"Scientists headed by David McKay of the JohnsonSpaceCenter in Houston found that the rock, called ALH84001, had a peculiar chemical makeup. It contained a combination of minerals and carbon compounds that on Earth are created by microbes. It also had crystals of magnetic iron oxide, called magnetite, which some bacteria produce. Moreover, McKay presented to the crowd an electron microscope view of the rock showing chains of globules that bore a striking resemblance to chains that some bacteria form on Earth. “We believe that these are indeed microfossils from Mars”"
I was disappointed that the story fizzled out. One microbiologist concluded that bacteria from Earth had "contaminated the Mars meteorite. Other scientists pointed out that nonliving processes on Mars also could have created the globules and magnetite clumps." But I don't think life is ruled out. This meteorite is hanging in as a "just maybe" like the Viking mission discovery.
I too find it strange that multiple landers have been sent to mars since Viking, ostensibly looking for evidence of present or past life, and have yet have carried no tests for it. I find the best way to find something is to look for it.
This significantly increased my frustration with NASA.
If genetic material did travel in either direction, it would be easily verified.
However, there exists or has existed one planet with the first civilization ever.
Even if each of those events were actually inevitable, planet size, radiation received from host star, exact chemical makeup of atmosphere/oceans and any number of other variables could affect the time scale for a planet to fruit.
If it is difficult for civilizations to develop, then our existence is so implausible already that being the first is not such a leap.
There are a 100 billion galaxies. I'm ready to guess each has at least a few planets theoretically capable to sustain life for long enough.
is thought provoking.
1. ET life formed and vanished so quickly that they didn't even get to the stage where they generate electromagnetic signals.
2. ET life formed and got to generate EM waves, but:
- they're either too far from us that we haven't detected those waves yet;
- they only recently got to this stage and the signals they produce have not reached us yet;
- or both.
3. ET life formed way sooner than we did; figured out how to generate EM waves, and then vanished entirely. So, any signals of their civilization they must have sent out there have already reached earth, but before we began listening for such signals.
4. Then again, since there are practically infinite number of planets with habitable conditions for ET life, statistically speaking, we must have already received a signal from at least one of them.
Which leads me to this:
5. ET life doesn't exist, because the universe as we know it is most probably a simulation inside a computer and the computational resources can only render so many different objects at a time. (This is serious stuff, researchers have already proposed methods for verifying this:
Um, sorry to break it to you but the horse has left the barn in regards to future prospects.
The best broad test to look for life would be to look for an entropy source.
On August 2008, the Phoenix lander detected perchlorate, a strong oxidizer when heated above 200 °C. This was initially thought to be the cause of a false positive LR result. However, results of experiments published in December 2010 propose that organic compounds "could have been present" in the soil analyzed by both Viking 1 and 2, since NASA's Phoenix lander in 2008 detected perchlorate, which can break down organic compounds. The study's authors found that perchlorate can destroy organics when heated and produce chloromethane and dichloromethane as byproduct, the identical chlorine compounds discovered by both Viking landers when they performed the same tests on Mars. Because perchlorate would have broken down any Martian organics, the question of whether or not Viking found organic compounds is still wide open, as alternative chemical and biological interpretations are possible.
In a paper published in December 2010, the scientists suggest that if organics were present, they would not have been detected because when the soil is heated to check for organics, perchlorate destroys them rapidly producing chloromethane and dichloromethane, which is what the Viking landers found. This team also notes that this is not a proof of life but it could make a difference in how scientists look for organic biosignatures in the future.
It's funny that perchlorate is likely what confounded the LR experiment, as the discovery of perchlorate in the soil made a lot of folks less optimistic about life being able to survive on the Martian surface.
You’ve been a great audience, I’ll be here for the next 7 sols!
I'm very surprised by that.
Especially since, as the article says, "NASA maintains the search for alien life among its highest priorities".
I thought that would obviously translate to sending life-detection instruments to B̶a̶r̶s̶o̶o̶m̶ Mars.
A big discovery has a high burden of proof and that’s basically where we’re at. There’s definitely reason not to rule it out but I can’t believe conclusive evidence is being sat on by all of NASA for funding reasons.
