We're Probably Wrong About What Alien Life Looks Like

[@fr57ujf]

The early start life got on Earth, and the presence of extremophiles both suggest that simple life will emerge whenever possible and may be rather plentiful in space. The criteria for the emergence of complex life, however, are much tighter. That's why it took complex life another 3.5 billion years to appear after the bacteria evolved. Complex life is what is most fascinating about alien life because it is a prerequisite for intelligence and technology.

[@avandorhu-3389]

In fact, some more recent studies may or may not suggest that complex life appeared around 2 billion years ago. But it never evolved hard shells or anything more complex than jellyfish or worm like creatures, and it eventually went extinct. If this is true, (hard emphasis on IF) This would mean that even if complex life evolves, it is not guaranteed to suceed immediately.

[@fr57ujf]

I've read the proposal that hydrothermal seawater eutrophication may have triggered local macrobiological experimentation 2.1 BYA in the Francevillian sub-basin. The speculation is that the limited range of this congenial environment prevented life from getting a larger foothold, making it more vulnerable to extinction. But even after succeeding on a global scale, the five mass extinctions since the Cambrian and the sixth mass extinction now underway show that there is nothing guaranteed at all about complex life.

[@_Painted]

Or the early start life had on Earth was extraordinarily improbable and the chances of life beginning quickly enough to allow the time needed to develop complex life, let alone spacefaring life, is slim to none. With a sample size of one, we just don’t know.

[@fr57ujf]

Abiogenesis occurred within a few hundred years of the Earth's formation, probably in hydrothermal vents. This suggests that, given the right conditions, it is not an improbable event. Since chemosynthesis does not depend on light, the right conditions may occur in many non-Earth-like settings - for example, in the subsurface oceans of Europa and Enceladus.

[@lamujerbrillante]

we keep searching for life that is like us, but if life can exist in places on earth that humans could not tolerate, then why couldn't there be developed life that don't require the same conditions?

[@pineapplepenumbra]

A good question, but the extremophiles are limited in how complex they can become. Because carbon is so capable of linking up with so many other elements in stable, useful forms, in so many different ways, it makes sense for any complex life to be carbon based. Silicon based life would almost certainly be more basic.

[@Cheesepuff8]

I think when we say “like us” that often includes animals that can exist in places humans cant

[@CaritasGothKaraoke]

Why just animals, Cheesepuff?

[@pineapplepenumbra]

@@CaritasGothKaraoke When I read your comment, without the context, I thought of a planet where Cheesepuffs roamed wild, and, perhaps, were the dominant predator, rather than the prey they are here?

[@dallyinghualian]

I've been wondering this too

[@snozzmcberry2366]

Lisa speaks about this subject with such joy and passion. It's enchanting.

[@TopTierKnees]

Both of the interviewees did such a great job communicating their excitement.

[@WouterVerbruggen]

It's life, Jim, but not as we know it

[@blueabattoir]

WouterVerbruggen Yes, but who will teach them about love?

[@Roguescienceguy]

🖖

[@kellyrobinson1780]

I'm a DOCTOR, not a bricklayer!

[@Roguescienceguy]

@@kellyrobinson1780 devil in the dark

[@blucat4]

In a pig's eye it is!!!

[@tesseract_1982]

I'm rooting for black plants and purple oceans, because that'd be hella goth. 😅 💜🖤💜🖤

[@CaritasGothKaraoke]

Agreed

[@badabing3391]

trying to see anything would be so ass without infrared binoculars

[@strandedstarfish]

I contemplate the planet with an ocean of alcohol that logically must exist somewhere in this vast universe.

[@dannyg.4421]

I watched a science video a few years ago that said a planet rained diamonds. Idk the legitimacy

[@mosquitobight]

There are pitch black bushes with black leaves, stems, flowers and berries growing right in the English garden of my city park.

[@psigh8161]

The fact that most light from red dwarves (obviously) comes in the form of red and infrared oddly supports the idea of entire ecosystems with animals equipped with predator vision

[@joelellis7035]

They may have Predator vision, but they're skin may not be adapted to handle the UV rays. They may get third degree sunburns within minutes!

[@psigh8161]

And if there are species advanced enough they would have to wear protective suits or armor just to be able to stand in our sun's light if they decide to visit or invade, great idea!

[@stevenverrall4527]

Thank you for providing a link to an open-access paper. The public must demand that all publicly funded research is published open access. If this means that authors and their institutions must pay thousands of dollars for each publication, then so be it. This will encourage more interdisciplinary collaboration and more research participation from undergraduate students. More coauthors implies more cost sharing for risky theoretical projects that are unlikely to receive funding.

