Is there a Black Hole in our Solar System? - Sixty Symbols 

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Yeah but, not a watermelon, a number 10 pin. I guess they couldn't get a bowling pin for the video to use as reference?

​@@azdgariarada You'd need half the size of a ten pin ball for the video. The watermelon fit that size I guess.

That poor printer

@@azdgariarada It says "ten pin bowling BALL". A "traditional" bowling ball. Which is about the size of the displayed watermelon.

They do depend on light for the most part, the rest is done indirectly. So something that can be felt due to gravity pull, but doesn't glow, is a challenge.

It’s easier to see someone 100 yard away across a field, than someone standing right behind you

We can detect exoplanets that pass in front of their star and block out the light or if they are large they can move their parent star's orbit. The planet we are looking for would be dark against a dark background and too far and too small to move the Sun appreciably.

@YeYaTeTeTe The wobble from such a planet would be centuries or even millennia long, so it would be hard to detect regardless of the start it is around.

@YeYaTeTeTe yes, planets don't glow by themselves. But I get this alternative hypothesis is just another option for the planet one...cause a watermelon-sized black hole is even "darker" than a planet. Further information/data may help decide what is the right hypothesis.

It would be the only way we would ever get to actually study one up close.

@@RinnzuRosendale Within our limited lifetimes, sure. But in the grand scheme of things, it is entirely feasible to imagine scenarios where we, as a species, might get close to not just one, but many black holes.

imagine what a golden opportunity would be to study this thing!!!

@@renx81 Or if not us, at least machines built by us.

@Ra assuming faster than light travel is possible. Though we have every reason to believe it is not. While our species may spread beyond the few closest systems on generation ships, I doubt our society will ever reach beyond just a few systems away. Likley our solar system is where we should be focused.

haha yeah bunch of bollocks loved by fear mongers

_That_ particular theoretical object went moot when Voyager 2 measured the precise mass of Neptune, in 1989.

Planet X is also one of my favorite board games, about trying to locate Planet X based on the position of other bodies.

If we discover a new 9th planet, I’m going to call it Planet X for old times sake.

@@Name-ot3xw No, we should name it Pluto! 😅😁

I can also imagine a doomsday scenario where several different countries send probes to make discoveries first for the sake of capitalism. Fear and tension would rise for the entire trip there. I know, I'm a pessimist.

This is a pressing issue. We bet a lot of chips on science in recent history (our civilization basically runs on it now) and nowadays the masses seem to glorify ignorance of science and are obsessed with putting science "in its place", based on misconception of motives and simple lack of knowledge of what science is really about. We're really screwing ourselves over there, I believe.

Agreed! If only just to bring some of these amazing minds to light :D

This touches on why we shouldn't see even primordial black holes evaporating. If their mass is greater than the moons their horizon temperature is less than that of the CMB so they have a greater mass gain from absorbing CMB radiation than the mass loss from their hawking radiation

​@@alonzoc537 shouldn't there be a cold, moving spot when mapping the CMB?

​@@jackbennett2760 cmb mapping take a long time, I think, and it would be a moving object. For the same reason why other objects in the solar system don't generate spots I suppose.

@@jackbennett2760 An object that small will be a fraction of a single pixel in the data. You'll never see it.

She’s still Jenny from the block

No thanks.

No, actually. Any black hole larger than about the mass of the Moon has an effective temperature lower than the Cosmic Microwave Background - which means they actually get heavier from infalling CMB faster than the lose it via Hawking radiation.

It takes a super tiny black hole to have any significant hawking radiation

@@VoidHugger , melon-sized *is* "super tiny" on a galactic scale. A micro black hole just means it is less than 1 stellar mass.

@@SgtSupaman Yes but i truly mean super tiny, like on a solar scale For a black hole to radiate with an effective temp of 1 Kelvin, it would have to have a mass of about 2% that of Earth's For it to be room temp, it would need to be 0.006% the mass of Earth If we were going to detect it from such a huge distance it would have to be radiating pretty powerfully, so even that is too big

As long as the black hole is colder than the cosmic microwave background, it isn't visible. Background radiation has now a temperature around 2,7 K. A black hole with the mass of 10 Earth is much colder, 0,002 K. This black hole can't "glow" with Hawking-radiation, because the CMB would still heat it up.

You would get brightness differences too. Think about the gravitational lensing acting like a magnifying glass, and how you can turn the sun's light into anti-ant death ray by focusing it.

It's whatever they need it to be. Fun fact about gravitational lensing, it's NEVER been observed outside of the solar limb of the sun (allegedly). So technically no one has ever seen gravitational lensing outside of computer generated imagery and broad assumptions about the nature of light.

