They would die because the gravity, temperature, air mixture, water mixture, or whatever environment they need is probably not what Earth has. Translation, they'd decompress, fry, suffocate, or get poisoned quickly, just like we would on every single one of the planets in this solar system except our own.

That said, the microbes probably would be the least of their worries since the microbes are equally not evolved to invade the alien host.

And then there's the inevitable greeting the humans would give. I have little faith in humanity's likely response to a visitor displaying obvious superior technology.

Sounds like you answered your own question. It is most probable that those creatures would not survive in our environment; however, there is no way to know.

Yes, they would die, because we'd kill them out of fear and hatred.

The way you set the scenario up says we should have no problem with the basic physical environment. The air would be breathable and not poisonous if the composition is the same as Earth.

So how would we cope with alien micro-biology?

Microbes are either going to harm us by infection or poison. So given that their biology is bound to be too dissimilar for an infection issue, then only an inadvertent toxicity would be a problem. Being microbial in scale, and the poison production obviously not enough to alter the general atmosphere, then any harm is likely to be slow acting. But also of high probability just because our immune system would likely have a big allergic reaction to strange organic compounds.

So a lungful of alien air might send us into anaphylactic shock. But more likely is that there will be unpleasant consequences that manifest over a few more weeks on the planet.

The focus would be on the immune system, as you suggest, just not on whether we could fight an infection. It would be about the shock of alien organic chemistry on an immune system not brought up to deal with it.

Tardigrades arguably arrived via interstellar spores. There's some thought that the octopus family might have as well. In fact if panspermia is true, then we all started out as aliens, and adapted to Earth by evolving to do so. So maybe we’re all aliens, and this is our spaceship; in which case, we’d better start paying attention, because it’s beginning to get dangerously over-crowded and over-heated.

Tardigrades arguably arrived via interstellar spores. There's some thought that the octopus family might have as well. In fact if panspermia is true, then we all started out as aliens, and adapted to Earth by evolving to do so. So maybe we’re all aliens, and this is our spaceship; in which case, we’d better start paying attention, because it’s beginning to get dangerously over-crowded and over-heated. — Wayfarer

Although panspermia is possible as far as I know, it is an unsatisfying theory. It doesn't really answer any question about the genesis of life. If life didn't start on Earth, it is just as much a mystery how it started elsewhere. Since all life on Earth we know of has the same type of DNA, it seems that all life evolved from the same source, wherever it came from originally.

Such speculative claims that cannot be verified by the scientific method raises dubious results that may perhaps be creative but ultimately a very poor conception of natural reality. Can the OP or others explain to me how this is either philosophy or philosophy of science?

So, my point is, even if we found an Earth like world - with similar gravity, atmospheric composition etc - this similarly is only superficial - and its biosphere - especially life at the microbial level - would make moving and colonising this planet impossible - unless we develop immunity to its biosphere as we have done here on Earth. — JohnLocke

Nobody knows what life that started on another world would be like. Would it have some sort of genetic coding that is recognizable? That's why finding life on another world will be the biggest scientific discovery ever. There is no way to know how life works extrapolating from a population with a sample size of one.

Such speculative claims that cannot be verified by the scientific method raises dubious results that may perhaps be creative but ultimately a very poor conception of reality. Can the OP or others explain to me how this is either philosophy or philosophy of science? — TimeLine

A lot of latitude has been given in the past for discussion of scientific subjects that are not specifically philosophical. I hope that can continue. I think many of them have interesting and important philosophical implications. I don't think this is pseudoscience, which I know is of concern to you, although it is speculative. It can be verified by the scientific method. There are scientific efforts going on now to identify life on other worlds, e.g. SETI.

Such speculative claims that cannot be verified by the scientific method — TimeLine

Which speculative claims exactly? And how is science not able to constrain the speculation involved?

Sounds like an updated version of "War of the Worlds".

If we had the tech to make it to another live-able planet, I think we would have the tech to confirm it was live-able.

This never stopped Kirk.

Would it have some sort of genetic coding that is recognizable? — T Clark

There are those like Nick Lane who make a good case that the basic metabolic options for creating life are so limited that it is much more likely that all life would have quite a lot in common in terms of the basic respiratory chain machinery. That counts as a surprising recent twist in theoretical biology.