[@SarunasZukauskas]

Multiple authors don't pitch in to cover papers costs.

[@DeltaNovum]

Hear, hear.

[@SubvertTheState]

Or we just ban JSTOR and make whatever insignificant costs to run it, a public database the public can access. We need to do this with all Case Law as well. Its criminal to require a defendent to hand over money in order to access case law. This only makes sense. And it IS NOT expensive to maintain a website with access. Now if there's proprietary research then thats different. But JSTOR doesn't ever pay Accademic Paper Authors lol.

[@musicsubicandcebu1774]

"O God, I could be bounded in a nutshell, and count myself a king of infinite space-were it not that I have bad dreams". (Hamlet)

[@sstorm1328]

I have seen what looks like trilobites or isopods about an inch or inch and a half wide swimming happily in blood red sulphuric acid ponds and lakes on top of a Cu Zn mine tailings deposit. Could never find anybody else in the world who knows of this life form or variety..... Which is weird. If you work more than few days on a drill on this site, your clothes fall into pieces due to the acidic air on top of the pond.

[@tesseract_1982]

That's interesting. 😮😎👍 It's indeed not guaranteed that scientists researching extremophile lifeforms already know about these. Have you considered catching a few with a net, together with a water sample (big jar, for longer chemical stability)? Hard to refute their existence with the jar in hand, and the species/family could be identified... or named after you, if new... 😁👍 I'd assume the isopods or whatever you saw, might be hardy enough to venture briefly into the toxic water for food like biofilms of extremophile bacteria, while not living in it constantly. So if you really decide to collect some, to increase the likelyhood for them to reach the scientist/university/lab alive, I'd recommend to put some of them in a dry jar. (Isopods are weird and primeval. There are isopod species that live on land as well as aquatic ones, the land-dwelling ones basically are breathing with modified gills. They are closer related to lobsters and crabs, than to insects.) I'd compare their implied lifestyle with that of eels diving into brine pools at the bottom of the oceans. If they stay even seconds too long, they get a toxic shock... saw that in a video filmed by a science probe.

[@benmcreynolds8581]

You should really try to get this information to individuals who research Extremophiles. There is still so much more that can be learned and discovered in this unique category of biology and science as a whole. Just a guess but those isopods probably developed a symbiotic relationship with specific bacteria that allows them to pull nutrients from these extreme environments. Then overtime they keep adapting to better endure such extreme environments such as the one you described..

[@sstorm1328]

@@tesseract_1982 unfortunately... I had nothing like a glass jar to put them into when I was watching them... Would have been easy to catch them too.... When I returned a year or so later to catch a few.... The damn environmentalists had covered the place in earth and grown grass over the site.... I have seen plenty of identical sulfuric acid tailings pond before then.... But never with any life forms visible.... I wrote to many biologists afterward about these" trilobites". Even researched how acidic the first oceans may been.... Wondered if first trilobites might have lived in similar acid conditions... Maybe first species never got preserved??? Not many sedimentary rocks of that age in the world.... I have seen a lot of weird things as a field geologist exploring older formations.... But the living "trilobites" were very puzzling... I could never find any species of Isopods who looked as squat and chitinous as these ones.... And they all seemed to be fresh water species.... I'm not a biologist though nor any kind of isopods expert. It was very unlikely that freshwater tough isopods wandered into these toxic waters from any nearby fresh waters though.... The ponds were at higher elevations than any freshwater sources.... And drained downward... Rain would have been only source of dilution.... Also there are many beautiful clear ponds and lakes that are located ober rock formations than contain enough sulfides in the rock to create mildly acidic waters that harbour zero aquatic life.... Still great tasting drinking water though! (hope it never hurt my health) and not even bugs or mosquitoes hang around these areas for some reason... No fish... But I never studied or looked too hard at the biology here... There is a big difference between ruby red sulfuric acid liquids (mixed with H20) and clear limpid acidic waters that taste great.

[@sstorm1328]

@@benmcreynolds8581 that makes a lot of sense.... These creatures had to be anaerobic and also very complex and evolved. Maybe people need to start exploring more non-rehabilitated tailings sites... But the mines are not more than a century old..... So where did the isopods or whatever come from or evolve from so quickly... Maybe you are right.... Extraterrestrial colonies??

[@GeoffCostanza]

​@@sstorm1328 where was this? What country/ state/ city/ street/ coordinates/ etc?

[@lady_draguliana784]

Modern Humans: about 300,000yrs on earth Photography: 2k yrs max... MAX... 🤷 if there's life in our own solar system, we lack the ability to detect it atm, much less lightyears away!

