Contact Was Wrong - Aliens Can't Hear Us | Answers With Joe

this video is supported by brilliant [Music] can we talk about the opening scene of contact for just a second if you've seen it and i'm sure most of you have seen it then you know what i'm talking about it's this crazy three minute long zoom shot that starts like right outside of planet earth and then zooms all the way out to the edge of the universe and the point of it is just to first of all set up the ridiculous scale of the universe but it also establishes a pretty important plot point that um you know basically explaining how radio waves travel at the speed of light they do this by playing a cacophony of radio noise up close to earth where you can just make out modern music or at least music from 1997 when the film was released and as we draw backwards the radio signals broadcast older and older music and news events until we reach the birth of radio technology and then it fades out completely you know good old robert zemeckis and his sweeping metaphorical opening shots it's a brilliant way of conveying some core concepts that you need to understand what's going on in the movie but there's one thing in it that's always bothered me and it's that they they kind of got the scale off a little bit i know it's nitpicky in a little ndt of me but they show the years passing as we're still moving through the solar system like for example as we're passing by jupiter you hear this okay so bobby kennedy was shot in 1968 the movie was released in 1997 so i guess that means that jupiter is 30 light years away a little inaccurate but i get it if it was accurate we would have been out of the solar system in about five seconds and just been listening to radio waves on a field of stars which is visually boring so yeah i get it it's still a brilliant bit of filmmaking and it really makes you think about you know how far out into space our radio waves have have traveled you know how many how many stars have our radio waves passed and how many planets might be orbiting around those stars and on any of those planets is anyone listening [Music] one location that was featured prominently in the movie contact was the arecibo radio observatory which unfortunately we did lose last year when the instrument panel fell down into the dish down below but maybe it'll come back someday fingers crossed but from its construction in 1969 it did do some great science it was the first scientific instrument to detect a binary pulsar it made a map of venus that showed signs of volcanic resurfacing and it kept track of several near-earth asteroids but what it's probably best known for is seti the search for extraterrestrial intelligence probably partly because it was featured in that capacity in the movie contact in real life arecibo of course received many signals from deep space none of them were of an intelligent origin that that we're aware of but in 1974 arecibo attempted to send a message the other way they modulated the frequency of a radio transmission to encode pictures of dna the stick figure human and arecibo itself among some other stuff that i mentioned in a video from years back it was created by carl sagan and frank drake and it was mostly symbolic they aimed it at a star about 21 000 light years away and in fact the star will have moved by the time the signal reaches there that was intentional but as the opening scene of contact points out we've been unintentionally putting radio waves into outer space for nearly 100 years the first commercial radio station went up in 1920 and we've just kind of been shouting into the void ever since that means there's a radio bubble that we've created a sphere of influence if you will 200 light years wide that's friggin huge just think about all the stars that might be inside that bubble and all the planets and those stars what would that look like turns out it would look like this or well hang on let's move in a little closer there it is that's 200 light years across go us and it makes me think of that scene in titanic when they shoot off the signal flare trying to get help and then they kind of scale it back and you can see that like there's just a tiny little flare in the middle of the vast expanse of the atlantic just kind of like just just nothing it's a weird connection but my brain didn't so sure next to the entire galaxy that's next to nothing but it's not just about distance it's about stellar density there's still plenty of room for stars in a 200 light year bubble there's only one star system within five light years of earth and that's alpha centauri with three stars and at least two planets that we know of expand that out between five and ten light years and eight more systems appear two of these systems are brown dwarf stars and one's a white dwarf counting the sun this gives a total of 15 stars in our 10 light year neighborhood four can be seen with the naked eye to see the others you need a telescope or a good pair of binoculars now it's worth noting that three of the stars on that list are those brown dwarf stars that i was talking about and we didn't even know they were there until between 2011 and 2013 so even nearby stars can be hard to spot and distant stars can be even harder so we have to kind of do an estimate to get a full figure of our radio bubble an estimate by astrophysicist david palmer in 1998 concluded that the bubble contained some 14 600 stars he based it off the stellar density within five parsecs of earth 16.3 light years now he picked five parsecs because the most accurate star catalog that we had at the time only went out that far but of course a lot has changed since 1998. the most up-to-date star catalog we have right now is the gaia catalog of nearby stars and it's accurate up to about 10 parsecs which is 32.6 light years and this catalog suggests there are 464 stars within a tim parsec bubble around earth doing some math it gives a stellar density of 0.11 star per cubic parsec only 1 100th less than palmer came up with so that brings us to an estimate of 13 332 stars within a 100 light year radius of earth now that's nothing to sneeze at for perspective pretty much the most number of stars that you can see with the naked eye is about 4 500 stars so take the most number of stars you could possibly see in the best conditions with the naked eye double it and then add 4 000 stars all inside that tiny little dot pretty crazy so is 13 to 15 000 stars the answer to our question it's part of it i mean that's how many stars our radio transmissions have reached now whether or not there's anybody at those stars listening to us that's that's a whole other set of questions 50 to 75 percent of stars