What Happens If A Black Hole Hits Earth?

[@Ole_Rasmussen]

That is a very reassuring thumbnail that makes me feel calm and safe.

[@benmaynard3059]

😂😅

[@Goblinoid-o]

don’t worry, it would be much much more destructive

[@benmaynard3059]

@@Goblinoid-o depending on size

[@amehak1922]

Is it possible? Yes. Is it likely? No. The odds are not zero, it's 1/100000000000000000000000000000000000000000000000000000

[@i-am-evil-morty6710]

I made this to 70 likes... Unfortunately had to unlike. Nice.

[@not-high-on-life]

PBS release always makes my day a little bit brighter, doesn't matter how much I understand but I always take out something valuable. Huge respect for this show to all involved and Happy New Year.

[@superluminalsquirrel9359]

I feel the same way. Not to mention the humor and Matt’s presentation make it even better to watch :)

[@mangethegamer]

Nothing like getting your daily shower of anti-god propaganda.

[@shoujahatsumetsu]

@@mangethegamer How is this anti-god propaganda, unless you take holy scriptures literally instead of metaphorically?

[@daltontinoco7084]

Thinking about a black hole hitting earth made your day o.o my hats off to you

[@jimmyjasi-anti-descartes7088]

I can't understand why aren't everyone screaming in orgasm at MOND news? It was unsolveable mystery why Gravity is the weakest force. There were even some odd ideas about Gravity leaking into other probably non existing dimensions. With MOND it becomes solved Gravity isn't leaking anywhere it just gets properly Strong only on Galaxy scale distances!! Dark Matter is probably a Modern Day Aether and like Morley experiment paved the Way vía Lorentz into GR. When MOND gotta be proven would also start Revolution unseen since learning that Time is Relative in 1905!! Of course these Axions, Neutralinos or others supposed "Dark Matter Particules" may exists as well but they are just not necessary Dark Matter Not necessary to bind the Universe. What do You think about MOND explaining Mysterious Gravity Leaked?

[@standinby]

I just want to say I'm grateful for Matt when he explains the scientific mindset and thought process.

[@LuisSierra42]

Amen brother

[@NoahSpurrier]

The entrance and exit of a PBH isn’t necessarily antipodal. That is, the exit doesn’t have to be on the opposite side of the planet because a PBH is unlikely to strike exactly perpendicular (normal) to the surface. A glancing blow seems more likely.

[@MechanoRealist]

And then its trajectory would also be potentially bent by the gravity of the mass it enters as it's traveling through it.

[@rexis188]

Also curved because the planet is still rotating

[@chrismaynard5]

A PBH would have a mass of a large asteroid so regardless of it's trajectory it would get pulled more and more perpendicular to earth's diameter on its approach, although never perfectly so. The overall shape of the trajectory would be parabolic to the barycenter of the two masses. In other words it would not go straight through nor would it be a glancing blow, instead it would be pulled towards the core of the earth and accelerated out just like a comet coming in from the oort cloud on a close approach to the sun.

[@rfvtgbzhn]

@@chrismaynard5 actually asteroids are often too fast that this effect is big enough to make the impact almost perpendicular. For example the angle of the KT impact that killed the dinosaurs is estimated at 45-60° and the 2013 chelyabinsk meteor had an angle of even only about 18°. Actually even an angle close to 0° is possible because asteroids often have a relative speed that is greater than earth's escape velocity.

[@chrismaynard5]

@@rfvtgbzhn that is true. The difference is that PBH would continue unimpeded, but not in a straight line as the video suggests. It would get a sling shot boost around the barycenter of the two masses and exit at an inverse trajectory more or less.

[@AboveTheNoise]

Thanks for the shout out for Above the Noise and our episode on the pros and cons of billionaires in space! We appreciate the support!

[@livinlicious]

Its kind of interesting to think of atom sized black holes with the mass of some asteroids. Too big to evaporate via Hawking Radiation, too small so "interact" with normal matter in a significant way. On paper these objects behave like the dark matter particles we are searching for, meaning they only interact via gravity. It would seem that "black hole"matter has similiar properties to this "dark matter particle"matter. Interesting idea.

[@nosuchthing8]

They had a show discussing the possibility of dark matter being primordial black holes. They seem to think its not a good possibility. Imagine acquiring several of these miniature black holes and allowing them to combine .

[@cowboybob7093]

They can't evaporate because the known universe is too warm. In a few trillion years every size black hole will be evaporating.

[@gJonii]

Asteroid size one wouldn't just evaporate, it would explode. With the power of billions of atomic bombs. Within microseconds. I don't remember exactly what size black hole would be stable enough to survive longer than a couple of seconds, but it's at least heavier than Earth.

[@nosuchthing8]

@@gJonii A primordial black hole with an initial mass of around 10^12 kg would be completing its evaporation today; a less massive primordial black hole would have already evaporated.[1] en.wikipedia.org/wiki/Micro_black_hole Ceres - The largest and first discovered asteroid, by G. Piazzi on January 1, 1801. Ceres comprises over one-third the 2.3 x 10^21 kg estimated total mass of all the asteroids. Studied from orbit by the Dawn mission in 2015-2016. So a small asteroid would be a stable black hole

[@GoCoyote]

No black hole is to big to evaporate via Hawking radiation, as that evaporation is constant, and mass can only be gained by trapping new matter. The issue is that there would now only be black holes left that started out at a certain size over the minimum material required to make a black hole, as all of the black holes that were below a certain size from then, would have had time to evaporate given the age of the universe.

[@brotalnia]

This is the best educational channel on KZbin. I've been watching for 4 years now and never miss an episode. It's just that good!

[@doomed.661]

Loved physics in early senior highschool. Couldn't continue it as a subject as I needed other subjects for my uni course. Thanks for making videos that enable me to indulge in my love for physics and explore interesting ideas and content like this.

[@Zei33]

That was an unbelievably good video. Amazing work. I can’t believe how much work is being done in these fields.

[@NaturalBloom7]

I’m in love with this channel, thank you professor♥️🤍

[@alexpearson7459]

Man this is like the 5th time Matt has talked about primordial black holes. You guys think it will be on the final?

[@sicfxmusic]

What do you want on a space channel, Anime?

[@vijaysuneelkumarlohana2457]

)

[@rainbowbutterflyfan]

Yes! Finally a new video :D I’ve binged all the other ones so I’ve been eagerly awaiting a new one

[@gaymer618]

Hi Matt :) awesome channel. Thanks for making this pandemic this little bit more easier.

