What If Alien Life Were Silicon-Based?

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Life as we know it is carbon-based, but does it have to be this way? There’s another element on the periodic table that shares some of the key properties of carbon but is far more abundant on most planets. I’m talking about silicon. So is there silicon-based life out there?
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What If Alien Life Were Silicon-Based?

[@pbsspacetime]

For clarity: estimates for diatom oxygen production mentioned at 13:36 range from 20%-50% on an annual basis. If there’s any specialists in the audience who could provide greater clarity about diatoms and oxygen production, please reply to this comment!

[@larry785]

Humans are oil-based. We eat oil, we drink oil, we burn oil, we put oil on our skin, on our food...

[@osmosisjones4912]

Ben 10 aliens were carbon based

[@osmosisjones4912]

So conditions without water 💦 mite have life

[@Erik-pu4mj]

@@osmosisjones4912 Excitement aside, spamming may not be the best method for getting anyone's attention.

[@NikitkaDreamer]

2:23 yeah... that's trinitrotoluene

[@Cholm]

This reminds me of a rare event in the game Stellaris where you find a cavern full of buildings and extremely detailed statues deep within a planet. After researching deeper, turns out the civilization wasn't long extinct, but instead was Si based, and when you broke through the cavern wall, the chamber flooded the area with O2, it turned them all into stone. Kinda scifi and quite a grim discovery, but a pretty cool storyline!

[@BenWard29]

@@RossiGastone You mean flat earth nonsense? I've seen it- there's nothing but speculation and misunderstanding to it. There is no evidence for a silicon age.

[@aelolul]

@@RossiGastone "documentary" lol

[@Plaitonic]

That sounds like a cool game

[@imveryangryitsnotbutter]

Oh god, now I'm imagining benign alien archaeologists visiting Earth, thinking that there must be no life because nothing could possibly survive our nitrogen-rich atmosphere, and proceeding to burn away all our breathable air so they can go down and explore.

[@thirdeye4654]

Now I want to play Stellaris again, I didn't come across this event.

[@miguelarribas9990]

In a distant planet in a distant galaxy, a silicon based TV host explains if carbon could be the basic building block for life in a strange world, since it is so simmilar to silicon.

[@kevinroberts1052]

Which also has a comments section mirroring ours talking about Silicon Based life. Making the readers laugh and click over a 100 thumb ups.

[@larryblake842]

Wondering what they eat, how they breathe and how they develop. Calling the people who believe carbon based live exists crazies and outsiders

[@crywolf826]

Brings up a point that carbon is highly likely building blocks but that would require some liquid built out of possibly hydrogen-oxygen liquids such as h2o which we know is highly destructive on our planet xD

[@luisgurumendy5561]

They possibly consume elements of what they are made of, like other living beings made of silicon, or they may even have stomachs that can digest some rocks or minerals and extract the silicon.@@larryblake842

[@youriricher1123]

- "But how does life could exist with water, water is so....soft, and clear !" *Takes a sip of sulfuric coffee*

[@ellanv]

One interesting variation is the horseshoe crabs and other crustaceans (lobster?) which use copper instead or iron to carry oxygen around their bodies. Aliens are more likely to be little blue men rather than green. This could hint that if silicon-based life had ever evolved, some could have survived, maybe in critters like the flying spaghetti monster.

[@thatsclownshit3145]

omg like jaadu

[@Optable]

This comment made me ponder those *green men* and copper. What happens as copper ages? And oxidizes? Maybe these dudes just have *a wicked patina.*

[@WaterspoutsOfTheDeep]

Nothing evolved, evolution isn't real. Mindless matter and mutation can't manifest code. Evolution is a mythology of magic(rationality from irrationality).

[@PaulBrower-qr8hf]

@@Optable Copper salts are mostly in the blue-to-green range.

[@Manj_J]

@@thatsclownshit3145 Jaadu!! I love him, nice to see someone else who watched Koi Mil Gaya here!

[@roypiltdown5083]

about 50 years ago Isaac Asimov (the sci-fi author, yes, but also a professor of biochemistry) wrote a series of essays on this very subject, starting with why carbon was the only option for Life As We Know It (i think the title was "The One And Only") and carrying on with various options for the life-giving solvent (methane, ammonia, etc) - well worth the read if you can find them these days.

[@paulsmart4672]

I was recently trying to find some serious speculation on how ammonia-solvent life might work and couldn't really find any. I need to remember to look for this essay.

[@mandiemoore3272]

You're awesome you're my favorite person today

[@roypiltdown5083]

@@mandiemoore3272 it was published in a collection called "The Tragedy of the Moon" in 1973 - an excellent book, and available online.

[@poutinegraphics2017]

And Asimov was famously opposed to introducing aliens in his novels

[@1Chitus]

“It’s … sand. It’s coarse and rough. And it gets everywhere” A man of culture indeed.

[@joaocalhandro]

I wonder who's evil... from his point of view, of course.

[@TheFrostyboiz]

@@joaocalhandro from my point of view carbon based life forms are evil. theyre course and rough and gets every where... I hate carbon based lifeforms

[@snaffu1]

I had to pause the video and have a good chuckle. Cheers Mr O'Dowd!

[@davecai999]

Dune? Oh, it came back to me -- Anakin to Padme.

[@zal119]

The fact he kinda resembles an older looking Hayden Christensen makes this even better.

[@NotreDanish]

The reason why arsenic is toxic is actually fascinating, I’ve never heard that anywhere before and I took a lot of science courses and been watching channels like this for a large portion of my life now

[@NotreDanish]

Also what if silicon aliens don’t exhale silicon dioxide but instead excrete the silica sand? That sounds like an interesting story about humans meeting an alien that could give us extreme quantities of a material we use for a LOT of things.