@@space_auditsLensing has been observed conclusively in many areas of the sky.

@@space_audits That's not a fact, that's straight up misinformation. Gravitational lensing has been used in countless observations in the past decades, it is one of the most effective ways to observe extremely old galaxies in the early stages of the universe.

@@space_audits gravitational lensing is what proved general relativity, and we have also observed lensing for massive galaxies too

I think black holes can have an efficiency of ~46%. Compare that to fusion in the ballpark of 2%.

500 AU out is not exactly in our backyard.

Slingshot maneuver target, definitely

Event horizons will prevent us from learning much, but we could at least try the backwards time travel idea that was proven to be possible using a pond, a vortex and a whole lot of science.

Ehhh slow down there haha, the planetary definition is already unscientific as it comes, lets not stretch it into obscurity xD Also, spherical is debatable, since the black hole itself has a yet to be determined geometry, and its only the event horizon which is spherical. The event horizon itself is just an area and technically not part of the black hole itself, just a result of its effects

If it comes to that, I think they'll change the definition again. :D

black holes are a type of star

@@remnant342 black holes are not a type of star, they are their own phenomenon. We are not even sure in what sense we can even call them objects, since they are a region of spacetime, not a physical object like a star or a planet

@@MrMegaMetroid black holes are super confusing. In my head there is a (solid surface) at the core of a black hole. (Surface in the same sense a neutron star has a surface.) But I also know that one you cross the event horizon distance measurements turn to time. I guess my brain can't let go of the Newtonian physics.

My question exactly. Im sure they either adressed this in the paper already, but it would still be great to hear at what point we could detect hawking radiation. My first thought when watching the video was "shouldn't this be mega bright in some wavelength?"

It would be still be much, much colder than the background radiation. The threshold to be hotter than the background is around half the mass of the moon. If we could study it in detail, we might learn something interesting about hawking radiation, but from far away its just a wash in the background noise.

5-10 earth masses not solar masses if it was solar masses we would be orbiting it not the sun.

@@thomaskey9688 Not necessarily. It could be 10 solar masses and dragging our whole solar system around it. And we would not really notice that (yet) due to the obnoxiously long orbit time, and we haven't had enough time to do a proper parallax measurement to see if that is so. But to be honest, if a black hole was present out there, it should have spewed out radiation by now from stray Oort cloud objects being shredded into an accretion disc before being swallowed by the event horizon. And with a black hole so small, the accretion disc is also compressed into a tighter disc, it would be so luminous it should deffo be visible from Earth based telescopes at the very least. So I consider the chance of us having a black hole in our back yard, extremely low, near zero.

​@@paulmichaelfreedman8334good remarks you have, but could it be really, really low mass one?.. still, I myself would bet on rather cold gas giant... not being even a hobbyist astronomer though.

Yes, like snakes. The real big ones are much easier to spot!

One could be behind you right now

​@@WAMTAT one of my worst fears. I've had delusions about this before 😭 I thought they were imperceptibly small and passing through my brain or the palm of my hand and that's why I was having thought blocking 😵 what a relief to know how unlikely it is, and to be better now

I imagine it like a patch of quicksand in a cartoon.

Imagine that thing where a bug flies into your face, but actually now the top half of you is spaghettified for billions of years lol

It's always been easy to just throw cold, almost inert objects in the outer solar system and/or interstellar medium in the end of a paper as a way to explain discrepancies in observations. Similar to how some have wanted to explain dark matter as just actually regular matter that is just really dark (solar-mass black holes, cold neutrino-like particles). The paper is relevant because it's solving two discrepancies at the same time and suggesting testable experiments in our reach. So it could result that these crazy objects, that have become sort of the meme/joke suggestion to solve everything or added to your paper just to reach the word count for the discussion section, may actually be real.

Sky survey programs don't just run for one night. They run for years, and over that time it allows them to cover more than half of the entire night sky repeatedly, depending on their location. And the big surveys have telescopes in both hemispheres to cover the entire sky. Satellites in space can also cover the entire sky over the course of a year.

That's Betteridge's law of headlines.

Light rays bend more the closer they are to the center of mass. Light rays can pass a whole lot closer to the center of a watermelon sized 5 earth mass than they can to a planet sized 5 earth mass. In other words, space is curved much more dramatically near the black hole event horizon than it is near the surface of a planet. At greater than a planetary radius away, there's no difference.

It's not that scary. It has the mass of Neptune or so, so it poses about the threat of Neptune or so.

FTL travel is equivalent to time travel. Do you see any time travelers? QED

@@Siddingsby We're all time travelers. Forward.

@@Siddingsby not unless you are faster than instant. It’s evident once you start drawing space time diagrams.

