because of the time light takes to traverse
| the length of the source.
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