Feynman used to give a similar lecture, where he joked "if we agree on physics with the aliens, and explain our customs, and they come visit: if the alien offers his left hand for a handshake, *don't* *shake* *it* ."

@infinitenex8165

Жыл бұрын

I dont understand the joke

@MOSMASTERING

Жыл бұрын

@@infinitenex8165 We live in a right handed universe. So, if they are opposite, they may be made of anti matter and you would explode into energy.

@hazardeur

Жыл бұрын

@@MOSMASTERING are you sure? i always thought our universe is left handed biased

@trollking202

Жыл бұрын

What time is the alien 👽 birthday? 😅

@erichluepke855

Жыл бұрын

​@@infinitenex8165 If we agreed on physics then they'd also be using the right hand rule if they were made of regular matter and used their right hand as their dominant hand. If they reached out their left hand that means their left hand is likely their dominant hand, which implies either our physics aren't really the same or they are made of antimatter. If they were made of antimatter, shaking their hand would blow everyone up in an explosion many times worse than a nuclear weapon.

My take away from this, as an engineer, is to be sure to write down ALL of my assumptions for every design, no matter how obvious I think it is.

@ojazzista

Жыл бұрын

Same goes for software architecture/engineering my friend.

@scaredyfish

Жыл бұрын

1. The flow of time is positive 2. The end-user is always wrong

@Lustie

Жыл бұрын

Just don’t write your assumptions upside down… or maybe do??? 😅

@mallobag

Жыл бұрын

//commment for Kaka //beginning of comment section Yeah. I use to comment every line of code i write //comment end //this ends the comment

@robertcanup4473

Жыл бұрын

You're an engineer? Good, I can talk to you. Want to create an actual singularity in the real world? OK, take a standard NPN transistor RF amp, capacitive coupling to the base, inductive load on the collector, grounded emitter. Connect the output (the collector) to the input capacitor. Analyze the circuit behavior, using both speed of light delays and transistor storage time delays. Note that there is a frequency where the phase shift of the input and output circuits cancels the delays in the physical hardware. At that frequency, there is a singularity, a division by zero in the math of the circuit. The output of the circuit is an actual division by zero.

At first my thought was "well, if they're smart enough to be sending us these instructions, then surely they're smart enough to also know which choices are arbitrary, and include some sort of practical guide to minimize the possibility of error (maybe through miniature test circuits, like hey if you built this correctly, and our arbitrary choices matched, the lightbulb should turn on)." and then I realized that this was a trick! I've been tricked into learning about symmetries! Nice work, loved the video :)

@andymitchell8644

Жыл бұрын

They could be testing reasoning as well as you advancement technologically

@GregorBarclay

Жыл бұрын

Also they could probably send us some videos, right?

@icecold9511

Жыл бұрын

Or just visit us in their star ship......

@shipwreck9146

Жыл бұрын

Or they could be messing with us, and this is their way of making us build a device that destroys our civilization so that they can come and take earth with ease.

@zedantyorant

Жыл бұрын

Its also wrong to assjme anything about alien. They might have advanced tecnology,but they might not necessarily be smarter in all fields,thus simply overlooking obvius things like languange barriers.

This alien device is sounding more and more like an intelligence test lol

@chrisnichols9014

Жыл бұрын

More than half the planet will fail the test. The average person isn't very smart.

@kevinclass2010

8 ай бұрын

IKEA is a alien civilization

My favourite parity confusion occurs in Australia where there are apparently trails of "arrows" leading away from water sources. In actual fact they symbolize birds foot prints as they walk towards the water. This convention has likely been a source of fatal confusion for more than one of the more recent colonizers of that continent.

@TAP7a

Жыл бұрын

I love it when a sensible use of available resources also works as guerilla resistance against aggressive occupation

@Neme112

Жыл бұрын

Is there a photo of this anywhere?

@natenczaswojski7228

Жыл бұрын

Well... You should always remember that everything in Australia is trying to k.ll you.

@Rebius

Жыл бұрын

do these birds fly, or are they only walking? And how far can they walk?

@gl1500ctv

Жыл бұрын

Just another proof that EVERYTHING in Australia tries to kill you.

That was a very clever and awesome way to explain the relevance of symetries and the importance of identifying what is a convention and what is actual physics.

@sunrealclothing

Жыл бұрын

It was a very cool possibility to consider!

@josephmastroianni1560

Жыл бұрын

@@sunrealclothing passing a US HISTORY TEST might be required to leave. Media. It started a revolution. FakeNewZ was sent everywhere. 3/5/1770. One man called us an enemy Feb 24 , 2017. And people think we can leave Earth.

@sunrealclothing

Жыл бұрын

@@josephmastroianni1560 thinking for yourself is cool. But don't get it twisted...

@josephmastroianni1560

Жыл бұрын

@@sunrealclothing If you cant pass a simple history test, what makes you think we can traverse space....and what if they wont let us.

@sunrealclothing

Жыл бұрын

@@josephmastroianni1560 eat some more space cakes bruh!

This kind of thought experiment seems like it would actually be really useful for trying to root out unconscious or unnoticed arbitrary conventions in physics.