Let’s speculate for a sec. Tardigrades can survive space. Things have been hitting us knocking earth stuff into space for billions of years. Some of that stuff probably made it to Mars and back in the day it was pretty liveable. It’s not far fetched. None of that negates the above.
Yet here we are, discussing it as if this is fake news. I don't think we need to call this a "conspiracy", just the lack of official confirmation makes anyone saying that there's life on Mars sound like a crackpot.
Given all theories and evidences we've observed thus far it's expected that we are not the only living things in the universe. Except for some fringe theorists, everyone expects life to exist in other places besides Earth. Finding out that life exists elsewhere in the solar system would just be more evidence for what we already belive to be true. So, not really huge news in itself.
In evolutionary terms, it does not seem to be pro-survival attitude.
That doesn't mean they can't be harmful though. Bacteria that quickly eats through concrete for example would be just as bad to bring back.
Human physiology depends very much on various bacteria. Supposedly, there are 10 times as many bacterial cells than human cells in our bodies. Perhaps you should reconsider your attitude if you take into account that bacteria from Mars might wreak havoc on these bacteria?
Does anybody know either way?
but also, if it doesn't find food we are not safe yet. the bacteria itself could be toxic in some way and it could reproduce elsewhere and enter our body through food or other ways.
it doesn't need to target our bodies. it just needs to cause an averse reaction of some form.
compare to chemicals for example. they don't target anything. they are inert. yet some chemicals are poisonous.
There is a standard and open pipeline to getting an instrument on these missions. Scientific American is not part of it. It’s more like AGU, LPSC, Icarus, and the National Academies decadal survey — writing actual instrument proposals with hypotheses and trace back to hardware that can make the measurements needed to test the hypothesis.
If humans go to mars we will be proceeded by the robots.
Constructor bots instead of explorer bots.
Popular sentiment would quickly swing (or be swung) towards leaving Mars alone. "We've f*d up one planet, let's not destroy two!", "leave Mars to the Martians", etc.
Vested interests opposed to the space program would get legislation passed that declared Mars indigenous life to be a protected species, and interference with a planetary ecosystem a criminal act.
That would be the end of any exploration or settlement.
But if they don't include life detectors, and declare that "no life has been detected there", then discovering that they were wrong will happen once the colony is already in place. Too late, the ecosystem is already altered, might as well keep going and study it.
Better to ask forgiveness than permission.
I was surprised by this statement. I thought atmosphere on Mars is too thin to support any kind of combustion.
After some searching the closest thing I found was a bunch of popular science articles seeing aliens in white pixels on images from Curiosity . It seems all very much like people trying to make a thing out of image artifacts. NASA's much more reasonable explanation is stray reflections in the optics or cosmic particles striking the detector.
If perclorates were the cause of the Viking positive as many suggest, why not send a new experiment designed to rule that in or out? Why not send a whole lot more chemical tests for biology, or a microscope for that matter?
I suspect there is strong concern about the social effects of the revelation of any extraterrestrial life, even microbes. From what I see of the mass psychosis that is most of current political discourse this concern might not be unfounded.
Who categorizes science as an intrinsically atheistic endeavor other than religious apologists?
The nature of general religious beliefs is that they're essentially non-falsifiable.
And particularly in this case, life on mars wouldn't be shocking due to the fact that there is life on earth and there is a small amount of mass transfer. If there isn't some amount of microbial life on mars it would only because of the dumb luck that there hasn't happened to be anything on earth that could get transferred, survive the transfer, and survive on mars.
If the planet is dead, we as a civilization get the privilege to do whatever we want with it. Also a dead planet means the idea of the Monotheistic God kind of remains.
Ignorance is bliss.
I don't follow why life on another planet would have any bearing on the idea of a Monotheistic God.
The garden of eden could be in some far flung galaxy, from which we “life”, were expelled as microbes, thanks to the sins of relatives we wouldn’t recognize. The rib of Adam could symbolize the arbitrary evolution of sexual reproduction from asexual origins. The forbidden fruit could represent some inevitable nuclear holocaust spurred on by some intra-species conflict, which prompted life to be cast out and begin on another planet. Something unique about our shape of life means that we’re stuck in a cycle of destructive evolution that cannot be saved from itself, excepting for the divine intervention of some less imperfect shape of life.
