Mapping the Multiverse 

I feel like every time we see a Penrose diagram in Spacetime, it is slightly larger than the previous one.

6:51 "Our balls, and the geodesics they follow, rebound and travel back out." -Matt O'Dowd, 2020

"Multiverse cartography..." This is gonna be one of those hard mode episodes, isn't it?

I'm disappointed that the ring singularity wasn't called a "ringularity"

"this may sound fun, but there's the inconvinient fact of your utter obliteration" got a real chuckle outta me

*Before watching* "Yeah, I think I'll understand a little of this..." *After watching* "I can feel the warp overtaking me... IT IS A GOOD PAIN!"

I just found out Matt O’Dowd is almost 50 years old. Which of the time machine options have you used to look 20 forever?

Can I get this Penrose diagram embossed on a towel? I'd like to pack as light as possible for the trip...

This is an especially great video, even by PBS-ST standards.. I've been waiting for this one since pt 1, and it didn't disappoint. Love the stuff on the inner structure of the Kerr black hole especially, there's next to no information about this online that doesn't require a graduate-level (or higher) understanding of math/physics to even be able to read.

When travelling the Multiverse, always remember : Don't panic and always carry a towel.

: Reads the headline: - yeah... I'll definitely understand this...

I've been staying home, dealing with depression, everything is just kinda 'meh' in my life... And then this. No idea why, but I got so excited while watching this video! I muttered to myself multiple times in an effort to actually understand things, 'rewound' (is that word even used anymore?) probably a half-dozen times to make sure I really took in what was being said... This made me so happy. I'll never truly *understand* most of these videos, but it's so so fun to watch and think about anyways.

"Repulsive naked singularity"? Way to give the singularity body image issues, Matt.

*My Brain at the start of the video:* “Multiverse _[Captivating Scientific Gibberish]_ . In English this is *[Captivating Scientific Gibberish with a hint of English]!* ”

"Our balls, and the geodesics they follow, rebound and travel back out." Haha, you tease!

You know you're in trouble when an astrophysicist calls you a nerd.

T-shirt idea (from 8:05) - "Naked Singularities are Repulsive"

Well, this was an unexpected place to come across a Mage: The Ascension reference. Thanks, Matt! We actually have a Kickstarter ending in about a week for a deluxe edition of our upcoming "Technocracy Reloaded," so please do check that out if it's the sort of thing that interests you.

Yes lads, good to see everyone checking in nice and early.

It's really strange watching videos from a channel for years and barely understanding a thing. But I have to keep watching, it's so interesting!

This is absolutely wildly interesting and elegant, I can conceptually comprehend maybe 19% of the whole concept at this time in this version of this existence in this universe.

Wait, where is the bookshelf in this diagram? I need to float to behind the bookshelf...

*Takes plunge into black hole* God I wish that were me.

Am I the only one that laughed uncontrollably at "this may all sound fun but unfortunately theres the inconvenient affect of your utter obliteration" @11:10

Matt: You're inside the inner erogsphere and could die. Me: Haha spinny lightspeed ship go brrrrrrrr...

Good luck with that map, Google.

Question: So now that you've got this figured out for us, how about showing us what happens to matter and space time within these boundaries, but during a black-hole merger? Please and thank you :)

Don’t you mean “the multiverse of madness”? Also, I’m guessing the hitchhiker’s guide to the galaxy isn’t gonna help me with these new universes?

It just feels like you're explaining how the universe is gonna start and end over and over again.