[@TheShadowwrend]

You build your houses out of our WHAT?! - Silicon based aliens, probably

[@bennyaction]

@@NotreDanish If the energy is derived from separating oxygen from silicon, they could "exhale" oxygen immediately and let the sand build up in a bladder-like organ, and yeah as you say poop it out later leaving sparkly piles of sand

[@dipolifom]

Sand pooping worms, anyone?🙄 almost like Dune, maybe the Emperor is ruling some planet right now

[@jamesmnguyen]

@@TheShadowwrend More like, "You make your computers out of what?!"

[@freda5344]

Dendrocnide excelsa - stinging tree, the hairs on the leaf are silica based and so small, even a slight brush of skin along the leaf, the hairs will just penetrate, and will give you an indelible pain and rash, until your body eventually replaces that skin. I love pointing out this tree when with friends and come across it in nsw bush, its just a remarkable piece of evolution,one of very few biology on our planet that uses silicon, and yes something has evolved to eat those leaves! There is a beetle, that has long legs and so can walk on the leaves with impunity. Just amazing.

[@stiffyo6068]

When dealing with stuff of this nature, the answer is always "yes it is possible". The real question is what's probable.

[@painpeko8805]

This is an exceptional video. I studied biochemistry and the way you built up an understanding of what it takes for life to happen while making it accessible to the general public was just fantastic. Love this channel.

[@ebubekiraka4595]

A pharmacist here. Loved it!

[@boahnation9932]

@@ebubekiraka4595 thank you for doing such a crucial job and keeping us all alive and healthy 😁

[@willo7734]

yes, this one was amazing.

[@TheCynicalPhilosopher]

Also a biochemist. This video made me feel seen.

[@aloysiusdevadanderabercrombie8]

As a chemist who specializes in ochem, I wholeheartedly agree. It's also sort of funny knowing now how physicists probably feel watching this channel.

[@alt8791]

I am now convinced that the Sandworms from Dune are silicon-based. Their aversion to water and huge production of sand seem to align with being silicon based.

[@LimeyLassen]

Yeah, I remember that being a plot point from the book, that terraforming the planet would liberate the natives but would be the end of the worms

[@FreakazoidRobots]

They produce a kind of "sand" too.

[@joshlasky8138]

The sandworms are just trying to keep kids off spice...

[@Boris_Chang]

Just say Doh

[@blasted_dre]

They didn't "produce sand". They produce spice from the sand. The problem with making Arrakis a blue planet is it'll kill the baby worms and won't allow bigger ones to come to be. Everyone in the Galaxy is addicted to spice by this point and once you consume spice, you have to keep consuming, or you'll die

[@hegemonersmith1048]

The chemical structure shown in the graphic at around 2.24 is TNT, not nitroglycerine.

[@erice.3468]

Alan Dean Foster wrote a great story titled "Sentenced To Prism". It explored and did a nice job of describing silicate life and its interactions with carbon life.

[@Thomas.Wright]

"Sand is course and rough, and gets everywhere." You, sir, HAVE THE HIGH GROUND.

[@itisALWAYSR.A.]

Another facet of Matt's Australian extraction, no doubt 👀

[@memopinzon]

Truly one of the quotes of all time. Bravo Lucas.

[@Kwauhn.]

If he's saying he doesn't like sand, wouldn't he technically be the one with the low ground?

[@Sonny_McMacsson]

@@Kwauhn. Yes, mountains are rock. Valleys are where the sand accumulates.

[@jackdare]

He was sooo lucky she had no experience with dating! 🤖

[@HassanGaba1]

This topic has been done to death by other KZbinrs, but PBS Space Time has really shown how to properly address this topic, bravo!

[@MrJojoholmes]

Isaac Arthur's version was just as good

[@RossiGastone]

I prefer the "There are no forests on Earth" version.

[@samuela-aegisdottir]

@@RossiGastone I did not know that and googled it and found out it is a part of the Flat Earth theory. It is fascinating how crazy people can be.

[@xenuno]

@@yttrxstein4192 You kidding me? Bonehead to Spock "Now you're telling fantasies. Silicon based life is impossible". Devil in the Dark was 25th episode of Season 1. There were events in the 24 episodes before it that broke laws of physics and chemistry with the incompetent one there to witness. Kelly got the worst lines of any major character on the show, other than Sulu (but he really isn't a major char). All in all, while only a few episodes are total disasters scriptwise (That Which Survives, Obsession), not one of the rest didn't have moments of rather illogical, terribly written script ..

[@xenuno]

@@yttrxstein4192 Yur latest reply didn't make it past the censors baby boy. Try another tantrum maybe a bit toned down?

[@edvinasorentas6939]

2:27 the molecule shown is not nitroglycerin, it's trinitrotoluene (TNT)

[@eltonbinlibin4852]

Meanwhile in other planet's youtube, "What if alien life were carbon-based"

[@marilynwasserman3273]

Thank you, Matt, for all you do for PBS Space Time! At 83 years old I'm too old to do a lot of things, but never too old to listen and learn!! You're the best!

[@voodoodolll]

You're amazing!

[@Loveshisfamily]

83 years young

[@k.hassiba6426]

amazing. you are the best too.

[@ellianadailey]

It makes me so happy to see you still want to learn. You are a role model for those your age 🤍

[@ChemEDan]

@@ellianadailey All of us!

[@vgernyc]

Fun Fact: Xenomorphs also use Fluorine in their blood which is powerful enough to break down Si-O bonds but also Si-F bonds are not as stable. Possibly the source of their acidic blood.

