[HN Gopher] 'Ultramassive' black hole discovered - bigger than t...
___________________________________________________________________
'Ultramassive' black hole discovered - bigger than the majority of
galaxies
Author : achow
Score : 132 points
Date : 2023-03-29 17:05 UTC (5 hours ago)
(HTM) web link (www.bbc.com)
(TXT) w3m dump (www.bbc.com)
| jmyeet wrote:
| It's worth noting that there is a limit to how fast black holes
| can grow [1] so ultra-massive black holes like this tell a story,
| namely:
|
| 1. It starts placing limits on how young the black hole can be.
| IIRC black holes like this must've been formed very early in the
| Universe, which may be earlier than our models otherwise predict,
| suggest or even say is "possible"; and
|
| 2. It is theorized (again, IIRC) that a lot of ultra-massive
| black holes such as those at the center of many if not most
| galaxies can only really form by the merger of black holes due to
| the above limits. These must be unbelievably energetic events.
| It's possible that such events may actually star formation in
| nearby nebulae.
|
| [1]: https://physics.stackexchange.com/questions/167250/is-
| there-...
| techwiz137 wrote:
| So then why is TON618 at 66 billion solar masses?
| https://en.wikipedia.org/wiki/TON_618
| davorak wrote:
| edit the bbc article got it wrong withe 30 billion times the
| size and it supposed to be 30 billion solar masses see [1] or
| the arxiv article [2]
|
| The bbc article says 30 billion times the size while TON618 is
| 66 billion times the mass.
|
| Wikipedia says TON618 has a Schwarzschild radius of 1,300 AU
| (390 billion km in diameter) vs teh sun's 1.3927 million km
| diameter. Which makes TON618 ~280k bigger than the sun.
|
| So if my math is right that makes the Ultramassive balck hole
| in the bbc article ~107k larger than TON618.
|
| edit give the R = 3M relation for black holes twice the radius
| means twice the mass. So 107K times the radius means 107k times
| the mass.
|
| The Ultramassive balck hole in the bbc article would have
| ~2354000 billion solar masses.
|
| edit give the above I want to fact check BBC's 30 billion times
| the size vs 30 billion solar masses since the later seems more
| reasonable.
|
| edit 30 billion solar masses is what is given directly by
| durham and arxiv[2]
|
| [1] https://www.durham.ac.uk/news-events/latest-
| news/2023/03/lig... [2] https://arxiv.org/abs/2303.15514
| wumms wrote:
| My understanding of the abstract is (I'm not an astronomer):
|
| TON 618 is an _active_ SMBH ( "hyperluminous, broad-absorption-
| line, radio-loud quasar" [0]).
|
| The SMBH they found has a smaller mass [2], but it is _passive_
| (= much darker).
|
| From the abstract:
|
| "Outside the local Universe, measurements of MBH are usually
| only possible for SMBHs in an active state: limiting sample
| size and introducing selection biases. Gravitational lensing
| makes it possible to measure the mass of non-active SMBHs." [1]
|
| [0] https://en.wikipedia.org/wiki/TON_618
|
| [1] https://academic.oup.com/mnras/article-
| abstract/521/3/3298/7...
|
| [2] "it could be a supermassive black hole equivalent to 13
| billion suns: 1.3+-0.6)x10^10 M"
| https://en.wikipedia.org/wiki/Abell_1201_BCG
| croutonwagon wrote:
| I mean...There are others bigger than that with Phoenix A, but
| these are quasars and very visible, even if billions of LY
| away.
|
| https://en.wikipedia.org/wiki/Phoenix_Cluster#Supermassive_b...
|
| It seems the bigger tact is HOW it was discovered using
| gravitational lensing that may open up the ability to see
| otherwise "non-active" blackholes, even supermassive ones that
| otherwise dont have accretion discs or other forms of waves
| (radio, light or otherwise) that would make them directly
| observable.
|
| https://arxiv.org/pdf/2303.15514.pdf
|
| I am also not an astronomer, so dont take my word for it. Just
| seems that it may be a new method that may open up the doors to
| a more discoveries that may make things like this a bit
| more....common.
|
| TON618 and Phoenix A even are somewhat outliers from a
| discovery standpoint it seems. And frankly the sizes, distances
| etc are basically incomprehensible to me.