[@bendybruce]

If you are searching for alien life look no further than the back of my refrigerator..

[@Tschudenizer]

This reminds me of one specific episode from Cowboy Bebop where the crew struggles with exactly this problem 🙂

[@76rjackson]

Our version of life has its sweet spot using a specific chemistry within a narrow range of temperature and pressure. But we don't know very much about how permutations of those parameters ultimately favor or hinder the development of other kinds of life. Are there other collections of chemical that will undergo abiogenesis in different environments? Could there be cold life on ice moons, metabolizing and reproducing super slowly over thousands and millions of years? Or as one scifi author put forth decades ago, could there be super fast life existing on the surface of neutron stars?

[@DataRae-AIEngineer]

This was super interesting! Thanks for posting it.

[@antiquehealbot6543]

This is the exact thing I've been thinking. I was always wondering why are scientist always assuming life will need water to survive while it can have totally different structure.

[@michaelclark4876]

Short answer: because you need a solvent for life’s chemistry and water is a very good one. Longer answer: Because water is such an effective solvent for a wide range of compounds and because you need a liquid solvent to do chemistry at low temperatures. Water has an unusually wide range of temperatures and pressures it is liquid. This is promoted by solid water being less dense than liquid, allowing insulating cover of solid (ice) over liquid (water) keeping bodies of water from rapidly freezing solid. It has a high capacity to hold heat, so it smooths out extreme environmental temperature shifts. And it has strong surface tension which is important in the transition to life on land, among other things. And it is critical to the one example of life that we know about.

[@sebhin1168]

@6:35 it's not FAR infrared. It's NEAR INFRARED (NIR). Anyways good video!

[@MJane-sensei_darlins]

Her voice is soo calming

[@rocksnot952]

I'd be really surprised to find life that doesn't use water. It's the closest thing to a universal solvent that exists.

[@hoi-polloi1863]

Scientists: There used to be purple life on Earth! Laymen: So what happened to it? Scientists: Cyanobacteria killed it by producing toxic oxygen. But don't worry, there may be purple life on other planets! Cyanobacteria: “I sense something, a presence I’ve not felt since…”

[@esko911]

Make a 1 hour compilation for us to fall asleep to!! I love your channel

[@SiqueScarface]

I see two problems to be solved in the search for Life: 1. Life is based on Physics and Biochemistry. Any life still has to conform to basic natural laws, and thus is limited to be physically possible. Hence Life does not differ in principle to non-life places. 2. Life evolves and thus with time will use all available resources. It also means that with time, it will use all possible energy gaps, making its detection more complicated. On Earth for instance, the current oxygen levels are not the highest anymore. It's possible that Earth in the future will have even lower oxygen levels, because later iterations of complex Life will be even more efficient breathing oxygen and thus can cope with increasingly lower oxygen levels.

[@paulbennett772]

Thanx, I learned something today

[@TruthWillFreeYou]

I learned this was just a bunch of theories without any evidence to back even one of the suppositions. Also, I doubt that is the worlds leading expert in that field.

[@nbell63]

As per Jack Cohen and Ian Stewart's "Evolving the Alien: The Science of Extraterrestrial Life" [2002]? - the book originating with a lecture that Cohen had revised over many years, which he called POLOOP, for "Possibility of Life on Other Planets".

[@blueabattoir]

That’s the sound my toilet makes.

[@The_SOB_II]

This comment section is now under control of the Plup Club

[@jmmahony]

Blue stars are big and hot, but burn so fast they have short lifespans. So short, it is unlikely life would have time to evolve there.

[@KaiHenningsen]

On the other hand, the opposite is true for red dwarf stars. So they have a lot more time than Earth to evolve complex life. So even if complex life needs much more time to evolve under those conditions - it has that time.

[@Scotty-vs4lf]

@@KaiHenningsenyeah but all of our energy comes from the sun, so if the star isnt giving the planet enough energy then complex life wouldnt have enough energy to evolve

[@user-xh9pt8zu2l]

​@@Scotty-vs4lf - In a simple way life does not need energy to evolve. All that life needs is energy to survive and multiply. The ones that do this better will be around for the longer term and evolution is the passive (no extra energy needed) result. What isn't discussed is how to determine the minimum energy needed for complicated life forms. Specifically is there an energy saving in being a multicellular wolf on Wall Street life form versus just remaining the best possible microbe under the red dwarf.

[@AdamLinton]

Assuming their concept of time would be similar to ours.