~ A blackhole that has no spin or charge is basically neutral/static, it basically consists only of a mass constituent. A neutral/static blackhole is essentially a wormhole without an E.M. energy jet stream. ~ A blackhole that has spin or charge has motion due to induced energy, so it is not a neutral blackhole but instead a dynamic/energetic blackhole. It is essentially becoming a wormhole that has both motion & spin because of centripetal & centrifugal forces that are caused by induced energy, with more prominent Grav. blackhole & E.M. jet stream characteristics. ~ The more extreme the mass of the Grav. blackhole vs the more energetic the E.M. energy jet stream, the more prominent & extreme their mass/volume (density) characteristics become. ~ A neutral wormhole has a Grav. mass accretion disk & E.M. energy volume jet stream which are both in balanced density equilibrium. The matter mass vs energy volume ratio is balanced/equilibrated. A stable wormhole supports a peaceful existence for life. Our solar system is close to being in this state, therefore it supports life as we know it. ~ Inertial Permittivity x Potential Permeability = Static/Dynamic Kinetics. ~ (Grav. Mass Accretion Disk Blackhole) / (E.M. Energy Volume Jet Stream) = Static/Dynamic Density Wormhole.

Haven’t watched it yet but I don’t get it.

"Our balls, and the geodesics they follow." (6:51) I chuckled.

Can you guys do a video on naked singularities, or the anti gravity universe you get into by traveling through the ring's wormhole?

“When your balls rebound...let’s push a little harder” - not a TOS violation, I swear!

Last time I was this early, all fundamental forces were unified

Deadpool: breathes a sigh of relief at his balls rebounding out of the Ring Singularity

Lets take a moment to appreciate everything Penrose has done for the advancement of our understanding of space-time, and the surprises that he might still have up his sleeve in his ever-ongoing research.

When a topic on this show has a black hole and Matt talks about space and time switching. The end should be time-space instead of space-time

I have watched a lot of your videos. I mean a lot. This one right here is the best one for a lot of good reasons. I don't know why I missed it. Maybe I just watched it again? IDK, but great topic, really well written and exposed. And those very last seconds were amazing. I'm a nerd too, and I'm happy to know there's plenty of others around. Thanks!

9:55 The extra "l" stands for extra parallel.

Just to clarify, this concept of “multiverse” has NOTHING to do with the multiverse predicted by quantum physics, right? If there are two universes, one with the alive, and the other with the dead cat, I cannot use a black hole to travel from one from the other, because that is an entirely different concept, only the naming is similar.

"nerdery".... as of today, definitely one of my favorite words! 🤓🔎

Nobody warned me that we need drugs to watch this episode.

Question: As black holes are said to evaporate (something that I assume also applies to Kerr black holes), and space and time switch places beyond the event horizon, would the effect of passing through the event horizon effectively be the process of this evaporation? As you (a 3 dimensional object) pass through the Kerr black hole and are annihilated by these incredible forces, some of this energy and information is deposited in the form of energy during evaporation. So the white hole is actually a mathematical representation of this process of energy conversion. In essence, the question I am asking is how much of this changes when not dealing with an eternal black hole? Is it simply interpretational or is it possibly completely different?

What does it mean to "fall" and "inside" mean when one crosses a black hole event horizon where, what was a space dimension intersecting the singularity, is now a time dimension that I presume now intersects the singularity?

happiest moment of my day: seeing a notification from this channel

We’re about 50 iterations off the Finite Central Curve.

“Let’s push a little harder and try to get through the ring”

"Now you're thinking with portals"

Penrose has also recently extended the diagrams to the left and right, in the Conformal Cyclic Cosmology model. Are we going to have an episode on that?

Kudos to the guy that went out and mapped the multiverse for us to see.

i'm totally imagining a sci-fi civilisation that teleports "singularity-mills" directly past the inner horizon to extract energy from the inner rotation, which would somehow be entangled to some turbines outside the black hole to make energy None of it really make sense but it sound too cool so I need to create some lore around that. The madness of physics is just so much of a infinite well of inspiration

SPACETIME! Day saved! Edit: This broke my brain. More than any other PBS Space Time episode. I will have to re-watch tomorrow.

This is among the trippiest videos I've ever seen . . .

I always start these videos so strong, but things start getting really hazy around halfway through, maybe 3/4 on a good day. Thank you for being genuine education, not just edutainment. Not that there's anything wrong with that of course, I consume more than my fair share. I just appreciate the reality check. :-)

>”or maybe hufflepuff” If this guy isn’t ravenclaw, ravenclaws don’t exist.

Very interesting, informative and worthwhile video.

