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Does anyone else find this...unsettling? Floating around in the void of space, alone, is an almost invisible monster that can gobble planets and stars.

hyperhello 1y ago
Relax, it’s probably traveling in a straight path at constant velocity.
mytailorisrich 1y ago
It can't gobble planets and stars any more than any stars of the same mass.
- jsbisviewtiful 1y ago
  For sure - The largest threat would be traveling by our solar system close enough to throw off the orbits of earth or any of our nearby neighbors.
- saltcured 1y ago
  I'm trying to picture intersecting paths though. Does a faster moving black hole cause more or less damage to a target? Imagine a black hole on the quite small end, intersecting the core of a planet. Unlike regular matter, it can't really produce bow shock through collisions, right? All the target matter in the direct path just "falls in" and in elastically reduces the black hole momentum a tiny bit? Some matter outside the direct path could be accelerated towards the black hole but slingshot behind it, rather than into it. So this material could produce an impressive wake, with material spraying outward from the collision path and interacting with the remainder of the target. But, all this visible chaos comes from gravity rather than more direct kinetic interactions, right? If the black hole is moving faster, doesn't the target's material gets less gravitational acceleration as it spends less time in the near field? So, if the blackhole is moving very fast, does it bore a smaller hole and have less interaction with the target? Or do other effects of relativity make this more convoluted to think about? I'm imagining a cylindrical plug of a planet "instantaneously" disappearing, and then the remainder of the planet collapsing inward to fill the void, bouncing off itself, and ringing like a bell.
  - windsurfer 1y ago
    > Does a faster moving black hole cause more or less damage to a target? When a black hole accretes matter, the matter can create tremendous radiation before it crosses the event horizon due to the atoms experiencing many effects such as rapid nuclear fusion and becoming new forms of matter such as neutronium. The precise amount of energy released depends on spin, charge, and size of the black hole, and the speed at which the matter approaches the black hole. If a tiny black hole (Let's say 10cm across) ripped through the earth at significant speed it would be like the center of the planet momentarily became the center of a star and (hand waving a bunch of assumptions) the total energy could easily be greater than the gravitational binding energy of the planet. The planet would explode.
psunavy03 1y ago
It can't really "gobble" anything any more than a star "gobbles" things that fly into its photosphere or a planet "gobbles" things that crash into it. Unless you cross its event horizon, its gravity works just like any other celestial object. Maybe at worst it slingshots you off in a different direction.
- deadbabe 1y ago
  He technically did not say the invisible monster was a black hole.
- stouset 1y ago
  I think the concern is that if a star was headed in our direction we’d see it coming. We don’t see one, so we know there is no anticipated threat. A small, lone black hole could be on an intersecting trajectory with us within a few years and we’d be completely oblivious.
  - Ancalagon 1y ago
    As if there were any different actions that could be taken to avoid a star vs a black hole. I’d probably welcome the quicker demise tbh
    - stouset 1y ago
      It’s less about actions we could take and more about knowing we don’t have to worry about colliding with a star for the moment.
      - Ancalagon 1y ago
        You probably wouldn’t want society to know we were about to collide with a star-sized mass, visible or not.
        Swizec 1y ago
        > wouldn’t want society to know we were about to collide with a star-sized mass I may be misunderstanding the distances involved but wouldn't such a collision take centuries if not thousands of years to play out? For the most part it would just look like we had 2 suns, one of which gets a few millimeters bigger (to the naked eye) every year.
casenmgreen 1y ago
In practical terms, not so very far away from the NEAs that we have no idea of, and which we notice after they've just skimmed by the Earth.
tejtm 1y ago
