Mindscape Ask Me Anything | March 2020

Web site: www.preposterousuniverse.com/...
Patreon: / seanmcarroll
Mindscape playlist: • Mindscape Podcast
This is the monthly Ask Me Anything episode for the Mindscape podcast. It is offered courtesy of Patreon supporters of the podcast, who are invited to ask questions every month.
This is the first public release of these AMAs, and I'm still working out kinks. Ideally there would be a way to list the questions with timestamps, or even a full transcript. Stay tuned!

[@rodrigosilvanader]

It’s incredibly hard to find people who can explain physics with this level of clarity. Thank you for sharing.

[@jamiboothe]

This is very hard to do, but the ones that know their subjects very well and are humble enough to accept that they may not fully understand the subject, can explain it in a way that is easy to understand by those of us who are interested but do not yet possess the tools to disprove.

[@dean3850]

Both of you guys sound like your grasp has exceeded your reach. Because Sean Carroll's not a fine-tuning expert by any reach of the imagination. He is good in a debate with a theist though in my opinion.

[@rodrigosilvanader]

Dean Crisco yes that might be true. But his ability to translate a highly technical language into plain english is impressive. Most of the videos on these subjects are either too vague or too technical, Sean has a very good way with words and speaks as a medium between experts and us (laymen interested on the subject, having no time to get into the math to comprehend relatively simple concepts).

[@sirilandgren]

Also this Q&A felt like a really generous thing, such a luxury getting to ask someone like you about these kinds of things!

[@freeair9460]

I'm so impressed with Sean. Better teacher than I ever had. And so greatful for his open mind and not judgemental.

[@russellblackadar425]

Great podcast, but I think the cat question at ~30:00 deserves a better answer. It has nothing to do with nonideality or any interaction with the air. Rather, somewhat counterintuitively, it is simply a fact that an isolated object with moving parts *can* change its orientation in space while still conserving angular momentum. Imagine floating in space without rotation... now swing your arm in a wide circle. Your body rotates a bit in the opposite direction, keeping the total L=0. Now stop your arm and bring it back to your side. You are now once again without rotation, but are facing in a different direction. Seems like magic, but in a way, you "paid" for that reorientation by moving your arm in a full circle. That's essentially what the cat does, aided by its tail and a supple backbone. It's also (albeit oversimplified) how the Hubble Space Telescope positions to different targets without the need to fire rockets or interact with any other body. I find it interesting that angular momentum allows this, whereas, what the analogous effect would be in linear momentum -- moving one's center of mass to a new location by internal motions alone -- is not possible.

[@russellblackadar425]

Thinking about it some more, I believe this difference is due to the periodicity of rotational motion. You can bring your arm back to its original position (relative to you) without ever reversing the direction of its motion.

[@cleon_teunissen]

Hi, I also commented on the cat part, I failed to check whether someone else had already commented on the cat part. I don't know whether Sean reads youtube comments. I'll give a thumb up to your comment, maybe that can help.

[@brandont4259]

Timestamps with the questions listed in the comments would be a MASSIVE contribution to these videos. Very common for long podcasts to timestamp topics / questions.

[@dean3850]

I believe this guy just found a new job for himself you go right ahead and do that for us thank you.

[@tripp8833]

Brandon T here’s your time stamp bitch 4:20

[@mojo3898]

I agree there is no clue what any of the content is in a 2 hour podcast.

[@radicalmoderate2730]

@@dean3850 Amen brother lol

[@djay3312]

Be the change you wish to see in the world

[@irekklimczak3661]

Great idea Sean! You're totally right that we need to "both survive and also move forward". Sharing knowledge is the way to do it. Thanks.

[@desiderata8811]

This “ Ask me anything “ is gold ! What an opportunity for us !

