Beware of Biosignatures - Sixty Symbols

[@ShandyTheMan]

6:42 I've been watching Sixty Symbols for a while now and I'm genuinely incredibly impressed by how sharp Brady's questions have got. More and more he asks the very thing that's also on the tip of my tongue and brings up the key counterpoints straight to the heart of the matter. Again another absolutely fantastic coverage of the topic by Prof Mike, a true credit to his field and institution! Notts are very lucky to have him!

[@christiannorf1680]

Indeed. Brady's genuine curiosity about science has allowed him to learn an awful lot from all the scientists he spent a lot of time with. I wish a lot more people had such general curiosity

[@sixtysymbols]

Hey thanks.

[@sentientflower7891]

If he is reading your mind that just means that your mind isn't cluttered enough.

[@whoeveriam0iam14222]

I really like the remark at 4:49 it makes Brady's channels so much better than they would have been if all we had was professors talking about their expertise

[@RonJohn63]

He's been asking those sharp questions for a number of years. In the early ones, he didn't ask too many questions (curious, but knowing that he didn't know). Obvious growth in acquired knowledge.

[@GoldSkulltulaHunter]

It's always such a delight to hear Prof. Merrifield talking about these topics.

[@RichardHolmesSyr]

"Biomarker" is absolutely a better term than "biosignature" in that it carries less of an implication of proof. In everyday life, after all, a signature is often what makes the difference between true and not true. Careful choice of terminology is incredibly important and far too often neglected.

[@iambiggus]

Always a pleasure to see Professor Merrifield!

[@lenowin]

Great video explanation of the problem. It's happened a few times as well, where someone gets excited about biosignatures on mars or venus, and it later turns out to be natural phenomena.

[@praveenb9048]

From the title and thumbnail I thought it was about cybercrime involving biometric IDs.

[@grndkntrl]

That would've been on the Computerphile channel though, not here on Sixty Symbols which is physics & astronomy.

[@TheRealInscrutable]

@praveenb9048, Me too!

[@JaneShevtsov]

The other thing to keep in mind is that just because something could be made by a nonbiological process doesn't mean it was. In some cases, the nonbiological process might be so rare that life is a likelier source.

[@breadfan262]

In clinical diagnostics, the term, biomarker, has a very specific and widely known meaning. For example, PSA is a biomarker for prostate cancer.

[@Penrose707]

Always a pleasure to hear from Professor Merrifield, Happy Easter all

[@EebstertheGreat]

These papers are important, because fields like this (and I guess all fields) have to be interdisciplinary. I wouldn't know what the difference between a 'biomarker" and "biosignature" is, but it sounds like that's a huge distinction in some fields, so it's good that a summary of all these terms is published to demonstrate the potential confusion.

[@Felix-nz7lq]

Can confirm as a biology student, don't think we'd ever use those words interchangably. A biomarker is more akin to a heart rate monitor detecting the internal state of an organism, while a biosignature is more like DNA-evidence at a crime scene indicating who has previously been present at the site.

[@amyclea]

It is always a pleasure to see and hear a lecture by prof Merrifield. Perhaps, though, for the sake of completeness, something should also be said about phosphine (PH3).

[@beng6149]

Great to see the same people still making videos. Been watching you for like 15 years.

[@nick2me1]

Great video with a great point. I always enjoy Prof. Merrifield’s videos!

[@Domihork]

I dunno, as an astrobiologist myself, I rarely ever (if ever) hear anyone use the word biomarker in the same sense as biosignature. Actually, I hear it more often from my partner who does neurobiology when he talks about molecules found in the body, signaling for example the first stages of Alzheimer's or ALS.

[@Triantalex]

ok?

[@CatzHoek]

Neat, i love this guy

[@HellMuttCoppersnake]

I like how the graph depicts "I did my own research" vs actual science :D

[@joeyhinds6216]

I cant help but notice how similar the search for dark matter is to the search for life. Its fascinating to me that both would be so elusive and hard to describe.

[@robertstonephoto]

Ozone is produced by common events, such as electrical discharge both in lightning storms and volcanic eruptions. A short lifespan I suspect, so detection may be transient?

[@belg4mit]

The production of ozone by lightning requires the presence of free oxygen, thus it is no different than ozone created by ultraviolet light. Both transform O2 to O3, and that' hat matters, not the mechanism. I expect volcanic O3 is a similar story.