@revenevan11

10 ай бұрын

Great for engineers and teacher too, to realize what assumptions and knowledge they're seeing as obvious that they should really be specifying for others!

@goboy6882

9 ай бұрын

and for identifying blatant errors.

I’m imagining - somewhere in a galaxy, far, far away - an alien Matt O’Dowd, flapping his tentacles around, warning his viewers about the dangers of Earthling Physics. But could he do it without violating nerd parity?

@DontYouDareToCallMePolisz

Жыл бұрын

All parities are broken :)

@paultheaudaciousbradford6772

Жыл бұрын

@@DontYouDareToCallMePolisz You speak as someone who has first-hand experience. Perhaps you’ve tried to communicate with alien scientists.

@DontYouDareToCallMePolisz

Жыл бұрын

@@paultheaudaciousbradford6772 maybe i am an alien scientist..

@sachiekat1238

2 ай бұрын

​@@paultheaudaciousbradford6772 to them we are the alien scientists

PBS space Time is a prime example of a KZread channel with high quality content. Great job mate.

@gamerfortynine

Жыл бұрын

Looks pretty, who cares if its not scientifically accurate right?

@kingsman3087

Жыл бұрын

as smart as humans get, the aliens still think we are dumb territorial savages

@Shadow-In-The-East

Жыл бұрын

@@gamerfortynine Username checks out.

@afriedrich1452

Жыл бұрын

I am listening to a broadcast from planet XURB67-b. Sorry, but their version of PBS Space Time is much more advanced than Earth's.

@TheClintonio

Жыл бұрын

Time is easiest. Describe an event in the past along with the time, and current time, and the sign of the difference will give us the information we need.

It would be kind of hilarious if we got an alien transmission, and after a huge struggle to decode it it just turned out to be a recipe for some weird alien food. :)

@peterkelley6344

Жыл бұрын

Picard to the Klingon's: Oh, It was a old family recipe of a soup that you might be interested in. I'ld be happy to send you a fully translated copy of it ... If you'ld like. Klingon's go storming off in a huff. While what was really offered was the key DNA sequence between the Human's, Vuican's, Klinon's and half dozen other races in the Milky Way galaxy,

@anon_y_mousse

Жыл бұрын

@@peterkelley6344 That was simultaneously a great and horrible episode.

@khairulhelmihashim2510

Жыл бұрын

to serve man (twilight zone)

@ianboelts

Жыл бұрын

mm good soup.

@NTJedi

Жыл бұрын

We would decode the alien writings and it would be called "How to Serve Man" .... it's a cookbook.

Given the fact that our universe contains almost no anti-matter in it, I'm pretty sure the aliens would send us instructions on how to build a spaceship with time flowing forwards. Although, one can't entirely be certain since we chose the electric charge convention so poorly. ^_^

@castonyoung7514

Жыл бұрын

Why is it poor?

@skillfulfighter23

Жыл бұрын

I wish you were wrong

@Azarilh

Жыл бұрын

That's an assumption made on the observable Universe. Anti matter could be more abundant, just not in the area we live in, we don't know.

@kaitlyn__L

Жыл бұрын

Even with the same actual experience of time, you can view the future as negative. Eg start of clock is 0, then -1, then -2, etc. This is a positive flow of time but a different signing convention, exactly the same as with the electron. (In fact, some societies on earth conceive of time in this way in their languages!)

@aarondavis8943

Жыл бұрын

​@@Azarilh It's extremely unlikely for antimatter to be in harvestable clumps anywhere in the universe where there is also enough normal matter for a civilization to emerge. We can be certain that the aliens had to produce it themselves in a similar manner to us and would therefore understand our possible limitations. And in any case just containing antimatter requires advanced civilization.

This was a masterpiece of a video. Holding the manual right side up feels like something that would be written in bold in a book with the words "Don't Panic" printed on the cover.

If they aliens were also aware of these symmetries/ambiguities, perhaps they'd be kind enough include a suite of tests that fledgling civilizations could run on key components, before risking planetary destruction.

@Jossandoval

Жыл бұрын

And ruin the joke? Just imagine, some kind of Space Streaming with the title "Will they get it right, or will they blow themselves up?"

@MCsCreations

Жыл бұрын

Actually, we have that already. It's called a multimeter.

@davidozab2753

Жыл бұрын

Unless they were planning on us blowing ourselves up.

@TheSCPStudio

Жыл бұрын

@@MCsCreations that’s… not how that works lol

@MCsCreations

Жыл бұрын

@@TheSCPStudio For charge? I'm sure it is. 😬 CPT... I mean the C part.

This was an insanely clever episode. Not only good enough to help me better intuitively connect the symmetries in my head, but also simple enough to send to my friends to teach them about CPT symmetry without it being scary.

In the military, we used electron flow instead of current and employed the left hand rule. When I reentered the civilian world, which uses positron flow as current, I was introduced to the right hand rule. It can get very confusing, although it is simply dependent on the convention used. I definitely can see major issues developing with engineering a system where the "normal" is not actually defined or even unknown. Looking for the "up" arrow on the alien instruction manual...lol

@sachiekat1238

2 ай бұрын

Not in the military but in my physics class I always use electron flow and it always confuses me when people do the opposite

Just imagine the aliens use a body part to help remember a physics thing like we do

Me: Wait. Our physics are the same? Astronaut with a gun: No. Never has been..