No, not me anyway. we are all floating (falling) in the (nigh) void of space (equally) alone ... which is great protection from all the monsters everywhere! Deliberately hitting things in space is hard, accidentally, more-so. Consider the chance of our sun getting whacked when the entire Andromeda galaxy gets here ... billions or more likely trillions to one. The chance of a single mass in our own galaxy getting us should be less than that. edit: as far as I know the only difference between getting gobbled by a black hole v.s. anything else is our atoms won't get to continue their evolution into larger atoms in this universe. (or maybe see it as our atoms get to complete their evolution in this universe)
sega_sai 1y ago
The size of the black hole described in the paper is ~ 20 km, so it is tiny. Even we have millions of such objects (and most likely we do), the chance of hitting something, given the enormous size of the galaxy is negligible.
- rad_gruchalski 1y ago
  Would we notice if it was to point in our direction?
- windsurfer 1y ago
  The black hole in the paper is also ~7 solar masses. If that passed between the Earth and the Moon it would rip apart the earth from just the tidal forces.
  - lazide 1y ago
    Well, if present anywhere in the solar system it would also completely fuck our orbits all to hell too eh?
  - sega_sai 1y ago
    the chance of that is negligible.
belter 1y ago
Are you worried? :-) I bit like bringing sunscreen to the apocalypse no? :-)
hnuser123456 1y ago
It would be nice to get a rigorous estimate on how big and nearby a black hole could be before we'd notice it with routine sky surveys or orbital deviations. A 6-solar-mass black hole only has a radius of around 18km or 11 miles. How often will one pass in front of a star precisely enough for OGLE and MOA to detect it, as they did with this one? Apparently the Roman Space Telescope will be great at detecting these, if it doesn't get cancelled.
thangalin 1y ago
> gobble planets and stars Direct interaction isn't needed for havoc. A supermassive object sweeping by the Solar System could destabilize Jovian orbits. In the Nice model, Neptune flung Kuiper belt asteroids sunward, gifting the inner planets with a late heavy bombardment. Rogue gas giants, brown dwarfs accelerated to relativistic speeds, giant asteroids approaching from the Sun's direction, Carrington Events, an ill-directed gamma ray, etc. So many ways life on Earth can see its 250 million remaining years cut short, and those are only a few of the cosmic threats we can imagine. A black hole with a Schwarzschild radius of 20 km would weigh about 6.8 Solar masses. It wouldn't even need to get super close to affect the Solar System.
- vanattab 1y ago
  Where is the 250 million years come from?
  - ftrobro 1y ago
    Perhaps a reference to Pangea Proxima? https://en.wikipedia.org/wiki/Pangaea_Proxima https://en.wikipedia.org/wiki/Pangaea_Proxima Life might very well exist on earth even through those conditions, but not to the extent we have today.
  - thangalin 1y ago
    https://www.nature.com/articles/s41561-023-01259-3 https://www.nature.com/articles/s41561-023-01259-3
  - dredmorbius 1y ago
    There are a number of likely mass-extinction / life-terminating events which will occur within the next billion or so years, either deterministically or probablisticaly (e.g., increased solar insolation and plate tectonics are deterministic, massive gamma-ray burst or killer asteroid are probabalistic), of which supercontinent-formation is only one. Wikipedia's "Timeline of the Far Future" lists several: <https://en.wikipedia.org/wiki/Timeline_of_the_far_future https://en.wikipedia.org/wiki/Timeline_of_the_far_future> We likely exist in the late afternoon if not evening of Earth's habitable period.
ajb 1y ago
There are many theoretical astronomical risks. For example, if we happened to come into the path of a relatively nearby gamma-ray burst, it could eliminate all life. Given that life has existed on the earth for quite some time, the 'Lindy effect' suggests that the sum of these presumably-constant risks is small. We are much more likely to become extinct due to an anthropogenic cause.
- somenameforme 1y ago
  A gamma ray burst is one of the possible hypotheses for the cause of the Ordovician mass extinction event, one of 5 big ones Earth has had. No idea why the Great Oxidation Event isn't included there as it was also one of the deadliest mass extinction events - plants and their vile poisonous oxygen killing off basically everything else. So I don't think the 'Lindy Effect' would apply as species are mostly perishable, just on longer timeframes. Humanity is hopefully the exception, but absence of evidence of other advanced intelligences in the universe doesn't paint the most promising picture there either. On the other hand we're already on the cusp of colonizing other planets and once that process begins the odds of humanity ever going extinct will approach zero. On the other hand at greater distances "humanity" will likely splinter fairly quickly (relative to on a geologic or even species survival timeline) into numerous distinct species.
