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The title is misleading. Just to be clear, theory predicts that blacks holes shouldn't be created between 50 and 130 solar masses, but there are plenty of black
by brianberns 7y ago
The title is misleading. Just to be clear, theory predicts that blacks holes shouldn't be created between 50 and 130 solar masses, but there are plenty of black holes >130 solar masses. This is just an observation of a black hole that falls inside the supposedly "forbidden" range.
- jacobush 7y agoI agree except the word "just". It's really interesting that it exists contrary to current theories.
- NikolaeVarius 7y agoThe article discusses that there are multiple theories explaining the possibility of alternative modes of formation.
- joemag 7y agoMisleading indeed. And I’m surprised the article did not talk about binary black hole mergers being potential sources of such black holes, since that seems like the most plausible theory.
- ars 7y agoDid you read the whole article? It did talk about that. It gave a whole explanation.
- eesmith 7y agoI thought it did talk about binary black hole merges as one source. Here's a quote from the article which seems to match what you describe: > Inside a globular cluster, a 50-solar-mass black hole could merge with a 30-solar-mass one, for instance, and then the resulting giant could merge again. This second-generation merger is what LIGO/Virgo might have detected
- joemag 7y agoArgh, you are right - the ad fold made it seem like the article ended, yet there were two more paragraphs below it. Still, rereading the article, the main body seemed a bit coy. It kept talking about how such black holes should not exist, yet I kept thinking “hasn't LIGO detected formation of 60+ solar mass black holes via mergers?” But perhaps I’m in an extra criticizing mood before my morning coffee.
- samstave 7y agoOk, so now i realize that i have absolutely no idea what a black even actually is. Can HN ELI5 what a black hole actually is and explain how they even come into existence, let alone that binaries can combine??
- chousuke 7y agoI'm not an astrophysicist but I think I can provide a reasonably accurate answer anyway. Basically, you get a black hole when you push matter together tight enough. This happens when some stars die, and the processes inside the star can't counteract its own gravity. Light is affected by gravity. A black hole is an object whose gravitational "pull" is so powerful that inside a certain radius, everything gets inevitably pulled into it. This causes the event horizon, where even light can't get away. What's inside the event horizon is not known, as far as I know, except that it has mass, charge and angular momentum Black holes colliding is essentially no different from any other two objects colliding in space, except for the cataclysmic scale. They behave pretty much like any other object of their mass would, which means you can have two black holes orbiting each other in a binary system just like two stars would.
- samstave 7y agoI really loved this ELI5, thank you.
- chousuke 7y agoI guess it was more of an ELI5 for kids with exceptional vocabulary. :P One thing I neglected to mention is that the effect of gravity gets weaker with distance, so conversely it must get stronger the closer matter is pressed together. And as it gets stronger, the object gets denser because (in the absence of counteracting forces) its matter is further pulled together, and it becomes a loop until you get a black hole. Beyond that things get weird and we don't know what exactly is going on, but we do know that it happens.
- samstave 7y ago
- SkyBelow 7y agoIs there an ELICU (college undergrad) as to why 50 to 130 is forbidden but below and above is allowed?
- saagarjha 7y agoHow’s the one the article mentions? > A pair-instability supernova happens when the core grows so hot that light begins to spontaneously convert into electron-positron pairs. The light’s radiation pressure had kept the star’s core intact; when the light transforms into matter, the resulting pressure drop causes the core to rapidly shrink and become even hotter, further accelerating pair production and causing a runaway effect. Eventually the core gets so hot that oxygen ignites. This fully reverses the core’s implosion, so that it explodes instead. For cores with a mass between about 65 and 130 times that of our sun (according to current estimates), the star is completely obliterated. Cores between about 50 and 65 solar masses pulsate, shedding mass in a series of explosions until they drop below the range where pair instability occurs. Thus there should be no black holes with masses in the 50-to-130-solar-mass range.
- changoplatanero 7y agoWhat if two blackholes with 50 solar masses collide into each other?
- lostmsu 7y agoAFAIK, nothing prevents that. You'd want blackholes with 100 solar masses though, as the collision will apparently shed significant part of the mass in gravitational waves.
- TCR19 7y agoSo does that mean during a collision between blackholes mass actually does/can escape a blackhole? I thought mass couldn't escape, at least not in any observable way that we can detect. [I don't know a ton about astrophysics, so apologies if this question doesn't make sense].
- saiya-jin 7y agoCouldn't it evaporate into this size, or consume enough stars / other material to grow so large? Universe is young, but not so young this should be impossible
- semi-extrinsic 7y agoWrt. evaporation: no. Here is a handy online black hole calculator http://xaonon.dyndns.org/hawking/ http://xaonon.dyndns.org/hawking/ Punch in 130 solar masses, and you get a lifetime (before evaporation) of around 10^72 years. Age of the universe is 10^10 years, so evaporation is utterly negligible.
- tgb 7y agoThis was my first question, too. Disappointing that HN downvotes good-faith, on-topic questions.
- asdfman123 7y ago> This is just an observation of a black hole that falls inside the supposedly "forbidden" range. So you're saying it's of a mass that was thought to be impossible?