But then while it might be that protein structures formed from amino acid sequences is somehow evolutionary optimal, would the DNA coding machinery have to look so much the same? Arguably not if all the code has to do is represent the instruction to go grab some particular amino acid.

So logically, the metabolic similarity might be surprisingly more close than expected, while the genetic coding mechanism would almost surely be a completely different kind of language as the meaning of a sign is essentially arbitrary.

So logically, the metabolic similarity might be surprisingly more close than expected, while the genetic coding mechanism would almost surely be a completely different kind of language as the meaning of a sign is essentially arbitrary. — apokrisis

Wouldn't you love to find out for sure? It only takes one example. I hope I live long enough to find out - as long as "To Serve Man" is not a cookbook.

The worry I am experiencing here is the scope is broad and beyond verifiable observations that impulse grand narratives justified by highly technical modes of thought that obscurely engages within the sphere of natural science. The result would be perennial criticisms that lack any real relevance. You can discuss the atomic structure of our biology in an attempt to constrain this speculation, for instance, but unless you are attempting to form a hypothesis, it becomes rooted in very clever but unreliable claims that overall remain non-productive. We confuse speculation with experimental data.

Philosophy of science is "a field that deals with what science is, how it works, and the logic through which we build scientific knowledge" and thus about the methods and implications. I understand your point of view because you and others are capable of this capacity to constrain, but even so, I would still like to understand how this question bears any relevance to the philosophy of science.

Pfft. T Clark is right. SETI is accepted science. There is a ton of constraints based papers seeking to sharpen an understanding of the probabilities. A question about the risks to aliens landing here is the mirror of the one any space expedition to Mars would have to answer. You will have to be more specific to show how the discussion might be unscientific, let alone unphilosophical.

Tardigrades arguably arrived via interstellar spores.

Do tardigrades have the same type of DNA as humans?

I did not realise that tardigrades arrived via interstellar spores and so did octopus and that we are actually aliens. My bad.

Or those rovers running around on Mars.

This never stopped Kirk. — Cavacava

Because Kirk & Company had series continuity, a powerful feature of televised life forms. He HAD TO SURVIVE all aliens, or it would have been the premature end of the show, and that in turn would have violated a contract. Our first visitors to an alien planet will not, nor will our first alien visitors here have the powerful protection of series continuity.

They'll take a deep breath, croak, and that will be that.

Or not.

Oh that. Yes, it seems crackpot. But Francis Crick for one published an argument for directed panspermia - deliberate seeding by aliens - in the 1970s. Scientific experiments have been done - https://www.space.com/22875-alien-life-claim-space-microbes.html

So it is certainly within the bounds of science. It is not regarded as impossible or uninvestigatable.

That article you attached shows skepticism and scrutiny from the scientific community and for good reason. Astrobiology is an intriguing discipline but within reason and a balloon collecting microbes from the stratosphere is hardly evidence of extraterrestrial life. As it said: "If they were able to show that it was composed of all D amino acids (proteins in Earth life are made of L amino acids), that would be pretty convincing to me... If it does indeed share Earth biochemistry, proving that it is of alien origin is probably impossible." There is no scientific credibility in the claim.

I’m not convinced for a minute, so kindly don’t address me as if I am saying it is something you ought to feel convinced about.

But it is published theory. Experiments have been done. The issue you raised was whether it is sufficiently within the purview of the scientific method. Clearly it bleeding well is. End of.

I'm certainly not; as I said previously you and others are capable to constrain such grand narratives, but even so, the article that you posted itself says:

"However, astrobiologist Dirk Schulze-Makuch of Washington State University thinks the study team should have performed such follow-up analyses, and consulted diatom experts, before publishing its provocative claim."

The scientific community is very competitive.

From the fact that I deliberately posted a sceptical response you ought to be able to deduce where my own sympathies lie.

But it remains the case that science treats it as a possibility even if an unlikely one. That seemed to be what you were asking for opinions on.

But it remains the case that science treats it as a possibility even if an unlikely one. That seemed to be what you were asking for opinions on. — apokrisis

Because, as I said earlier, if you are attempting to form a hypothesis, then speculative theories are understandable, but it is easy to confuse speculation with experimental data and it can become a very clever way to justify unreliable and non-productive claims just like extraterrestrial life or worse, things like Would Aliens die if they visited Earth?