[@crusherolies8195]

well first as the video explained, silicon life aint gonna happen, secondly the beings dumping their DNA on worlds to kickstart them also kickstarted us with their DNA. the xenomorphs come from the same DNA the first race has so they shouldnt even be this fantasy monster of silicon life. and you need to keep in mind they didnt know this stuff yet when the first couple alien movies came out. so the silicon life fantasy was still a possibility back then. to prove this point even futher how can there be aliens of a completely different chemical makeup that magically somehow merge with ripley dna to make the half human xenomorph in the 4th alien film. there are animals that have acid attacks on earth so we dont need to make up silicon life to have beings who have acidic chemicals in their bodies.

[@tomizatko3138]

oxygen would be very deadly to them that for sure.

[@dhayes5143]

Was that a post-hoc explanation or is that actually included in the first movie?

[@lantrick]

That certainly isn't an actual fact.

[@mojeimja]

@@tomizatko3138 they surely didnt care in the movies

[@tugbatok9008]

Apart from all the great content, your style evolution is fantastic, Matt. You look so good in your new videos compared to older ones.

[@JAKOB1977]

Completely forgot how good some of the videos from SpaceTime actually is. I could watch this all day..pure braincandy,

[@jso6790]

"Life is an ongoing chemical reaction" is perhaps one of the cooler scientific descriptions of life that I have heard in a while.

[@Pheonixco]

Yep, you're part of an ongoing chemical reaction that started around 4 billion years ago.

[@cypherusuh]

I also learned that even our "feeling" is just chemical reaction in our brain, hence why it's possible to temporarily fixed mental problem by using medicine

[@MadScientist267]

You're a self aware self improving chemical reaction capable of making more that all do the same thing. That said this is no kind of new revelation.

[@MadScientist267]

@@cypherusuh *electrochemical

[@TimPerfetto]

@@MadScientist267 What if alien life were silicon based?

[@ricardoludwig4787]

I think an underrated aspect of carbon chemistry is the fact that you need really exoteric conditions to get a carbon making more than 4 bonds. That's useful because a lot of how organic chemistry works relies on the consestency of 1 bond being received meaning another one is broken, which is especially important for enzymes. The fact that silicon can much more easily be coaxed into making more than 4 bonds make these chains either far more complex or far mor limited. Also, silicon can hold a charge much better which has its ups and downs

[@uncleal]

Esoteric? Sn2 displacements go through five-coordinate carbon.Six cordinate carbon, and no metals involved, DOI 10.1002/anie.201608795; Pyramidal C6(CH3)6(2+) "8^>)

[@ItzDanielTheGhost]

@@unclealhello can I hav a chat with you

[@equidistanthoneyjoy7600]

More like has its positives and negatives, amirite?

[@tomlxyz]

But silicone can't make as many different combination of molecules

[@bamboobridge-of8yd]

​@@unclealtrue.. now put this molecule adrift and isolated in a planet, how long does it take for it to decay and how long till the next time it forms spontaneously again... just this is already improbable to happen frequently enough to even give opportunity for it to increase in complexity in comparison to silicon based compounds

[@crusade3802]

I thought the title said Sicilian based and was so ready for that

[@jameskirk4692]

Thank you! Very educative episode which I could understand more than usual. 😊

[@darknight991]

“It’s … sand. It’s coarse and rough. And it gets everywhere” 😂 A man of culture indeed.

[@ho-ko]

"I hate it" launched my sides into orbit

[@drgn1290]

I loved that comment!

[@seilaoquemvc2]

I laughed my ass off when he said it.

[@hweidigiv]

"it", not "it's"

[@darknight991]

@@hweidigiv incorrect. “It sand”? That’s grammatically wrong and also not what he said.

[@christiannorf1680]

As a chemist I first thought "Oh no, not this again". But you made really really good video explaining why Si based life is highly unlikely. Good job!

[@entropybear5847]

You must be new around here, welcome! PBS-ST is a pretty solid science channel.

[@olejnik5165]

The vastness of space and numbers make it kinda likely

[@falnica]

I get the feeling the writer thought to himself "how do I take a topic that has been done to death and add something new to it?". Like the part about why Arsenic is toxic, and the Diatoms! I had never seen them mentioned when talking about silicon life

[@RealPesto]

Highly unlikely, maybe on Earth, yes. Give it 100 billion galaxies in the seeable universe, which in turn includes 100 billions of stars, which we now recently have found that most if not all has planetary bodies circling it, then take into account that even our own solar system has a planet like Venus and moons like Titan. Then give it a few billion years to evolve on those planets that are VERY likely to exist, and presto.. It becomes (edit) not impossible at least (since people have such a big gripe against the word likely)

[@JLchevz]

did you really think Matt was gonna just clickbait us with shitty info lmao

[@bigbobt45]

I could listen to this guy all day, he explains things exceptionally well, only just found out what his name was, Matt O'Dowd, well done your documentary's are outstanding.

[@Smoke_Cloud]

When I was a kid, learning this stuff felt like a chore in school. Now it's just really interesting. I'm glad things like this channel exist so I can still learn even though I missed my chance in school.

[@CircuitrinosOfficial]

The way schools are operated isn't good for promoting the will to learn. Unfortunately.

[@deepblue812]

pretty sure a high school physics class would just be better off going through the SpaceTIme playlists

[@Trollogrefey]

My dad and I concluded separately on a phrase we both love to repeat, "History is a fascinating subject only when you're not learning it for a grade." This can apply to any subject and is overall true in my experience. Love history but it's easily my most hated university subject.

[@dangerfly]

Perhaps actual learning feels like a chore because it requires work. Passively watching a video doesn't create working knowledge because there's no manipulation/use of the knowledge. Also, when we're older we have a much larger store of experiences (sci-fi movies etc) that we can cross reference to create meaning from the abstract.