[@dennisbmx]

Thank you for putting this on youtube

[@cleon_teunissen]

At 00:29:50 there is a question about how cats are able to land on their feet. You attempt some answer, but unfortunately your answer goes astray. As physicists do, let me discuss a simpler case, the simplest that reproduces what a cat does. Take a flexible rod. Add internal hinges and machinery so it can bend itself into a U-shape, plus some other machinery that I will get to. Release the rod to free fall. In order to make itself land in a particular orientation the rod bends into a U-shape. Now the rod rolls in such a way that the ends of that U are *counter-rotating*. On reaching the desired orientation the rod stops rolling and straightens itself again. The way cat reorients itself is not the same as described above (different sequence), but it is the same principle. The key point is that the cat uses its muscles to move parts of its body relative to each other. For comparison: a spacecraft with an internal reaction wheel. The spacecraft is in a particular orientation, the reaction wheel is stationary with respect to the spacecraft. To reorient itself the spacecraft spins up the reaction wheel. On reaching the desired new orientation the spacecraft halts the reaction wheel. Both in the start configuration and in the end configuration the reaction wheel is stationary (wrt the spacecraft), but the spacecraft as a whole has been reoriented.

[@xqw4851]

yes

[@Atm_0s]

I went to see you in Melbourne, thanks for that. It was a bit less in depth than I would have liked but I managed to pick up a signed book so I'm happy XD

[@spnhm34]

I really enjoy the insights.

[@austinjohnson4782]

Funny to hear Sean's pen preference is the same as mine, I've been using those uni ball vision elites exclusively for years

[@huepix]

Hey. Hope you can address this question. It's just an idea, so I'm hoping I can explain it adequately. The idea is that areas ("fields") of space are moving at different velocities to other areas of space. Considering relativity, in particular, time dilation and space contraction, I propose the faster areas of space are tiny and "permanent" (I'm not sure permanent is the correct word. More permanent may be better). So if we imagine the universe is like bubbles that are expanding towards each other. The edges of those fields can move toward each other, but as the (relative) speeds approach significant %ages of the SOL, the space between them collapses into tiny areas that appear to have permanent "points" within that field. This isn't the place to expand on to many details, but the idea is that a sub atomic particle is actually an area of space that is moving so fast it appears to be permanent. Remember, the observer is also moving, so the point of the field we observe will be unpredictable and move. In its entirety, the concept can explain the double slit experiment, unifies the 4 forces and explains the (apparent) acceleration of the expanding universe.

[@drygulch1000]

Joe Zawinul, a keyboardist who wrote "In a silent way.", and played with Miles Davis said his playing completely transformed after taking LSD a single time.

[@kizza1645]

Sean! Please for the love of all things science, please, please get Brian Cox on the podcast. Both you and Brian are my favourite scientists in the world and I know a lot of your listeners would agree, that a podcast with Brian would be the most amazing piece of audio to listen to! Thanks for all the work you're doing. I listen to these podcast everyday and absolutely love the work you're doing. You have no idea how much you are helping the general public. I support you on patron and am considering donating more - as this information is priceless to me. Thanks Sean.

[@ENikolaev]

I disagree. Epstein or AGB would be much better

[@liti1554]

Thank you!

[@insanezombieman753]

you could live stream during the session on top of this

[@life42theuniverse]

49:00 What feelings should I have about decisions people made centuries before my birth? Or even those decisions that people make without awareness of my existence. 1:20:00 I remember hearing something that the interior of a black hole time and space become inverted, at least theoretically. In this way every black-hole is expanding from the singularity to its collapse.

[@SupremeScientist]

Loved the AMA. Thanks for reminding that I'm really not as smart as I pretend to be. Lol.

[@JiminiCrikkit]

Great episode thanks... Would you consider asking Nima Arkani-Hamed onto the podcast? :)

[@IntraFinesse]

At 55:50 this is contradictory to what Kip Thorne said. He said there is no matter inside a black hole, that its been converted into warping space. The interview is one of the Closer To Truth videos on utube

[@RyanReece]

Moving Naturalism 2.0!