[@poposterous236]

It's like when your google maps says "food near you" but it turns out to be an arby's

[@GeoffryGifari]

Is oxygen not common in exoplanet atmospheres without life?

[@ArawnOfAnnwn]

@@GeoffryGifari Oxygen is quite reactive. So if you don't have a constant generation of more of it, which life provides, it tends to get absorbed into the rocks and stuff and thus loses concentration in the atmosphere. You can see this with another reactive element - hydrogen. Despite being literally the most common element in the universe by far, elemental hydrogen is rare on earth. We have to generate it ourselves for industry. We actually have plenty of it around, it's just locked up in compounds with other stuff - like oxygen, forming water! Cos life keeps generating more oxygen, but not hydrogen.

[@ArawnOfAnnwn]

@@GeoffryGifari Oxygen is reactive. So if you don't have a constant production of more, that life does, it tends to get absorbed into rocks and stuff and thus its concentration in the atmosphere plummets. You can see this with another reactive element - hydrogen. Despite being literally the most common element in the universe, elemental hydrogen is rare here. We have to generate it ourselves for industry. We actually have plenty of it about, it's just locked up in compounds with other stuff - like oxygen, forming water. Cos life keeps generating more oxygen, but not hydrogen.

[@ArawnOfAnnwn]

@@GeoffryGifari Oxygen is reactive. So if you don't have a constant production of more, that life does, it tends to get absorbed into rocks and stuff and thus its presence in the atmosphere plummets. You can see this with another reactive element - hydrogen. Despite being literally the most common element in the universe, elemental hydrogen is rare here. We have to generate it ourselves for industry. We actually have plenty of it about, it's just locked up in compounds with other stuff - like oxygen, forming water. Cos life keeps generating more oxygen, but not hydrogen.

[@ArawnOfAnnwn]

@@GeoffryGifari Oxygen is reactive. So if you don't have a constant production of more, that life does, it tends to get absorbed into rocks and stuff and thus its presence in the atmosphere plummets. You can see this with another reactive element - hydrogen. Despite being literally the most common element in the universe, elemental hydrogen is rare here. We actually have plenty of it about, it's just locked up in compounds with other stuff - like oxygen, forming water.

[@Android480]

I was just thinking about this the other day! That Venus paper was such massive news at the time, kinda sucks that it just fizzled out

[@JCO2002]

Publish or perish combined with wishful thinking. The very poor data didn't merit a paper. Pretty much the Avi Loeb approach to science on that one.

[@TrapperKeeper32]

I'm somewhat surprised the detection if dimethyl sulfide by James Webb on that exo-planet didn't come up. From what I read, we do not know of any other way that DMS is produced besides phytoplankton.

[@nastasch]

because James Webb is a hoax. both the person and the telescope.

[@kbrizy7490]

Finally, a merrifield video!

[@jonwill]

More Prof. Merrifield please!

[@Juarqua]

[6:39] in studying body language they refer to this as a clustering of individual signals. One or two ambiguous signals are never enough but if they show up as a cluster of at least three signals it's getting more and more sure the signals have been interpreted the right way.

[@tamasburik9971]

Love Professor Merrifield

[@ebtsoby]

I'm not a chemist or biologist, but it feels like there is no molecule that would be impossible to be produced by non-biological processes, so I feel like we'll never know based off biosignatures alone, but they can be used as a preliminary search for exoplanets worth further investigation

[@DanKaschel]

I don't think that's the bar to clear. The bar to clear is, "life is the best explanation we have for what we're observing."

[@passerby4507]

It's the same deal with cheat detection, it's a matter of how lucky is too lucky.

[@ASLUHLUHC3]

Why tell us your feelings if you're not a chemist or biologist

[@ebtsoby]

@@ASLUHLUHC3 to try and learn from those who are more knowledgable, I voice my understanding of topics so that I can be corrected so that I can learn more

[@DanKaschel]

@@ASLUHLUHC3 what, can only chemists and biologists have feelings now? We must have missed the memo.

[@D1ndo]

Was this shot before your retirement?

[@AstroMikeMerri]

Yes. But hopefully I’ll still be making some more.

[@IanGrams]

​@@AstroMikeMerricongratulations on retirement! I've so enjoyed and appreciated learning from you and hope to still see you around on Brady's channels.

[@memoryman8462]

Oh no. It looks like he is clearing out his office. I hope we won’t be seeing less of Mike if he is retiring.