When you think you understand, then you have to start watching all of the videos in the series again to figure out where you got lost.

Sooooo technically i can with my trusty map get "back" to the origin universe by going forward until i find a replia of it due to being able to go forward to new universes for as long as i want ... Got it.... Thought experiments aside, how would all this look like if we hold to our "knowledge" of not being able to exceed the speed of light in the torus on the other side of the ring singuularity, does it only do away with the time travel or the entire white hole part?

Thank you to you and your team for producing these videos! They've long moved past my understanding, but I enjoy them all the same! If we had physical access to a black hole what are some experiments that could be done that could advance our understanding of space time?

This time I really do think you made everything up.

The Penrose diagram image at :40... I want that as a black light poster please.

Your explanation of complicated science would make a great setting for star trek episodes

I've always been a time traveller. Going at a steady pace of one second per second.

Sam: "DESTROY IT!" Kerr: "No."

The ring singularity feels like a mistake resulting from the assumtption that the spin is about a single axis, this assumption was likely perpetuated by visualising the fabric of spacetime in 2D. But in space, objects can spin about all 3 spatial axes, gathering angular momentum in each of these as stuff hits them at different trajectories. For example when the earth formed initially it's spin would of been entirely in plane with the sun, but as objects collided with the earth this spin axis precesses due to angular momentum carried within the other axes. Wouldn't a black hole also be able to hold angular momentum in all 3 axes, spreading the singularity over an elliptical surface thus making the region within the ring inaccessible?

At every horizon is associated a Temperature, since Kerr (and Reissner-Nordström) Black Holes have two horizons an observer in the region between these two horizons does see both radiating?

This video turned me into an unstable genius

This is funny because when I saw the Penrose Diagram the first time I thought "If time turns 90° doesn't it turn again coming out?" and wondered if that would be covered at some point. Here we are!

How much of the weirdness is actually weirdness, and how much is the math being broken? Because the whole "closed timelike curves" thing usually means math is broken.

"Order of Hermes, or maybe Hufflepuff." Man, if you thought the Mage RPG folks were coming for you before...

I figured something similar out more than a decade ago........that the negative spacetime region gives birth to infinite negative mass energy and the positive region gives birth to infinite positive mass energy. As negative mass pushes outwards the result is indeed a big bang/white hole. I'm glad i've found someone who has reached the same conclusion.

He is not a man. He's the holy Half-Dead who has seen the UnderVerse!

Psh, Everyone knows that the fifth element is love... It's how we got our moon.

so..when does Hollywood make a movie inspired by this episode?...what a wild ride that would be!

in the theory of the big rip/stretch at the end of the universe, when space-time itself accelerates faster then the speed of light, dose the ring singularity brake apart? or dose it lose it ring shape and become a line singularity, and if so, how dose that affect the inner workings of the black whole?

7:53 "...the ring is a naked singularity, as well as being repulsive." Way to astral body shame, Matt. Right up until a moment ago, you were calling it attractive, too.

Thanks Matt. I just watched a lecture by Sir Roger Penrose at Gresham College and had to watch your video again in an attempt to learn a bit more. Turns out quite a bit more. Thanks again for your time and work putting it all together.

Matt, I’m curious, how do these spinning Kerr black holes relate to the information paradox?

Been waiting for this episode a long time; seems you guys have a lot of stuff on your mind! Great video, by the way. Also, can you please print this map on posters? I would totally buy it, and so would other spacetimers. Edit: Also please print it on a towel as quite a few people want it. _(Insert reference to A Hitchhiker’s Guide to the Galaxy here)_

Again I have the feeling that if I whatch it 100 times I will get it... So it is not possible a white hole existing or matter going trough it but is possible that the fabric of space itself can go through it? If that will be possible, it will make sense that the big bang could be a white hole that is accelerating the fabric of our universe by pouring "space" into our universe "from another universe" and we will never be able to see it because it is in our past? It's a total non sense I know just curious and ignorant. Great episode.

Question: What would happen if an entangled particle fell into a singularity. Would we be able to receive measurements from it?

