>Watching that launch will be the most heartstopping moment of my life.
You got that right. When Elon launched the car I was like "eh this will be just like any other launch" then as the launch started I was perched on the edge of my chair shouting "CLIMB CLIMB CLIMB BABY CLIMB" at my phone. JWST will be one of the most nerve-racking moments of my life if I watch the launch due to it's many delays.
I wish they've invented notebooks or something. So we could build a second JWST at a smaller cost.
Very similar with how building a Saturn V today is logistically impossible, even if we can build more modern, efficient and cheaper rockets.
At best we could send a robot, which would probably be more easily operated from the ground.
Even coming up with something from scratch is unlikely to cost the $10B we'd lose from a failed JWST.
Near Infrared Spectroscopy [0]. JWST will be the first instrument in space capable of performing NIR spectroscopy, which will be used to analyze the starlight shining through exoplanets' atmospheres for evidence of biological molecules.
[0] https://dms.cosmos.esa.int/COSMOS/doc_fetch.php?id=3372219
If the odds of life spontaneously starting and then surviving are really low, then there really may be no other life in our galaxy (<1 trillion stars) or even the observable universe (<1 trillion trillion stars).
We have a sample size of just one (our solar system). But we already know that life on Earth began very soon after it cooled enough to have liquid water - that gives us some confidence that it can't be that hard for life to start.
We know life's been around on Earth for ~4 billion years, surviving multiple insane climate swings from subtropical vegetation and species living in the Arctic to the entire planet freezing over, multiple massive impacts from space, insane volcanism that people today just would not even recognize as volcanism. Hopefully that means life's somewhat durable.
Eukaryotes are basically a fluke. The symbiosis event that created Eukaryotes from a random combination of Archaea and Bacteria appears to have happened only _once_ in the entire history of the earth.
It's arrogant to assume that life as we know it is both inevitable and inevitably complex in a manner similar to our complexity.
A practically infinite universe means potentially infinite diversity, including phenomenon that may not recognize as life at all to us, but should be equally interesting.
That story is very much in flux still. We're not very certain on how that occurred, let alone how many times over those billions of years.It's linked to the Great Oxygenation Event, likely, but we're still in the very early stages of understanding that era.
> A practically infinite universe means potentially infinite diversity, including phenomenon that may not recognize as life at all to us, but should be equally interesting.
As is usual in science, it depends. If you are dealing with matter like us, then there are only a few universal solvents (5? I can't find the citation). In those solvents, there are a countable amount of ways that the chemistry will allow for 'life' to 'evolve'. The ways that the life can then evolve are really complicated and diverse, but there does seem to be a evolution/development trade-off, where you have to go through developmental 'keyholes' to get to a new level of complexity. Is that infinite? I've no idea, but it feels like a different ordinal of infinity.
https://en.wikipedia.org/wiki/Timeline_of_the_evolutionary_h...
Isn't it possible that once it happened, it filled a niche that prevented something similar from happening again? Thus, the fact it only happened once doesn't tell you how probable it was to happen at all.
I have the impression other similar things may have happened as well. Recent articles about a viral-like protein that may be crucial to how long term memory works suggest that chance combinations of life that melded may be a theme.
Except it did happen again. Chloroplasts and mitochondria organelles are so different they are considered to have been generated from separate events.
Assuming that there are niches though is dangerous, because it assumes the evolution is guided, which it isn't. It's entirely possible that this has happened many times throughout history, but the resulting new organisms couldn't compete and died off without a leaving a trace.
That's why assuming it only happened twice is survivor bias.
No, I wasn't suggesting that evolution is guided. If something evolves, and it ends up in the way of anything evolving similarly, it's not purposeful. It just is, as long as some catastrophe doesn't clear the way.
Edit: your comment "It's entirely possible that this has happened many times throughout history, but the resulting new organisms couldn't compete and died off without a leaving a trace." is a distinction without a difference to me. That's what I meant by it not happening, and the existing organisms occupying a niche.
No telescope will tell us what the ribosomes of Barnard b look like, of course.
But if only macroscopic life excites you, is it clear that you need eukaryotes for complex (multi-cellular) life? And how can you know it happened only once? It could also be that it happened multiple times, but one strain outcompeted (or just ate) every other. There could be undiscovered alternate "eukaryotes" if they remained single-cellular, too.
Also, complex multicellularity (IIRC defined as differentiated cells) has evolved (according to the latest theory) six times. So that looks pretty likely to happen eventually, as well.
Human-level technological civilization, yeah, that looks like a one-time thing so far.
Edit: check out this article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3910982/ They just casually mention "diatom-derived plastids", which are basically organelles that used to be diatoms, eukaryotic organisms in themselves!
Uh, that would be absolutely, positively very exciting to find microbes that originated someplace other than Earth. If you expect we'll find little green humanoid-looking things, you're going to be highly disappointed for likely centuries.
Well we could never be sure of that without real samples. Who's to say it's not all the result of panspermia?