[@captainzappbrannagan]

I"m going to need a more detailed explanation about the edge of the universe (or boundary). Space and time likely started at inflation and big bang, we know how long ago that was, how can there be something that exists outside of the boundary of that expansion of space time? Even in the multiverse theory where there's eternal inflation each bubble is a pocket of space time... there would be a boundary for each bubble. Only ever going outside the bubble if it crossed with another bubble...

[@captainzappbrannagan]

@@Valkhiya I'm not talking about visual horizon, i'm aware that doesn't show us the whole universe. It does show most of it though. There is a particle horizon which would definitely have a boundary if there is no multiverse of inflating universes (not a theory yet just hypothesis). You start with a balloon and inflate it , it still has its edges which you can't get past or the universe breaks.

[@kathyorourke9273]

What’s a bummer is, you never experience more time. You only experience regular time no matter how fast or far away you go.

[@jeannieh3661]

By calling it "nothing" does it thereby become "something"?

[@TurdFerguson456]

Damn good podcast👌

[@scooby990]

Hi Sean, your podcasts are addictive. I have a question. When we observe some part of the universe does the wave function collapse there and we end up affecting the progress of the universe

[@Jason-gt2kx]

I don't think he will reply. The title just means this is his Q&A he already did, but he may. I am just glad he is posting these for free.

[@scooby990]

@@Jason-gt2kx , I completely agree, these scientists are normally extremely busy and his level of thinking is just astounding. I was in a talk last week presented by Professor Brian Cox and had a deep question for him about the ever expanding Universe. He was, I am Sure familiar with the detail but his explanation wandered to the Holographic Principal. I didn't get the answer, so I am going to pursue further.

[@freeair9460]

Can I please get an opinion from anyone. Does anyone think percesion the 24,000 year woble of the Earth account for some climate change because of the change in the angle of the sun light hitting earth in places it hasn't in many years

[@freeair9460]

@@Valkhiya I agree. But is there a chance the amount of time exposed being different. If in one 12,000 year cycle the noth Pole points at the sun the the next 12,000 the north pole points away . Because there are loads of cities under water. Long before the industrial revolution

[@joshua3171]

would you help build a real life working warp drive????

[@xspotbox4400]

I have a question, gravity is 0 at the center of Earth, so there should be same point of equilibrium at center of every galaxy, also. Maybe not just one, galaxy could have many separated, but interacting gravitational systems.

[@MarakanaCacak1989]

Where's the legend with the list of questions at?!

[@eatingtacos000]

yay!

[@emilylowrance7930]

not everyone agrees but I think those people are wrong - Genius

[@livedierepeat420]

👏👏👏 👍💯

[@kennethbosch9]

cat on head? I sure hope it's a peaked cat

[@deeptochatterjee532]

Wait I don't understand. You can decide to treat all humans a certain way and all other species a different way, that's fine, but why? Isn't the distinction at some level arbitrary (let's say we're considering the circumstances given by John's question, then it does appear to be at least somewhat arbitrary)? How do you justify that arbitration, because if you want to protect one animal's rights and not another's there has to be some logical justification.

[@sirilandgren]

Oh my god Lee Smolin as a guest would be such a treat! On the level of David Albert, which was like mind porn to me.

[@Tylerthety]

Yodles!

[@mokamo23]

"i don't think [psychedelics] can give you any deep insights...." :))

[@1tecladocasio]

And what can?

[@bobbob-sv4mk]

1:58

[@nickelmouse451]

ASL?

[@neetbucks521]

species normality :o

[@thomasl.hutcheson2226]

Sean, In the conversation with Derek Leben, there was on point I wish you had pushed him on. In the bicyclist with and without a helmet problem, is not wearing a helmet a kind of cooperative behavior that we wish to promote? If self driving cars are known to always chose helmeted bicyclists, does that not encourage not wearing helmets? What about jay walkers? That was sort of negative to his POV, but on the positive side, he seems to think that which algorithm we build into a vehicle is fixed one and for all. In practice, I would expect the algorithms to evolve in part in response to tort law. Take the case of swerving to break the legs of 50 people to avoid two broken legs from continuing straight. Will car owners buy cars with that algorithmic result if the liability insurance premia (based on results of tort suits) are higher for cars with that algorithm?