Anyways, I’m rambling! I hope this sparks somebody’s theological-scifi bug and produces a mildly entertaining narrative in somebody else’s head. :)
Stuff like that.
But I think the reason it’s not talked about more is that our knowledge is essentially non existent and hasn’t really changed in, say, the last fifty years?
The Drake equation is a nice framework to determine the probability of life outside of our planet. Sure, the end result is still a big mystery, but many of the variables in the Drake equation have been solved or narrowed down (e.g., star formation, planet formation, etc.). To say that there has been no progress in the last 50 years is silly.
I think that would be a different answer if we found inorganic life, as that would blow up the concept of organic life as singular in "life" bearing capability. I doubt we would recognize inorganic life as "life" in that case however, as humanity has a poor working definition of "life."
Absent a recognizably intelligent form of life found off planet, I doubt much would change (practically or existentially) for us here on earth.
If you don't consider "does life exist on other planets?" to be a fundamental, existential question, can you share an example of what you do think is such a fundamental question?
Finding life on Mars wouldn't necessarily resolve any fundamental questions, but it would open up a whole new realm of questions. Is it similar to life on Earth? How similar? Is there evidence for or against some form of panspermia? (at its most extreme, life arriving on Earth from outside the solar system, but this could also be life arising on Earth and being transported to Mars via impact ejecta, or vice versa)
Also, lots of worthwhile science is done even though it doesn't have an immediate and obvious impact on everyday life. I can't think of any particular way in which the discovery of gravitational waves has changed my life, for example - but I recognize that the work that's gone into it has advanced human knowledge, and probably will indirectly benefit my life (or my descendants' lives) in ways I can't predict.
Is the concept of objective meaning valid in any possible universe?
Is it possible for the universe to be a fully observed deterministic system?
Is there a universal objective function motivating what we consider reality?
Is it possible to determine with certainty the origins of what we can conceptualize as reality?
Is it possible to forecast with mathematical certainty events in future time steps.
Basically just off the top of my head my questions boil down to: Can laplaces demon actually exist, is there a resolution to the munchausen trilemma and is godels incompleteness theorem disprovable.
Do you actually understand its proof? On what basis would it be disproven? It's really difficult for me to even conceive of what disproving it would even "mean" - you seem to think that it's somehow tied to whether the universe is deterministic, but it's not. A "disproof" would essentially break the very logical tools used to construct itself (since it is the nature of these that Godel's theorem concerns); it's like trying to drive further north than the north pole - there simply isn't a conceptual direction to go unless you completely redefine the meaning of "north".
Edit: Also, Laplace's demon has likely been formally proven to be impossible: https://phys.org/news/2018-05-proof-reveals-fundamental-limi... Perhaps your apparent belief in Laplace's Demon combined with the comparison of this proof to Godel's Theorem is your motivation to suggest that it can be disproven?
I'm not proposing solutions or saying that there are errors with these proofs. Rather, when I finally understood them years ago it induced an existential crisis that I don't see any pathways to resolve.
My hypothesis is that humans aren't capable of conceptualizing experiments or building tools that could approach the three most intractable problems in epistemilogy. Maybe we don't have the math to do it, or it's fundamentally intractable and it will never be resolved, I dunno. But those are much more interesting questions than "is there an amoeba on europa?"
(That being said: I personally find "is there an amoeba on Europa?" to be supremely interesting, but to each their own.)
I should also state, I certainly find the concept of life on other planets extremely fascinating. However as I said above its insufficient to give clarity to some of the more fundamentally existential questions around our existence.
So there’s at least one of us.
That being said, for most people who aren't operating on your level, the fundamental existential questions haven't changed much in a few hundred years. "Are we alone in the universe?" is probably among the newest for us.
Your questions are valid and really interesting, but that doesn't make the questions of "Do other planets have life?" and "Where did life on Earth originate?" invalid or uninteresting. Personally I'm interested in all of them.
And yet despite the certainty of death, we, individually and as a group, seem to have an unquenchable desire to know more. To know is to grow, and this collection of processes we call life has never been seen off the planet so yeah, it'd be quite some growth.