[@Scotty-vs4lf]

@@user-xh9pt8zu2l yeah evolution doesnt require energy (well any more than is needed for survival to begin with) the problem i was thinking about was that complex life forms inherently need more energy for larger brains, and bodies that are useful to actually do something complex. if a worm had 10000 iq i still wouldnt consider it complex cuz all it can do is slither around

[@conradbo1]

Very informative and interesting video. Amazing examples of thinking outside of the box.

[@Revonish]

Excellent video. Thank you.

[@justinhunt3141]

The problem with red stars is that energy is quantized and the energy from a red star has less energy than a yellow star and this chemistry that is possible from a yellow star isn’t necessarily possible in a solar system with a red star. Considering we don’t know how life started on earth and what was necessary it may or may not even be possible with a red star.

[@stahlbergpatreon6062]

also, aren't red stars usually older than average, meaning the systems formed around them might not contain a lot of heavier elements, like our system apparently does? For instance, iron and phosphorous, which are crucial in many life cycles on Earth

[@petesandwich3246]

I find it annoying that people say Earth is unique due to planet detections around super small dim M-type stars. It’s like someone who lives on a large farm in a rural area only looking at condos in Mid Town manhattan and concluding “no other home is large or had cows!”

[@harrygoldhagen2732]

If life began at deep sea hydrothermal vents, then I suspect that life could adapt to red light as well as yellow light.

[@justinhunt3141]

That is a fair point, but it ultimately depends on what kind of life you are looking for. I am sure that single cell organisms will be far more common type of life to be found, but multi cellular and then intelligent life will be less common. Basic life will be able to evolve certainly, but maybe you need a yellow star for more complex life.

[@zgred1-kv1gz]

Cool! And I definitely opt for more David Bowie samples.

[@strandedstarfish]

I know what alien life looks like. I am the very definition of life in outer space. Isn't it more probable that alien life will be machine based? I hate to bring up the hysteria over AI but... It's less likely to be "Take us to your leader", or "Look at the pretty coloured bacteria"and more likely to be, "We are the Borg..."

[@NeovanGoth]

The question would be, what "machine based" even means. If you look close enough, we are machines too, just on biological basis, with proteins acting as nano-actuators, and so on, which has a lot of advantages over mechanical systems. So if the question rather is, if there are lifeforms out there that have been designed by other lifeforms, those may not necessarily look like a machine how we understand it.

[@JoseAlba87]

A Decade in Blue (Da Ba Dee) - eiffel65 "I'm Blue If I Was Green I Would Die, I'm Indeed I Will Die, If I Was Green I Would Die.."

[@mitseraffej5812]

0:37 What about the other reason we haven’t found alien life? This being that it is extremely rare in the universe, but this does not mean that earth is unique. The cosmos looks rather hostile out from under earths warm but perilously thin atmosphere.

[@harrygoldhagen2732]

A terrific video, Dr. Ben! Lots of great interpretation by you to explain some otherwise complex principles, with lots of relevant "b-roll" and the occasional cute clip. I recently read Dr. Kaltenegger's enjoyable book, so it's very nice to see her and her colleague talking about the challenges and what we should actually be looking for. Personally, I suspect the universe is full of planets hosting bacteria, and maybe a few with complex life, but highly doubtful we'll find technologically advanced life -- even here on earth, advanced life (radio waves, etc) only accounts for 3*10[-6] % of our planet's existence! Don't blink, ETs, you might miss us!

[@pauldwyer7736]

Great content but, (and it's probably just me) being spoken to like I'm a kindergarten child grates on my nerves after a while. Some museum tours do this too. I think this is the first time on this channel I couldn't watch till the end. I'll probably get flamed but I thought Ben should have the feedback just in case it's not just me.

[@nicksutton6373]

It's not just you

[@KateeAngel]

Yup. I have also noticed a lot of popular content about science in English talks to people like they never learned anything after mid school. Including books. More intellectually challenging content is more rare. P.S.: And most thing explaining photosynthesis simplify it so much that information becomes inaccurate. Like equating type of photosynthesis to colour of cells. There are greeen sulfur and non-sulfur anoxygenic photosynthetic bacteria, there are also many cyanobacteria which look purple due to lots of phycoerythrin, same with red algae. Also, colour depends on the exact proportions of numerous pigments they have, and that depends on lighting conditions, so the same culture changes colour under different conditions! So that is the topic I know. Over-simplifying it can give people false ideas. Maybe the same is true with other topics as well.

[@fburton8]

5:17 Fortran… woohoo! 😍

[@sebastiangodelet9996]

Why do we call our sun yellow star when it emits black body radiation and peaks in the blue/green wavelength?