- endorphone 7y agoIf there were prior observed cases, then it certainly wouldn't be thought to be impossible. Instead it's just that theory can't yet explain how. In the same way that it is, or was, ludicrous when people say it's impossible that bumble bees can fly, when clearly they can. Instead our understanding of their flight mechanics was incomplete.
- papreclip 7y agoMaybe he didn't word his post perfectly but he's still pointing out an important distinction. If you could conjure a star of 0.001 solar masses, or one of 1000 solar masses, the first would be a gaseous planet incapable of sustaining a nuclear chain reaction and the second would produce enough energy to overcome the force of gravity at its periphery, blowing away its outer mass and shrinking. Those masses are impossible for stars A 1000M black hole would be stable, there's just no likely way to end up with one in the first place.
- eloff 7y agoAh but even the extremely unlikely is likely to happen many times in a universe with such a mind bogglingly large number of glasses and stars. Such as primitive life evolving into conscious intelligence capable of measuring the minute disturbances from distant black hole mergers. I would have been on the nature finds a way side of the wager.
- wtdata 7y agoNo, it is of a mass that according to our still standing understanding of astrophysics, is impossible to create by the collapse of "a single star". But you can very well have this mass by the colapse of two black holes, or by one black hole that ends up consuming one or more stars nearby in due time.
- 7y ago
- sandworm101 7y agoAlso misleading because it is not that the existence of these holes is physically impossible, rather that their formation was extraordinarily unlikely. They can exist along a range of masses, and it is technically possible to make nearly any mass in the range by merging holes. It just very difficult to imaging how such mergers would have happened.
- CarlosCabrito 7y agoThe title doesn't seem to be misleading, it seems to be boardline. How would you re-write the title in a way that is engaging and still gets the point across?
- tzs 7y agoFor those wondering what the heck you are talking about, it appears that this criticism is of the title of the actual article, which is "Possible Detection of a Black Hole So Big It ‘Should Not Exist’". I don't know if that was also the HN title at some point, but now the HN title is "Possible detection of a black hole with a mass that was thought to be impossible".
- gameswithgo 7y agoon hackernews the top voted comment is always either * pedantic quibble with title * criticism of style of website on mobile it makes this kind of a silly place.
- _jal 7y agoDon't forget the "I agree with you substantively, but aesthetically I must object" genre of political critique.
- dang 7y agoThat made me curious to look at the current top comments. Here they are: https://news.ycombinator.com/item?id=20822461 https://news.ycombinator.com/item?id=20822461 https://news.ycombinator.com/item?id=20822567 https://news.ycombinator.com/item?id=20822567 https://news.ycombinator.com/item?id=20823089 https://news.ycombinator.com/item?id=20823089 https://news.ycombinator.com/item?id=20820337 https://news.ycombinator.com/item?id=20820337 https://news.ycombinator.com/item?id=20822562 https://news.ycombinator.com/item?id=20822562 https://news.ycombinator.com/item?id=20821984 https://news.ycombinator.com/item?id=20821984 https://news.ycombinator.com/item?id=20823146 https://news.ycombinator.com/item?id=20823146 https://news.ycombinator.com/item?id=20823164 https://news.ycombinator.com/item?id=20823164 https://news.ycombinator.com/item?id=20823170 https://news.ycombinator.com/item?id=20823170 https://news.ycombinator.com/item?id=20823062 https://news.ycombinator.com/item?id=20823062 https://news.ycombinator.com/item?id=20821332 https://news.ycombinator.com/item?id=20821332 https://news.ycombinator.com/item?id=20818721 https://news.ycombinator.com/item?id=20818721 https://news.ycombinator.com/item?id=20820497 https://news.ycombinator.com/item?id=20820497 https://news.ycombinator.com/item?id=20822627 https://news.ycombinator.com/item?id=20822627 https://news.ycombinator.com/item?id=20820161 https://news.ycombinator.com/item?id=20820161 https://news.ycombinator.com/item?id=20822859 https://news.ycombinator.com/item?id=20822859 https://news.ycombinator.com/item?id=20818811 https://news.ycombinator.com/item?id=20818811 https://news.ycombinator.com/item?id=20819619 https://news.ycombinator.com/item?id=20819619 https://news.ycombinator.com/item?id=20821850 https://news.ycombinator.com/item?id=20821850 https://news.ycombinator.com/item?id=20818903 https://news.ycombinator.com/item?id=20818903 https://news.ycombinator.com/item?id=20819782 https://news.ycombinator.com/item?id=20819782 https://news.ycombinator.com/item?id=20821601 https://news.ycombinator.com/item?id=20821601 Of those, https://news.ycombinator.com/item?id=20818721 https://news.ycombinator.com/item?id=20818721 is a website style complaint; you get a point for that one. But it's also a classic example that standard moderation would mark as off topic. After doing that, the new top comment is https://news.ycombinator.com/item?id=20820028 https://news.ycombinator.com/item?id=20820028, which is a fine comment. So for this cross-section of stories your description covers 1/30 prior to standard moderation and 0/30 after. That's actually better than most claims of "always"!