[@leightaft7763]

More easier eh? Lol

[@anarchyantz1564]

In relation to the Tunguska event. Recent findings discovered meteorite particles such as iron and iridium deep in the peat around the blast area as well as embedded in tree samples taken. Due to the small size and depth of most of these which has been dated back to around the time of the blast they concluded it could have vaporised high up in the atmosphere with the shockwave blasting down scattering the fragments. Simulations of a more icy body like a comet would cause the destruction shown without leaving the usual expected meteorite shards one normally sees from standard air bursts like the one over Chelyabinsk which left larger meteorite fragments.

[@dopplervocals]

I’d honestly like an in-depth analysis of the many ways we could destroy/survive/prevent cataclysmic planet killers.

[@theundone777]

I love how you respect the other space times by specifying that you are talking about *this* space time .

[@chrismaynard5]

Best comment by far!

[@PeterGaunt]

Thanks Matt. I actually understood that without flipping backwards ocassionally. I like the reference to SF towards the end of the main part: good SF breaks science's 'laws' in an internally consistent way which makes it good for exercising the brain cells.

[@MosheFeder]

I look forward to and enjoy every episode of “Space Time,” but I especially appreciated this one for its thorough treatment of a fresh topic I’d never considered before in this form. I learned a lot and nothing pleases me more. Great job!

[@Belas_Photography]

Wonderful discussion, Matt. It immediately brought to mind David Brin's "Earth", with its renegade black hole in the earth's interior. Of course, that one was man-made...

[@Selevas]

Great book. The first time I tried I couldn't get into it due to all the different points of view at the start of the book. Second time I made my way through and it was worth it.

[@captainastral]

Also made me think of Greg Benford's "Eater"

[@ericchambers9023]

J. Craig Wheeler, The Krone Experiment. Rich genius tech guru tries to harness micro black holes for clean energy, but they fall out of containment and start oscillating through the Earth.

[@jonathanrobertson3406]

I enjoy all of the videos here, but I think this one was especially well done. The explanations, even if theoretical, were exceptionally clear.

[@poppedweasel]

I do like the idea of measuring accretion disc temperatures using the Hilarious scale.

[@MrScrofulous]

I've been looking for that reference, but can't find it. Time stamp ? Pretty please ?

[@poppedweasel]

@@MrScrofulous 6:14

[@sdfkjgh]

12:50 _Death by Black Hole_ would be a great name for a Hardcore Physics Metal band. Since there is yet to be such a subgenre, I hereby dub it Demon Core.

[@bananabourbonaenima]

Occam's razor: Only add complexity if it actually improves your predictions.

[@bbbl67]

Must be how String Theory got started.

[@CousinWhatIsIt]

"Earth" by David Brin, written back in 1990, is sci-fi based on a lab-made microscopic black hole getting loose and growing in Earth's core. Not all the physics are right, obviously, but it is hard-based in a lot of science, and is a very interesting read, considering how it predicted a lot of today's technologies and social issues.

[@CaptainKirk01]

Thank you again, Sir! My favorite channel. Again, you helped me understand some long-standing questions I have had.

[@ExternusArmy]

I'm getting desensitized to Matt blowing my mind. Like yes, what intuition will Matt obliterate this week? Freaking geniuses, bro.

[@ChaJ67]

With the JWST recently launching and astronomy obviously leading to a lot of physics being done as evidenced by this episode, what about doing an episode on the physics we could be learning from the JWST, granted it fully deploys and can do its science mission? While there are bound to be unknown unknowns until JWST happens to spot it while other instruments just don't have that particular detection capability, it seems there are a number of things we know needs a closer look such as the early universe (which you touch on here) and a number of study topics that went into the design of the JWST. Maybe even just spend some time talking about the physics of why doing the infrared studies is so important once you have a more visible light telescope such as the Hubble in space. (Even something like explaining why hunting for planets in the infrared is a good idea.) I have talked to people about my knowledge of doing scientific studies in the infrared and taking infrared spectrographs and how that applies to what the JWST is designed to do and they had no idea JWST was even an infrared telescope or why that was important. While a lot of people know about the JWST, obviously from the people I have talked to about it at least, they have no idea of what it is supposed to do or how it is supposed to do it. I don't think the JWST can be well understood, especially front the standpoint of what it is designed to do that other instruments we have can't do, without a good physics explanation to it.

[@scaredyfish]

I remember an old sci fi short story about scientists that accidentally created a tiny black hole that instantly fell down into the centre of the earth, dooming the earth to eventually be collapsed into it. It would be interesting to know what would happen to such a black hole - would it actually do that?

[@nolanwestrich2602]

Intuitively, I think it would, since the black hole would start at zero velocity on the Earth's surface, and friction would slow it down until it eventually settled in the core. But it would take a long time to slow down, and would take an even longer time to eat up the Earth.

[@louise_rose]

I recall this comment from some very prestigious popular book about astronomy: "It has also been posited that the entire universe might be seen as a black hole - after all, the very definition of the universe tells us that nothing can ever escape from it. This theory though seems impossible to either prove or disprove; for this reason (and others) it is not really a scientific theory, and it will not be further discussed in the present book." :D

[@TheDavidlloydjones]

@@nolanwestrich2602 Hunh? Why would it "fall" any more slowly than anything else would? (If it starts at zero, how could friction "slow it down" as you claim?) The oddities are two, aren't they? Depending on its size the Earth might be falling toward it rather than vice versa? Also depending on its size, it might, if small enough, just pass between all the atoms around it. Once the two are settled, the lefe-expectancy of Earth is then ver-ree sort, surely?

[@debunkthis]

No it’s would more than likely just evaporate

[@darrennew8211]

en.wikipedia.org/wiki/The_Hole_Man Not the same, but similar. Also the Hogan novel "Twice Upon a Time" that primarily involves a time machine but also problems with accidentally producing black holes.

[@josephertz5786]

Thank you for what you do on this channel I'm not the brightest person but I always come away with more knowledge then I had. It also gives me something to investigate to expand that knowledge. Again thank you

[@Tigtone_85]

Woohoo successful launch of James Webb!!! Brought me to tears watching it after seperation as it was unfolding its solar panels. God speed James Webb can't wait to see what we'll learn. What a awesome xmas gift for all of humanity

[@christian6278]

What would a collision of a PBH with the sun look like? I would imagine such an impact more likely to happen, with the sun being much bigger than either the earth or the moon. But could we actually detect this scenario?