I thought this was gonna be more "linguistic", about decoding alien messages from the physics in them, but that was glossed over right at the beginning to talk about symmetries.

Жыл бұрын

That would have also been an interesting topic, but much more speculative?

@siritio3553

Жыл бұрын

@James Henry Smith what are you on about?

@timseguine2

Жыл бұрын

@@siritio3553 He's a nutter spamming the same comment in every thread

@MrAranton

Жыл бұрын

Linguistics has never been a topic on this channel; at least as far as I know. And trying to decode an alien message from the physics in them, isn't going to work unless you have a way to figure out which parts of the message actually reference physics. Imagine you were an alien looking at a text full of symbols you don't recognize and that mean nothing to you. How would you know the symbol sequence "F=ma" is not how Humans spell "orange juice"?

"In physics, if you can't tell the difference, then what's the difference?" CPT symmetry is, as far as we know, unbroken. If we could tell the difference, then it would be broken. If we can't tell the difference, then it's unbroken. So if building the ship CPT reversed makes it explode, then we can tell the difference, CPT symmetry is broken. Or CPT symmetry isn't broken, so the ship can't explode.

@tomctutor

Жыл бұрын

That's very circular, it reminds me of when they were making the first atom bomb because of scarcity of the fission element they suggested "Just drop it and see if it will work rather than speculating".

@Lustie

Жыл бұрын

@@tomctutor “When it doubt, drop it out .”

we'd hope the aliens have accounted for their arbitrary conventions, and given us tests we can do, which we can compare against their results, to determine this.

If we really do make a CPT-reversed version of the machine, we will at least know their convention was different when there's a big burst of energy as we try shaking limbs with them.

What about if the aliens have found new symmetries beyond our imagining? What if CPT is actually broken and we just don't know it yet? How can we make any assumptions about anything?

@therealb888

Жыл бұрын

Now we're talking. Just as the strong & weak forces weren't known when newton observed the apple fell we may have an incomplete model of our symmetries.

@colinsmith1495

Жыл бұрын

Because then they'll have equations and particle descriptions that don't match anything we have in any way, and that will be exciting.

@MrDJAK777

Жыл бұрын

They were broken weren't they a few times? but it always seems like "nah we broke it symmetrically so it's fine" or something like that

@nickcunningham6344

Жыл бұрын

I think the idea is that the aliens would start at the very basic level of physics and slowly teach every level of physics, building off of the basics, up to their understanding. So they would send knowledge of everything we already know and then more

@malachi-

Жыл бұрын

You may like, Bohr. kzread.info/dash/bejne/dHqqrLGTZZTancY.html

18:59 I love the deadpan, straight face when he casually drops the poop.

It's out now , it's a joy to watch and dig into these subjects and get striked and stunned by the beauties of every bits of information

"Accept that you do not know what life in the universe is like, how it exists, how it interacts with itself, what to expect regarding visitation to your world and what to understand about the visitation that has already occurred here. Accepting this limitation gives you the greatest opportunity and possibility to see beyond your current limits, to see beyond the confines of this world and to see beyond the confines of human interactions." A quote from *Life in the Universe* by Marshall Vian Summers. Check it out, it's free online.

@johnchapman5125

Жыл бұрын

Thank you, Ivan.

so, I noticed that this was really a sneaky way to give a basic physics lesson, still, excellent, always good to hear about some sciency-stuff

@michaelfried3123

Жыл бұрын

sci fi you mean. its crap.

@theslavicharuspex

Жыл бұрын

@pyropulse maybe he got it in his recommended feed

Robert Forward solved that issue by having two sails. The first sail used for acceleration is larger and is detached during deceleration it is used to reflect the laser light BACK to a second sail on the decelerating ship (of course, it too is accelerated again by reflecting the laser beam back to the second sail) The details of his Beam-powered propulsion are in his book, "Rocheworld". He was a brilliant physicist and great SF writer who died well before he could write enough books for us to enjoy.

Light could be used to transmit audio data, so the first part of decoding any message would involve determining distance so that a compression of the light wave could reveal it's secrets

@potatoheadpokemario1931

Жыл бұрын

but if the pixels are read left to right when it should have been read right to left we'd have a mirror reversed picture

At 8:01, the force acting on the electron should be into the screen (not out of the screen), since the electron has a negative charge.

@ronaldwilhelm3449

Жыл бұрын

Yep, you beat me, I was going to say the same thing. Electron moving in +x and B in +y will make positive charge move in +z (out of screen)

@kevindwyer639

Жыл бұрын

was looking for someone to comment

@valdemarfrederiksen4987

Жыл бұрын

Yep

Seriously this video is amazing. Back in highschool & first year of college I had these same questions about how the signs for polarity, direction of hand rules, etc were determined. But my teachers would shrug of my deep doubts & tell me to finish the assignments. Thanks for finally clearing these up for me! On a side note, those brownies look delicious.