Edit for a TL;DR - The basic idea is that, if we don't see evidence of intelligent life in the universe, it must be because star traveling species must be rare. If we find life evolving twice in one solar system, then the early parts of life evolving must be relatively easy - which suggests the later parts of life becoming technologically advanced are the hard parts. In other words, life on Mars may mean that there may be more problems ahead of us than behind us.
Simply verifying distance between two similar things isn't a sufficient variable to answer questions about distinctiveness of origin.
2. Multicellular life
3. Intelligent life
4. Interstellar colonization tech
If you make it through all levels you should be colonizing the galaxy and detectable by us therefore.
Finding life with a separate origin than ours removes one of the possible spots for the great filter and makes it significantly more likely that the great filter is ahead of us rather than behind.
This is a question that will help with the survival of humanity.
It depends on how different it is chemically form earth life. If it is similar enough that it shares a common origin, it's no big deal. If it isn't, then that's a massive deal because it means life originated twice in one solar system, therefore is probably widespread.
Or we might get a repeat of when the Spanish brought disease to the Inca and Maya.
The mere knowledge of life is viable off-Earth is huge. If we find it on our nearest neighbour, the chances of encountering it elsewhere rise markedly. Hopefully it would trigger a search elsewhere in the solar system, like Europa.
Unlikely. There's been no animal hosts on Mars, in which such a micro-organism might have evolved to threaten humans on Earth.
Not to say we shouldn't be careful for other reasons though. The bigger risk is the sudden extinction of entirely different branches of life, by more highly-evolved Earth-originating species.
This is popularly misunderstood. We obviously don't see Type 3 civilizations, but if another of our own civilization was in our galaxy, we would have had an very small to extremely small chance of seeing it.
I'd wager life is everywhere, and just as is the case on earth, it pays, in terms of survival, to blend in with your surroundings.
The anthropic principal becomes less compelling; to say nothing of the religious implications.
Religion will last for a very long time into the future, forget about major lasting change on that front other than some rearguard action to ensure survival.
Until the 1970's or so it was getting better, since then it's gotten worse if anything.
On the Christian side we have whole continents that are following some cliff notes' version of Christianity, mostly centered around money and some opportunistic politics. On the Islamic side a small group of fanatics has managed to divide the world in a way that seemed unthinkable 25 years ago and so on.
Some people think Christians would have a hard time with extra-Terran life because the Bible doesn't mention any life other than the life here, and therefore any such life would arguably be free from the weight of Original Sin, yada yada yada. But I'm pretty sure if life on another planet was discovered (even intelligent life) they would just reinterpret the Biblical references that seem to refer to "Earth" as referring to "The Universe" and make "The Garden of Eden" a metaphor, and the flaming sword would become a supernova, blah, etc., yada, blah, blah, blah. At the end of the day, approximately 0.0% of Christians would say "Hmm... the Bible is obviously incomplete and or inaccurate, so maybe the whole thing is a load of bollocks" or whatever. And I expect it would be about the same for every other faith.
Aside from the narrow one involving the oxidization of carbon, I have a hard time coming up with a definition of life that doesn’t consider storms, planets, or star systems “alive”. In particular, they are all time-limited phenomena that are organized but somewhat unpredictable at macro scale and chaotic at micro scale.
For plenty of us, AndrewKemendo is right... learning that there is life on Mars would not answer any particularly fundamental questions. Maybe because a lot of people simply take it as a given that life exists on other planets (whether or not Mars is one of them isn't really a big issue) because they don't have the hubris to believe that there's anything so special about Earth as to believe that life could only emerge here.
Frankly, you can count me in that crowd. I'd be more surprised if it was somehow proven that there isn't life anywhere else.
To me, "fundamental questions" would be more like:
1. Is free will possible? If so, how?
2. How did the universe begin? If there was a "Big Bang" as popularly described, where did all the matter come from that expanded out of the initial singularity? If time did not exist before the universe began, how did the transition from state "no universe" to state "universe" happen, since - presumably - nothing can "happen" without time.
3. What is time?
4. Is space discrete or continuous?
5. Is time discrete or continuous?
6. Are there multiple dimensions of time, analogous to the multiple dimensions of space we know about?
7. Is our "4-D" world actually embedded in a higher-dimensional reality of some sort that we can't access/understand/see/etc.?