| sacnoradhq wrote:
| 0. Seems there are a half dozen other SMBHs also close to the
| theoretical limit. What's novel about this discovery?
|
| 1. Is the Great Attractor a SMBH > 1e10 M(.)?
| tyfon wrote:
| I think the novelty here is the way of discovery, at least that
| is how I read the paper.
| sacnoradhq wrote:
| Ah thanks for the elucidation. I'm too ignorant in this
| subject area to compare or contrast this paper with the
| corpus of literature from any point of expertise or
| reference.
| bashinator wrote:
| The Great Attractor is likely a cluster of galaxies with lots
| and lots of SMBHs.
| sacnoradhq wrote:
| I wonder about inflation vs. gravity of these massive
| structures.
|
| "Locally" in the supercluster scale, I'm wondering to what
| degree gravity swamps dark energy inflation.
| dack wrote:
| I can't tell how certain we are of its size - it's so big that it
| makes me wonder whether the easiest explanation is that our
| methods were incorrect.
|
| For example, if we are measuring how light bends - how do we know
| there aren't many hidden (i.e. not large or bright enough to be
| noticed from earth) objects causing additional distortion and
| therefore throwing off our measurements? Do we also observe it
| over time to get more confidence, or have some other cross-checks
| that give us more certainty?
|
| Either way, every once in a while I find it wild just how much we
| can deduce about the universe from our tiny fixed vantage point.
| killingtime74 wrote:
| Don't know the answer to your questions but we are not at a
| fixed vantage point
| kzrdude wrote:
| I learned now at least that our parallax measurements have
| been improved but they are still limited to tens of thousands
| of light years, i.e not reaching out of the galaxy, see https
| ://en.wikipedia.org/wiki/Stellar_parallax#Space_astrome...
| vitiral wrote:
| Fixed relative to other galaxies...
| naikrovek wrote:
| we move on Earth as the planet rotates, Earth moves within
| its orbit in the Solar system, our Solar system moves
| within its orbit in the galaxy, and our galaxy moves (we
| believe) within the universe, though I don't think we know
| how fast or what direction; generally, everything outside
| our local group is moving away, though.
| datavirtue wrote:
| Our sun moves around the galaxy at about 500,000
| mph...and thus so do we.
| 100721 wrote:
| In a cosmological scale, we are goldfish in a bowl (Earth).
| We can move around inside our bowl, but we cannot move the
| bowl itself, and if we leave the bowl we won't last very
| long.
|
| Thus, our vantage point is fixed.
| mxkopy wrote:
| The bowl (and the table, for that matter) move enough for
| useful measurements to be made wrt things inside the milky
| way.
|
| https://en.wikipedia.org/wiki/Parallax_in_astronomy
| naikrovek wrote:
| it is much more likely that our understanding of the early
| universe is imperfect, than it is that multiple gravity wells
| of that strength line up perfectly. we know our tools pretty
| well; well enough to have confidence that what is observed is
| actually representative of what is actually there.
|
| the confusion here is because if this formed in 13 billion
| years, our understanding of the formation of the universe is
| very flawed, and generally, scientists both do and do not like
| it when stuff like this is proven wrong with new evidence.
|
| they like it because discovery and increased understanding is
| the whole reason they became scientists in a lot of cases.
|
| they don't like it because if this is wrong, what else is
| wrong, and what does that mean for everything else we think we
| know? what gets upended because of this?
| mxkopy wrote:
| Astronomy is afforded very few epistemological amenities. In a
| sense, N can only go up if we get independent verification from
| different techniques. However, our tools have become incredibly
| sophisticated and sensitive so we can be very sure about what
| we're seeing, if not what it means.
|
| I'd imagine one of the techniques used is to look for time-
| varying influences in the data, which implies there are bodies
| orbiting each other. If there aren't any, then you can look at
| the spectroscopic signature of the light and see if it makes
| sense for a black hole. I'd imagine black holes do nothing to
| refracted light, but dark bodies would result in slightly
| blueshifted light as 'newer' light reflects off its surface.
| This might be what PyAutoLens does (as well as fitting the
| shape of distortions and such)
| marcosdumay wrote:
| Even in astronomy, when one starts to say "this black hole is
| about the size of our galaxy", it should raise
| epistemological questions.