Ok I've reached the point where I couldn't understand 99% of this. :) I'm too dumb for this level of video.

Ergosphere surface and event horizon diagrams are almost correct. The event horizon is the spinning sphere that we are contained in crumpled up inside. You learn how all of them are contained based on their spin and angels should line on at one point within our galaxy. Somehow I believe the forces line in some orientation towards or away from the great attractor. That is one of my crazy ideas.

Does this mean that I can now get in my spaceship and start my promising career as a space cartographer?

OK... I will watch to this one few more times than usual, before conceding I did not understand it at all.

I BLOODY LOVE SPACETIME!!! You guys are brill!

So what about a rotating charged black hole at the same time how much charge and rotation is needed to stabilise the singularity

I noticed you seemed to include the term “antiverse” in your diagram at the beginning of the episode, but then never mentioned it later on. Was this a term y’all decided to discard; is it that “bizarro” region you described?

This explains how Sonic was able to turn back time during his fight with Speed Demon Mario in TerminalMontage's Subspace Emissary video. He went so fast that he created a naked ring singularity out of pure energy (called a 'kugelblitz'), which allowed him to accelerate faster than light, which allowed him to jump back in time.

7:48 - that's when you know it's time to get schwifty

"Relative to the rest-frame of the cosmic microwave background radiation". So is the CMB considered to be (as close as possible to) an actual rest-frame? Do the virtual particles that pop in and out of existence do so also "at rest" relative to the CMB? Note: Note a physicist, so please forgive me if I used some terms poorly (or worse). :)

Can we please get a shirt with the full Penrose diagram? Instant buy.

Great cartography skills. Recognized my home stright away just from the thumbnail! P. S. I believe i was lost once outside that map.

6:16 No, this is not correct. It's easiest to see this in the Kruskal-Szekeres coordinate or the Penrose diagram. Also, space and time do not change directions, this is just an artefact of a strange coordinate system being used (namely, the one that results from first arranging the yet unknown metric into a diagonal form which is done merely to make solving the Einstein equation easier, or even possible, in a closed form). Such coordinate systems are singular at the horizons and due to a quirk of the mathematics involved, the letters labelling radial and time directions end up being reused at the resulting disconnected patches. But this is just a bit of notational laziness. Hawking and Ellis in their book try to counter this by switching the letters "r" and "t" for the interior portion of the Schwarzschild metric, for example. 7:33 It does not "become" repulsive. The ring singularity is gravitationally repulsive on both sides of the disc. The mass is not "negative", it's just that the radial coordinate labels become negative. Same thing about the "nakedness" of the singularity: it is so on _both_ sides (once inside the inner horizon), not just inside the "negative space". 14:15 This is very commonly asserted but it's just not true: Einstein was very likely not even aware of the Michelson-Morley experiment (USA was a scientific backwater then). His motivation was different: he was trying to resolve the infamous conundrum of Maxwell's equations not being true in a uniformly moving system. Since Newtonian mechanics obviously is not like that, and mechanics was supposed to be an effect of the microscopic electric and magnetic forces, this drove everyone crazy. His 1905 paper was in fact about justifying why the electromagnetic fields E and B were _physical_ after a Lorentz transformation (before him everyone assumed that those transformations were only mathematical curiosities). This was _the_ main conclusion of this paper in which he demonstrated how this reality of the transformed fields resolves the magnet-and-coil paradox he sets up in the introduction to the paper. But, as it very quickly turned out, probably within weeks of the publication, it was the first, kinematical (introductory) part of the 1905 paper that was the smoking gun (special relativity). So today hardly anybody even _reads_ the actual main (second, electrodynamical) part of the 1905 paper.

It's videos like these that make me love the Universe and it's rules because you can exploit them to do all kinds of weird things

So black hole is a sink that sucks you in and the white whole spits you out. Kinda like life.😂

It’s about time that we see a relative comment that doesn’t take up too much space.

hope that all the viewers understand your videos because they are awesome)

Sometimes time travel maybe nessarary for causality like. Creepy action at a distance