8. Is our world a simulation (ala The Matrix)?
9. How, exactly, do fields (electromagnetic field / higgs field / etc) permeate all of space and permit the existence of particles like photons or the higgs boson?
10. Is there actually a way to unify gravity and quantum mechanics?
11. What is dark matter? Where did it come from?
12. How will the universe end? Big crunch? Big freeze? Big bounce? The simulation ends and we all just disappear? Other?
13. Why is there any matter at all in the universe? The fact that there is implies a certain fundamental asymmetry to the universe, since if matter and anti-matter were created in equal amounts at the beginning, they should have annihilated each other leaving no matter behind.
14. Why are right-handed people more common than left-handed people?
15. Why does the universe itself appear to have a "handedness" property?
I feel like this should be more pervasively held belief to a bunch of people with a higher than average propensity of consuming scifi. Star Trek did a pretty thorough job of showing that the same fundamental questions persist even if we assume there exist more intelligent species out there.
You would know there's tech out there, the first able to reach to it will have the edge over the rest for centuries ahead.
The effects will be massive, no one dolar, yuan, yen, gold bar would be left unspent in the quest to get there and learn before the others.
Then there's the realities of being an american adult where even science is politicized. Think of all the boomers that grew up watching the space race with baited breath. I bet some of these same people today would support a politician who would defund NASA if it meant saving $30 a year on their taxes.
Bated, as in abated.
Fun fact: bated breath was coined by Shakespeare.
Thus many scientists try hard to dismiss evidence of alien life, because that is fashionable. Or at least, the alternative is very kitschy.
The reason people try to discount aliens is because you can attribute literally anything to aliens. And so you reach another equally simplistic binary. You discover some unknown phenomena. It is aliens, or not? Well we've discovered a whole lot of unknown phenomena throughout the years (and centuries and millennia depending on how you want to play this game) and often times it really did look a whole lot like aliens, but to date it's never yet turned out to be them.
And since the determination of an unknown phenomena often comes down to probabilities, aliens get weighted down a good deal. But nonetheless, I have no doubt that at least lurking in the back of every physicist's mind is that something now as regular as a fast radio burst could indeed finally be those LGM - the kind of joking nickname given to the first radio pulsar discovery. Standing, of course, for little green men. Is it? Well probably not, but it'll always be probably not - including when it finally is.
It is "inconclusive" at best.
Ultraviolet (UV) activation of the Martian surface material did not, as initially proposed, cause the LR reaction: a sample taken from under a UV-shielding rock was as LR-active as surface samples;
Complex organics, have been reported on Mars by Curiosity’s scientists, possibly including kerogen, which could be of biological origin;
Phoenix and Curiosity found evidence that the ancient Martian environment may have been habitable.
The excess of carbon-13 over carbon-12 in the Martian atmosphere is indicative of biological activity, which prefers ingesting the latter;
The Martian atmosphere is in disequilibrium: its CO2 should long ago have been converted to CO by the sun’s UV light; thus the CO2 is being regenerated, possibly by microorganisms as on Earth;
Terrestrial microorganisms have survived in outer space outside the ISS;
Ejecta containing viable microbes have likely been arriving on Mars from Earth;
Methane has been measured in the Martian atmosphere;
microbial methanogens could be the source;
The rapid disappearance of methane from the Martian atmosphere requires a sink, possibly supplied by methanotrophs that could co-exist with methanogens on the Martian surface;
Ghost-like moving lights, resembling will-O’-the-wisps on Earth that are formed by spontaneous ignition of methane, have been video-recorded on the Martian surface;
Formaldehyde and ammonia, each possibly indicative of biology, are claimed to be in the Martian atmosphere;
An independent complexity analysis of the positive LR signal identified it as biological;
Six-channel spectral analyses by Viking’s imaging system found terrestrial lichen and green patches on Mars rocks to have the identical color, saturation, hue and intensity;
A wormlike feature was in an image taken by Curiosity;
Large structures resembling terrestrial stromatolites (formed by microorganisms) were found by Curiosity;
a statistical analysis of their complex features showed less than a 0.04 percent probability that the similarity was caused by chance alone;
No factor inimical to life has been found on Mars.