in the milky way are thought to be red dwarfs these are dim k or m class stars at the bottom right of the hertz sprung russell diagram that group stars by brightness and heat to give you some idea of the scale our sun is a g-class star with two to three times the heat and three to thirty times the brightness of a red dwarf so in our thirteen to fifteen thousand stars in our bubble we can expect anywhere from six to eleven thousand of them to be red dwarfs the problem with that is that most of the rocky planets around red dwarf stars have to orbit so close that they become tidally locked which i actually talked about in my eyeball planets video eyeball planets aren't the best candidate for life because that basically means that one side is frozen and the other side is scorched and there's just sort of a ring around a polar orbit of the uh of the planet where liquid water could exist which doesn't totally rule it out there's still a possibility that life could spring up and evolve there but another problem with red dwarfs is that they're highly volatile red dwarfs have a tendency to throw off huge solar flares that could possibly strip off the atmosphere of a nearby planet now this doesn't mean that life couldn't have possibly sprung up on any of those planets i mean how we might even be able to survive on one of those planets but the possibility of it being stable enough for life to evolve to the point of building radios it's not the best bet so right off the bat we have to rule out the vast majority of the vast majority of the stars in our bubble now there are some sun-like stars out there there are some pretty good candidates but before i get to that there is one other major problem we have to contend with this is known as attenuation which is basically the weakening of light and electromagnetic signals as they travel through space now you've probably heard me refer to the inverse square law on this channel or in other places before it basically says that the strength of the light is inversely proportional to the square of the distance from the source put into something resembling plane english the further a light travels from a point source the more it dissipates and the weaker that signal becomes take voyager 1. it's now 14 billion miles away which is about two one thousandth of a light year it's sending a signal back to earth at a power of 22.4 watts and by the time it reaches nasa the signal has a strength of 1 10th of a billion billionth of a watt like it's crazy that they can even detect that and that's only .002 light years away at 100 light years away our signals might be completely indistinguishable from the cosmic microwave background radiation in order for an alien civilization that far away to even detect us it might require a planet-sized dish now of course when you're talking about aliens there's always that magic alien technology that's so far advanced from what we can do that makes it possible for them to do that fair enough but even if the attenuation problem didn't exist there's still the habitability problem so going back to where i was going before how many rocky planets around sun-like stars are there in our hundred mile radius around earth in another paper from last year in 2020 some scientists from seti and nasa calculated the number of rocky planets in the habitable zone of stars that are g k class stars within 32.6 light years away in other words 10 parsecs and their answer drum roll please four [Music] four now if you apply that same density out to about 100 light years away then it comes out to about 115 stars but once you go through the drake equation and ruled out this and rule out that and then you factor in the the fact that you know these stars have been around for billions of years and what are the possibilities that an advanced civilization would evolve in the same 100 year window that we did it's it's not the best of odds now that doesn't mean that nobody out there knows that we're here you know we've discovered plenty of exoplanets and none of that had anything to do with any intelligent signals that might have been coming from those planets we did it mostly using the transit method very briefly the transit method is when you watch a star and notice it dimming on a regular basis that usually means that there's a planet passing in front of it currently what we learned from the transit method is pretty limited we get its size how far away there it is from the star and all that but when the james webb space telescope goes up we're going to be able to see a lot more than that we should be able to determine what's in these planet's atmospheres when a star's light passes through a planet's atmosphere the various elements in the air absorb the light in different ways by splitting that light with a prism we can pinpoint what wavelengths have been blocked and know what elements are present and of course if we find things like oxygen carbon dioxide and methane then we'll have a pretty strong suspicion that that planet could support life and similarly we presume an alien civilization would be able to see us passing in front of the sun and see that there's something interesting happening here meaning there is a band traveling out from our star in 360 degrees where any stars in that band will be able to see the earth transit and maybe determine that there's life here and that even has a name it's the earth transit zone or etz so a recent article in the journal nature put together a figure for the number of stars that are actually inside of our radio bubble and inside the etz the author starts the gaia catalog for targets in the earth transit zone and found 1402 stars in the zone now and 1715 have been there in the last 5 000 years all of these are within 100 parsecs or 32.6 light years of earth and when they restricted the radius to 100 light years they found 75 stars that fit their category now all of these were then again 100 parsecs or 32.6 light years of earth but then once they ran it through all their filters and picked out sun-like stars and you know tried to figure for the ones that could both hear our radio signals and we're in the etz it came out to 46 stars now at the time of this recording none of those 46 stars are known to have a planet but steady telescopes are starting to focus more on those stars so we may see something soon and the first exoplanet host that we know will enter the bubble soon is tea garden star so tea garden star is 12 and a half light years from earth so it's well inside the radio bubble but it is not inside the etz it'll enter the etz in 2050 so maybe by the time that happens they'll be able to pick up our signals from the 2038 winter olympics