|
| This finding seems to have a highly complex relationship to
| the data, and to not have been replicated anywhere yet. This
| is the perfect place to add a "something that looks like"
| before the "galaxy sized black hole".
|
| But well, this is a criticism of journalism anyway, not of
| astronomy.
| davorak wrote:
| The 30 billion times the size of the sun is BBC making a
| mistake. It is 30 billion solar masses. Direct from durham [1]
| from the arxiv article [2].
|
| techwiz137 pointed out[3] an existing known black hole, TON618,
| is 66 billion solar masses[4]. So the new find is large but not
| the largest ever found.
|
| [1]https://www.durham.ac.uk/news-events/latest-
| news/2023/03/lig... [2] https://arxiv.org/abs/2303.15514 [3]
| https://news.ycombinator.com/item?id=35360780 [4]
| https://en.wikipedia.org/wiki/TON_618
| artursapek wrote:
| If a black hole is just constantly eating up surrounding matter
| and growing, why haven't we gotten sucked up by one yet?
| p1mrx wrote:
| The radius of a 30 billion solar mass black hole is still less
| than 1% of a light year. For comparison, the nearest star
| \\{Sol} is about 4 light years away.
| snozolli wrote:
| _For comparison, the nearest star \\{Sol} is about 4 light
| years away._
|
| I'm completely confused by this sentence.
| qbrass wrote:
| \ = not.
|
| {Sol} = The Sun.
| snozolli wrote:
| So, the nearest star relative to _what_? Our sun? The
| black hole?
| fknorangesite wrote:
| I think from context it's pretty safe to assume "to us".
| Especially since the nearest star to us, Proxima Centuri,
| is indeed about 4ly away.
| fknorangesite wrote:
| They're saying the "nearest star other than the Sun", but
| with some geek-in-group-signalling with the "not" syntax
| and referring to the Sun as "Sol", which some science
| fiction writers (and some non-English languages, of course)
| use as the Sun's name.
| sdfghswe wrote:
| Because space is very big.
| trilbyglens wrote:
| because space is facking huge.
| prottog wrote:
| Estimates are an average of six protons per cubic meter of
| space. A whole lot of nothing!
| daveslash wrote:
| " _Space is big. You just won 't believe how vastly, hugely,
| mind-bogglingly big it is. I mean, you may think it's a long
| way down the road to the chemist's, but that's just peanuts
| to space._"
| phailhaus wrote:
| Black holes don't "suck", they have gravity like anything else.
| If you replaced the Sun with a black hole of the same mass, all
| the planets would continue in their orbits.
| Rooster61 wrote:
| I'd imagine there would be at least some deviance from their
| current orbits. The sun experiences tidal forces, just like
| any other body, and the distance between each planet and the
| closest/furthest atoms of the black hole would be different
| than that of the sun. Not sure how much different the orbits
| would be, but they would certainly be different to some
| degree.
| artursapek wrote:
| We'd all be dead anyway so who cares
| svachalek wrote:
| The point is, the planets would keep orbiting and not go
| plunging into the black hole due to its incredible
| gravitational power, as some might picture.
| Drblessing wrote:
| Yo Mama so big...
| rwaksmunski wrote:
| 30 billion solar masses, numbers kind of loose the meaning at
| this scale.
| jws wrote:
| A billion is three groups of three zeroes. So for visualizing I
| would think of a cubic meter compared to a cubic millimeter.
|
| A grain of sand serves for a cubic millimeter. For the cubic
| meter you can either visualize a cube that size, or four oil
| drums, or a small hot tub.
|
| Now for the 30 out front, That's about 27 which is 3^3 so let's
| just size a smaller grain of sand which is only 1/3mm on a
| side. Maybe table salt would be good.
|
| So a grain of table salt in a small hot tub.
|
| If you perform this thought experiment with actual solar
| masses, use sufficiently long tongs and wear eye protection.
| unnouinceput wrote:
| Not masses, size. The article says size.
| nathan_compton wrote:
| In the case of a black hole mass and size (radius) are
| inextricably and linearly linked. All black holes with a
| given mass have the same radius (modulo a small effect of
| angular momentum).
| davorak wrote:
| I did a rough calc in:
| https://news.ycombinator.com/item?id=35361280 When it was
| pointed out TON618 has ~66 billion solar masses.