Similarly, the above list of facts is indirect evidence for life on Mars.
This could all be explained by a weather balloon being dragged to Mars and releasing swamp gas
It's his life's crowning achievement as the project leader, and seeing indicators that turned out to be nothing must be a tough thing to come to terms with.
If we make an AI whose thoughts and communication are practically indistinguishable from humans, and it controls a bunch of things that affect the physical world, is it alive?
If there's a disembodied mind somewhere that can think and imagine but never communicate or interact with anything, is it dead?
What about a human in a coma or permanent dreaming state? What about when they later wake up?
Okay nevermind thoughts and communication; What if there's an armada of "dumb" robots, spawned from a single factory, that can't think, only acts according to preset instructions, but still goes on to affect many things for hundreds of years, what should they be classified as? Would they be considered "artificial" life or automatons even if they existed for thousands of years and their creators were no longer around?
I don't think there is any single absolute criteria to classify all possible entities that must be out there or could theoretically exist, but the answer to "What is life?" is probably this:
Whatever other life thinks is life.
That definition catches every single thing you'd call life, excludes all the things that clearly aren't, disambiguates some grey cases, and illuminates one or two new phenomena to be life which you might not have realized.
To be clear, Darwinian evolution means:
- It makes copies of itself (reproduction)
- The copies take traits from the original (inheritance)
- The traits can vary among the copies and between generations (mutation)
- The copies' ability to make more copies depends on the traits they inherit (selection)
Again, what about species that don't reproduce themselves, but spawn from a single "factory"?
That factory may be nothing like them. It could be a mechanical factory producing automatons (with human-level thought if you need that criteria), or a universally-unique "mother" creature, or even a non-sentient spawning pool where they spontaneously form every now and then.
If there are entire planets populated by such entities, and they have governed over many things for as much time as we have occupied our Earth, would you still classify them as not-life in your dealings with them?
That would be like not considering Taiwan a country. (Sorry, couldn't resist injecting contemporary political commentary.)
How did the "mother" creature come to be? By what mechanism did its complexity emerge?
There is no known or plausible mechanism by which complex life can arise without evolution, and technology which does not change its design is (very appropriately) by the definition above, not life.
It could be a human "mad scientist" creating hordes of Pikachus.
Suppose the scientist has also attained biological immortality for himself, and the Pikachus have spread to multiple planets over thousands of years.
You come upon such a colony planet, but you have no knowledge of their creator. They display no clues that hint at the scientist's role in their civilization (for a civilization it has become by now.)
You cannot discern how the Pikachus are coming into existence. Would you classify them as life? Why not?
How would your interactions with them and their interactions with the universe be fundamentally different than any other life you encounter?
What if they were robotic instead of flesh-and-fur?
Can they mutate? If so, then they satisfy all four boxes and they count as life.
If the Pikachus are made of cells, they'll certainly mutate/vary, since their heritable material is DNA, which is quite fragile.
Really, it's hard to imagine having "reproduction" without "mutation" in the imperfect physical world where errors are possible— I can't imagine any copying process, even a technological one, which succeeds with perfect fidelity and 100% probability. So if you have #1, #3 is basically going to be a given, because the universe is imperfect.
I don't think "what material they're made of" matters much, except that by definition flesh has to be alive, since it's made of things (cells) that tick all four boxes.
If the Pikachus don't reproduce themselves, and/or are created with perfect fidelity every time, then yes, I would call them technology and not life. We certainly wouldn't say that iPads (Pikachus) coming from a factory ("mother creature") are alive.
No, they're all created by the mad scientist but can think, reason, communicate, teach, interact, invent and construct perfectly fine on their own.
> I don't think "what material they're made of" matters much ... If the Pikachus don't reproduce themselves, and/or are created with perfect fidelity every time, then yes, I would call them technology and not life.
So, to distill your criteria for life, it comes down to:
• Species must consist of "individuals" who join in pairs to produce another individual.
• New individuals must be slightly different from the individuals who reproduced them.
In other comment  you say that you could consider software to be alive:
> Note that "alive" by the given definition doesn't imply "conscious" or "intelligent"
> We certainly wouldn't say that iPads (Pikachus) coming from a factory ("mother creature") are alive.