[@DrBenMiles]

great question - the long tail of black body curve affects its perceived colour even though the peak is approximately blue here's a link with a handy table I look at sometimes (replaces the 3 "(dot)" 's with "." 's) www.atnf(dot)csiro(dot)au/outreach/education/senior/astrophysics/photometry_colour(dot)html

[@sebastiangodelet9996]

@@DrBenMiles thanks that's a great resource, also explaining why we don't see red stars in the night sky and why we have to use averted vision when observing extended objects in a telescope. From the table let's say a deep red carbon star (M-class?) as photographed with a CCD of CMOS is actually an "infrared star" in a sense that most of its emission is in the infrared?

[@hinesification]

700 nm is NOT the Far-Infrared! 700nm is barely into the Near-Infrared. That’s why it’s called the Red Edge and not the Far-Infrared Edge! FIR is more like 100,000 nm! Sigh…

[@DrBenMiles]

Good catch. I'm not sure what happened in my brain here.

[@blucat4]

@@DrBenMiles Alien mind controlling parasite. Don't worry, it happens to the best of us. 😄

[@Neekalos]

No need to be condescending, he simply misspoke

[@Flesh_Wizard]

Edging the infrared spectrum

[@KateeAngel]

True. I study cyanobacteria which use far-red light 700-750 nm. So it is "far-red" not "far infrared".

[@dang-x3n0t1ct]

There's a bot with a lewd pfp here, please ignore and report.

[@blueabattoir]

What’s the name? Don’t make me go look for it.

[@miscbits6399]

The reasons for Chlorophyll's light absorbtion spectrum are rather interesting There are other forms of primitive life on earth that absorb green (blue/green "algae") and early earth oceans were likely to have been full of them - meaning chorophyll probably evolved to absorb what was available at depths sufficient to block UV penetration On a more terrestrial note, there are some experiemnts to try and tweak chlorophyll into absorbing a wider spectrum of light - which would result in BLACK plants

[@dc9926]

No one mentioned life around the deep sea vents. I understand that it is a very different way/place to live.

[@zaubergarden6900]

wonderful visuals, what a well produced video! great for kids to learn something :)

[@markedis5902]

Hang on, isn’t alien life ‘grey’?

[@blueabattoir]

Always, unless it isn’t.

[@puffinjuice]

I'm glad you adressed the fact that life might look entirely different on an alien world. Whenever there is a show saying that we're looking for oxygen and water I immediately discard the study because they are too narrow minded to ever find life.

[@Cheesepuff8]

They do that because it’s easier, it narrows down our options

[@monikakuchynova4603]

wow, great video 😊

[@sunalwaysshinesonTVs]

Wait, how could be wrong about something we have no idea exists? Dark matter.

[@fractalwalrus5409]

We know that dark matter exists, we infer its existence as we can see its effects on the universe, we just don't know what it is. For example, people knew things fell to earth before Newton described gravity.

[@sunalwaysshinesonTVs]

@@fractalwalrus5409 Exactly. Straw-man. Granted, you started with "we infer", in the subsequent argument you baked the conclusion into the premise. The observation is true, the cause however is speculative.... and Scientists conclude "dark matter" cause they dont want to entertain maybe they just dont have the full picture on physics. It's equally valid to conclude there's more physics out there we havent discovered yet. The idea there exists some weird form of un-observable/un-detectable matter is the science version of Jesus.

[@artman2oo3]

Isn’t the main issue with planets in the habitable zone of red dwarf stars is that they would have to be too close to the star and be exposed to too much of its radiation? And also too close to its gravity well and possibly be tidally locked to the star? And that solar flares from the star would happen too frequently to allow life to gain a foothold there?

[@stephanledford9792]

Based on the countless Star Trek and other space movies I have seen; most aliens look amazingly like humans. Also, outside of our immediate solar system, most planets / moons not only have a climate suitable for humans to be on without a protective suit, but also have breathable air. We are unfortunate enough to only have one planet, Earth, that meets those criteria. Even more amazing, the majority of these planets also speak very passable English.

[@Martial-Mat]

It never ceases to amaze me the arrogance of scientists who think that they understand all the parameters constraining the formation of life.

[@fractalwalrus5409]

It never ceases to amaze me the arrogance of commentors who use the blanket term "scientists" without being able to name a single one who thinks they understand all the parameters constraining the formation of life.

[@KateeAngel]

Many bacteria which use infrared are still green to our eye. Like green sulfur bacteria. Yet everyone talks only about purple bacteria...