[@waff6ix]

I LEARNED SO MUCH MORE FROM YT THAN I EVER DID IN COLLEGE💯YT UNIVERSITY IS THE NEW IVY LEAGUE😮‍💨

[@aleenaprasannan2146]

I asked kind of a similar question to a very prominent scientist in our country (Dr Yash Pal), when I was in highschools. But my focus was on why we are looking for 'water' as a possible sign for life and why can't an alien life form be dependent on something other than water. He went on to give a really long winded answer which basically boils down to....cosmochemical abundance. He thought for any lifeform to be successful, the best would be for it to evolve to depend on what's the most abundant element and that's Hydrogen. So following on that train of thought, maybe we shouldn't be looking the base of our life as just 'carbon' based and instead as 'Hydrocarbon' based and Silicon's preference for oxygen over hydrogen might actually be the reason why life didn't form around silicates. Maybe having a very strong preference to choose an element that's abundance is just 1% in the Universe over the vastly more abundant Hydrogen which is about 73.9% in the Universe, might have become the roadblock to being the unsuitable for being a base of lifeform. Since flourishing of life is directly correlated to abundance of resource, the same principle might have possibly been applied to the very molecular level

[@KarlaKandy123]

Why isn't this comment more popular

[@IwasFRAMEDiTELLyou]

That's a really great point

[@ASlickNamedPimpback]

@@KarlaKandy123because people want to be philosophical and argue that "maybe we're the outliers"

[@joshilvaddi2868]

wow well said. I never thought about it like that.

[@gabrielperez-ze9tk]

Great comment, however you are slightly conflating a question regarding possible alien life and the way life developed specifically on Earth. Earth is not itself proof of the standard for life on any planet across the universe, and so using it as an example for why "life didn't form around silicates" is moot, as Earth very specifically is a water world that would have been adverse since a very early age in its existence. So, this is not a "roadblock", as Earth is a sample size of one, but rather it is an interesting concept that likely correlates to the majority of life across the universe, but not the end-all. The flourishing of life is connected to the abundance of resources available, so much as life is a walking example of entropy bringing more complex molecules down to a simpler form, and moreover resources themselves are these higher energy molecules. There are however plenty of resources available in this universe that we as hydrocarbon based life cannot process and access, and other examples of entropy taking more sentient forms around different molecular structures is completely possible and plausible. Life itself, remember, does not translate to sentient, or even complex life. Given this, extremely simple forms of life, those between simply chains of chemicals that process other chemicals, to the proto-organic life that formed early in our planet's history, may just take forms that are not prevalent on Earth, or indeed do not conform at all to our ideas of biochemistry. This is different that examining Silicon itself however, as there are plenty of planets in this universe, through what we have observed, that do not have the water necessary to promote carbon based life. They do, however, have the ability to promote silicon based life, based on all of the examples brought forth in this video. Rarer does not mean impossible, and I would counter that our own knowledge of planetary bodies across the universe, combined with our more correct knowledge about water levels across the universe, are not even enough to posit that the majority of planetary bodies would be carbon-preferable to silicon. We do not, for example, have the current ability to conceive life at all on gas giants, given their fluctuations, cloud layers, and still mysterious energy levels that may differ from one body to the next. Rocky planets that do not lie in the small zone in which water is in liquid form are more prevalent to planets that are, so liquid water is quite limited and so its volatility is only a concern in that minority of cases, in which carbon life would naturally be a stronger choice besides. You also say that life has a preference for hydrogen over silicon based on percentage amounts, however hydrogen would play into a silicon-based life form's processes just as much as it does in carbon based life. More comparable is the raw amounts to carbon and silicon, but it is not significant enough for your argument there. Overall, I think that the scientist you talked to, and more scientists that search for alien life, are searching for not only the same type of life that we are--as it is known, but also sentient life, which carries with it a completely different set of parameters. If we were merely looking for any life, primitive or otherwise, we would simply be left in the dark most of the time. Indeed, life could exist already within our own solar system on other planets and moons, but would be undetectable by our current standards. It is simply more interesting and productive to search for conditions similar to Earth, as it is known. We also search for chemicals in the air that would distinctly be the mark of the artificial--surefire proof of more advanced creatures. The search is therefore constrained to what we know, as we cannot search for something we do not know anything about--like the search for dark matter or energy. We are literally in the dark there as well, for we have no concept of how to search for it, how do you search for something that is undetectable besides. So it is with simple life, which itself could more feasibly be comprised of completely different groupings of atoms. Silicon, however, may just be the only reasonable, and rare, alternative to carbon based life. In the game of numbers that is the universe, where a one in a billion chance per star system could be considered commonplace, there may just be a silicon based life form gazing upon the stars, and wondering if there indeed is a chance that carbon based life is a possibility. (In their case, they would probably think it very possible, and would interestingly think of themselves as the exception which is cool)

[@--JawZ--]

Liking the information in this, was a good surprise to stumble upon. I liked the star wars sand reference also, hehe

[@Youser57]

Subbed, great content and some interesting comments and questions from your users, thanks for the responses too. PS no issues with the accent here mate ; )

[@thecandlemaker1329]

One thing not many people talk about is that under extreme pressure (routinely found deep within gas giants), nitrogen can form chains that are even more diverse than carbon chains.

[@rmduwk]

But from that extreme pressure and high temperature in gas giants, life cannot emerge can they

[@aristotelesmartins3339]

No that's false. Why do people need to lie. No other chemicals form complex molecules like carbon.

[@hypersoop13]

@@rmduwk Maybe different life can.

[@idiotidiot5821]

@@rmduwk for all we know right now carbon based life could be the outlier in the universe.

[@wasabista1613]

Never knew that. Of course, if they depend on extreme pressure, such life forms could never escape their planet. On the other hand, we haven't done much better. And if they're living in Jupiter, they've got a lot of room to roam around in.