Not even an undergrad, but the orbit needs to be stable. Your clump of smaller bodies won't stay a clump on sufficient time scales.

You'd need to explain how your clump of planetoids managed to get into a clump in the first place. And now you're back where you started, needing a planet 10 to explain your explanation.

Planet/Black Hole 9 isn't expected to be anywhere near the Oort cloud. It's expected to be about 250 AU out. The Oort Cloud doesn't start till about 2000 AU out.

it doesn't need to be alive :)

Underrated comment! This is a great question that no one has even bothered to bring up.

Only very small black holes lose mass to evaporation. They have to be hotter than the cosmic microwave background, or they'll absorb more energy than they radiate. That happens around half the mass of the moon. Anything larger than that would be too cold to lose mass today, and the universe was hotter in the past. This object would be several times the mass of earth. It would be quite stable.

Because a 5 earth mass black hole has a lifetime of 10^52 years.

Yes, it could be Pluto's big brother.

The point of the video I think is to say it's very possible, but that they're not sure how probable, so they're thinking about diverting resources to look for planet 9 in different ways

@@ayembic7933 that makes sense. ty

Some people are of the idea that the planet should be big and warm enough relative to the background (considering it should be an ice giant) that it should have been found already. So that's why the exotic possibilities are starting to get more attention.

You might have a plane about to crash into your home right now as well. That's actually far more likely - maybe a few trillion to one. And while we wouldn't be able to detect such a black hole using a telescope we _would_ notice it though it's gravitational pull

These objects are small by comparison to a galactic core formed one. You wouldn't notice it. You are clearly hearing him say its an object 5 to 10 times the mass of Earth. You are easily scared.

Rouge black holes exist regardless of PBHs existing or not. Just like planets can be ejected from solar systems, so can stars from star clusters. If one of them goes supernova, there you go. (the black hole itself can obviously also be ejected)

Oh you would see it coming. As it moves to a more dense environment it would start consuming matter, an accretion disk would form which would start to glow very brightly.

True, but the odds of that are essentially zero.

Given that the former are still hypothetical, I think it makes perfect sense to only refer to real black holes (formed by stellar collapse) as black holes. Why change the name when we don't even know if the other version even exists?

@@SgtSupaman Well, we know there are supermassive black holes that are too massive to have formed by accretion from stellar-mass black holes, so some other process must have formed them. This said... I agree that there isn't too much of a point in calling them something else, particularly if the no-hair conjecture is actually true in physical reality (rather than in some mathematical representation of a particular physical theory).

The minimum safe distance for a spacecraft is likely something like 100000km, much less if you have a lots of delta-V availble. Of course you wouldn't want it anywhere in the inner solar system as it could disturb the nice regular orbits, but even so it's effects would likely not be even measurable until it gets within tens of AU and probably not significant if it runs through on a nice clean parabolic orbit.

Theoretically yes, but: 1. To get sufficiently close to the black hole that you get significant time distortion means spaghettification (the gravitational gradient of small black holes is hugely sharp). 2. Voyager 1 and 2 have been travelling for ~45 years, but are only about 130 AU away. Fair enough, their trajectories were optimised for other objectives than going out 500AU, but it gives you some idea of the time spans involved... 3. You can only travel "to the future" (time for the astronaut slows down vs. Earth), so we may be in for a _veeery_ long wait: 50 years to get there, another 50 to come back, and then the 'time compressed' period orbiting the black hole that doesn't quite take as long for the astronaut as it does for us, but it's still got to be significant enough to be measured.

No, to get significant time dilation you have to be within a few Schwarzschild radii of the black hole, three for 80% IIRC. Just getting into a orbit that close is very difficult with even a supermassive black hole as there are NO orbits below 1.5 radii and likely nothing stable below about three due to the spinning black hole doing "frame dragging". This black hole would be about the size of the astronaut's head.

Exploiting black hole time dilation requires a very large black hole. The tidal effects around small black holes would completely rip any object to atoms before it could get close enough for substantial time dilation.

As you approached it I imagine you'd then realise that your trajectory is changing because it's mass will exert more influence on you.

You can feel it but you can't see it.

You might be able to see it if there happens to be any matter around because it would glow from the acceleration and friction. With a specialized probe you would also be able to detect the Hawking radiation if it indeed exists, same for the gamma ray emissions from the dark matter halo. However, technically I think it would be a _much_ greater challenge to detect this thing accurately enough to actually send a probe to it than it would be to avoid accidentally flying into it. I mean, space is _vast,_ especially at such an immense distance from the sun. Hitting such a tiny object basically face-on is basically impossible if you aren't trying very very hard to do so.