[@Ayumu31]

As a child I was always annoyed as to why they always thought that alien life would resemble our form of biology...thankfully they are shifting their thoughts process

[@sassa82]

12:31 I didnt know that scientist had only kept looking for "green life". Im sceptical of that statement.

[@SenZenZero]

No lie I thought scientist or biologist looking for life already took this into account, I didn't know this was a revolutionary idea, like even a video game like No man sky predicted this

[@limsalalafells]

0:33 only place we found life... Umm how many other places we been? When did we make interstellar travel? Or even just a camera capable of capturing any information about the inner atmosphere...

[@High-Tech-Geek]

Did you not watch the video? He explains very clearly how we currently hunt for life on planets, moons and exoplanets. We haven't found the spectrum signatures yet that match the signatures here on Earth. So yes, Earth is the only place we have found life. And yes, we have also travelled to other planets and moons and taken and analyzed samples. Only a handful, but you don't seem to understand how the hunt is done. It's primitive, but we have looked at over 5000 planets.

[@limsalalafells]

​​@@High-Tech-Geek No 33 secs in and at that point idiotic obvious but not helpful statements were made. Phrasing was also intentionally done in opposition to life existing. Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space. - Douglas Adams. It's like closing your eyes and saying you can't find single celled organisms. First of all you probably won't see most single cell organisms with your eyes open... Much less with them closed. The rest of the video just goes on to say the same. We don't have the technology yet. Got a few general ideas.... And sure we are looking but we don't have the tools yet. Saying we haven't found life is like saying the chicken is cooked as you watch it lay an egg. It ain't even prepped to cook...

[@High-Tech-Geek]

@@limsalalafells I understand what you're saying, but spectroscopy analysis is pretty cool. It can tell us the composition of the atmospheres around these 5000+ planets. Imagine if we find oxygen and methane gases in the same proportions as here on Earth? That would be a good indicator of life. It wouldn't confirm it, but it would be a great sign. But the lack of seeing these elements so far in the right proportions and on the right type of planet speaks volumes. We haven't found these proportions yet. But the whole point of this video is to say that maybe life on another planet doesn't emit the same gases that life on Earth does. So they are looking for other combinations of gases. Very cool stuff.

[@limsalalafells]

@@High-Tech-Geek all great, bad intro. If I start a conversation by saying your worthless and will never do as well as your great grandfather. Explain his achievements loses some of it's meaning to you. If instead I start by saying you've got a lot to strive for, or you got potential.... It puts the story about your great grampa in a whole different light. While you still may not live up to the same standards you at least aren't being knocked down before you have a shot.

[@DukeofEarl1961]

No mention of alternate forms beyond carbon based life. Maybe a follow-up that goes back a stage to chemistry and discusses which elements could be built into chains (e.g. silanes) would be good.

[@blucat4]

It's pretty much carbon or very unlikely silicon, everything else can't form life in any way that we can imagine.

[@michaelclark4876]

To elaborate, carbons ability to form long chains is leaps and bounds ahead of silicon which is in turns many leaps and bounds above anything else.

[@KateeAngel]

Nitrogen compounds under huge huge pressures can have interesting chemistry. Also, other liquid apart from water can be used. Some bacteria even on Earth live in liquid CO2 lakes on the ocean floor.

[@michaelclark4876]

@@KateeAngel I assume you're talking about Qian et al., 2016 Nature paper ("Diverse Chemistry of Stable Hydronitrogens, and Implications for Planetary and Materials Sciences"). I wasn't aware of this paper. It demonstrates nitrogen can form very long chains under pressures over 36GPa (about 5.22 million psi). This conditions do exist deep inside gas giants. But one problem jumped out at me and did not escape the author's notice either. As they say "Nitrogen-based life could be possible, but the likelihood of this is highly limited due to high temperatures in these planets’ interiors, which could make lifetimes of metastable compounds too short." Use of a liquid other than water seems far more likely than silicon or nitrogen based life. Water just has a combination of many chemical and physical properties useful for life, but those are not unique to it. Even so, living in a liquid is not the same as having biochemistry based in that liquid. The bacteria living in or at the edge of undersea lakes of CO2 still use water as their intracellular biochemical solvent, not liquid CO2.

[@Cheesepuff8]

They’re just gonna look like regular crabs

[@michaelclark4876]

The color may be different but those microbial ecosystems are biofilms, aka slime. And that’s the way life on earth existed for most of the time life has been here. For all the speculation on what form alien life might take, we already know what most alien life will look like, at least to our eyes: slime on rocks.

[@calorion]

I thought that even regular plants were once purple, even to the point that many dinosaurs ate purple plants.