[@alveolate]

while the specific paper seems to be more about the sociolinguistics of a term perhaps overused in popular science media, there is definitely great value in becoming more precise with the technical definitions within the field. we could have "level 1" biosignatures for rather ambiguous traces with X% chance of being the real thing or Y sigma confidence however they wanna define it... all the way up to maybe "level 5" (or whichever higher number makes most sense) for an actual smoking gun where researchers have really eliminated over 99% of possible non-biological origins. we do these scales for everything in science and it helps to communicate just how significant a discovery might be. case study: the detection of phosphine gas on venus should probably be only level 1 or level 2, even at the time of discovery with less certainty. there could also be parallel scales, one for the upper track in the diagram "where along the causal chain is this biomarker", and one for that lower track "how many non-biological alternative origins have we eliminated". so phosphine on venus could be a "type A biomarker, with level 1 certainty" or just type 1a, etc.

[@kristopheranderson53]

Thank you for being a standard of

[@ulfpe]

Its difficult to exclude life that uses different chemistry.. Even energy could be from light but also other things.

[@SubTroppo]

Going with title of this channel, is there a symbol for TLWA (Theory Loaded With Assumptions) or the like? If not perhaps there could be one with a suffix reflecting the number of assumptions associated with any given theory.

[@room5245]

Brady deserves to be knighted for his contributions to youtube history and educating nerds

[@Dan-B]

My dumb ass thinking this was going to be about not giving your fingerprints to big tech

[@jh-ec7si]

I think that's biometrics although someone probably calls that biosignatures as well

[@rolfs2165]

That would be a Computerphile video, though.

[@xCorvus7x]

Maybe these signs should be framed as indications, possible symptoms of life. Symptom might be the most accurate term here; building up evidence for life out there seems pretty similar to medical diagnosis.

[@anapananapa]

Gets even more tricky when you consider there are anaerobic bacteria that don’t even need or use molecular oxygen. So we could be looking for the entirely wrong signatures.

[@23bcx]

There's also the other side of this. Why are we assuming that the chemical possesses that drive life on earth are the same possesses that drive life on other planets. Just from universal abundance we can assume most life will use H2O and not the chemically similar HF but most isn't all. The same thing with Carbon vs Silicon. There's life on earth that uses Copper where most organisms use Iron.

[@PopeLando]

Oh. Thought it was going to be about opening your phone with your fingerprint.

[@draheim90]

An inescapable thought I’ve had for a while with AI becoming a thing is that machines might just be the evolution of our species on earth and in the not-so-distant future maybe there won’t be any humans left (once we’re no longer useful to the machines). By extension, maybe it may be all intelligent life’s destiny to essentially wipe themselves out by creating technology more advanced than it, and so finding fully organic, intelligent, life elsewhere will be really challenging (more so than it already is) because it exists on its planet for such a short timeframe…i.e., there’s a very small window to observe it. Maybe we’ll get lucky and find one of its exploration/welcome probes like our Voyager though.. Of course the more classic idea that it’s in the nature of intelligent life to destroy itself through other self-destructive means is also something I consider a lot.

[@cyrilio]

Does mercury have ozone considering it has some oxygen in its ‘atmosphere’?

[@boglenight1551]

I’ve heard that there are rocks in the ocean that may possibly be generating oxygen through electrolysis.

[@AlphaFoxDelta]

Professor Merrifield! Epic!

[@simonf8370]

I was more worried for the professor's poor bookshelves. Is he in the middle of moving?

[@evanparsons123]

Biosignatures? We can barely perform a Standard Candle 🌞🔥

[@haydentravis3348]

Smoke doesn't always mean fire.

[@sk8rdman]

I recently took an Astronomy 101 course and at one point it we were tasked to write about whether it was worth us investing millions of dollars into the development of telescopes, but the prompt was entirely framed around the premise that these telescopes were being used to find life or habitable planets around other stars. Obviously these are interesting prospects that are worth exploring, but they're such a tiny part of what new telescopes are being designed to study, and even then nothing we can detect currently (short of direct contact) even comes close to being conclusive regarding extraterrestrial life. There are simply far too many confounding variables. To suggest that the search for life is the core motivating factor behind telescope technology is an insult to the entire field of astronomy. The fact that this poor framing of the role of astronomy made it into a college astronomy course, even an introductory one, is appalling to me. Poor science communication, as described in this paper, is a part of the problem, and it's even bleeding into education.