@sunrealclothing

Жыл бұрын

😎🤙 ...it'S UNREAL Bro!

@falnica

Жыл бұрын

I was also very angry that teachers don’t explain where conventions come from and instead treat them as dogmas. That’s probably because they themselves don’t know

We really take the editing and design team for granted on these speacetime videos.

We could show the Aliens an animation of the Earth's magnetic field being bombarded with charged particles from the Sun, that would show them a definite direction that they are already familiar with. If they are visual creatures it probably wouldn't be that hard

I feel Matt is already anticipating our input on discussion of "how presented idea of positronic circuits is obviously nonsensical".

@Merennulli

Жыл бұрын

The whole episode was recorded on time reversed positronic devices.

@marcelo55869

Жыл бұрын

@@Merennulli don't forget reversed hand mirroed

@jakublizon6375

Жыл бұрын

@@marcelo55869 And then we flipped the charge... Again. Wallah! A symmetric univ.... Wait, the weak interaction? Wtf? The universe has a preferred direction?

@Merennulli

Жыл бұрын

@@marcelo55869 I hate to nitpick your nitpick of my joke, but changing the chirality (parity) like you're describing isn't correct. A positron has the opposite charge and chirality from its electron counterpart, so time-reversing a positron turns it into its electron counterpart (both charge and parity flip). What you've done is reverse the chirality back so now you have an electron with the chirality the positron had. I don't actually know what happens if you reverse the chirality of an electron in a circuit inside a digital camera. Given how electric fields work with chirality, my guess is you've made the first transformer in the camera's primary circuit melt.

@solsystem1342

Жыл бұрын

@@jakublizon6375 we haven't found a break in CPT symmetry yet that I know of. It's CP symmetry that we know is broken.

Clearly, we need to find an Alien Decoder Ring. * starts digging through cereal boxes *

@1234j

Жыл бұрын

Dibs on the plastic diver. I still have plenty of bicarb left over from the 1960's

@NewMessage

Жыл бұрын

@@1234j Guess we've aged ourselves here...

@thewiirocks

Жыл бұрын

@@NewMessage I'm surprised I'm the only one who thought of The Greatest American Hero when he talked about holding the Alien Instruction Manual upside down. (Now THAT will date anyone who gets it.)

@sunrealclothing

Жыл бұрын

🛸Wear what's real!🛸

@NewMessage

Жыл бұрын

@@thewiirocks I totally missed that, but I get it!

I remember that for physics exams, we used to write a little cross on our left hand. Since most of us write with our left hand, and the right holds the pen, some of us inadvertently looked at the wrong hand for our vector multiplications.

1. Hey! Long time fan - you guys rock 2. This is in many ways more a language problem than anything else (bias - I’m a language teacher). If the aliens try to describe an electron, they very well might define it the way we learned as children - the thing that orbits the nucleus of most atoms, and is the opposite charge of the nucleus. Effectively, it’s a convenient way to summarize the reality that the math explains - you find more electrons in the universe than positrons. The question would be, how thorough and Socratic would the aliens be about their explanation of what they are doing on the ground? 3. Thank you for explaining symmetry in this way! It’s great!!!!

7:56 The force is the other way around (into the screen) because the electron is negative.

Physic Dude has Same haircut since Stone age...

What a brilliant way to review some physics concepts as well as physics history. Awesome job!

I love and hate at the same time how smart this guy is. Keep the amazing videos coming!

So basically, Matt is making a case for why Aliens need to hire more technical writers.

@davidmladenov2926

Жыл бұрын

As an engineer I can tell you, a well written documentation (manual) saves a lot of time in tech support hours!

1) Another amazing, fascinating, and informative episode 2) We trust you to decode it when the time comes, Matt 3) lots of memeable imagery in this episode.

I'd just like to point out that there is another way to use a lightsail for braking, I believe the idea is from Forward: drop the big lightsail used to accelerate, and adjust it to reflect the light back (and more concentrated) to a smaller remaining lightsail. The braking power, just like the accelerating power, comes from the same large lasers. (The big lightsail continues to accelerate and is eventually lost.) He also points out the fundamental weakness of this method: it relies on reliable politics back home to keep the lasers running.

Dogs are the most advanced organism in the universe. They have symbiotically attached themselves to the only known life form capable of creating chocolate brownies

@nmarbletoe8210

Жыл бұрын

The answer to life the universe and everything: "walks."

Neglecting the fact that we don't need much training in blowing up our planet anymore, it's just a matter of pushing the right buttons... Could small scale testing reveal this?

@gogauze

Жыл бұрын

My assumption is that, in a real world scenario, extensive testing would be done to confirm the alien civilization's physics as being compatable with our orientations. The thought experiment is just to demonstrate how we've made a bunch of arbitrary decisions in the way we describe phenomenon and that our conventions aren't universal.

Stephen Wolfram has speculated that alien physics could be utterly incoherent with our own based on the observer's reference frames.

@nickrindal2787

Жыл бұрын

I'm working on a new system of reality that's consciousness based.. mass is just radiating spacetime.. it's obviously the same reality but in essence everything is reduced to space.. focusing on what's between the particles vs the particles themself.