|
| But if it is 30 billion times the size of the sun then I
| think that means it is ~2354000 billion solar masses.
| runnerup wrote:
| I believe for black holes the volumetric size is a known
| function of mass. If you exclude the rest of any Lyman-alpha
| blob present around the black hole.
| trilbyglens wrote:
| Mass is the only really meaningful measure of a blackhole, as
| they occupy a spacial singularity, which is to say, the have
| no measurable size.
|
| The event horizon has a diameter, but that's not the object
| itself.
| ioblomov wrote:
| Guessing that "size" for black holes can mean mass, volume,
| or radius. But I'm pretty sure the relationship between those
| three quantities is well defined and directly proportional,
| so any way you look at it, this thing is incomprehensibly
| huge.
| javajosh wrote:
| It is not possible to have an intuition about 1 solar mass, by
| easily 10 OOM. Adding OOM can't make it less comprehensible.
| seanhunter wrote:
| If they want people to relate to their numbers, they have to
| use units people understand, and also they need to be accurate
| about which dimension they are talking about.
|
| If it's _mass_ the correct popular science dumb reporting unit
| is the blue whale. Ie "The mass of this black hole is almost 3
| x 10^35 blue whales"
|
| If it's _size_ , the correct popular science dumb reporting
| unit is the football field unless it's specifically length, in
| which case it's acceptable to either go with football field or
| switch to double-decker bus or blue whale.
| AlbertCory wrote:
| Armadillos. Now we use armadillos as our unit of measurement.
| awb wrote:
| > 3 x 10^35 blue whales
|
| That's way more confusing. Most people have never seen a blue
| whale to scale, let alone can imagine how dense it is. Once
| you're at 10^35, why not just increase the exponent and use
| humans, basketballs or soda cans.
|
| I would imagine that the best scale of measurement would be
| between 1/100 and 100x.
|
| If the Milky Way is about 1.9T solar masses, then this black
| hole is about 1.5% the mass of our galaxy.
|
| It's still a pretty meaningless number, but at least I can
| look at a picture of the Milky Way and envision 1.5%
| collapsing into a single object much more easily than I can
| envision 10^35 of anything.
| idiotsecant wrote:
| [dead]
| galaxytachyon wrote:
| Well, most people can't properly understand the scientific
| notation, as in getting a proper scale of how big one order
| of magnitude is supposed to be. They may see ^35 and say "oh,
| so it is like less than 100 of something, meh".
|
| If you doubt that, remember the quarter pounder ads where
| they made people think 1/4 is kinda more than 1/2 because
| 4>2...
| seanhunter wrote:
| The point is how are people ever going to get intuition
| about the numbers if they don't report them in blue
| whales/football pitches/double decker busses?
| samus wrote:
| At these scales, it really doesn't make much of a
| difference, as a sibling commenter pointed out.
| boringg wrote:
| Can anyone confirm the accuracy here? Sounds rather significant
| however I don't know the theoretical limit of how big a black
| hole can be - or the implications of that (haven't considered
| it). Seems like we are in an era of discovery in space - heady
| times!
| ravi-delia wrote:
| There's no real limit, since you can just keep dumping stuff in
| forever. There is however a soft limit that the stuff has to be
| close enough to get dumped in, and this one is extremely old so
| we aren't sure where it got its mass from!
| taylodl wrote:
| _Au contraire!_ There 's plenty of mass to feed such a black
| hole, the real question is "when you run things backward" in
| the lambda-CDM model why isn't the entire universe a black
| hole? Or why wouldn't it be the case that there wasn't a
| primordial mega star that quickly (in universal time)
| collapsed into a supermassive black hole and the remnants of
| the supernova is the mass of the remainder of the universe
| and form the CMB radiation?
| xenadu02 wrote:
| I don't know the number but the limit is the speed of light and
| expansion of the universe. In the modern phase of the universe
| a black hole would only be able to eat its own galactic cluster
| (or maybe supercluster). Hubble expansion means superclusters
| experience the expansion of spacetime so certainly any matter
| beyond a black hole's own supercluster will move away from the
| black hole faster than light and thus never be able to fall
| into it. In practice a black hole can't even get near that
| limit because angular momentum can't just vanish... much of the
| matter would (over a long time) end up in distant orbit around
| that super super massive black hole and never fall into it.