[@jamesoleruster]

In theory, wouldn't it look like a comet about to strike the sun?

[@logichammer8073]

I think the event would be to small to notice, given the size and fluidity of the sun, as well as the sheer amount of energy already leaving the sun. *Although, technically, if it hit on the side of the sun earth is facing, maybe we could detect it? Idk though.

[@TheNasaDude]

There is a new telescope dedicated to precise observation of the Sun surface. IIRC it came online this year and it can resolve single convection cells very nicely. It should be able to see the immediate aftermath of a black hole impact, but the Sun is very big and very dynamic. Implementation of an algorithm/ai able to automate the recognition of these events will probably be hard. I suppose we would see some sunspot like phenomenon

[@eroraf8637]

DKIST will be able to resolve details as small as 20 km on the solar disk. However, the impact processes described in this video probably wouldn’t be visible at that scale, except maybe as an unresolved blip indistinguishable from a nanoflare. I wouldn’t hold my breath.

[@Delibro]

If we can't detect them on earth, how could we detect it on the sun, as it is much larger, much much fluider, much much farther away...

[@ldmcnutt]

That was delicious! Thank you for the outstanding work that you do. My only request would be to make more episodes for my enjoyment!

[@alansnyder8448]

Thanks for this fantastic episode!! Two questions. #1) Can we set any limits on the asteroid-sized PBHs within the solar system, but looking at the deviations from the predicted orbit of satellites in geostationary orbit. It seems those satellites which should be at well-known places could as a group be a sensitive detector for any asteroid massed objects passing close by. #2) If Hawking radiation causes the smaller PBHs to evaporate, could we calculate if there is a "stable" size of PBHs that would exist within a galaxy since it would consume about as much mass as it radiates and maybe that could explain why "dark matter" seems to cluster around galaxies. These two things: PBHs and galaxies feed each other.

[@alansnyder8448]

I did a quick calculation of the (hawking radiation) temperature of the largest of the possible PBHs, and come up with something like 10 degres Kelvin. (a) Someone please check my math. I'm trying to determine IF it is possible that a Spitzer or a JWST could see this as a stream across a field of view if one was close enough. Does this line of observation make sense to the professionals here? Update: Further checking it seems JWST is 40 K, so it could not detect a 10 K object is my guess.

[@jeffreydungan1377]

3:17 - 'If they were smaller than about 1 trillion kg, they would have already evaporated by now'

[@cornbreadfedkirkpatrick9647]

PBS please never stop cranking out fantastic content such as this, and Eons, until I get my place my PC is the only place I can get you. You are and will be my first true station without interference from back in the day.

[@warlordwest7673]

Hey Matt and team...love the videos..but I have been a supporter since before PBS started taking over..you will always have my support !

[@mito._]

Finally, something that asks a new question! It would be interesting to see a full physics simulation of the event!

[@rossk7927]

Why would we expect PBH impact speed to be so low? Is there anything keeping their possible speed from reaching significant fractions of C? I've coded some simple gravity body simulations - because they're a fun way to learn a new drawing API - and large point masses will always fling smaller ones to excessive speeds due to how close they can get to eachother.

[@bluewales73]

I think part of the assumption is that the vast majority of PBHs in our galaxy must be gravitationally bound to our galaxy, so they must be moving at speeds appropriate to orbiting our galaxy. Extremely speedy PBHs which are momentary visitors to our galaxy are not the ones we expect to interact with, because they'll spend almost all their time in intergalactic space. The observation that dark matter seems to be clustered around galaxies and not evenly distributed throughout space supports the idea that dark matter is gravitationally bound to galaxies, which gives us an idea about the velocities of whatever dark matter is made of, in this hypothetical primordial black holes

[@danieljensen2626]

If the velocity is too high the black hole wouldn't be gravitationally bound to our galaxy, so the chance of it hanging around long enough to hit us is very low. (Most of the time it would just fly out into the empty void of intergalactic space.) I think the speeds mentioned in the video are what you'd need for it to stay bound to the Galaxy and this keep swinging around until it hits us.

[@juzoli]

It is very rare for ANY bigger objects to reach relativistic speeds. Maybe if it is coming from the region of a supermassive black hole, but that has really low chance.

[@mattfleming86]

My concern/curiosity are for objects traveling at slower speeds, specifically those at or below escape velocity in relation to the object it is interacting with. Was there not a paper a while back detailing some randomly missing stars that disappeared over time on images taken of the same area?

[@juzoli]

@@mattfleming86 Those need bigger black holes, which have been ruled out as a source of dark matter. They may exist, but relatively rare. So you don’t need to worry about them.

[@cheEZy_boi_nips]

Would the entrance and exit of the black hole impact be distinct from one another? Cool video. I have never heard of such and interesting theory.

[@ScienceDiscussed]

Another excellent video. Thanks.

[@Q--_--90909]

Your welcome

[@dougirvin2413]

Love your channel! Was the Fly's Eye detectors 1991 OMG particle really a PBH?

[@johnramsden5758]

If a black hole of roughly meteor mass passing through Earth causes Hiroshima sized flashes in the atmosphere and gains around 1000 tons in mass, I wonder what the effects would be if one passed through a neutron star, which has billions of times the density of Earth, and would presumably tend to attract far more of these small black holes. FWIW, considering the density of matter during the Big Bang at the stage when tiny relative fluctuations in it were enough to produce primordial black holes, the idea of any having mass comparable only to that of a meteor seems to me ludicrously unlikely, as if 1000 tons of TNT exploding practically under one's feet would only rattle a tea cup in its saucer!

[@imheretocausetrouble2156]

Are you a scientist?

[@filip0x0a98]

Couldnt we verify(or at least learn something new ) about those primordial black holes by calculating their effects on observable parts of the universe? For example, they only pass throught planets like Earth. But perhaps some of them can be slowed down enought to ''get stuck'' in some stars, cant they ? So then they would ''eat'' those stars -> Would that effect be common enought to be detectable ? (more stars ''burning out'' then expected?) PS: Merry Christmas everyone :) Have a nice day.

[@SnowblindOtter]

What you're talking about is known as a Thorne-Zytkow Object.