@sid_edwards

Жыл бұрын

@@nickrindal2787 Wolfram's project makes a similar claim; that everything in the universe is basically knitted out of space itself and that structure is the result of a specific space-updating rule.

@yxx_chris_xxy

Жыл бұрын

@@nickrindal2787 I am working on a new system of reality that is based on Donald Trump's. That's more appropriate because the universe is so bigly big.

Great job at presenting an advanced concept in an accessible but not watered down way

This was one of favorite PBS Spacetime videos, and would make a great Futurama episode. I can see Professor Fonzworth trying to explain how we can’t interpret the charge, chirality, etc. of anything in the intercepted alien message. Ohohoh myy.

Seems like they could just include a quick blurb about how the particle used is the antiparticle to the more common version and bypass the problem altogether. If they were smart enough to build the ship, I would think they would be aware of this problem and communicate in a clear way which they used.

@Mernom

Жыл бұрын

What if they live in an anti matter pocket?

@staylor5990

Жыл бұрын

@@MernomEasiest way to rule that out would be to point our instruments towards the area of the sky the signal came from and look for the likely massive amounts of energy coming from the annihilation of matter/antimatter on the border of their pocket. Also, if the universe is truly symmetric in the way stated in the video, making our spaceship "backwards" should still work, otherwise there would be an asymmetry. If the universe isn't truly symmetric, another way to tell would be to simply make the spaceship, and when it doesn't work, try the other way.

@Mernom

Жыл бұрын

@@staylor5990 the first point is not really true, since the void of space is almost completely empty, but the second is VERY true. There shouldn't be a difference between a positronic and electronic circuit. Not even starting to consider that a positronic circuit would destroy itself due to the reaction between the positrons flowing and the electrons of the wires.

The direction of force at 8:00 is wrong. Since q is negative and electron is moving to the right, the q*v product actually points to the left, so the index finger should point to the left and the resulting magnetic force should point away from the audience.

@cefarix

Жыл бұрын

Additionally, if we adopt a positive sign convention for the electron then the magnetic field switches directions and this preserves the correct behavior of the electron moving away from the viewer.

@miodragilic4427

Жыл бұрын

True. The animation would have been right if the charge was positive.

Thank you, Matt and the team for a very interesting episode! 😊

Can't wait to see what you guys do in the future. Thanks for everything

What a coincidence. I was just reading Freudenthal's _"Lincos: Design of a Language for Cosmic Intercourse"._ Which is basically a proposed language for communicating with intelligent alien life, founded upon mathematics and logic. An interesting read- perhaps you guys could do a video on Lincos sometime? 😇

@Mohammad__M__

Жыл бұрын

Good idea for acquiring FLT- compatible genes 👍

@limiv5272

Жыл бұрын

Sounds like an idea for a linguistics channel

Thank you for making science accessible to people like me :) I’m genuinely grateful 🙏🏼⭐️✨

You could also connect an alien battery to a human battery in parallel and series and check voltaje to deduce nomenclature

If we are trying to decipher alien spaceships blueprints, we will run into a bigger problem : what units are they using ? After all, all base measurement units are essentially arbitrary. If they didn't supply some kind of comparison scale we can recognise, we're essentially screwed

@jsl151850b

Жыл бұрын

Maybe the warpship plans should be preceded with something simpler. Something that only works with electrons and something that only works with positrons so we see the difference.

@limiv5272

Жыл бұрын

If they can relay equations and schematics, I think they can relay the information for defining units. Mols would be very simple to explain to an alien and in the recent past we've changed the definitions of some units so that they're based on physical properties and not on a comparison to a specific object. If aliens also define their units in this way I don't think it would be much of a problem.

@gandolph999

Жыл бұрын

Light wavelengths.

Enjoyed the video ✅ Awesome clear explanations ✅ Made attempt to understand ✅ Actually understand anything ❌ Amazing content, please keep it up 👍🏼

@frun

Жыл бұрын

👍

If failure means planetary destruction, could we maybe fund a scientific station on Ganymede? To do this dangerous research?

@murasaki848

Жыл бұрын

Unfortunately the transit time puts it beyond the election cycle, so nobody wants to get the blame for blowing up the budget yet giving their successor the ability to take credit for the achievement when it happens.

@Booga300

Жыл бұрын

@@murasaki848 I guess on the bright side, if there's no Earth left, then there's nobody left to claim credit for your work.

@1776_Reasons

Жыл бұрын

And no one to blame you for it.

@BENCMEN

Жыл бұрын

So good, Sir, so good...

@Miranox2

Жыл бұрын

@@Booga300 Sounds like a win-win to me!

Creative fun exploration of chirality and matter vs. anti-matter!

Yeah, Feynman with through all of this in the Messenger Lectures back at Cornell in the 1960's. Got a good chuckle from the kids in the audience when he said that if the alien you were just meeting reached out his left hand to shake hands, RUN!

It seems, that if the aliens describe radioactive decay and fusion, we could figure out what their convention for charge is, when we figure out their charge assigment of hydrogen cores, hydrogen shells, beta decay and decay routes with positron emission. Edit: And if they live in an anti matter pocket of space and know interstellar travel, its safe to asume, that they know this too and tell us, so we know to flip the signs.