I thoroughly enjoy threads like this and my asking opinions from others is really to ascertain where to strike a balance because to me, the OP is one giant splatter of nonsense. Anyway, thanks and I will think about speculative theories and the boundaries to scientific method a bit more.

I thoroughly enjoy threads like this and my asking opinions from others is really to ascertain where to strike a balance because to me, the OP is one giant splatter of nonsense. Anyway, thanks and I will think about speculative theories and the boundaries to scientific method a bit more. — TimeLine

I sounds to me, and I'm sure to others, that you are considering stopping or deleting this thread. Whether or not that's true, as a moderator, and one who has explicitly taken on a role to tighten restrictions on what you consider pseudoscience, your opinion is no longer just your opinion, it is a potential threat.

Your responses have been dogmatic and you don't seem to have listened to the reasonable arguments from people who know and care about science. I know you also have scientific credentials. The subject being discussed is not extreme science, fringe science, or pseudoscience. It's not even weird. I have commented before that the moderation of science posts on the forum has been pretty lax. It seems like maybe you plan to take it way far in the other direction.

I worry that if you are considering drawing a line at a point I consider pretty mainstream, you will object more strongly to other subjects that I and others consider appropriate for discussion but which are even more speculative. Here's what it comes down to - although, as I said, moderation of speculative science has been lax, I can't see any evidence that it has undermined the voice, quality, or credibility of the forum. We are not overrun by pseudoscience. I endorse your goal to crack down on goofy theories, but I think you are being heavy-handed.

US Defence Department this week acknowledged for the first time that they ran a UFO program.


Parts of their shadowy work — which is still continuing to this day — are classified. But the Pentagon confirmed that audio and video of two US Navy pilots chasing an unidentified flying object near San Diego was investigated as part of the program.

The footage, released in August, showed that the UFO rotated and maintained a “glowing aura”.

I worry that if you are considering drawing a line at a point I consider pretty mainstream — T Clark

Are you done? It is not mainstream science. And clearly the thread is still here so what exactly is your point? There are just as many people who would disagree with you and say that the level of PhilSci is lacklustre at best and should be moderated.

It is not mainstream science. — TimeLine

You appear to be confusing mainstream research with mainstream belief. If you check, you will find there are journals of astrobiology and centres of astrobiology these days.

A good example of credible research is https://arxiv.org/pdf/astro-ph/0403049.pdf

Now cynics like me would also be quick to point out the self-interest NASA has in generating public hype about the value of a manned Mars mission. Why wouldn’t it seed curiosity by supporting panspermia research?

However as a general issue of policing debates here, this site ought to be enforcing standards of critical thinking, not trying to enforce some mainstream belief system. It is how folk handle what seem to be extraordinary claims that matters. And going and checking the facts - is panspermia a mainstream research topic? - would be an example of critical thinking in action.

However as a general issue of policing debates here, this site ought to be enforcing standards of critical thinking, not trying to enforce some mainstream belief system. It is how folk handle what seem to be extraordinary claims that matters. And going and checking the facts - is panspermia a mainstream research topic? - would be an example of critical thinking in action. — apokrisis

I have seen some amazing responses in other threads that could parallel the potential mainstream belief issue you are attempting to convey - because I agree that it is about ascertaining the scientific amidst the broad and often highly imaginative narrative - but this constraint is reliant on both on the OP and on the posters. I respect you as a poster and know you are capable of this, but when you reflect back on this thread, has there really been any critical thinking in action? An octopus is now an alien and they probably can start predicting who will win the world cup. That is not probability theory, that is just insanity. I do respectfully agree and reiterate that I will certainly be cautious before ever making a decision otherwise, but my intention really was to understand whether this subject could indeed be considered Philosophy of Science and not about moderating risks and what not.

I have actually been to a lecture by Davis, by the way, and I find his ideas on evolution and cancer research to be really compelling. His suggestions about tracing this works similarly to his ideas of Mars, of going back to a time when it may have been habitable and how this could indeed initiate the biosignatures now on Earth. It is also not without controversy.