[@antonystringfellow5152]

@Christine LaBeach Very unlikely because of the relative speed of most interstellar objects. Most would fly straight through the solar system and any object they passed through.

[@antonystringfellow5152]

Such events would be very rare because of the relative speed of most interstellar objects. A star's physical presence would do little to alter the course or speed of a tiny black hole. Even if such an event did occur within the observable Universe, its detectable effects wouldn't last long. So, extremely unlikely we'd get to observe it.

[@l1mbo69]

@@antonystringfellow5152 why? It should take as long to eat that star from the inside as normally right? And we observe plenty of black holes eating stars the normal way

[@Dragrath1]

@@l1mbo69 The black holes Eddington limit sets an upper limit to the amount of material can fall into the black hole regardless of how much stuff there is to feed on. In effect the radiation pushes away infalling matter more than gravity or even eventually kinetic impacts can overcome arresting the accumulation of further matter. Add onto that the high velocities of objects in interstellar space and the odds of this primordial black hole eats a star scenario having happened anywhere within the history observable universe becomes vanishingly small.

[@torinireland6526]

One of the things I've been wondering about for awhile is how far we are technologically from being able to from make and contain tiny black holes (kugelblitzen) as a power source. If we get better (more sensitive) gravitational wave detectors, would it be possible to detect primordial black holes and triangulate their positions that way? If we could do that, might we be able to develop the technology to trap a small black hole (perhaps bombarding it with huge amounts of electrons to make it charged, then using magnetic fields to hold it in place), or might this always be impossible?

[@garethdean6382]

Currently it's physically possible, but as to how long it'll take us to get enough space presence to do that sort of thing, estimates vary from 50 years to centuries. The future and technology are hard things to predict. Flying cars are too inefficient, AI is way more tricky than though, but doubling crop yields has been surprisingly easy.

[@bengsynthmusic]

Well since it's a large mass, it's gonna be impossible for a while. We need to understand more about gravity and maybe come up with anti-gravity flotation systems.

[@michaelbuckers]

At the level K2.5 I think. Condensing a large asteroid worth of mass into a singe hydrogen atom worth of space is difficult enough to be impossible by natural processes (which sometimes are VERY violent) after the big bang.

[@tinto278]

Extremely dangerous, the micro black hole would sink to the center of the earth.

[@winstonknowitall4181]

Great video as always. Thanks.

[@jasonfoster4769]

Great episode!!!

[@tpog1]

Hi Matt! Could you maybe do an episode on shell collapsars? I always wondered how a black hole can ever grow in size if it is said that one can never see anything pass its event horizon as time slows down asymptotically for an outside observer. Maybe nothing ever does and black holes as we currently understand them don‘t exist but its really concentric frozen shells of all the stuff that fell in. Couldn‘t that explanation also solve the information loss paradox? When somebody falls into such a shell structure, will they see the shells in front of them rapidly radiate away via Hawking radiation before they reach the event horizon? Could there be a relation to the black hole firewall idea? So many questions... :)

[@antonystringfellow5152]

You should watch the video on Fuzzballs that he talks about here. This is the most promising theory of black holes I've seen to date. It's the only theory I've seen that doesn't contain paradoxes and so it's the only one I can take seriously. In this case, it's pointless talking about the "inside" of a black hole because there simply isn't one. Spacetime ends at the horizon.... there is nothing beyond. All that arrives at this edge of spacetime continues to exist only through being encoded on strings. Everything becomes a hologram on a 2 dimensional surface. There never was anything beyond/inside.

[@Laff700]

Man, I would love a video on those. I'd also like it if they could bring up the energy and momentum density of a shell collapsar with a lot of angular momentum. Potentially charge too.

[@dare-er7sw]

@@antonystringfellow5152 Interesting. I'll check. My understanding is that all matter falling into a black hole is converted to energy. Can planck scale contain infinite amount of energy?

[@mikehuff9793]

SEA’s video on super massive black holes goes into this subject. It’s awesome

[@tpog1]

​@@GeorgeM-zh4ot I know that you see the in-falling object get red shifted more and more but as far as I understand it this is an asymptotic process and an outside observer will never see an in-falling object cross the event horizon, even if one could see light of arbitrarily long (red) wavelengths. So if you never see anything cross the event horizon, how can you ever see the black hole grow in size? Black holes with an event horizon are valid solutions to the Einstein field equations but this doesn't necessarily mean that they could ever form (they could exist but maybe not come into existence). Maybe if you are close to a black hole and you had infrared telescopes which see further and further into the red end of the spectrum you could still see everything that ever fell into the black hole as concentric frozen shells without an actual event horizon. And for the in-falling observer: maybe he would see the stuff in front of him speed up drastically and evaporate due to Hawking radiation before he could reach it so the black hole would disappear before he could ever actually fall into it (cross an event horizon that really isn't there). I would really like to hear Matt's explanation. I guess the cental question is how an outside observer could ever see a black hole grow without anything ever falling into it. Even the process of merging black holes could be just a rearrangement of their respective concentric shells.

[@pizzacrusher4632]

wouldn't they only go through if they are going very fast relatively to earth? what if our closing speed was slow? (like we were headed generally in the same direction and speed?)

[@Thomas.Wright]

Any such object entering earth's gravitational influence would be accelerated by earth's gravity on approach. As such, it's relative outbound velocity would be roughly equal to its inbound. Friction or accretion most likely wouldn't be enough to slow such an object down. Besides, for an object like that to follow the kind of trajectory you propose, it would have to be roughly following earth's current orbit already.

[@pizzacrusher4632]

@@Thomas.Wright really good point. it would have to be corkscrewing through space somehow, which seems very unlikely. I think any object entering our gravitational influence would get accelerated an incremental amount in our direction (like 11km/second or whatever our escape velocity is?).

[@tannerbailey6444]

@@Thomas.Wright Friction would be less than that of ordinary matter, but matter within a distance of a small molecule (on the order of 0.5 - 1 nm assuming ~Milky Way rest velocity for the BH) would be trapped by its gravitation. That matter wouldn’t be able to accrete as quickly as it was picked up (outward thermal pressure would be around the Chandrasekhar limit at a radius of around 1 pm), and I have a feeling the molten firewall that would surround it might slow it down.

[@SoftYoda]

Hi, nice topic, there is a lot to learn. One question tho, why would the asteroid size blackhole only have random position/velocity ? Why couldn't it orbit stars (like real asteroid in kepler belt) or even planets ?