@NullHand

Жыл бұрын

What if the alien transmission came from a distant region of the universe that had a slight anti-matter abundance instead of matter abundance?

@SleepyHarryZzz

Жыл бұрын

@@NullHand then instead of being embarrassed when we arrive, we'd just annihilate.

@aaronlincoln4836

Жыл бұрын

Are there anti-photons? If so, would we be able to detect their communication at all?

@Laff700

Жыл бұрын

@@aaronlincoln4836 Nope.

@happyman6102

Жыл бұрын

@@SleepyHarryZzz We'd make light of the situation? *ducks*

I guess the real danger would be that aliens use a completely different set of properties and equations that achieve the same final result as our own but are completely incomparable. For that matter they might not even do math the same way.

@songcramp66

Жыл бұрын

Computers don't do math the same way we do but it can be translated. I suppose if they don't use concepts like multiplication and division that would be more challenging.

@farfa2937

Жыл бұрын

@@songcramp66 True, but computers are made up by us too. It’d be a different story if they just appeared.

@zharul8716

Жыл бұрын

Their constant might be different from us

phheww this one is a doozy! Most PBS Space Time videos are pretty deep and advanced but this one is one a whole new level

I could spend your two weeks off just watching this video on repeat and I still wouldn't really get it, lol. Great job guys, this channel is horrendously underrated.

Decoding alien physics would be a great premise for a science fiction novel. It would be interesting if they used different concepts than we do to describe the same reality. I'm not sure how that would work. Maybe the rotation of electric/magnetic charges in Maxwell's equations or how Lagrangians/Hamiltonians transformed classical mechanics could be a model.

@spacechecker4983

Жыл бұрын

Isn't that what happened in Carl Sagan's novel "Contact"?

Potentially ignorant question here, but if the alien civilization's equations around entropy describe energy becoming more or less ordered over their time, wouldn't that neatly describe our orientation to their arrow of time?

@tribunealpha1059

Жыл бұрын

Unfortunately, entropy is an emergent property, something that only appears as a product of individual particle interactions. This means 'order' and 'chaos' are both mathematically identical, since particles act the same in either situation. Thus, there isn't an equation to describe chaos and order at the ground(simplest, particle to particle) level. It only shows up in complex systems such as temperature, which needs time to be determined. So, you need time direction to find time direction, and we're back where we started. (Not sure I'm totally accurate, but that is my understanding of the issue)

@DrWhom

Жыл бұрын

@@tribunealpha1059 No, you're not being accurate, not at all, but you don't seem to be dumb so you will find your way to good books and deeper understanding...

@gogauze

Жыл бұрын

@@DrWhom may I ask, if their explanation was inaccurate, if my question was somewhat correct based on my limited understanding?

@I_SuperHiro_I

Жыл бұрын

How would that help though?

@johannesh7610

Жыл бұрын

Yes, and they can also tell us which one of matter/antimatter (in their terminology) is more abundant. However, they could (theoretically and only for sake of the argument) live in a patch of the universe where e tropic time is reverse and/or antimatter is abundant...

I feel like a LOT of work was put into this episode

i just cannot get over the upside down space ship thing i am dying laughing about that whole scenario

If you have a description of the elementary particles, and assuming the aliens do not live in an anti-matter pocket of the universe, wouldn't including a description of the hydrogen atom provide an absolute charge definition?

@kittythepet485

Жыл бұрын

Also curious along these lines; seems like there would be a way to differentiate protons, found in nuclei, from orbiting electrons, and arbitrate charge based on this natural phenomenon.

@karimfrempong1996

Жыл бұрын

Yes a description of hydrogen would suffice if you know that they are made of matter, but if the entire planet is staked you might consider to double check your assumptions ;)

@JohnDoe-qz1ql

Жыл бұрын

If they can build faster than light travel, I'm Quite sure that finding common scientific ground would be trivial.

At 5:40, there's a mistake in the animation: The electrons/positrons should change sign as the graphic changes color to visually imply charge conjugation. As for the video content: I feel like there should be a thermodynamics way out of the problem of deciphering the aliens' direction of time. After all, Cosmic Microwave Brownies don't start as baked delicious treats and end as uncracked green eggs and purple sugar!

The latest few episodes have been a bit philosophical; loving it!

Very interesting, followed what I could. Did dawn on me that the film “Contact” would have been a completely different film if we considered all of these points.

If the aliens had a similar realization, that decoding all of their own arbitrary conventions is impossible given just the equations, are there any trivial experiments they could also include descriptions of in the data which might reveal the alien's choice of conventions? This is naturally based on the assumption that their understanding of... i guess information theory?... is at least as advanced as ours is. Knowing physics does not necessarily mean that they would have realized their own linguistic assumptions.

@ExternusArmy

Жыл бұрын

Why couldn’t you use objective standards that are broken down by fundamental constants? Speed of light, decay rates of radioactive particles. Something like CPT symmetry should be universally understood by these people.