[@tommyvictorbuch6960]

So far 14 has died from this CCP virus (Covid -19) in Jylland, Denmark. That is quite a lot, and the number will rise. Superb podcast.

[@Jason-gt2kx]

Novel Dark Matter Hypothesis Dark Matter is simply unaccounted for gravity. GR states that gravity is the consequence of the curvature of spacetime. Is it possible that the structure of spacetime itself could be warped without the presence of mass? Spacetime has been shown to react like a fabric by warping, twisting, and propagating independently of mass, and all have been proven with observations from gravitational lensing, frame dragging, and now gravitational waves! Fabrics can be stretched, pressured, and/or heated to the point of causing a deformation. All of these conditions were extreme during inflation, so it is plausible that the “fabric” of spacetime analog could extend having its elastic property have hit a yield point. Therefore, if gravity is the consequence of the warping of spacetime, and fabrics can be permanently overstretched, then those empty warped geodesics would create gravitational wells independent of mass. My hypothesis of DM is subatomic black hole imprints of the quantum fluctuations that popped in at the moment of inflation. These would be clouds of quantum sized floating fixed geodesics, so they couldn’t expand or evaporate. Perhaps nothing has been detected because there is nothing to detect, and GR wouldn’t require modification of mass interactions because DM would just be an extension of how space-time behaves at extreme conditions. No WIMPS, no MOND, no parallel universes, just empty spacetime deformations that produce gravitational wells to help jump start galaxy accretion processes.

[@NaneuxPeeBrane]

NIce. thx.

[@raysalmon6566]

drive.google.com/file/d/1zwGx27mThh9C9FY6gLerEH8aGwCiF3RM/view?usp=drivesdk Just seeing if this link works Minute block form of transcript

[@PilsnerGrip]

The slaughterhouse question *seems* emotionally charged, because most normal human beings recognize how horrible the scenario is. But that's just daily reality for milions of animals. Of course people draw the line at humans, but can they actually justify drawing that line? I've never seen it justified. And I eat meat, I just think I'm horribly immoral because of it.

[@TurdFerguson456]

Brian Cox would be GREAT on here!

[@kennethbosch9]

surely the question on "brain damaged" individuals being unable to project a future for themeselves is a moot point, as this individual will invariably have family members and people who care for them, who have projected a future for the affected individual. It seems an error to think you can isolate individuals in this way to propose dubious ethical word games, life is a feedback loop after all and not an isolated experience.

[@PilsnerGrip]

So if we remove from this scenario any people that would care for that human, would it change your mind? I ask this, because I suspect you wouldn't, so it's not really about that.

[@kennethbosch9]

@@PilsnerGrip how do you propose doing that? If so I would have to agree, to paraphrase Bret Easton Ellis; nothing bad can happen if you are truly alone, and you really shouldn't be second guessing my motives

[@kschuman1152]

Nuclear proliferation is the most pressing issue.There are any number of ways that humanity may end or end up in a very difficult situation that no-one would want... but it's almost a certainty that if one of these other ways does get us, nuclear weapons will be there waiting to assure our doom. The problem is that the technology cannot be un-invented.* In fact, as long as our technological civilization exists, the only reasonable expectation is that in the future such weapons will be increasingly powerful, more readily deliverable, more generally effective at doing what they do. The Foundations institute estimates a 1% chance of a nuclear war annually. This seems reasonable, given that the world was at the brink of nuclear war in the Cuban Missile Crisis, which we may count as roughly 1/2 a nuclear war 'occurring'. So we find historically a 50% chance of such wars since the 'gadget' exploded at Trinity, in 1945, i,e., over a 75 year period. This is within the ballpark of consistency with the Foundation Institute's 1% estimate. Simple statistical analysis (using the formula to project a probability over a longer series) grind out the following numbers: Probability of Nuclear war over 100 years 1 - (1 - 0.01)100 = 0.63396765872677 Probability of a nuclear war in any given century = 63.4% Probability reaches 99% within 464 years Assuming that the chances of a human extinction in the aftermath of a given nuclear war is 15%...(a number pulled out of my butt)... Probability of human extinction resulting from nuclear war goes over 50% within about 2 millennia. Probability of human extinction resulting from nuclear war goes over 99% within about 21,808 years * some scenarios regarding the aftermath of a large scale exchange of thermo-nuclear weapons envision a post-apocalypse that returns humanity to a more-or-less neolithic ("stone age") level of civilization. These scenarios are not unrealistic, and outcomes like this do present a possible way to 'dis-invent' of nuclear weapons, at least until such time as humans re-discover the laws of physics and a similar cycle recurs.