[@RonJohn63]

0:36 We're minuscule, while the Universe is incomprehensibly ginormous and unfathomably old. _THAT_ could be why we've not found extraterrestrial life. And if I wanted to watch a music video, I'd watch a music video.

[@TracyGossett]

That lady makes me feel like I'm in 1st grade, and she's a college professor?

[@alshirley3444]

I am hoping to find Krypton

[@menosproblemos6993]

Might have to redefine 'life'. Maybe we have more 'life' on Earth than we currently know of

[@uncletrashero]

OR we stuck our hand in a glass of water and declared "I now know everything there is to know about the ocean. nothing to see here."

[@fredrichardson7082]

The enthusiasm of both your guests was infectios Ben, great segment and thanks. I totally agree that green, purple and pink life might well be spectrographically inferred on exoplanets. However. Gravity, atmosphere and pressure, UV/IR, chemical composition of the planet/moon etc are presumably massivly variable. WE know that life started early here - purple & pink, then evolved to free.. What I'm saying is that every colour will likely be represented given the unfathomable variety of sliding variable. I'm kinda leaning towards Lee Cronin/Sarah Walker [Assembly Theory] and I would LOVE to see you do a riff on them while you're on this topic. I love your work Dr Miles, thank you for your intellect and effort.

[@fredrichardson7082]

purple & pink, then evolved to free, doh, Green!

[@resurrectedstarships]

Umm aren't most m type stars flaring up all the time?

[@nschilk]

Why are we even wasting time obsessing over other life when we haven’t even mastered ours here on earth. We need more studies on psychology like Carl Yung said. Humans have their priorities mixed up.

[@jaglazzarinim2558]

Yeah you know only that the aliens must be interested in Apeman hahahahahaah

[@coreytomlinson9407]

Hey, I'm signed up for notifications, but I see notification for all the other youtube channel stuff but no video. How do I fix this so I don't visit for shorts or other stuff

[@objective_psychology]

Even if this were so, it wouldn't help solve the Fermi paradox whatsoever

[@freyatilly]

Very very interesting and eruditious.

[@jennimcinnes2825]

Why in the sphincter of Joss did they name them Bacteriochlorophyll? The chloro in the word means green, so they should have used the red prefix erythro and Phyll means leaf, but I will leave that alone

[@Shadowmaster625]

Alien life can be so different from anything we understand that we cannot even conceive of it. For all we know there is life that exists completely on the level of consciouness. It might exist in another dimension and can only access this dimension at certain points like for example the sites where quantum tunneling occurs. In our brains, in other words. This lifeform could be poking and prodding around and either knowingly or unknowingly influencing our thoughts and thus our actions. Imo they know what they're doing and are prodding us towards some end goal.

[@davestorm6718]

Because Carbon is really the only element that allows a level of chemical complexity required for the emergent properties of the building blocks of life, it makes sense that we look for carbon based life. Organic Chemistry (with high complexity) only happens in a rather narrow range of temperature and pressure, so looking looking at hot or cold planets is a waste of time (think about it). Suggestions of Arsenic, Silicon and Boron based lifeforms don't make sense (say at higher temps) as the complexity decreases with temperature (the ability to maintain stable bonds, maintain complex molecular states is simply not there).

[@farerse]

I knew Kaltenegger would be from Austria somehow

[@Raz.C]

The first step should always be to define what this "Life" thing is. As a chemist, my answer is rather blunt and presumably offensive to those who believe in a God (and who thus think we're special). Life is a series of ongoing chemical (or biochemical, if you prefer) reactions. In a sense, even fire is alive. But if we're going to look for alien life forms and we're concerned that we won't recognise alien life, even if we're looking at it, then the easiest way to allay such fears, is to recognise that life is just a series of self-sustaining/ ongoing chemical reactions.

[@josepheridu3322]

14:55 Oceans in the past were saltier? I thought that it was incremental and water was less salty.

[@Onajkunj2]

Wish you all the best man. You are a true bikers treasure.

[@pineapplepenumbra]

It might be that life manages to evolve on a planet around a bright star where the planet was slowly spiralling in, but, somehow, perhaps due to the gravity of gas giants in the system, gains a more stable orbit. It's an unlikely scenario, but with an estimated 10 to the power of 24 planets in our observable Universe, not quite as unlikely as it first seems.

[@CaritasGothKaraoke]

It’s a big universe. Odds are there is a species that looks like Greys out there. Or maybe it’s an infinite universe, which means there are an infinite number of species that look like Greys.

[@wabejoo]

We still don't know what exactly life is, so there's that.