@heaslyben

Жыл бұрын

That's so interesting! I was thinking along a similar line, like could the data include smaller test cases to validate assumptions like these, before getting to the level of planetary destruction. But yeah, wow, physics and self awareness and reflection seem like not the same thing. What unchecked assumptions did we encode in the Voyager records! Hopefully only silly, endearing ones, and nothing dangerous. Play the record backwards, it's still the same information, right?

@elliewinn1162

Жыл бұрын

@@heaslyben oh no, if they play the record backwards all they are gonna hear is the hidden Satanic messages! Or was that Led Zeppelin, I forget… More seriously, I was wondering that too! I suppose we will just have to wait for aliens to answer to find out!

@person8064

Жыл бұрын

@@ExternusArmy how do you know CPT is true? What if aliens discovered physics that contradict our own?

Can you imagine, construct or simulate a universe with totally different laws of physics? How far can you go with that, can you make the unimaginable?

when I read the title, I was hoping for a discussion about universal computability, universality of heuristics and cross-heuristic translatability - ie. whether we could ever understand technology built by minds completely alien to ours, except by simulating everything/testing distinct (random) global configurations...

@Manj_J

2 ай бұрын

Same!

Awesome Video. I wonder if there are any other choices that might not be truly arbitrary but difficult to decode, like if they represent things in a logarithmic scale or other conventions like that

I love this channel! Thank you Matt and all invloved!

Could doing physics/mathematics in an "unconventional" (other arbitrary assumptions) way help us make more discoveries? The human mind is susceptible to biases, maybe this could help aleviate them and make us think differently about problems.

My head just exploded. Especially when the brownies arrived. Thanks for the excellent description.

its funny how an alien, probably in our own galaxy or local group, is making this exact video on their version of youtube

I've heard recently quite interesting way of looking at U(1) symmetry of E&M that connects parity and charge symmetry. You can think about U(1) symmetry as the universe not caring what you define to be particle and antiparticle and you can freely interchange or rotate their definitions as long as they are perpendicular states.

@taw3e8

Жыл бұрын

@@hyperduality2838 i feel like the word "duality" has a different meaning in each of these examples And i actually have strong objections to some of them, like "duality" of space and time for example. What does the duality mean here exactly?

@taw3e8

Жыл бұрын

​@@hyperduality2838 what You are saying feels more like philosophy rather than physics... but to be honest i really don't understand what You are saying, maybe You could try to explain exactly what You mean by "space duality" let's start here maybe: what exactly (mathematically) do You mean by "Left is dual to right", what is the mathematical meaning of "left", "right" and "dual" here? I've never seen anyone talk about "left" and "right" in GR

@taw3e8

Жыл бұрын

​@@hyperduality2838 Ok, what do we get from that? Why would you introduce notion of "left" and "right" to General Relativity?

@taw3e8

Жыл бұрын

@@hyperduality2838 It's going nowhere... Notion of "duality" has a precise and quite deep meaning in physics and mathematics. You can't just say left is dual to right, it simply doesn't mean anythin.

@taw3e8

Жыл бұрын

@@hyperduality2838 Are You studying something? How old are You?

If getting one of these symmetries wrong leads to disaster, that can only happen through symmetry breaking and we can notice. If there is no symmetry breaking then which we use is, by definition, irrelevant… Until we activate the device and send our matter probe to their antimatter landing site, and they interpret that as an attack.

@TlalocTemporal

Жыл бұрын

Anti-solar wind would've melted any normal matter long before landing.

@danielrhouck

Жыл бұрын

@@TlalocTemporal I thought they were sending us the specs for a teleportation device

@TlalocTemporal

Жыл бұрын

@@danielrhouck -- Oh, you mean a teleportation *station.* I was thinking a teleportation drive, with a whole ship attached. Even if both parties were the same kind of matter, we don't know if the atmosphere is able to support earth life, or if there are dangerous microorganisms to contend with. Best to bring our own hardware before landing.

@danielrhouck

Жыл бұрын

@@TlalocTemporal I was thinking a station-to-station teleporter, although maybe one big enough for a ship. But yeah if itʼs not on the surface, anti-solar wind would be bad *but it would still mean sending a several kiloton anti-anti-matter bomb to their system*, which looks like an attack even if everythingʼs set up so it doesnʼt damage them.

@TlalocTemporal

Жыл бұрын

@@danielrhouck -- I'd say 50-50% on it looking like an attack in both cases. Assuming no communication other than the blueprints, they would see nothing but explosions, with no message or follow up. Unfortunate if the receiving station was near something important, but surely first contact using new tech should expect everything to explode at least once. Active communication would likely lower the chances of such a RUD being interpreted as an attack, for having no motive or indication. However, I could see a shaky first contact (significant cultural differences perhaps) making an attack seem more likely. That's assuming of course the nature of the explosion wasn't immediately apparent.

This is an amazing episode, and the first one to make me think enough to ask a question: If the aliens had a reverse time convention AND at the same time we managed to decode enough information to reach the consideration of CP symmetry, would it not already be implied the time convention is the same? If it were indeed backwards how did we decode anything in the first place? Is it already assumed that the encoding used is absolute and the information is fully available at time of receipt? Perhaps through a form of quantum entanglement "ansible"...

Love this channel. Thank you for providing it!