  - deleted 1y ago
    [deleted]
- windward 1y ago
  The anthropic principle is at odds with that. Lindy's doesn't reason about itself.
SllX 1y ago
No more unsettling than space in general is. It’s pretty hostile to life. We’re not just making turns around the orbital racetrack setup around the Sun, we’re also flying through space following the gravitational trail of the Sun as it races forward without a destination. I was playing with Universe Sandbox over the weekend trying to figure out how to terraform Venus. Changing its axial rotation period to a day to match the Earth while I screwed around with its chemistry was enough to cause Europa and some of the other famous moons of Jupiter and Saturn as well as Charon to yeet themselves outside of the solar system within about 10 or 20 years of simulated time.
- danparsonson 1y ago
  Why would changing the rotation speed of Venus have any noticeable effect on the outer planets? That sounds more like a limitation of the model than anything else. Especially over such a short time! 20 years is nothing to the orbit of Charon.
  - SllX 1y ago
    Probably, but if a Venus-sized mass showed up in the inner solar system because the Sun just picked it up along the way, it might not be instant death but we’re probably in for a rough time. It doesn’t have to be a black hole that does us in, it could be something much smaller that still strips the Moon away or causes Earth to readjust its own position in a way we, as in life, but also maybe we as in humans or we as in mammals just don’t like very much in a very short amount of time temporally speaking, and we couldn’t do anything about it anymore than we could do anything about a black hole because we’re just not the captains of this ship. We’re just some homegrown stowaways. But for what it’s worth, it’s also just so incredibly unlikely it’s not a scenario worth thinking about either, and thinking about it too much just invites existential dread.
dreamcompiler 1y ago
I don't. If the sun were replaced by a black hole of equal mass next Tuesday at noon, the only thing we would notice is that it suddenly got very dark and very cold. We would continue orbiting the thing while freezing to death over the next few days.
EnPissant 1y ago
It's really, really hard to fire something into the Sun. We can't do it. The same goes for black holes. Things don't just get sucked in. They usually end up in orbit instead.
- hollerith 1y ago
  That's not true. (1) We can launch a rocket that has a payload that hits the sun: it's just costly to do because the rocket starts out orbiting the sun, so we would have to expend delta-v to neutralize the tangential component of the initial velocity. (2) If you are in a space ship heading towards the sun, it is easy to hit the sun as long as you can steer, and even if you can't steer, if you are heading squarely at it and no planet gets near you to change your velocity, you will hit it.
  - EnPissant 1y ago
    [flagged]
    - dang 1y ago
      Can you please make your substantive points without swipes? This is in the site guidelines: https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html. Your comment would be just fine without the first sentence.
      - EnPissant 1y ago
        Pretty sure you (or someone else) decided to pour over my post history looking for violations after I posted this: https://news.ycombinator.com/item?id=43794576 https://news.ycombinator.com/item?id=43794576 This 3 day old comment was not flagged until just now, what I said is not a swipe at all.
        EnPissant 1y ago
        Correct link: https://news.ycombinator.com/context?id=43796297 https://news.ycombinator.com/context?id=43796297 Somehow, I can't edit a 5-minute-old post.
RataNova 1y ago
There's something existentially creepy about a massive, invisible object just wandering the galaxy, indifferent to everything
nelblu 1y ago
Space between stars is amazingly empty. It's almost unlikely that we would bump into another star (or black hole). For instance, if the whole Milky way were the size of the US (east to west), our sun would be smaller than 1/20th the size of human hair and the closest star to us would be at least a football field away. (Credits for this analogy: Kurzgesagt app https://play.google.com/store/apps/details?id=org.kurzgesagt.app.Universe&hl=en_CA https://play.google.com/store/apps/details?id=org.kurzgesagt... https://apps.apple.com/us/app/universe-in-a-nutshell/id1526364758 https://apps.apple.com/us/app/universe-in-a-nutshell/id15263...)