[@ardstota]

I think the key phrase here is when you said “if nature has a choice”. If nature is a force that tries to fit itself into any nook and cranny it can fit into, then it will, as a famous fictional character said “find a way”. If silicon is its best option, it’s going to use silicon, no matter how much it has to work around issues.

[@ginsederp]

The current photosynthesis cycle invented and used by all plant (and many bacterial) life, is highly inefficient. With some minor tweaks, biochemists have made scary improvements to that cycle in a very short amount of time, and GMOs are being engineered to improve the photosynthesis efficiency of crops. Why didn't life already find these improvements in the billions of years it has existed? Easy, life finds a way, but it doesn't have to be the best way, just good enough.

[@leikom2010]

@@ginsederp Do you have some sources for this? It would be an interesting read

[@ginsederp]

@@leikom2010 5:43 kzbin.info/www/bejne/rIq5hHtoh9V7mbM adding 2 new genes is all you need to increase C3 photosynthesis pathway efficiency by 15%, C4 pathway is better, but we haven't managed to modify any C3 pathway plants to C4 yet I believe.

[@ginsederp]

@Mario Lutz kzbin.info/www/bejne/poK3ZJJ4n9RohNU the C4 rice project is trying to increase photosynthesis efficiency in rice by 50%, using acetate, scientists can grow plants in the dark more efficiently than sunlight (up to a certain point), scientists modified bacteria to produce acetate with an equivalent efficiency to 10 times that of plants

[@leizero]

I've read this one book called Coming of Age in the Milky Way and it astounded me with one of its chapters discussing life's origin. It talked in great detail about what we can consider "life" by contrasting metabolism and reproduction. Apparently, one of the theories proposes that life may have begun from a time where there are only globules containing crystal-like structures that pattern the formation of molecules, favoring the ones stable enough to survive and "reproduce" by splitting into daughter globules which later may have become the progenitor "cell" that sourced every life on earth. My takeaway from this is that, it's not about nature finding a way but instead a form of "natural selection at the molecular or even atomic level". Your final sentence basically summarizes this entire essay, but with carbon being the option instead.

[@michaelstrieby6824]

I like how he used serotonin as an example at 1:43

[@nanotedot]

An excellent, understandable and SO INTERESTING chemistry lesson. Excellent. Thank you.

[@nirosolis485]

I liked the take the X Files had in the episode Firewalker. The Si lifeform they discovered was more like a fungus that incubated in your chest and throat. It was terrifying for little 10 year old me, and it's always been my favorite episode. I didn't even know what Carbon or Silicon based life even meant back then, and it really fascinated me. A nice bit of detail was that Scully even finds sand in the bodies left behind as waste from the organism.

[@thehermitman822]

Hmmm. Would a Si creature hate beaches and deserts?

[@volbla]

Isn't there a theoretical possibility that actual fungus could evolve to behave like that in real life? So X-files may not have been that far off.

[@Kick0a0cat]

@@thehermitman822 you mean because it's full of their waste :D

[@thehermitman822]

@@Kick0a0cat 💩

[@benedictul]

2:28 I'm afraid that's TNT (or trinitrotoluene) in the picture, not nitroglycerin - despite what we heard from the great chemists of AC/DC, they are different substances

[@nudebovine]

Glad Someone got on this before I could only 16 min after posting.

[@dantefernandez2455]

Lol, commented this then saw you beat me to it. Well done fellow chemistry enthusiast!

[@petersurawski7844]

I think the animators just failed first year chem...

[@benedictul]

@@nudebovine my apologies

[@chitlitlah]

I noticed this myself. I just didn't have the bravery to comment about a mistake that's so trivial and has nothing to do with the point.

[@Azrael__]

This felt nice. Finally a video I can fully understand.

[@aqua3418]

0:53 Spire. Ok, I got to respect that obscure reference. I loved MPH. :) :)

[@davidgro2000]

I'm surprised there wasn't a mention of the Horta from Star Trek (Original series). It's one of the few cases where they are truly alien - not bipedal, and them being silicon based was directly discussed by the other characters.

[@thomasvanetten1984]

I wondered about that too. As a ST fan, I felt it was overlooked. But appreciated the deep dive on the subject.

[@davejones9469]

The Horta and their eggs were even mistaken by the scientists/miners as rocks or strange minerals they were so unrecognizable. The silicon based virus in "The Observer Effect" from Enterprise was also interesting, but it was more about the alien observers than the virus.

[@justineld4905]

I also came looking for that reference. A little disappointed it was left out.

[@rakninja]

there was also the "microbrain" from the TNG episode, "home soil."

[@canuckprogressive.3435]

"Damn it Jim I'm a doctor not a bricklayer!"

[@ryandoyle3413]

Small correction, the molecule displayed next to the dynamite is trinitrotoluene (TNT), not nitroglycerin. Love the chemistry content, always fun to see people loving my field 😁

[@saim84526k]

Oh yeah I was wondering why he was calling methylbenzene glycerin. thanks for the correction!

[@Yasen6275]

Not only that but molecule of CO few seconds later is drawn with triple CO bond.

[@pansepot1490]

In fact I thought it courageous for a physicist to make a video based on biochemistry. 😅

[@TD39504]

@@Yasen6275 actually, with leap of faith you could assume it's free radical / transition state in the midst of chemical process :D

[@Yasen6275]

@@TD39504 Sience has notohing to do with faith and radicals are denoted with dots, not with imaginary bonds.

[@sargepent9815]

In some Sci-fi stories, silicon based life exist on cold worlds. In which they use ammonia as their solvent

[@geniej2378]

Brilliant video, exceptionally well explained!

[@marcusm808]

This is the best biology lesson I have ever seen and it's from a physicist not a biologist or chemist. I think the explanation of the different pathways of biology makes it more understandable. Looking at the idea from multiple facets makes it clearer. Fine work, sir.