[@GRosa250]

I think he’s only talking about the affects of an asteroid mass black hole hitting the earth. There’s no reason why one wouldn’t be able to orbit the sun or a star just like any other object. There’s even been speculation that planet nine could potentially be a small black hole.

[@davidgoodwin4148]

Proxima Centari is travelling away from earth faster that Jupiter orbits the sun. The sun orbits the galaxy 400 times faster than Jupiter orbits the sun. And the black hole could be orbiting in the opposite direction. So 1 to 800x. Not impossible but part of it's orbit would have to be inside Jupiter and for the very fast ones very close to the sun. So like a long period comet.

[@garethdean6382]

In general it's going to be tricky for such an object to get into a solar orbit, as it is with any object which is why we don't expect to find any exo-solar asteroids orbiting our star nicely. They're more likely to be dropping in like oumuamua.

[@thomasrobertson8109]

Thank you for your Channel update God bless you

[@macronencer]

13:42 Congratulations. You are the FIRST channel ever to explain to me exactly why everyone is so keen for me to hit the "bell icon". I knew there had to be a reason that nobody was mentioning. Of course I still probably won't do it, because I never watch anything just because I've had a reminder and I prefer to batch my viewing - but I'm probably unusual and thus statistically irrelevant, so I don't have to feel guilty. :-\

[@legitbeans9078]

I'd like to know if every black hole evaporates at the same point in their mass reduction or does spin or the initial mass make any difference.

[@detectiveoftheeast8378]

At any given point in time, wouldn't only the spin/current mass matter? Hawking radiation, as far as I know, doesn't 'accelerate' or 'decelerate' , so it should have a constant speed (or at least a a predictable speed based on the current mass/spin) at any given point in time.

[@bengsynthmusic]

I saw a vid somewhere that the smaller the blackhole, the faster the decay.

[@renatokuurstra5957]

This is amazing! :D Really enjoyed it! This make me thinking, could be that mantle plumes sometimes are caused by such events? In the end it would create a funnel from top to bottom of superheated and maybe melted materials that could trigger the super plume? Maybe few of the plumes are caused by these events?

[@alexandertaylor2951]

That's interesting. recent research shows that this is highly unlikely and so rare. Cerns super collider data would suggest that this mass could even pass through you, like a quark. Still would be so cool to observe evidence of pill holes in the earth with signs of damaged rare elements. Would be quite the core sample

[@renatokuurstra5957]

@@alexandertaylor2951 I see! I just refered to the stats in the video: one such collision happens at most every few millions years and most of the time are without conseguences. Super plumes are even more rare, it's just the conseguences lasts millions of years

[@MCsCreations]

I wander if JWST could find a few of those... After all, if Hawking's radiation is real they should look somewhat "hot"... Right? Anyway, I guess we shall see. 😬

[@danieljensen2626]

IIRC black holes are actually very cold, although smaller black holes are somewhat warmer (up to maybe a few Kelvin). I don't think Hawking radiation would ever really be practically observable unless you were really, really close to a black hole with no accreted matter, since it's an incredibly low amount of power being radiated (due to the low effective temperature and small surface area). And if a black hole had no accreted matter you wouldn't be able to see where it was to get close to it.

[@kukulroukul4698]

@@danieljensen2626 last time we pointed a telescope into the sky some nebulae pointed us a FINGER :( Maybe this time we get lucky

[@kitemg]

Best KZbinchannel :D thanks for all of the work! Every Video makes my world a littlebit bigger :D

[@ProbablyNotAChicken]

screenshotted 3:55 and this is now my phone background

[@smoorej]

The idea that black holes are whizzing around the universe and at any moment one could plow through the atmosphere, me, and the entire earth without warning is the type of existential horror that makes pursuing art, music, math or in fact anything but physics look like the best life choice.

[@victorpapaavp]

This is why high level theoretical physicists and mathematicians have such weird hair...

[@electrified4251]

Same thing with gamma rays. Space is just plain scary.

[@protocol6]

Wouldn't there be X-ray bursts from small black holes passing through large masses? Even if individual events are rare, a sky survey for otherwise unexplained X-ray bursts in the right energy range should turn up a decent number if that's the case, right?

[@garethdean6382]

Yes, this also applies to hawking radiation from evaporating holes. In the case of collisions with mass though, the bursts should be both rare and also small and dim -on an astronomical scale. The Earth emitting a few hundred nuclear bomb's worth of X-rays is easily dwarfed by the sun and its 4-tons-of-mass-into-oure-energy emission. The best we can hope for is a weak background of X-rays and there are already poorly modeled sources that produce similar things. So so far this hasn't really helped us.

[@bengsynthmusic]

I think high energy rays are from big blackholes that form acretion disks. The blackhole would have to be big enough to interact with matter more, which PBH can't do much. I could be wrong on that though.

[@jaimecastells4283]

Matt, I have a long standing problem with most models for dark matter that touches directly on PBHs. If dark matter or PBHs are assumed to be very common (>80% of all mass) shouldn't we see lots of effects from interference with local physics? For example, Sol's mass appears to correspond strongly to a certain mix of mostly H some He and a little heavier nuclei. Its energy production, size and emissions would all be different if a significant amount of its mass were not participating in the fusion process, but did contribute to the gravitational forces. So, we must conclude that little or no dark matter is part of Sol. Similarly, our models of solar processes largely correlate well to observations of many stars. The patterns we observe across the population of stars in our part of the Milky Way would be disrupted and more complex if some had a substantively large fractions of their mass in the form of mass that does not participate in fusion. Again, the most obvious conclusion is that most (or all) the stars we observe lack significant dark matter. And so on at larger scales. I believe this problem arises with any model of dark matter that has the dark matter particle interacting with the gravity of normal matter as we predict normal matter to act. In other words, dark matter must not be attracted to concentrations of normal matter in the same fashion as normal matter while exerting more or less normal gravity on normal matter at least on the large scale. Given the other interactions significant PBH concentrations would create with normal matter, I believe this argument is stronger in that scenario. What are your thoughts?

[@davidgoodwin4148]

My amateur take. PBHs are frictionless so they wouldn't gather into a star at it's formation or too each other. But there could be PBHs that pierce the sun regularly like a frictionless long period comet.

[@kekmeister42]

​@@davidgoodwin4148 Not a physicist, so please be patient with me ;-) Why are PBHs frictionless? We are talking about gravitational / dynamical friction, right?