hyperhello 1y ago

Relax, it’s probably traveling in a straight path at constant velocity.

mytailorisrich 1y ago

It can't gobble planets and stars any more than any stars of the same mass.

jsbisviewtiful 1y ago
For sure - The largest threat would be traveling by our solar system close enough to throw off the orbits of earth or any of our nearby neighbors.
saltcured 1y ago
I'm trying to picture intersecting paths though. Does a faster moving black hole cause more or less damage to a target? Imagine a black hole on the quite small end, intersecting the core of a planet. Unlike regular matter, it can't really produce bow shock through collisions, right? All the target matter in the direct path just "falls in" and in elastically reduces the black hole momentum a tiny bit? Some matter outside the direct path could be accelerated towards the black hole but slingshot behind it, rather than into it. So this material could produce an impressive wake, with material spraying outward from the collision path and interacting with the remainder of the target. But, all this visible chaos comes from gravity rather than more direct kinetic interactions, right? If the black hole is moving faster, doesn't the target's material gets less gravitational acceleration as it spends less time in the near field? So, if the blackhole is moving very fast, does it bore a smaller hole and have less interaction with the target? Or do other effects of relativity make this more convoluted to think about? I'm imagining a cylindrical plug of a planet "instantaneously" disappearing, and then the remainder of the planet collapsing inward to fill the void, bouncing off itself, and ringing like a bell.
- windsurfer 1y ago
  > Does a faster moving black hole cause more or less damage to a target? When a black hole accretes matter, the matter can create tremendous radiation before it crosses the event horizon due to the atoms experiencing many effects such as rapid nuclear fusion and becoming new forms of matter such as neutronium. The precise amount of energy released depends on spin, charge, and size of the black hole, and the speed at which the matter approaches the black hole. If a tiny black hole (Let's say 10cm across) ripped through the earth at significant speed it would be like the center of the planet momentarily became the center of a star and (hand waving a bunch of assumptions) the total energy could easily be greater than the gravitational binding energy of the planet. The planet would explode.

psunavy03 1y ago

It can't really "gobble" anything any more than a star "gobbles" things that fly into its photosphere or a planet "gobbles" things that crash into it. Unless you cross its event horizon, its gravity works just like any other celestial object. Maybe at worst it slingshots you off in a different direction.

deadbabe 1y ago
He technically did not say the invisible monster was a black hole.
stouset 1y ago
I think the concern is that if a star was headed in our direction we’d see it coming. We don’t see one, so we know there is no anticipated threat. A small, lone black hole could be on an intersecting trajectory with us within a few years and we’d be completely oblivious.
- Ancalagon 1y ago
  As if there were any different actions that could be taken to avoid a star vs a black hole. I’d probably welcome the quicker demise tbh
  - stouset 1y ago
    It’s less about actions we could take and more about knowing we don’t have to worry about colliding with a star for the moment.
    - Ancalagon 1y ago
      You probably wouldn’t want society to know we were about to collide with a star-sized mass, visible or not.
      - Swizec 1y ago
        > wouldn’t want society to know we were about to collide with a star-sized mass I may be misunderstanding the distances involved but wouldn't such a collision take centuries if not thousands of years to play out? For the most part it would just look like we had 2 suns, one of which gets a few millimeters bigger (to the naked eye) every year.

casenmgreen 1y ago

In practical terms, not so very far away from the NEAs that we have no idea of, and which we notice after they've just skimmed by the Earth.

tejtm 1y ago

No, not me anyway. we are all floating (falling) in the (nigh) void of space (equally) alone ... which is great protection from all the monsters everywhere! Deliberately hitting things in space is hard, accidentally, more-so. Consider the chance of our sun getting whacked when the entire Andromeda galaxy gets here ... billions or more likely trillions to one. The chance of a single mass in our own galaxy getting us should be less than that. edit: as far as I know the only difference between getting gobbled by a black hole v.s. anything else is our atoms won't get to continue their evolution into larger atoms in this universe. (or maybe see it as our atoms get to complete their evolution in this universe)

sega_sai 1y ago

The size of the black hole described in the paper is ~ 20 km, so it is tiny. Even we have millions of such objects (and most likely we do), the chance of hitting something, given the enormous size of the galaxy is negligible.