[@orionx79]

I believe in the rare Earth theory, many unique situations occurred on Earth to bring us to this point. I also think our technology isn't advanced enough to travel very far. Our signals weaken significantly after 100 light-years due to the inverse square law, making them unsuitable for galaxy-scale communication, let alone in a timely manner. We expect too much. We have intelligent life in the oceans, but they would be reluctant to; send signals to outer space, forge, or use electricity in a capacity for machines.

[@orionx79]

Even if intelligent life exists in the Milky Way, we’d be unlikely to detect it if it were farther than 150 light-years away and using the same technology as us.

[@corwynmatthew6625]

Life is likely abundant in the universe. It's technology that's rare.

[@StevenHughes-hr5hp]

It probably is mostly life as we know it. So many moons in our solar system with subsurface water oceans. If this is true throughout the universe what we find around deep sea ocean vents on Earth should be fairly normal.

[@corwynmatthew6625]

Autonomous AI agents will be the first to discover ET life, likely by reexamining our archives with new insights like these.

[@ricolorenz7307]

Really glad to have a new science channel after kutgesagst was exposed as a shill.

[@georgepayne9381]

I noticed two things that conflicted with what I thought I knew about sunlight. If I'm wrong, I'd be grateful for some details to correct me. First, if green plants are reflecting infrared, wouldn't that imply that they don't absorb heat? My understanding is that infrared isn't just the wavelength of a color our eyes don't register, it's the wavelength of heat itself. Either I'm wrong (totally likely) or I just never noticed that green plants don't get warm. Second, I'd heard that our Sun is actually a white color, tinted imperceptibly green, and that the yellow is due to the effect of the Earth's atmosphere. I can understand if chlorophyl based life adapted to the color of the light that gets through the atmosphere, and it seemed weird to me that chlorophyl would reflect the most abundant color of light, so are we sure what color the sun is? The rest of it is fascinating. Looking for the color of the gases that might have been metabolized by living organisms when the planet occludes its sun, then looking for the color of the reflection of those organisms' actual surfaces based on what their environment might encourage them to have. It's amazing what you can at least guess at from a distance you couldn't possibly travel with current technology.

[@erumaaro6060]

step 0: define what can be considered life.

[@jonmichaelgalindo]

But a red star planet in water-cycle range ends up tidally locked, right? No day-night cycle, and insanely hot/cold extremes on the two hemispheres.

[@MattPerdeck]

TLDR; we don't know what we're looking for.

[@mrkeepingitreal4927]

What we need to look for is oxygen and methane in a atmosphere really.we need to find other planets to live in and evolve further to secure our future,but we should focus on more sustainable living instead of being greedy and wasteful production living

[@Sq7Arno]

*some alien life. The universe is big enough for almost anything we can imagine from a scientific perspective is possible. Even a lot of things that are mere whimsy. Even species that look nearly exactly like us. Or possibly, exactly.

[@me_at_blue_sky]

@16:20 Plants did not evolve FROM bacteria.

[@alanmckinnon6791]

Do keep in mind that all Earth life to a first approximation, is an insect

[@sjprdude]

Finally, cause all that “life as we know it” crap I hear in other science videos always gets me mad. So pretentious to think that the type of life on earth is the only possible type of life out there!

[@High-Tech-Geek]

But we don't look for green. We look for the byproducts of green chlorophyll. So why don't we instead look for the byproducts of purple bacteriochloryphills? We can do that now with existing telescopes.

[@CanaanKoontz]

Vegetation IS life, though...

[@PoseidonOilRig]

For us, on Earth, yes. That doesn't mean all life looks like that.

[@christopherneufelt8971]

Lovelock Gaia anyone? This answers much more that you can get.

[@marksmadhousemetaphysicalm2938]

What kind of life are you looking for? If it’s any kind…that’s one thing…if you mean technologically advanced…by that I mean…capable of communicating with us over light years…or capable of building star ships…I really wonder if anything but our type if possible…due to the need for chlorophyll and mitochondria and oxygen

[@mvvpro8688]

But do we want to meet other lifeforms like giant bacteria with a superior intellectual capacity?

[@culturebreath369]

We are definitely a science experience by aliens. 😂 Our planet is so interesting and weird. 😂❤

[@Wizardess]

Purple Life Matters. {O.O}

[@tylerproctor4878]

Only an elementary school student would come to the conclusion alien life would have great similarities with life on earth. Come on man. I can't get this time back. I thought this video would have hard evidence of what a particular planets life might look like. Can't believe i watched this whole video. I learned nothing

[@user-xd7zk1pw5y]

Red dying sun, intelligent life gone