@@unvergebeneid the Hawking radiation from a black hole this size would be less than the cosmic microwave background, so you're not going to find it that way. but yeah, people underestimate just how big and empty space is and how unlikely it is to encounter anything by accident (or how hard it is to rendezvous intentionally)

Thats the fun part

Perhaps Sol's uniquities might be explained by absorption of the object which caused these anomalous gravitic perturbations?

Gravitational attraction (or curvature, if you want to play Einstein rather than Newton) is directly proportional to mass - so your premise that the lighter the object the more force the black hole has, is wrong to start with: each body would be "attracted" to the (supposed) black hole with a force proportional to its mass. On the other hand, we are talking of a very small black hole: with a mass of 10 times the Earth, it would have a mass about 1/33,000 of the Sun's, which is why we see the dynamics of 'more stuff going towards the Sun than the black hole' in any case. The observations of 'how much mass there is' (on average) at the extreme of the Solar System can be consistent with the presence of a point mass 1/30 that of Jupiter 500 AU out there. But "out there" there is very little mass indeed, and a mass would need to be 180 times closer to the black hole than to the Sun to be attracted 'more strongly' to the black hole than the Sun; that would mean that masses in 497 out of the 500 AU would 'on average' tend to orbit closer to the Sun than to the Black Hole. Things get really complicated in terms of dynamics, as the bodies are orbiting each other, not standing still at a fixed distance, and there are other bodies (e.g. the planets) that also have mass. Let's think of it another way: there is no accretion disk around Jupiter, that has a mass 300 times the Earth... although it has a lot of moons, and thus a significant concentration of mass vs. the 'empty' space of most of the Solar System, yet the mass of the Jovian moons is a tiny percentage of the mass of Jupiter (which is in turn much bigger than the supposed black hole), and the moons had much more material to grow from than the density in the Kuiper Belt or the Oort Cloud.

It would take 140 hours round trip at 500AU. You'd need a very powerful laser indeed, and if it was a black hole, you'd not get anything back anyway.

Voyager 1 is about 160 AU away, and that has taken about 46 years.

Having said that, I think if we're to start building black holes we should probably only consider doing it in space and keep it nice and far away from the Earth.

​@@randomfarmerwe are nowhere close up being able to create black holes ourselves. Our highest energy particle colliders don't have enough energy by several orders of magnitude.

@@narfwhals7843 Ok. Cheers. My suspicion about the detection of the Higgs boson was that it was a naked singularity, but that's just my opinion.

@@narfwhals7843 Also, are you certain about that? I was under the impression that quite a few physicists out there suspect that microscopic black holes could be formed in the TeV range and hence would be possible in the LHC. Perhaps it'll become more important with the next generation of particle accelerators, but I'm not certain we're all that far away from actually creating tiny black holes.

@@randomfarmer There was a little craze when the LHC was about to start because someone, who had no idea what they were talking about, sued the LHC for attention, claiming there was a considerable danger of black holes. That was complete nonsense, which the LHC was forced to prove mathematically. Cosmic rays hit our atmosphere every day and cause collisions with much higher energies than the LCH is capable of. Black holes don't form in the atmosphere. So I'm fairly certain.

If you mean radio signals then yes and it should... but it won't be used for that at least not for awhile.

This object would be out at the very edge of the Kuiper belt. Individual objects out that far are almost certainly further apart than anything in the inner solar system.

TNO objects are extremely difficult to detect. We've found a handful of them. We wouldn't know if there was a gap.

It's so tiny, the accretion disk would still be there. It just wouldn't have much to it. I think the gamma ray bursts mentioned in the video are due to asteroids being added to the accretion disk.

It isn't likely to have an accretion disk. It is a tiny object, and the space out at 500AU is very, very, very empty.

5 earths worth of mass will take a long time to evaporate

@@giovannibini6809 I would think so, but if you start shoving mass in to get energy out, does that accelerate the process. You get some insane return, in theory. Like the most efficient energy exchange there is. It would seem like there’s a price to pay somewhere.

Personally I’d just feed it asteroids and pull energy out of the accretion disk

Sure you could. In fact primordial or kugelblitz black holes would probably be preferrable since we wouldn't need an ungodly amount of materials to build the penrose sphere. Building one around a stellar mass black hole would be as insane of an undertaking as building a dyson sphere

A 5 Earth mass black hole would take about 10^52 years to evaporate.

Over the course of a year, those telescopes can image their entire hemisphere. And we have telescopes in both hemispheres, so we can cover the entire sky. Space telescopes can cover the entire sky in a year.

The primordial origin they are going with means it would have formed at the beginning of the universe. It is pretty much the only way a black hole could hypothetically exist at such a small size. The black holes that we know of were formed by collapsing stars, so are much more massive.

And how would you usefully make use of that from 500 AU away?