[@viliml2763]

@@kekmeister42 No, they're talking about ordinary friction, things bumping into each other. In star formation, a cloud of gas loses energy through inelastic collisions and eventually collapses into a star. Dark matter doesn't collide with ordinary matter so it wouldn't lose energy that way. Although if a bunch of dark matter were already in the cloud with low enough energy to stay inside the cloud, the cloud would collapse around the dark matter as its core.

[@davidgoodwin4148]

@@kekmeister42 same here. I'm using frictionless to describe the behavior. An atom would be slowed by forces. Light would be absorbed. Even a neutrino would eventually hit something. But a atom size PBH would just absorb atoms it passed though. Even the tons of material it absorbed would only slow it down relative to it's mass. Since it's speed is barely effected I'm calling it frictionless for lack of a better word. As it enters it speed up as it falls then keeps going slowing slightly as it rises on the other side netting zero speed change other than the mass it absorbed.

[@busteraycan]

@@davidgoodwin4148 I yhink the mater its swalllows up as it travels through a planet or star could even accelerate it.

[@xaviermartin3156]

I just binged watched all of PBS spacetime, finished about 10 minutes ago. Now to watch it all again so that I understand it.

[@mariaanast276]

Fascinating thank you!!

[@Omnifarious0]

This kind of an event seems like it might be powerful enough to be noticed by telescopes if it happened on the surface of Jupiter. Jupiter has a much larger surface area, and stronger gravity. It seems like impacts there should be more likely. Has anybody thought to look into this?

[@mementomori7160]

Well, Jupiter is a gas giant and even has an Earth size storm. As detecting the hit on Earth at present would be hard and in past we have no way of knowing, I would say it's even more impossible for Jupiter, although I agree that it would be hit by some more often than Earth

[@Omnifarious0]

@@mementomori7160 - I would expect an event like that would be noticed now on Earth. Previously, we didn't have the detector equipment to see it unless we were able to see it directly, and many parts of the Earth are very sparsely populated. And if Tunguska was a black hole event, then the energy released, and how it's released seems to me like it should be noticeable even in a roiling maelstrom like Jupiter. After all, we were able to see the fragments of comet Shoemaker-Levy 9 hit Jupiter.

[@johnmorrell3187]

For a Jupiter impact, we would see only the event itself. On the earth or moon we can see evidence of impacts over millions or billions of years. I'd guess this longer time outward the bigger surface area.

[@Omnifarious0]

@@johnmorrell3187 - That's a good point.

[@busteraycan]

idk how we could differentiate between a meteor strike and a blackhole strike on jupiter without a satellite constellation around its orbit.

[@thinkingoutloud6741]

I would be interested in hearing more about the influence that one of these PBHs might have on the Earth’s orbit… even a near miss. It seems to me that a Phobos-sized mass would be enough to make a small orbital change to both the Earth and the Moon. In fact, a near miss passing close by the moon would seem to be a worst case scenario. That’s the sci-fi disaster scenario… the moon itself becomes the object that impacts the Earth. Like in a solar-system sized game of billiards.

[@allangibson2408]

The moon cannot impact earth. It is actually moving away due to tidal coupling (the energy that produces the tides is slowing the earth’s rotation and accelerating the moon which lofts it to a higher orbit). The same effect drags satellites down from below geosynchronous orbits.

[@thinkingoutloud6741]

@@allangibson2408 All that makes sense and applies to what we see today. I was just speculating on how much the balance of the earth-moon system might be disrupted by a significant mass, in the form of one of these theoretical black holes, passing through the vicinity.

[@allangibson2408]

@@thinkingoutloud6741 A black hole throws everything out the window - particularly if it is sufficiently massive to alter the Earth’s orbit (which would require an equal or larger mass to the earth to pass in close proximity - with an equal mass the earth would alter its orbit significantly as well and you have the fun of calculating a four and five body problems…

[@thinkingoutloud6741]

@@allangibson2408 except it would not require a mass “equal to or greater than the earth”. A moon-mass, passing by our area would perturb the orbits of both the earth and moon. Just a matter of how much and in what direction. I appreciate your comments, but I wasn’t looking for an explanation. I did my undergrad work in physics and mathematics and have a reasonable grasp of orbital mechanics. I was just offering comments on a possibly interesting situation that involves black holes.

[@allangibson2408]

@@thinkingoutloud6741 The shift from a small object would not be particularly noticeable - and even a quite massive object would be a question of duration and proximity. Earth has been HIT repeatedly by Phobos sized objects without significant orbital changes. Relative mass and speed is significant.

[@Violent2aShadow]

Crazy question: Wouldn't the Sun also be subject to these black hole collisions? And since the Sun would be much more massive, wouldn't it be likely that black holes would be captured within the Sun's mass? Thus eventually turning it into a stellar black hole?

[@chrismaynard5]

Awesome question! I may be wrong but a PBH would be too small to interact with matter in a way that would cause it to grow, at least not on a time scale that would be meaningful to our sun. If an PBH is around the size of an atom it would rip apart any atoms as they approach the event horizon. The resulting energy would be like a constantly detonating tiny atomic bomb and create a plasma shockwave around the PBH preventing most matter from passing the event horizon. Any matter that does get absorbed would be smaller than an atom and just as a large asteroid condensed into a black hole would be the size of an atom, an electron condensed in a black hole would contribute an unimaginably small amount to a PBH at that density. I don't see why a PBH could not get stuck in a stars gravity and float around adding some chaos to the fusion. Who knows maybe PBH's are what initially what ignites a star. Or maybe star fusion doesn't even exist, it's just a bunch of PBH's floating around in the middle making plasma!

[@gmeletrk]

I have been wondering if this might be possible for the earth as well.

[@Thomas.Wright]

Probably not. Any such objects coming into the sun's gravitational influence would be accelerated on approach as much as they would be decelerated outbound, meaning their inbound and outbound velocities would be roughly equal. Friction would do almost nothing to slow such an object down, and it wouldn't accrete enough additional material to dissipate its momentum. It'd fly in and fly right back out.

[@mikesawyer1336]

This was so good. Thanks.. I rang the little bell and gave a thumbs up 👍 👍

[@DODFather]

I thought you guys weren't coming back til next year! This made my Christmas!