[@user-js8qy9pe7m]

Thanks for watching Tell Aɴᴅʀᴇɪ Jɪᴋʜ, you were referred by me he has something new to discuss with you easily get in touch with him👆✍️

[@dorothyphillips8318]

I'm glad that the explanation of the different pathways of biology has been helpful

[@cyrileo]

I couldn't agree more, Marcus! 🤩😊 PBS Space Time is the best channel to learn about the science behind life in the universe. Bravo!

[@mentalizatelo]

In Beverly Hills, California, life is pretty much silicon based. Excellent production, very informative, thank you!

[@feynstein1004]

Damn 😂😂😂

[@TragoudistrosMPH]

Botox is bringing bio back, baby!

[@ArminAriamajd]

The structure shown at 2:23 is not nitroglycerine, but trinitrotoluene (TNT). Sincerely, One of those people who don't even write Carbon in their formulas.

[@rlhugh]

awesome video. Note that there the audio volume seems a little inconsistent. I think this is mostly a note to myself, realizing that my own videos often suffer from the same problem, and noticing in this one specific video of yours something I should fix in my own. But anyway :)

[@Beateau]

I love that at 11:38 he makes a star wars reference. The meta reference is impressive. Most impressive.

[@jamesgadd5322]

Right after the power house of the cell 😂

[@victoriaeads6126]

Imagine, though, feathers grown by a silicon based life form. They might be so incredible! Like frost crystals on glass, or as reflective/refractive as diamond!

[@Tom_Quixote]

While feathers grown by carbon-based birds are all black and can be used to write with.. no, wait.

[@victoriaeads6126]

@@Tom_Quixote 😜 We have three peacocks, two peahens, some quail, and a very spoiled Black East Indies house duck (she lives in the house with us) We are familiar with bird feathers. The peafowl feathers ARE actually brown and gray, and microcrystalline structures on the feathers refract light in amazing ways. Imagine if the feathers were silicon based, and therefore inherently crystalline.

[@donquixoteupinhere]

@@Tom_Quixote fancy seeing you here hermano

[@PromisingPod]

I always imagine life as being see-through sometimes. Also, what why wouldn't rocks evolve to life forms here on Earth? Maybe over time, rocks will start evolving into life forms and we'll have Silicon life here on Earth.

[@aleenaprasannan2146]

@@victoriaeads6126 Have you heard of Agate?

[@jaylol7226]

Finally someone breaks this concept down in an easy way to understand. It actually confirmed a lot of my own assumptions about the idea of Si-life. Although now I'm wondering why, exactly, there aren't any really cool depictions of aliens that exhale sand in our literature. I should get on that.

[@aaronmarks9366]

Always glad to see a video presented by Matt

[@thedownwardmachine]

I laughed when he said he hates sand because I also hate sand. It removes friction when you want it (like in the middle of a turn) and it adds friction when you don't (like in gears and bearings). It's basically natures joke.

[@Chamois_Sings]

It was a Star Wars joke too. Anakin famously said “I don’t like sand. It’s course and rough and irritating… and it gets everywhere!” So you and the dark lord of the sith share a lot in common

[@thedownwardmachine]

Hah that reference went right by me. I didn’t care about Star Wars until Rogue One

[@ulti-mantis]

Only thing worse than sand in those regards is regolith (which is basically extremely fine sand)

[@Chamois_Sings]

@@thedownwardmachine honestly, same! I had never seen the original trilogy until after Rogue One. Now I know too much about the Star Wars universe. Thanks Tony Gilroy

[@jnawroc]

Xenomorph bleed acid and poop out glass beads - confirmed canon

[@DarkinBladeGaming]

0:54 ayyyy, spire finally gets some recognition. Even his own series has forgotten about him in favor of Sylux

[@Davethreshold]

HERE are three WONDERFUL FILMS featuring truly bizarre Life Forms: Andromeda Strain (1971 restored on Bluray and DVD), Alien (1979), Aliens (1986) and Annihilation (2018) TRUST ME: these are all spectacular with the deeper dive on science going to Andromeda, and Annihilation.

[@shannonolivas9524]

Thanks to the viewer who pointed out the thing about the structure of bird's wings. I was not aware that carpometacarpus even had a name nor how the bird had fused their vestigial hands in such a way. I understand how Matt might feel about having to check little offhand jokes (no pun intended) but what can seem like pedantry can actually be interesting and educational... on occasion.

[@digitalplayland]

Amazing video like always. Maybe you should make a video about SETI post detection protocol.

[@PlasticDoll.]

this was so enjoyable to listen to

[@tjthrash0143]

I feel that this type on content speaks to a broader audience than the math heavy ones. I do hope these continue every once in awhile.

[@mlaine83]

"I hate sand" what a great little Star Wars reference smuggled in. Matt you're my favorite. Great video. The search for the aliens that it never is... Until it is.... Continues.

[@makentosius]

11:35 nice reference to Anakin's quote from SW E1 👏

[@ReubenCooper]

11:36 I loved you PBS Spacetime! You were my brother!

[@matanjamin6546]

This video answered me questions I didn't know I have

[@beefpils]

The molecules shown at 2:35 are not nitroglycerin. It's Trinitrotoluene, aka TNT. The principle is the same, but visuals should align with the text.

[@isaacn5908]

Imagine if there was like a silicon-based society that created a video titled “what if carbon-based life exists” at this very moment?

[@isaacn5908]

@@Jay-cf6dz wdym

[@benedictul]

"That's nonsense, we all know that carbon-carbon bonds are too stable to allow for the production of complex molecules required by biochemistry. Carbon-based life is just a crazy fi-sci notion." (some irate silicon-based scientist)

[@ObjectsInMotion]

@@benedictulnot everything is symmetric. We easily see some options life could have taken that would actually be better, like alternatives to chloroplast, additional amino acids, etc. It would go more like this “While no evidence of carbon based life has been found, the possibility of such is a profound mystery as to why life on this planet is exclusively silicone, which can tell us much about how life formed here and potentially elsewhere in the universe where conditions may be more favorable for carbon chemistry!”