But if an iPad had a software process that connected to another iPad, and they both commanded the factory to create a new, slightly different iPad, would they be considered alive? :)
Where did you get pairs from? If the Pikachus reproduced by binary fission (splitting in half and then growing a new half, like cells do), or had 18 genders, they would still evolve. They only have to make copies. Doesn't matter how.
> No, they're all created by the mad scientist but can think, reason, communicate, teach, interact, invent
If they can't reproduce (and/or aren't made of stuff that can reproduce), I would say complexity of behavior is irrelevant.
For example, the identical iPads coming off the factory line are still technology, whether they are loaded with simple software or complex software. The complexity could go all the way up to AI, but they would still be technology.
Note that we are used to "intelligent" meaning "alive", because the only intelligent thing we know of at this point in history (us) is alive. But I think it is perfectly valid to suppose that non-living things could be intelligent or even conscious.
> So if an iPad [...] created a new, slightly different iPad, would they be considered alive?
Yes, under those conditions they would certainly start evolving, and I think that's a perfectly reasonable line to draw between technology and life. In this new example, the "phenotype" of the iPads would change in a self-sustaining way, emergently, independent of any design or intent.
Do I have it correct?
> An individual of an species has to initiate the production of another individual
> of the same species
It depends on what you're defining to be "the same species", but if we take that to mean "shares traits with the original", then that's "inheritance".
> new individual must have some differences
The one you're missing is "selection"— that the future success at copying depends on the traits you inherited.
If you have variable traits, but they don't at least indirectly result in either more or fewer copies, then there is no cause for some traits to become more prevalent than others in the population and evolution won't occur. You'll just get a jumble of random traits without any trend toward fitness (aka more efficient copying).
It is a fact of nature/mathematics that those four rules are necessary and sufficient for evolution to occur. If you set them up, evolution will happen, guaranteed. Those rules constitute an algorithm, carried out by the laws of nature on the substrate of physical matter, whose result is evolution— a trend toward increasing reproductive fitness.
Could software be alive?
Note that "alive" by the given definition doesn't imply "conscious" or "intelligent" (though that is certainly logically possible for software too, though I doubt that has happened yet).
If we make an HN account whose thoughts and communication are practically indistinguishable from Razengan's, and it makes similar comments in all the same threads, is this account actually Razengan's?
The answer to "Who is Razengan?" is probably this: Whoever other HN users think Razengan is.
It's more useful to situate concepts such as 'life' at the center of constellations of other concepts such as 'self-determination', 'will', 'evolution', and so on.
"A distinctive characteristic of a living organism from dead organism or non-living thing, as specifically distinguished by the capacity to grow, metabolize, respond (to stimuli), adapt, and reproduce"
This article does a poor job of explaining the experiment in question: "Labeled Release" (LR).
According to Wikipedia:
> ... In the LR experiment, a sample of Martian soil was inoculated with a drop of very dilute aqueous nutrient solution. The nutrients (7 molecules that were Miller-Urey products) were tagged with radioactive 14C. The air above the soil was monitored for the evolution of radioactive 14CO2 gas as evidence that microorganisms in the soil had metabolized one or more of the nutrients. Such a result was to be followed with the control part of the experiment as described for the PR below. The result was quite a surprise, considering the negative results of the first two tests, with a steady stream of radioactive gases being given off by the soil immediately following the first injection. The experiment was done by both Viking probes, the first using a sample from the surface exposed to sunlight and the second probe taking the sample from underneath a rock; both initial injections came back positive. Subsequent injections a week later did not, however, elicit the same reaction, and according to a 1976 paper by Levin [author of the linked article] and Patricia Ann Straat the results were inconclusive. In 1997, Levin, Straat and Barry DiGregorio co-authored a book on the issue, titled Mars: The Living Planet.
To recap, martian soil was incubated with small organic molecules bearing a radioactive label. A chemical process that converted them into CO2 would give off some radioactive gas. The gas was detected by both landers the first time the experiment was run, but not the second time.
It should be kept in mind that non-biological processes can also convert small organic molecules into CO2. Simple combustion will do this, for example.