[@jommeissner]

Would we regognize an impact on one of the gasplanets or the sun? The chance of that happening must be millions of times larger than one on earth.

[@colinmcisaac6263]

I wonder if such scars could appear as the massive gaseous hurricanes found on these planets, rather than the rocky craters found on cool-surfaced bodies

[@mediaaccount8390]

How likely is a PBH to pass all the way through the sun?

[@jommeissner]

@@mediaaccount8390 The problem is: would we notice it at all?

[@invalidopinion3378]

You know once you have the question and the hypothesis it's not that hard to find the answer. It'd be really neat If we find out that primordial black holes really do exist. It also just makes me wonder what sort of questions are we not asking?

[@sum_rye_hash_321]

There were orange glass spherules found on the moon, very out of place compared to the rest of the lunar rock. Do you think this could be the result of a primordial black hole? It is suspected it was the result of a volcanic eruption during a period of much lunar volcanic activity, and the glass cooled in the atmosphere these volcanos created. Could it be that the glass cooled in the gas released by the black hole eating its way through the moon?

[@garywpearson1955]

Again, great job on the video. You really manage to pack a lot of information into a short clip. On the evaporation rate due to Hawking radiation for tiny black holes, a small point. The Hawking evaporation rate only tells you the life of a BH in an empty Universe at absolute zero. A tiny black hole (say, less than 1E11 kg) can last much longer than the predicted Hawking evaporation rate by continuously eating things around it. One may imagine that in the very early, very dense Universe, this would have been the rule rather than the exception. Hence, a tiny black hole can very well live longer than 13.7E9 years.

[@Singulitarian]

One of your best videos.

[@BelleDividends]

Hi Matt! Could you make an episode about time at the beginning of the universe? I imagine that at the moment all matter is condensed together, time practically has to stand still. How did the speed of time evolve during the creation-process of the universe?

[@asherplatts6253]

Try reading Stephen Hawking's "brief history of time" as a primer, and then check out the videos they already did on the topic of gravity/time

[@Sayquidnidly]

I believe in Neal Stephenson's "Seveneves" the object that impacts/punches through the moon and kick-starts it's inevitable deterioration into more and more pieces is a micro black hole. Don't remember whether or not he specifically states it's a PBH, it's been a while since I read it. Anyway it's an awesome book for those looking for a hard science fiction

[@tedblu14]

It is never revealed what hit the moon in that book. Only PBH being the likely culprit

[@ranger2671]

Imagine this: A black hole with a mass of a small asteroid orbiting the earth closer than the moon , possibly even closer than the ISS.

[@Glitch315]

I am imagining nothing happening. Let's just hope it doesn't hit a crewed station lol

[@johnlynch6695]

Best vid yet , very interesting .

[@sulphuranonymous618]

Another great vid!

[@SangoProductions213]

Depends on the size. Could be anything from: We've already died long ago, and the collision doesn't matter to the impact not even being noticeable by the most precise observational tools we've built so far.

[@Jaqen-HGhar]

It would be interesting if we got hit by black hole a few years ago and we are already dead but time is all messed up so the Earth just hasn't "noticed" yet. I mean it didn't happen but it'd be a fun explanation for why time has been all wonky recently (not that everyone be dead would be fun just to be clear).

[@danielpeters9110]

If these black holes existed when the solar system formed wouldn't we have expected them to play a role in the accretion process? Shouldn't some of them eventually get captured and fall into the forming planet, eventually engulfing it?

[@llamawizard]

I think he’s saying it would have passed though the solar system. Not hit something and remained her…hit something, or not, and continued to pass through

[@johnmorrell3187]

Bits of dust acrete and form planets because they can stick to each other via electromagnetic forces, chemical bonds, etc. as well as gravity. They can have inelastic collisions that slow them down and let them clump together. Black holes don't have this; they interact via gravity but there's nothing to make them clump up with other matter, they'd pass through things if they collided and if they entered a solar system with greater than escape velocity they will just swing through and leave.

[@danielpeters9110]

@@johnmorrell3187 That makes some sense, but I'd have thought those interactions would have increased the mass of the PBHs over time and that eventually they'd eventually dominate.

[@daviddurham8583]

... Or just keep the core hot?

[@garethdean6382]

The trick is that, like other random extra-solar bodies, black holes should be moving quite quickly compared to the sun. We don't expect to find many (or any) asteroids from outside our system just orbiting, only ones like Oumuamua that come in on hyperbolic trajectories then leave. What this means is that while PBHs would stir things up a little, they're not likely to spend much time in our system, nor are they likely to be able to consume enough mass to slow down

[@Quickshot0]

After reading through the comments, I realized from one of them that there is probably an issue with black holes being common enough for them to be dark matter. Which is that neutron stars would presumably be massive and large enough to have some intersect them and at merely interstellar speeds one imagines a neutron star one imagines it could probably bring one to a halt even. At which point you'd get a prediction of the average life time of a neutron star, one that I suspect might not be all that long.

[@petrkubena]

If there's a chance of PBH hitting Earth once in a million years as stated in the video, then chances of hitting neutron star with 10km radius is 400 000x smaller (Ie once in 400 billion years). Chances of it getting stuck are probably small and even if it got stuck inside, it would not be able do eat that neutron star very fast - there's an extremely low limit of how fast it can feed that is many orders of magnitude lower than for example how fast our Sun is loosing mass to outer space.

[@Quickshot0]

@@petrkubena If the hit chance was pure radius, sure. But gravity actually strongly pulls their courses towards the objects and neutron stars have stellar level masses. So despite their small size, the real number of objects coming close should be massively higher then a linear estimation approach gives. Though I admit I wouldn't quite know how much higher. You make a fair point on feeding speed as well, though with in neutron stars the density would be massively higher, which may, or may not allow dragging in matter faster. But it seems likely that while it would start out slow, as it is small, it will get bigger as it goes which will massively increase how quickly it can consume matter. An exponential growth function with some end point when it consumes the entire object. And I'm not so certain the chances of getting stuck inside are really that low. I recall that neutron stars were used as a check against micro black hole production really being likely, in case the LHC could make them and then drop them in to the Earth to catastrophic results. And LHC black holes should be a vastly smaller object. If I recall correctly in that scenario it was stated that these black holes would end the star in a fairly appreciable time scale. Which did not match the observations and thus they concluded such black holes were not a thing. So of your points, I suspect the first one is the strongest one. Though its strength some what depends on what mass the PBH are if they exist, and thus how many encounter chances with a neutron star there really are. With the obvious how heavier they are how less of them there will be around to collide with anything. I kind of suspect the low end of the possible mass range would become excluded due to this though.