[@Michael18599]

I imagine they'd say: "Carbon based life is an interesting theory, but carbon is so rare it would be impractical and it is highly unstable in any sulphuric acid rich atmosphere. But it might be a possibility in some extreme environments."

[@alihms]

Some silicon-based alien comment: If there are carbon based life, they would be gross. Imagine inhaling oxygen and releasing the waste product CO2 from the same orifice. Eeeww! Not like us, we have separate orifices for them.

[@ihsahnakerfeldt9280]

Phenomenal work as always

[@rabbitttz]

That’s the coolest thumbnail I’ve ever seen. I want that photo, lol. Seriously awesome.

[@asdfghyter]

SiO2 being a solid was really the first thing that came to mind after you posed the question of what issues Si could have as a building block. All of life depends on breathing in some form and it would be a lot more difficult to breathe sand, especially since it's not water soluble

[@cormacb2326]

Incorrect. Plenty of unicellular and even some very small multicellular organisms don't need Oxygen. Replacing Oxygen as an energy source is far less ambitious than replacing Carbon with Silicon.

[@asdfghyter]

@@cormacb2326 but they would still need to have an environment that’s very low on oxygen to make sure not all silicone is in the form of sand? the combination of being both very stable and being an insoluble solid would make it very difficult for life to be able to access it once it has turned into silica

[@hugegamer5988]

@@asdfghyter sometimes I wonder if the first intelligent/animal like life we encounter will be relatable in any way. Like sharing no common senses, scale, or environment. Would be hilarious if it was 1mm tall, lives in a thin layer on partially melted bedrock, and can only exist at high temperatures and extreme pressures. Chemistry assumptions like solubility are completely changed in those cases.

[@cormacb2326]

@@asdfghyter Carbon planets (planets that are made of mostly Carbon) are theorised to exist and all Oxygen in them will be bonded to Carbon. While Most of the Silicon will be in the form of Silicon Carbide (which is just as if not more inert than Silica) there will likely be a decent amount in less inert Organosilicon molecules because the Carbon and Silicon don't react nearly as readily as Silicon and Oxygen. Carbon being everywhere isn't much of a problem since Carbon is always going to be common enough for life to evolve since it's one of the most common elements in the universe. So for Silicon based life to exist Silicon must be the superior canidate for the basis of life due to the conditions of the planets. E.g. in a really cold planet Silicon could be perferable to Carbon due to being more reactive and less stable than Carbon if you could fix the solubility issue. Alternatively, if you could have Sulphuric acid ocean form on a planet due to asteroids bringing it in it might be enough for Silicon based life to evolve as Silicon based compounds are more stable than Carbon based ones in certain Sulphuric acid conditions (Souce: www.mdpi.com/2075-1729/11/5/400 figure 8).

[@michealnelsonauthor]

@@cormacb2326 would it be possible for silicon based life to arise in space? Say, asteroid based? Or in planetary rings? Solves the oxygenation problems. A planet of different compositions than earth, an outer gaseous planet maybe?

[@angrygolemgames393]

Fascinating document. Thanks for sharing.

[@mdmsr2000]

Startrek did this in the 1960s. The episode was "The Devil in the Dark". They called the silicone-based lifeform the Horta.

[@silverback6497]

I really think it's likely that silicone life exists, it may be extremely specific but in this game of numbers it's got chance

[@goodmorning2386]

I agree, with how big and diverse the universe is, to me it’d be weird if the only life out there was carbon based

[@silverback6497]

@@goodmorning2386 I'm super interested to see what variety of life is possible. AI can really help us with this, I think quantum AI will be able to help us find aliens

[@goodmorning2386]

@@silverback6497 agreed, I feel like AI is going to kind of revolutionise stuff like this

[@dextreme1754]

Also it’s a pretty bad approach in my opinion to think life must be similar to the life we have here on earth like the example with sand in this video too and also the solvent part silicon based life if it exist maybe uses electricity instead of a solvent, also solvents like methane under extreme pressure can also be a great solvent for silicon based life it doesn’t have to be revolving around water

[@ronstewart5945]

If you consider a near-infinite set of possibilities, yes. Anytime it’s competing with carbon, though, it will probably lose, again purely by a game of numbers.

[@Psychx_]

2:23 The image shown and titled to be Nitroglycerin is actually Trinitrotoluene. Also, when blowing up something with nitro groups, you also get some N2 as product. These kinds of errors are kinda unusual for Space Time…

[@allthingsdestructive]

Glad someone else noticed that. I'm surprised as well.

[@tygbsn]

Blew my mind with diatoms. Thank you

[@darrnellnott07]

You and your team do great work!!

[@FlyingOverTr0ut]

At 11:40 I audibly yelled/groaned at the sand quote from Attack of the Clones. Great job getting that in there.

[@richardwalroth8879]

Great video, but the molecule shown at 2:25 was not nitroglycerin but tri nitro toluene (TNT). Also the lattice shown for metallic bonds at 3:53 applies to ionic bonds as well. Small points but otherwise really great stuff!

[@WhiskeyNeaty]

This guy chemistries.

[@Tangobaldy]

I never noticed or cared

[@imaginedbywestfall]

bad ass reply

[@aarondavis8943]

Is it true that TNT "sweats" nitroglycerine? I seen it in a cowboy film.