[@valtterisaarinen7420]

Make video of 3 body problem. Not a netflix series but the real 3 body problem.

[@s_m_north]

What happened to all your books???

[@beverleyportlock9680]

MIke's bookshelves look very empty! Is he retiring or moving?

[@lkgpuanimho0349]

5:22 Bio-markers are used in medicine and medical field to mean different things, I would strongly refrain to use "Bio-makers" if you want to talk about signs of life.

[@filonin2]

Cfc's would inarguably be biosignatures.

[@seantiz]

When we find signs of KZbin broadcasting on other planets…

[@electrikhan7190]

Google scholar, that's me. I also call myself the desktop dipshit kind of like the armchair quarterback of nerds.

[@JxH]

Remember this? "In August 1996 NASA researchers presented a Martian rock that they said showed clear signs of being affected by life. The rock, which had landed in Antarctica, contained holes and markings that appeared to have been formed by bacterial colonies living on it." Oops.

[@mikenoel3522]

I would think that a biosignature is a maybe of life and a biomarker is a mark of life.

[@VariantAEC]

Never have I once assumed a "biosignature" being detected on a planet means, 'There is complex intelligent life.' on said planet. Who thinks that? Nothing is wrong with saying "biosignature." If people take biosignature to mean life, I can't think of another description that wouldn't evoke similar thoughts, say: "Organic molecules detected in Venusian atmosphere." That would still evoke ideas of life for the same lot that is perpetually confused about the lack of reasonable evidence to believe there is any life is on the planet Venus.

[@pacotaco1246]

Yeah such a signature of intelligence is called a technosignature in the literature

[@entropyachieved750]

Remember, it's never aliens

[@Omevoc]

*until* it's aliens.

[@johnqpublic2718]

It will never be aliens

[@Kyle-gw6qp]

Eventually it will be

[@sentientflower7891]

Well there's these big rocks and who else could have moved them?

[@darstar217]

Yep. No matter what

[@faktablad]

Ruling out non-biological processes and shuffling through all of the different potential environments planets can have seems to me like a perfect job for AI.

[@beattoedtli1040]

Ya can't just count the number of times "biomarker" appears on arXiv! At least take frequencies relative to the total number of papers!

[@OBGynKenobi]

I thought is was when Kristen Stewart gives you an autograph.

[@musikSkool]

What would Mars look like from 500 lightyears away? Would it come back with a high probability of Biosignatures?

[@sentientflower7891]

Mars wouldn't even be a pixel from 4 light years away.

[@musikSkool]

@@sentientflower7891 But what color?

[@sentientflower7891]

@@musikSkool no color. The sun overwhelms the planets.

[@musikSkool]

@@sentientflower7891 Then how can they claim that a transit gives us color information?

[@sentientflower7891]

@@musikSkool the transit changes the spectrum of the star proving information about the atmosphere.

[@kapa1611]

1:05 now i don't like defending the media, but when you call it "bio"signature, they not crazy to assume it's life related. excusing that by saying "it's in a very specific technical sense" is a bit of a cop out, imo. in "technical sense" is "bio" not related to life?! xD maybe be more honest and clear, instead of blaming the media for taking what astronomers say seriously xD this isn't the only example btw, they also do this with "Earth like" planets. you know earth is unique (as far as we know) in that it has life, so it's misleading to name them that, especiall when it then turns out that they are tidally locked planets without atmospheres xD but you don't then call them "Mercury like". just try to be a little more honest and call them "small inner planets" or something. astronomers love to name things like they are life/earth related tho, it's misleading to say the least

[@steinarne79]

Hahahaha, Google Scholar !! Made my day

[@christiannorf1680]

Why?

[@jeremyscheatday7305]

At this point, there are many more benefits of space travel than looking for life. But I figure scientists have to keep asking that question to satisfy the public’s need to have a purpose. But I think we will learn more when we just accept that we will find life when we find it. We should be more focused on the logistics of space travel so we can actually put eyes on the ground and observe.

[@CutleryChips]

Uh oh,.. the three body problem

[@solospirit4212]

The other problem with looking for these biosignatures is that its assuming the buolchemistry of extraterrestrial life is the same as terrestrial life. And thats definitely not a certainty.