rad_gruchalski 1y ago
Would we notice if it was to point in our direction?
windsurfer 1y ago
The black hole in the paper is also ~7 solar masses. If that passed between the Earth and the Moon it would rip apart the earth from just the tidal forces.
- lazide 1y ago
  Well, if present anywhere in the solar system it would also completely fuck our orbits all to hell too eh?
- sega_sai 1y ago
  the chance of that is negligible.

belter 1y ago

Are you worried? :-) I bit like bringing sunscreen to the apocalypse no? :-)

hnuser123456 1y ago

It would be nice to get a rigorous estimate on how big and nearby a black hole could be before we'd notice it with routine sky surveys or orbital deviations. A 6-solar-mass black hole only has a radius of around 18km or 11 miles. How often will one pass in front of a star precisely enough for OGLE and MOA to detect it, as they did with this one? Apparently the Roman Space Telescope will be great at detecting these, if it doesn't get cancelled.

thangalin 1y ago

> gobble planets and stars Direct interaction isn't needed for havoc. A supermassive object sweeping by the Solar System could destabilize Jovian orbits. In the Nice model, Neptune flung Kuiper belt asteroids sunward, gifting the inner planets with a late heavy bombardment. Rogue gas giants, brown dwarfs accelerated to relativistic speeds, giant asteroids approaching from the Sun's direction, Carrington Events, an ill-directed gamma ray, etc. So many ways life on Earth can see its 250 million remaining years cut short, and those are only a few of the cosmic threats we can imagine. A black hole with a Schwarzschild radius of 20 km would weigh about 6.8 Solar masses. It wouldn't even need to get super close to affect the Solar System.

vanattab 1y ago
Where is the 250 million years come from?
- ftrobro 1y ago
  Perhaps a reference to Pangea Proxima? https://en.wikipedia.org/wiki/Pangaea_Proxima https://en.wikipedia.org/wiki/Pangaea_Proxima Life might very well exist on earth even through those conditions, but not to the extent we have today.
- thangalin 1y ago
  https://www.nature.com/articles/s41561-023-01259-3 https://www.nature.com/articles/s41561-023-01259-3
- dredmorbius 1y ago
  There are a number of likely mass-extinction / life-terminating events which will occur within the next billion or so years, either deterministically or probablisticaly (e.g., increased solar insolation and plate tectonics are deterministic, massive gamma-ray burst or killer asteroid are probabalistic), of which supercontinent-formation is only one. Wikipedia's "Timeline of the Far Future" lists several: <https://en.wikipedia.org/wiki/Timeline_of_the_far_future https://en.wikipedia.org/wiki/Timeline_of_the_far_future> We likely exist in the late afternoon if not evening of Earth's habitable period.

ajb 1y ago

There are many theoretical astronomical risks. For example, if we happened to come into the path of a relatively nearby gamma-ray burst, it could eliminate all life. Given that life has existed on the earth for quite some time, the 'Lindy effect' suggests that the sum of these presumably-constant risks is small. We are much more likely to become extinct due to an anthropogenic cause.

somenameforme 1y ago
A gamma ray burst is one of the possible hypotheses for the cause of the Ordovician mass extinction event, one of 5 big ones Earth has had. No idea why the Great Oxidation Event isn't included there as it was also one of the deadliest mass extinction events - plants and their vile poisonous oxygen killing off basically everything else. So I don't think the 'Lindy Effect' would apply as species are mostly perishable, just on longer timeframes. Humanity is hopefully the exception, but absence of evidence of other advanced intelligences in the universe doesn't paint the most promising picture there either. On the other hand we're already on the cusp of colonizing other planets and once that process begins the odds of humanity ever going extinct will approach zero. On the other hand at greater distances "humanity" will likely splinter fairly quickly (relative to on a geologic or even species survival timeline) into numerous distinct species.
- deleted 1y ago
  [deleted]
windward 1y ago
The anthropic principle is at odds with that. Lindy's doesn't reason about itself.