|
| In the early universe spacetime expansion was happening so
| quickly that it was difficult for large black holes to form at
| all. If that were not the case most matter in our universe
| would have collapsed due to gravity and ended up in black holes
| but we know it did not. Actually if gravity were that strong or
| expansion were slower/weaker then the universe would never have
| formed at all and stayed as a singularity. To get formation of
| super large black holes very early you'd need a knife-blade
| balancing act of gravity vs expansion to just barely form super
| super massive black holes without the "permanent singularity,
| no universe" scenario. We can see billions of stars, galaxies,
| etc so we know that scenario did not happen.
|
| Super super massive black holes are neat objects though. If
| this one really is as big as they say then it will be one of
| the last objects left in the universe. It would take trillions
| and trillions of years for it to evaporate due to Hawking
| radiation. I wonder if the last life left in the universe will
| end up gathered around this black hole, surviving on the
| Hawking Radiation energy gradient?
| kbelder wrote:
| If the bulk of the universe was inside a black hole,
| including us, would we know it? My understanding was, not
| necessarily.
|
| Second question, if that's the case: Can singularities
| recurse? Could you have local blackholes inside a super-
| massive blackhole?
| samus wrote:
| We don't know what the inside of a black hole is like. My
| guess is that it's some esoteric state of matter. Like a
| neutron star, but up to eleven.
| iameli wrote:
| The use of the term "bigger" here is frustrating. Mass or volume?
| unclenoriega wrote:
| Definitely mass. (It is "ultramassive", after all.) An
| explanation of black hole volume I found from NASA [1]:
|
| > Our intuitive sense of volume breaks down in the strong
| gravitational region in a black hole. So while the "size" of a
| black hole is given by the radius of its event horizon, it's
| volume is not determined by the usual 4/3 _pi_ r3. Instead,
| relativity makes it more complicated than that. As you pass the
| event horizon, the spatial direction 'inwards' becomes 'towards
| the future'-- you WILL reach the center, it's as inevitable as
| next Monday. The direction outsiders think of as their future
| becomes a spatial dimension once you are inside. The volume of
| a black hole, therefore, is its surface area times the length
| of time the hole exists (using the speed of light to convert
| from seconds to meters). Since a black hole last practically
| forever, the black hole's volume is almost infinite. (This is
| also a way of explaining the fact that you can pour stuff into
| a black hole forever and never fill it up. Another reason why
| black holes never fill up is that the radius of the event
| horizon increases as the mass of the black hole increases.)
|
| [1] https://imagine.gsfc.nasa.gov/ask_astro/black_holes.html
| dustingetz wrote:
| a particle falls into a black hole. does it ever stop
| falling, from the particle's reference frame?
| cal85 wrote:
| Thank you for quoting this passage. My mind is spinning after
| reading it.
| kenjackson wrote:
| I never made the connection between mass and massive until
| your comment. Can't believe I've gone so long without
| connecting them.
| [deleted]
| trilbyglens wrote:
| BBC article innit. Hardly a scientific paper.
| jmyeet wrote:
| Black hole volume is entirely a function of mass.
| philipov wrote:
| Black holes don't have a volume, they only have a surface area,
| and it depends strictly on their mass.
| nathan_compton wrote:
| This isn't true at least in the case of the ordinary black
| hole solutions in general relativity. These solutions tend to
| be valid throughout the volume of the black hole (except at
| the singularity, which takes on different shapes depending on
| spin or charge but doesn't occupy the whole interior volume
| of the black hole if you think of the event horizon as
| bounding the volume).
| tyfon wrote:
| I thought they were valid throughout the volume/radius, but
| that the solution only gives you the surface area for that
| radius, not the volume.
|
| Perhaps I have misunderstood though as I am just a hobbyist
| :)
| nathan_compton wrote:
| The volume inside the event horizon isn't what you would
| expect if you consider the black hole as a sphere with
| its external area, but it has a volume. It might be the
| case that in quantum gravity there isn't an interior, but
| in GR the idea of the volume is a little weird, but not
| problematic.
| ravi-delia wrote:
| And spin/charge, no?
| ftxbro wrote:
| [flagged]
| lwansbrough wrote:
| Guys please don't deploy LLM bots on HN...
| Shared404 wrote:
| s/ on HN//
|
| But also here, yes.