This possibility is discussed later in the Wikipedia article (but not in the linked article):
> Despite the positive result from the Labeled Release experiment, a general assessment is that the results seen in the four experiments are best explained by oxidative chemical reactions with the Martian soil. One of the current conclusions is that the Martian soil, being continuously exposed to UV light from the Sun (Mars has no protective ozone layer), has built up a thin layer of a very strong oxidant. A sufficiently strong oxidizing molecule would react with the added water to produce oxygen and hydrogen, and with the nutrients to produce carbon dioxide (CO2).
However, this does not explain the discrepancy between the first and second test. And it leaves open the question of why both landers' experiments gave the same odd result (first test positive, second test negative).
The small organic molecules used as nutrients were those produced in a famous lab simulation of early earth. Its results showed that many of the basic building blocks of life could be formed by passing an electrical current through gases thought to be present in the early Earth atmosphere.
Think about what you could do with an Apple II (8-bit CPU, 4/8/16k memory), and the Vikings were much more powerful. They were also the size of a Volkswagon, but I'm not sure how much was equipment vs computer.
A software update killed one of the landers by accidentally overwriting the antenna software. (40 years later, not much has changed...)
Anybody who thinks they want to move there should camp in Antactica for ten years, first.
I'm pretty sure this is the whole point of the article.
Planetary Protection is already a thing, even though we haven't found anything yet.
I want to believe.
Part of this is that it's expensive to do experiments on Mars, and space is limited. Each experiment you choose to do excludes you from doing others, so NASA has evaluated the evidence and doesn't think its the most efficient thing to pursue right now. Levin is trying to convince folks that the evidence is sufficient to warrant pursuing further experiments that would clarify what is going on here.
Consider for instance how many US citizens are still religious today, and largely govern their lives according to religious beliefs. Consider how the current president has deliberately weakened the separation of church and state by making it legal for churches to be political - pastors of tax-exempt churches can now outright advise congregation on who to vote for.
Discovery of life elsewhere threatens the foundation of a lot of religious dogma.
An irrefutable discovery of complex alien life on another planet would, in my opinion, undoubtedly accelerate that rate of diminishment.
In the mean time, many people use the absence of any such discovery, as proof that earth is inexplicably unique so some magic creator deliberately blessed us to be here on this sacred planet.
Maybe it was on earth
Maybe NASA should book space for a biologist on that flight. A botanist would do.
Xkcd reference that got me to read it: https://xkcd.com/1536/
If life is found NASA will not get funding.
Therefore NASA is doing all the science it can before it does a test for life. At least we will be able to say something about what it is and the context that it's in.
Then the plug will get pulled.
There are no aliens. With the money wasted on looking for aliens we could have saved millions of lives with clean water, shelter, food and education.
Scientists need to stop deluding themselves and tricking congress into funding pet projects that are so far fetched they border on fraud.
Military spending is a strawman whataboutism.
It's not about "cuts" it's about sanity. There are no aliens, no proof of aliens, nothing. These programs should not have been started in the first place.
If these peoples lives are so devoid of meaning that they have to spend their lives researching fantasies, they should fund in themselves instead of taking tax payer money for it.
There is no science being done on vampires, werewolves, dragons and all sorts of other fantasies. Aliens are more fantasy than these.
>...the Wright brothers...
Birds, bugs, even leaves were flying all around them. It was not fantasy in the least. Flying was purely a technical problem.
Aliens do not exist. Spending real money in the pursuit of pretend and non-existent things is pure waste.
Proving a negative in a virtually infinite universe looks like an uphill struggle, don't you think?
There is not a single shred of evidence _ever_ found to support one iota of research funding. It's science fiction run amok.
You only need to find a single instance of aliens to prove that aliens exist.
You need to carefully analyse the whole universe and not find anything to prove that they do not. Proving a negative is hard.
There is more evidence for big foot, lochness monster and vampires than there are for aliens.
Alien research is faith based, not fact based.
The Polynesians sailing into the unknown Pacific is a different case, but that was most likely (based on what I've read) a situation of "the poor" venturing out to find new lands for themselves, not well funded expeditions paid for by existing kings.
Aliens is 100% pure fantasy.