[@sudazima]

iirc the last time the doomsday clock was changed it was set closer to midnight because of the danger mainly from climate change, and it is now closet to midnight then it has ever been. so i guess experts think climate is a big deal. this 1% estimate is just total random so its pointless to use, futhermore the cuban missile crisis was not "half a nuclear war".. thats crazy. more furthermore weve already had a nuclear war ! WW2 remember? the cuban missile crisis was not even the closest weve been to nuclear war in the cold war. all the other numbers you use are indeed also just randomly pulled out your ass as you say or calculated wrong. worst case scenario for a full fledged nuclear war doesnt kill nearly enough people to makes us extinct. infact theres almost nothing that can anymore, pretty much just super AI and cosmic happenings (large comets, GRB etc). using nuclear waepons as effeciently as possible we can only kill like 1 billion, theres just too many humans.

[@rret6885]

Love you Dr. Carroll, but bad advice on traveling and the corona virus.

[@dreed7312]

It's March 22, 2020 at 4:30am mountain time. I would really like details on the apparatus used to "fire protons" because I don't believe that's what's happening. I think your pulling line off a reel in a big wavey loop and it's only when it interacts with something that it becomes a "particle." I'm aware of Rutherford and how we got here, isnt it time to abandon particles completely and the billions spent to crash them together? We're only confirming our own bad experiments, over and over again. Of course it's the most accurate predictive model, what else could it be? It is inherent. It's recapitulation. There is no particle so there is no reason to be amazed by the experiment. I don't know why everyone insists on starting with an erroneous model then trys to make sense of it. Obviously the model is wrong. I don't think protons or electrons exist. 'they' aren't things that can have positions, momentum's, spins, colors, or anything else. We're pulling loops off a fishing reel and when they meet we see the contact as a point. Remember the guy who proposed the idea of only ONE electron in the universe that appears whenever? Goes back and forth in time? Couldn't it be one big loop? A field? That takes on the same value everywhere? We only see what we look for. Once we look for that, we can't see anything else.

[@MrPDTaylor]

Third

[@MrPDTaylor]

Ender will save us all

[@MrPDTaylor]

My sister is at very high risk for death if she gets covid19 and I'll most likely come into contact with her so I feel obligated to isolate as much as possible.

[@MrPDTaylor]

@@schmeegil2240 wow, that is exactly the misinformation that is going to overwhelm the hospitals. 10x the death rate of influenza, but I'm sure their is no use using actual facts with you.

[@Imaginose]

The veiwer's idea that it is bad for animals too suffer and you should add more living things to the list, does not really make sense.

[@chewyjello1]

He seems to misunderstand Hoffman's theory. Hoffman is not saying that there is no reality, or we can't get to reality, or that different people have different realities or that we are creating fundamental reality. He thinks what we experience is not fundamental reality any more than an icon on a computer screen is fundamentally what's going on inside a computer. He thinks we do not yet know what fundamental reality is. He plugs in consciousness as fundamental to see if he can come up with a theory out of it that works. He expects he is wrong, but it's just a first draft. Consciousness being fundamental is not the theory. The theory is simply that space time is not fundamental and he "proves" this using evolutionary models. He may be waaaay off, but what I notice is that other scientists (while stating their skepticism about his ideas) have a hard time explaining why he's wrong.