[@Quickshot0]

@Thee Dude Maybe? It would depend how such a scenario would play out I imagine. Would it get eaten cleanly, or would there be some kind of flare off at the end.

[@garethdean6382]

It might be assumed that an object with more mass will encounter more PBHs due to its greater gravitational influence, but this is not, in fact, the case. If the objects involved are not already moving very slowly compared to the central mass (Such as asteroids in our solar system) then shedding kinetic energy is nearly impossible. What this means is that a neutron star will draw many PBHs into hyperbolic orbits around it but they will not be able to hit the star any more than Earth can hit the sun; they will be deflected around the star and flung back out into space. The only real viable scenario for a collision is a PBH randomly oriented so its trajectory crosses the body of the star. Even a PBH that approaches within 100 miles of a neutron star won't hit. It'll be moving very fast before being flung back out but it's not going to spiral inwards and collide. This should make neutron stars LESS likely than Earth to contact a PBH.

[@Quickshot0]

That's reasonably the case, yeah. Though not completely, the point is more that a neutron star will drag more lines of travel in space through it, so anything that lacks sufficient angular velocity to it should have some increased chance to intersect due to that. There we're imagining interstellar objects traveling by and not orbital objects, most shouldn't come close enough for this, or have enough sufficient angular velocity. But I still find it some what hard to imagine there isn't some increased chance compared to a less massive object of the same size. How much so though, that I do not know. Still, neutrons stars should place some limits of their own thus on possible mass ranges.

That episode was superb!

[@sameddington9072]

I am always excited for any mention of the Eddington Limit, because I like to imagine it's someone telling me what I can and can't do.

[@Numba003]

For some reason that I do not fully understand, the idea of the Tunguska event being a black hole impact (despite it having almost certainly not been that) just sounds super cool to me 😂. Thank you for a fascinating video on a topic I had never really considered before. Stay well out there everybody, and God bless you friends! :)

[@Numba003]

@Atheism Rocks! ?

[@oromandias]

I'd love to know whether anyone has done any modeling to determine whether a plausible black hole could cause the event that kicks off Neal Stephenson's novel "Seveneves" (i.e. the moon fragmenting into multiple large fragments in close orbit around the moon's center of mass).

[@FectacularSpail]

I'm glad I scrolled down before commenting, because I was thinking the same. I think in the book a primordial black hole was their best guess at an explanation, but the cause isn't really relevant to the plot so the story moves on. One of my top 5 favorite books.

[@DavidBeaumont]

Given what's happened in the last couple of years, this almost seems like an optimistic outlook.

[@Michael18599]

Maybe its next after this whole covid thing.

[@binaryvoid0101]

I want you to fly your massive spaceship into my tiny black hole #SpaghettificationGyration

[@francistherrien]

The visuals are always getting better!

[@derekholland3328]

love this guy..and his t shirt..awesome.

[@anotherronism]

Naive question: Would a gravity wave pass through a black hole? The wave has no mass so isn't subject to gravity but what about the curvature of space? If the wave is distorted in some fashion then wouldn't that distortion be a consequence of the information within the black hole. Would this not solve the information paradox as it is a mechanism to return information to the universe from inside the event horizon?

[@mainmanbumfuzz8983]

Good question. No, a singularity would bend space to such a degree that not even gravitational waves could escape. The insane fact about singularities is that space inside the Schwarzschild radius bends in on itself to such a degree that space itself start to bend in on itself. you could have a trillion billion star masses locked in a space so small that even with the ultimate microscope, we could never have way to physically detect it because the rules of our universe are so bent within a black hole, that it turns into an event, rather than a physical object.. What we *could* detect, is gravitational waves interacting with a black hole, a massively fascinating subject. For instance, we can detect gravitational waves from two black holes orbiting then colliding, complete chaos in space time, then uniform silence as both black holes turn into the same event that is impossible to observe or properly even predict given out current model of physics.

[@3dsmaxrocks699]

You're confusing sprocket with socket. Rookie mistake.

[@jmunt]

Blacks holes do have mass but the first comment is spot on. Imagine a pond with a pole, and a ripple wave coming toward it. The outside of the pole stops the wave from progressing, but the wave bends around the pole and you can observe the presence of the pole by looking at the new ripple pattern. But it tells you nothing about the contents of the pole. Is it hollow? Filled with ants? Solid? Doesn’t matter, all you can tell is the size of the pole and whether or not it is spinning or moving.

[@anotherronism]

@@jmunt of course black holes have mass. I meant the WAVE has no mass. And I get the pole thing but my question was would the wave go THROUGH the black hole. Would the sphere of the wave have a hole? Would the wave be intact?

[@johnmorrell3187]

Not sure what you mean when you say the black hole has no mass... Do you mean like the empty space within the event horizon? Gravity waves could travel into the black hole but never out of it, and since the black hole eventually evaporates without the gravity waves ever being able to leave the event horizon the paradox is not prevented.

[@qake2021]

👏👏👏great show 🥰🥰🥰

[@nosuchthing8]

What's the largest black hole that could zip through the earth with little side effects

[@p382742937423y4]

That moment when you realise you passed the even horizon....

[@LoneWolf343]

>new genre of black hole impact horror stories. "The Blue Afternoon That Lasted Forever" already exists.

[@SolaceEasy]

The chances of a black hole transit path intersecting the center of a planetary object as shown in your diagrams are slim.

[@SolaceEasy]

The Tunguska event in Siberia could have been an exit wound also.

[@revenevan11]

That explanation of continuing to think you're falling and continuing to exist as an oscillation on the surface of a fuzzball black hole blew my mind. What a crazy fate that would be!

[@dec335]

This is one of the first spacetimes that I could understand fully from start to finish

[@Spacium-133]

Great video

[@santoshinimohapatra4716]

Merry Christmas sir. Waiting for some more videos. I hope your next video will come soon

[@marcw3852]

Do enjoying this kind of silliness

[@karl7567]

This is such a great channel.

[@thed3m0n0id9]

Whoa! That transformation graphic from the early universe to the CMB to the current universe map was really cool!

[@dilipdas5777]

One of the best you tube channels

[@kuibeiguahua]

Thank you