SllX 1y ago

No more unsettling than space in general is. It’s pretty hostile to life. We’re not just making turns around the orbital racetrack setup around the Sun, we’re also flying through space following the gravitational trail of the Sun as it races forward without a destination. I was playing with Universe Sandbox over the weekend trying to figure out how to terraform Venus. Changing its axial rotation period to a day to match the Earth while I screwed around with its chemistry was enough to cause Europa and some of the other famous moons of Jupiter and Saturn as well as Charon to yeet themselves outside of the solar system within about 10 or 20 years of simulated time.

danparsonson 1y ago
Why would changing the rotation speed of Venus have any noticeable effect on the outer planets? That sounds more like a limitation of the model than anything else. Especially over such a short time! 20 years is nothing to the orbit of Charon.
- SllX 1y ago
  Probably, but if a Venus-sized mass showed up in the inner solar system because the Sun just picked it up along the way, it might not be instant death but we’re probably in for a rough time. It doesn’t have to be a black hole that does us in, it could be something much smaller that still strips the Moon away or causes Earth to readjust its own position in a way we, as in life, but also maybe we as in humans or we as in mammals just don’t like very much in a very short amount of time temporally speaking, and we couldn’t do anything about it anymore than we could do anything about a black hole because we’re just not the captains of this ship. We’re just some homegrown stowaways. But for what it’s worth, it’s also just so incredibly unlikely it’s not a scenario worth thinking about either, and thinking about it too much just invites existential dread.

dreamcompiler 1y ago

I don't. If the sun were replaced by a black hole of equal mass next Tuesday at noon, the only thing we would notice is that it suddenly got very dark and very cold. We would continue orbiting the thing while freezing to death over the next few days.

EnPissant 1y ago

It's really, really hard to fire something into the Sun. We can't do it. The same goes for black holes. Things don't just get sucked in. They usually end up in orbit instead.

hollerith 1y ago
That's not true. (1) We can launch a rocket that has a payload that hits the sun: it's just costly to do because the rocket starts out orbiting the sun, so we would have to expend delta-v to neutralize the tangential component of the initial velocity. (2) If you are in a space ship heading towards the sun, it is easy to hit the sun as long as you can steer, and even if you can't steer, if you are heading squarely at it and no planet gets near you to change your velocity, you will hit it.
- EnPissant 1y ago
  [flagged]
  - dang 1y ago
    Can you please make your substantive points without swipes? This is in the site guidelines: https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html. Your comment would be just fine without the first sentence.
    - EnPissant 1y ago
      Pretty sure you (or someone else) decided to pour over my post history looking for violations after I posted this: https://news.ycombinator.com/item?id=43794576 https://news.ycombinator.com/item?id=43794576 This 3 day old comment was not flagged until just now, what I said is not a swipe at all.
      - EnPissant 1y ago
        Correct link: https://news.ycombinator.com/context?id=43796297 https://news.ycombinator.com/context?id=43796297 Somehow, I can't edit a 5-minute-old post.

RataNova 1y ago

There's something existentially creepy about a massive, invisible object just wandering the galaxy, indifferent to everything

nelblu 1y ago

Space between stars is amazingly empty. It's almost unlikely that we would bump into another star (or black hole). For instance, if the whole Milky way were the size of the US (east to west), our sun would be smaller than 1/20th the size of human hair and the closest star to us would be at least a football field away. (Credits for this analogy: Kurzgesagt app https://play.google.com/store/apps/details?id=org.kurzgesagt.app.Universe&hl=en_CA https://play.google.com/store/apps/details?id=org.kurzgesagt... https://apps.apple.com/us/app/universe-in-a-nutshell/id1526364758 https://apps.apple.com/us/app/universe-in-a-nutshell/id15263...)