[@christiannorf1680]

It's not a certainty, but very likely. Our biochemistry is built around the fundamental chemistries of (mainly) carbon, oxygen and nitrogen which are also very abundant elements in the universe. If the conditions are not extremely different, it is reasonable to assume exobiology will work in a similar way as our biology. Popular sci-fi concepts like silicon based life or nitrogen based or whatever are nonsense on an earth-like planet. That is simply dictated by chemistry.

[@badlaamaurukehu]

Phosphorous

[@jeroenrl1438]

The problem is that all chemistry is the same everywhere. The fact that what we call life uses some chemical reactions doesn't make those reactions special. If they can be done in (earthly) life, they can be done in an extraterrestrial non bio environment.

[@CAPSLOCKPUNDIT]

The downside of having a sample size of one source for known chemical biosignatures.

[@solospirit4212]

@christiannorf1680 But even terrestrial biochemistry shows significantly varied forms..notably various extremiphile organisms...so assuming Ixygen as the major biosufnatore is definitely not a certainty..even on Earth. So, whilst I also don't expect very exotic, SF, lifeforms.. I still say there are alternate Chemistrys * even in the carvin based ones( that may generate different signatures. As an aside concerning silicon using lifeforms..there again are more than a few here on earth..so I won't rule that out as playing a bigger role in ET biology...

[@malavoy1]

And here I thought you were warning us against using fingerprints to access our phones. 😊😊

[@yoram_snir]

Giant monsters on far away planets 😀

[@frederic2166]

Don't get me wrong, I love it but, he wrote a paper on how to do science

[@LeeClemmer]

So what you're saying is, "aliens." It's always aliens.

[@mikenoel3522]

And why are we so afraid of being wrong. We are wrong about a lot of things, but we figure it out... Eventually!

[@43lk]

I'm making technosignatures almost every clear sky night, taking flashlight and flashing into the sky and moon in irregular and regular patterns

[@krumuvecis]

Uh oh, now we're doomed

[@johne.coughlan6824]

This is bugging me you do not need oxygen for life to exist.

[@filepz629]

👽🛸

[@_vicary]

The fact that I can easily imagine the reasoning of this whole video being played back as a ChatGPT conversation scares me, don't give AI access to papers.

[@itzhexen0]

What? Did the aliens leave some DNA in one of our fellow humans? Oh, still no aliens.

[@stoatystoat174]

:)

[@cerealpeer]

we should measure all the times our biosignature will take to reach a given exoplanet

[@Ray_of_Light62]

Biosignatures are conditions which are necessary, but not sufficient, to sustain life. Life is an anti - statistical phenomenon which is based on a series of chemical and physical processes that execute by themselves, until they generate a living being capable of reproduction. Animal life - or the genetic code that generate it - has been hacked to generate an even more unlikely series of electrochemical processes in the brain organ, able to execute processes based on symbols which aren't necessary to sustain life, but are necessary for transcending the phenomenon of life - moving toward complex objectives: that is intelligent life, which has nothing to do with life. The fact that humans all belong to the same biological species should be a strong indication of where things are standing...

[@pitthepig]

What a soup of words 🎉

[@MCsCreations]

Why the heck do scientists are so afraid of life outside Earth? I honestly can't understand it. After all, it's just a consequence of physics and chemistry.

[@docbones213]

Aliems.

[@MrTuffarts]

If we find one it will be slime farts

[@RagaarAshnod]

AI research needs this kind of collective organization

[@SolaceEasy]

Word meaning varies over time.

[@abigailcooling6604]

Normally this is perfectly fine, but the problem here is that they don't want the public, journalists or scientists in other fields to get the wrong idea about a potential sign of life (that might not even be life).

[@VariantAEC]

That's why we have dictionaries with definitions, so words aren't meaningless, and any changes to meaning are cataloged. There were no changes to the word in this case, though.

[@VariantAEC]

​@@abigailcooling6604 It is not about that in this case since the words' meaning hasn't changed over time.

[@KrisCarter]

shabriri grape thumbnail, E.R. mind rot is real

[@davidwatson7604]

Algo boost! Boom Lana Del Rey Lana Del Rey

[@Breyyne]

Google Scholars. 🤣

[@myceliation]

he has aged rapidly :(

[@byrnemeister2008]

Beards do no favours on that front.

[@sharqstep]

hi need some opinions for this FOR [0,1] TRAIN [MODEL] AS [AVATAR (x)] WHILE [USER='GOD(y)'] REFLECT(y=x)