On one hand, I want to think of the hypothetical "instruction manual" as essentially a Rosetta stone to being able to "translate" through the technology because we are essentially measuring the same thing. Unfortunately, all I can really see is, "Quick! We need a linguist to help us understand this alien language!" "We don't have one! We got rid of anything that wasn't STEM!"

@jaimejose8708

Жыл бұрын

Lol laughed harder than I should have. Thank you!

@definitlynotbenlente7671

4 ай бұрын

What is a linguist goeing to do ? Also STEM is the best

Amazing as always. Thank you!

Easily one of the best videos of this channel GJ!

Interesting way to explain complex physics, well done mate

For some really weird reason, I like the answer of No. Not just 'so advanced it seems like magic to us,' but more 'once you go down a certain pathway, you can't back-track and you end up with vastly different results.' Even if one species tries to 'fill in the gap' by presenting their side of the tree, it just doesn't compute once the other species have specialized into a different branch. Certain parts of the universe will always be unknowable to us, and there is a sort of beauty in that.... Oh, and the Fermi Paradox? What species choses Radio over Flog?!

(8:37) Today on Space Time, electromagnetism flipped off Matt. Physics is getting pretty out of control on this channel! 😉 I love it! 😎🤘☮️

Amazing episode! So cleverly done.

Live , love and mesmerised by the magnificents of universe it's laws

Wouldnt the definition of the flow of time be "Occam's Razor' d" to ever increasing entropy? As that is what fundamentally determines that the past was different from the present, and the future is guaranteed to be different than the past? Therefore being part of the same universe we could just accept that they have to use the same fundamental definition of the flow of time?

@lexguttman

Жыл бұрын

@pyropulse Im not talking about the laws of physics. The laws of physics are our model of reality. I was referring to reality. Reality is not time reversible. Unless of course you have a time machine hidden in your basement you've been hiding from everyone.

@nmarbletoe8210

Жыл бұрын

@@lexguttman the aliens could show on the blueprint how the machine is connected to the big bang. that could give a page on the blueprint a time direction. they could also diagram a CP violating process and this would orient the page ?

This video seems to go through a lot of extra steps to define things when it'd be easier to just relate terms to what actually occurs in the universe. Define matter and anti-matter by showing that matter is a lot more abundant than anti-matter. Define charge by showing the negative election surrounding an atom's nucleus has a lot less mass than the positive proton in the center.

@sion8

Жыл бұрын

He was talking about a positron, not a proton.

@KenMathis1

Жыл бұрын

@@sion8 He was talking about the definition of a charge and matter/anti-matter. The point being made was that you couldn't easily tell if it were electrons or positrons flowing in an alien schematic. However you could easily tell, because if they were positions, then the whole thing would be our definition of anti-matter. That in turn would mean that it'd explode with the force of E=MC^2 if the built device existed and tried to interact with matter. That's be _really_ hard to miss.

@limiv5272

Жыл бұрын

@@KenMathis1 Hmm could an antimatter solar system exist without being annihilated long enough for a technological civilization to evolve in it? The solar wind pushes back the interstellar medium right? that pushing back might be very explosive, but would it be enough to allow the solar system to survive?

@KenMathis1

Жыл бұрын

@@limiv5272 There are two reasons why we wouldn't unknowingly receive a signal from an antimatter solar system. The first is that it's extremely unlikely that an antimatter solar system could form in the Milky Way made of matter. Nothing would cause the antimatter to lump up. It'd be evenly distributed throughout the galaxy. The second reason is because all the inadvertent antimatter/matter reactions would be producing a heavy stream of gamma-rays that we'd detect along with the signal they sent us. So if we don't see those gamma-rays, we can be sure the signal isn't coming from a pure anti-matter solar system.

@limiv5272

Жыл бұрын

@@KenMathis1 1. I agree that it's very unlikely, I just want to consider the idea for fun 2. Why gamma rays? And why would their transmission, which presumably is made of normal EM radiation, create them? There's no anti-photon, right?

Very clever way of allowing understanding, you are a great mind and orator, I always see the multiverse visualized as multiple versions of a singular world. For symmetry, it feels more right to me that we have multiple versions of the sister-verse or mirror-verse, somehow there are two universes simultaneously coexisting, each universe the exact opposite even down to the flow of time.

I'm quite proud of myself for realizing this was heading towards CPT symmetry before it actually got there. Shows I'm actually learning something from all these physics videos after all.

Isn't this assuming that the complete picture of physics (at least as far at the aliens know) contains the exact same symmetry? What if the aliens had discovered that CPT symmetry was broken and that there was no fundamental symmetry of the universe?

It's funny to think an advanced alien civilization could beam the data for a "starship" for FTL but it actually just makes a black hole and destroys the planet

@nmarbletoe8210

Жыл бұрын

and then we see that the entire planet was transported FTL to the alien star system for a visit with lunch, ambassadors, and tea

This guy is clearly on another level, cant believe i just found about this channel a couple weeks ago... Edit: This guy is the new Richard Feynman

Given the relative abundance of matter vs. antimatter, it seems like an atomic diagram could clear up the charge issue pretty easily