[@richardwalroth8879]

@@aarondavis8943 this is a common mix up in movies, but TNT is a chemical and a solid, it's also very stable so it doesn't sweat anything. But dynamite is a stick of some kind of absorbent soaked in nitroglycerin which is more a liquid and can start to sweat out of older sticks of dynamite. At some point the two terms started getting used interchangeably in pop culture but they're completely different

[@bumblebootwiddletoes5185]

The ending of this was hilarious. Thank you

[@JanHirschner]

Great easter-egg at 1:46 when the line cuts off the OH group :)

[@samtux762]

2:40 - the molecule shown is TNT, not trinitroglycerin

[@Archgeek0]

Yeah, to a silicon-based life form, our silicate rocks are burnt-out ashes, and our world at large a huge wet nightmare lump of frozen ash (I say frozen because it's been speculated that silicon chemistry would work better for life at much higher temperatures - e.g. magma monsters). Also, today I learned that bats swim through air with their giant hands, and bird wings are giant index fingers covered in weird, super branchy modified scales.

[@crusherolies8195]

there wont be silicon lifeforms. dna forms on its own when the ingredients are there, the same ingredients that are in roughly the same proportions all over the universe. there is so much more silicon than carbon yet DNA didnt bother with silicon because chemically it doesnt work well enough. its almost like you didnt even watch the video explaining why silicon isnt an alternate to carbon.

[@Archgeek0]

@@crusherolies8195 Ah, speaking in absolutes and pretending DNA matters that much (RNA was first, and it really doesn't matter the form, you just need self-replication information structures). Methinks I've found the Sith. Silicon is pretty terrible for such chemistry at our temperature ranges, but what of others?

[@crusherolies8195]

@@Archgeek0 dna does matter that much, its what happens when you have all the basics hydrogen carbon oxygen etc. all life we find out there will also have dna because thats the shape the proteins make on their own. yes very good RNA was first, and required nothing more than the crap that is everywhere in the universe in the same amounts. we have things that live in extreme hot and cold here on earth, your temperature crap is just crap.

[@empyrionin]

@@Archgeek0 you don't understand, these people are real scientists! They know the truth! Like the people before Einstein who claimed Newtonian physics are absolute, so do they claim their version is absolute. What bothers me isn't that they might be right (possible), but this species of people who are completely inflexible in a domain which can only expand if you dare to explore (carefully), the what-ifs.

[@arnor398]

@@crusherolies8195 confirmation bias much? objectively speaking, the video ISNT about why silicon life cant exist. it simply isnt. the fact that you interpreted it so is alarming and should push you to examine your biases and the way you learn & interact with new information.

[@HeloisePansy]

Life is what you make of it. Always has been, always will be.

[@user-fy6ck9di1f]

Thanks for sharing this, massage about development of life consist a silcon

[@mcknottee]

"Also, all Australian birds have gigantic hands." Except emus. They have tiny little ones. How they still managed to win the Emu Wars is one of the great mysteries of military history.

[@matthewparker9276]

They had superior armour plating.

[@nizm0man]

@@matthewparker9276 and also speed

[@beardedcynic8213]

If it makes you feel any better Matt, I love your jokes, the critiques, and your continuation of the banter! Keep up the great work!

[@Tesis]

The Australian birds with giant hands - I would totally believe it. Also I’m sure the silicone based life will be found nowhere else but Australia. It just seems like the right place.

[@nomann5244]

I think this is the 1st episode of PBS I am going to understand.

[@GiRR007]

Its the mark of a true genius to be able to simply a complex topic so that others can more easily understand it. 👍

[@falnica]

Thank you

[@fransdekker111]

I really like pbs space time discussing chemistry, would love to see more of it. Well done

[@jackal8176]

This reminds me of mass effect, specifically the volus. They hail from Irune, which possesses a high-pressure greenhouse atmosphere able to support an ammonia-based biochemistry.

[@aox19]

damn pbs was successful on tv and also on yt what a crazy resilient company

[@bbirda1287]

I am also a fan of the Goldilocks theory of the Great Filter. Like the lottery, having many smaller factors actually decreases the odds of success rather than one giant obstacle.

[@limbridk]

For my taste, this is probably the best video on the channel. Answered soooo many questions I have had for years.

[@OxwoodBr-io6id]

Love work you streaming thank interesting points of views

[@carolynallisee2463]

Whilst I watched this I was struck by a thought: as silicon and silicon dioxide are so abundant, what is to stop an alien lifeform from using it in skeletal and other support structures? How does it compare in strength and resilience to the calcium phosphate crystals in our own bones?

[@DingoAteMeBaby]

This video perfectly addresses audiences with a high school chemistry education! Made it very easy to understand, thanks!

[@danielgolan]

Middle school, I would say. You can understand all of this with 8th grade knowledge.

[@zweefpiloot]

I like the way how PBS Space Time explains all these difficult topics in a very understandable way. These videos are just amazingly fascinating. Keep up the good work!

[@technoir2584]

This video was of interest to me because of the Arecibo message sent back in 1974 in Arecibo, Puerto Rico. This was a binary pulse message that was transmitted into a specific region of space. It contained a binary coded message that gave a description of human DNA and the location of earth in our solar system among other things. At the beginning of the message were atomic numbers that make up human DNA and Carbon is at the top because it is the most common element present in life as we know it. In the year 2001 in Hampshire, England near the Chilbolton Observatory somebody replied to the message we sent in the form of a crop circle that became known as the Arecibo Answer crop circle. The message was very similar to the one sent from earth with the information shared. They included the atomic numbers that make up their DNA but unlike ours, Carbon was not at the top of the list. Silicon was. Very interesting.

[@Saaahdood]

When theorizing about different life form bases, rule #1 is to only swap carbon out and keep everything that only works with carbon.

[@thomaskortvelyessy]

I loved it! Finally understood a lot more about this entire question. AND I loved that despite all examples we as viewers were encouraged to keep an open mind and not allow ourselves to become too self-centric here. Thank you very much :0)