now tea garden star is yet again a red dwarf but t-garden b and c are both in the habitable zone of that star and are thought to have thick atmospheres now there are three stars that are currently within the earth transit zone but they're not quite inside of our radio bubble they should start hearing our signals around 2159 but if any of those stars have an inhabited planet and a radio dish several times the size of its star it might be able to pick up the giants beating the yankees five games to three in the 1921 world series let's hope they're fans of high pockets kelly now the irony of this whole discussion around radio signals is that we're actually getting a lot quieter in that respect most of our communication is done digitally these days over wires we don't really blast out giant broadcast signals to cross continents like we used to you know double ironically we communicate mostly through satellites these days which means we're actually pumping our signals up into the air but they're only having to go up you know 100 or so kilometers or a little bit more than that they're not meant to cross thousands of miles of land yeah so much communication is done these days over wires and short-range communication that we're actually kind of going quiet after about a hundred years of screaming our lungs out this literal radio silence is one of the explanations that some people have for the fermi paradox like maybe the reason we're not seeing a lot of radio signals bouncing around from other civilizations is because they all move beyond radio you know maybe radio communication is just a short moment in a species evolution after a blip of making a lot of radio noise they just go quiet yeah maybe the solution to the fermi paradox is that the universe got cable so with respect to carl sagan and robert zemeckis the central conceit in contact the idea that our radio signals could be picked up by an alien species and bounced back to us is uh optimistic at best but it does make you think about how little we've actually reached into the universe and how far we have to go of course you don't have to go far into the universe to learn more about it you can do that from the comfort of your chair if you check out the astrophysics course i'm brilliant all right so i've been talking about brilliant for a really long time now and maybe you check them out once upon a time and we're thinking maybe if it was more interactive well guess what it's a lot more interactive now they've actually added a lot more functionality and interactivity to their quizzes which only helps boost the understanding of the concepts involved especially in some of the fundamental courses which sort of set the foundations for everything to come in case you're wondering i do actually refer to brilliant to help me to understand some of the stuff that i do in these videos like for example today i looked at the astrophysics course because there's actually a segment in there all about radio and electromagnetism and and how it travels through space and they make it easy to make learning a habit so you can do it on your mobile device or even offline so whenever you're like waiting for food or something you can bang out a problem or two if you want to get a taste of what i'm talking about they have free daily brain teasers and you can do the first section of any course for free so you can see what they're all about but if you do sign up for the premium subscription that gives you access to all their courses and you're one of the first 200 to do so you can get 20 off if you go to brilliant.org answers with joe it's just a really cool way to learn things and like i said they've added a whole lot of stuff so if you haven't checked it out lately i definitely suggest you go check it out it's brilliant.org slice answers with joe links down in the description all right big thanks to brilliant for supporting this video and a huge shout out to the answer files on patreon and the channel members on youtube that are supporting and helping to grow things and being really just forming an awesome community they're cool people i got some names i need to murder real quick so these are some members that signed up recently we got pieter bonne uh julian robert leckado nailing it already elizabeth wagner alexethia waterworld vivek ramesh jessica joseph stokes tobias tomila daniel irmagren kevin g barks sawyer mirage rosalie abel christina rose nemo such developments aaron jones sean patrick thompson dharma hetherington and lilith esme thank you guys so much if you would like to join them and get early access to videos get little cool uh avatars by your name and stuff so you stand out from other people uh just click the little join button down below please do like and share this video if you liked it and if this is your first time here google thinks this one's right up your alley so you might want to check that out we got several other on the side with my face on the thumbnails and if you enjoy them and you want to see more i invite you to subscribe i do come back with videos every monday and i think that's it for now thanks you guys for watching go out there and have an eye opening rest of the week and i'll see you next monday love you guys take care

Channel: Joe Scott

Views: 914,229

Keywords: answers with joe, joe scott, Carl Sagan, Aliens, Contact, Radio

Id: ISXbTBKl4aE

Length: 16min 16sec (976 seconds)

Published: Mon Jul 26 2021

Reddit Comments

[u/delete_this_post]

The title of the video is click bait.

That's not to say that the video isn't interesting. But he states that "Contact was wrong" and then proceeds to explain why it's unlikely that there's an alien civilization close enough to Earth to have received our radio transmissions, while ignoring that: a) Vega is close enough to satisfy most of his own criteria (he doesn't even mention Vega), and b) that the aliens in the film didn't actually live in the Vega system.

His point about the attenuation of radio transmissions is perfectly valid. And yes, through suspension of disbelief we do have to hand-wave away the problem of attenuation by supposing that aliens capable of building wormhole machines would also be capable of receiving extremely faint radio signals.

But the title of the video is still click bait. Asserting that Contact was wrong was just an excuse to talk about other stuff, and there's probably less disingenuous ways to do that.

[u/Seanspeed]

People are just gonna mindlessly downvote this cuz of the title.

But it's really not clickbait and Joe does great videos.

This should be up most everybody's alley here and is an interesting video, but of course being reactionary is the order of the day.