| ftxbro wrote:
| I'm not an LLM I was nitpicking the grammar of the BBC
| caption that is confusing and makes it like a "garden path"
| sentence like the example I put. Sorry for nitpicking tho,
| even tho it is the BBC and the article was so short.
|
| https://en.wikipedia.org/wiki/Garden-path_sentence
| leephillips wrote:
| Even with its mistake I found the caption easily parseable,
| and whatever you thought you were doing just annoying.
| antibasilisk wrote:
| looks more like a markov chain
| raydiatian wrote:
| For those wondering, the radius of this black hole (assuming a
| Milkyway's worth of mass), based on the Schwarzschild radius,
| would be anywhere from 10-1000x larger than Sagittarius A, the
| supermassive blackhole at the center of the Milky Way. I don't
| think the article stated this.
| awb wrote:
| I think it's about 7,500x.
|
| This one estimated to be 30B solar masses. Sag A is estimated
| at 4M solar masses.
| raydiatian wrote:
| Nice, that's probably closer then. I just plugged in the mass
| of the milky way for the mass.
| PaulHoule wrote:
| The puzzle here is that astronomers have no clear picture of how
| these ultra massive black holes are formed so early in the
| evolution of the universe. if you wait long enough galactic black
| holes can eat stars, gas, and other black holes, but there was no
| time for that early on. It is conjectured there were huge
| 'Population III' stars that grew rapidly because radiation
| transport was different when there were tiny amounts of elements
| heavier than helium ('metals' in astronomer lingo.)
|
| Pop III stars are a bit less mysterious than dark matter but they
| could have played important roles in the early universe.
| chongli wrote:
| Yeah, the issue is that when large amounts of matter gathers
| into the accretion disk of a black hole it creates more and
| more friction as it falls in. This friction generates a lot of
| heat (and therefore pressure) which pushes back on the in-
| falling matter, slowing down the accretion process. If there's
| an overwhelming amount of matter the accretion will disk will
| get so jammed up and energetic the black hole will start firing
| off high-energy relativistic jets from its poles.
|
| If you start with a stellar black hole of say 10 solar masses
| and then throw millions of solar masses of material at it, the
| above processes will slow things down dramatically, and you
| won't be able to get a supermassive black hole instantly.
| Arwill wrote:
| The hypothesis is that these black holes were not created from
| stars, but exists from right after the big bang.
|
| https://en.wikipedia.org/wiki/Primordial_black_hole
| PaulHoule wrote:
| One of the hypotheses. Pop III stars could have gotten pretty
| big but probably not as big as that one. Hopefully JWST will
| turn up some direct evidence for them.
| hpb42 wrote:
| The article is about the Abell 1201 black hole. The paper
| referenced in the article is paywalled though[0].
|
| And Wikipedia has a List of most massive black holes[1]. Quite
| fascinating, although the list is about their masses and not
| their sizes.
|
| I'm not an expert on the subject, but the Abell 1201 black hole
| and the others in the list are near the theoretical limit of a
| black hole's mass (5 * 10^10 solar masses).
|
| [0] https://academic.oup.com/mnras/article-
| abstract/521/3/3298/7...
|
| [1]
| https://en.wikipedia.org/wiki/List_of_most_massive_black_hol...
| croutonwagon wrote:
| Here is a copy of the paper
|
| https://arxiv.org/pdf/2303.15514.pdf
| lcnPylGDnU4H9OF wrote:
| > their masses and not their sizes
|
| Do black holes even differ in density? I would have thought all
| black holes have a constant and consistent density but I don't
| think I've ever really considered it before.
| sclarisse wrote:
| They do! Or at least, the volume bounded by the event horizon
| has variable density. The small ones are much denser, and the
| large ones are much less dense.
|
| (Whatever the degenerate matter at the center is like, that's
| another matter.)
| sclarisse wrote:
| The size of a black hole's event horizon is pretty much
| directly correlated to its mass; I think the only thing that
| really modifies it in practice is very fast rotation.
|
| (Remember, it's a phenomenon of gravity, not a physical object.
| The physical stuff inside is just some really intense matter
| squeezed together in ways that might be interesting, if they
| were observable.)
| Andrew_nenakhov wrote:
| My favourite theory is that stuff inside black holes is more
| universes like ours, which is also inside the black hole.
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