I think that most people, be them scientists, religious leaders, politicians, or even laymen, will have their lives changed forever. For the religious, discovery of extra-terrestrial bacteria will upend most of the interpretations of their holy books. Those books are the foundation of modern Western society (Do not kill, do not steal, do not take another man's wife, etc). By upending the basis of society we have no idea how humanity will end up. Will we throw everything based on the bible away? Reinterpret them? Will the Jews and Muslims reconcile? Will the Christians set out on another crusade? Will that crusade be to the extra-terrestrial bacteria to sterilize them?
> event that created Eukaryotes ... happened only once.
The insemination event which led to your birth also happened only once. However, it is does happen often enough in systems that have the right conditions. And there are trillions of available planets, right here in the Milky Way.
Scientists yes, the rest won't care that much. It'll make the news sure but it'll be out of the headlines within a week. Maybe I'm a cynic but I'd put money on that being the case.
Additionally speaking as a religious person, it wouldn't change any of my beliefs. And I'm struggling to see how it would for others of my faith really.
It's true the universe is very large and feels infinite, but we know that it's about 25 billion galaxies (the size of the Milky Way) and that it has finite mass.
Sure, these numbers are incredibly large, but like you said, we're dealing with probabilities that are also incredibly small. There should be a cutoff somewhere for the observable universe as to what it is probable or improbable of producing.
Claiming infinite space has infinite possibilities for life is quite literally a Celestial Teapot argument.
Not a physicist, so I'm probably dead wrong. But I would like to be enlightened.
I'm optimistic that there is life out there. And if so, we should be able to get hard evidence by studying exoplanet atmospheres in the next few decades. Until then, it is very difficult to assess.
We have a selection bias happening here. We observe life because if life didn't appear as soon as the Earth was cool enough, the odds of us being here and able to reason about that would be small. We shouldn't consider it particularly abundant until we find a separate biosphere where life developed independently.
I personally think it's really easy to get molecules making copies of themselves, but we don't have enough data to claim that.
The fact that we're not on some planet around a red-dwarf a trillion years from now discussing this, but on a relatively young world does in fact tell us something.
This planet is 4.6B years old Life is at least 3.5B years old. Maybe older. And for the first few hundred million, Earth was a fireball. So it happened almost as soon as it was possible to.
And after life reaches a certain point, wiping it out is incredibly hard. I don't know what it would take to wipe out all life, as in every last bacteria too, on Earth...
So while I might accede intelligent (especially technological) life might be rare, I sincerely doubt life itself is.
Not meaning to be condescending, that's not how probability works or is expressed.
Also, the fact that the ocean "is a large place" says nothing about how probable or not the events to create and sustain life are.
I understand most people have this gut feeling that because the universe is vast and ancient there must be something out there (and I have it too), but we just don't know.
We just have no idea exactly how hard life is to develop and be sustained. We just started having theories (a handful at that) about how we transcended from chemistry to biology. The prevalent theory for example is that the moon's unusually big size and proximity was the catalyst for that to happen. How many planets have extremely big moons in such close proximity? How many million other factors played a role assuming the tide theory is even close to accurate?
It's just an infinitely complex problem and we just don't know.
The moon stabilizes the earths rotation (due to orbital mechanics I don't understand), that's probably important for complex life.
Tides are probably important because they help mix up all the elements. Tidal pools also may have been critical for abiogenesis.
The creation of the moon be a huge planetoid hitting us may be responsible for plate tectonics that provide enough volcanism.
Abiogenesis isn't the same as evolution, and given what limited knowledge we have of prebiotic Earth, life shouldn't have naturally occurred here. Ocean size doesn't matter in this case when the ocean isn't able to form a single self-replicating cell. The dice being rolled don't even have the number you need.
The reason we know that aliens don’t speak English is that, as vast as the universe is, the set of possible languages is much larger and so rich with possibility that it need never repeat.
So why do we think the set of languages spoken by chemistry is any different?
http://winestockwebdesign.com/Essays/Alien_Life.html
Long story, short: It would have to be sentient life in order to get any long-lasting attention. In the recent past, plenty of scientists were sure that simple life (e.g., lichens) existed even on Mars. The general public didn't go nuts over that. So finding simple life—for sure, this time—wouldn't change anything this time around, either.
(And that's the main argument for the Great Filter being behind us, it is hard to imagine that we are fighting against astronomical odds to become space-faring.)
There should be life everywhere it's possible by technological panspermia - but we don't seem to observe that. What stops elder civilizations from doing this, is the big mystery.
Unless of course, as a poster above notes, if we fire up the JWST and discover chlorophyll-fringes in the spectra of just about every rocky planet we can see. That'd imply a lot.
I think that most people, be them scientists, religious leaders, politicians, or even laymen, will have their lives changed forever by the discovery of extra-terrestrial life. For the religious, discovery of even extra-terrestrial bacteria will upend most of the interpretations of their holy books. Those books are the foundation of modern Western society (Do not kill, do not steal, do not take another man's wife, etc). By upending the basis of society we have no idea how humanity will end up. Will we throw everything based on the bible away? Reinterpret them? Will the Jews and Muslims reconcile? Will the Christians set out on another crusade? Will that crusade be to the extra-terrestrial bacteria to wipe them out as well?
The religious might surprise you.
https://www.vofoundation.org/faith-and-science/life-in-the-u...
But, for most believers, I bet there will be a re-articulation of the tenets of the faith, a transformation of their existing doctrine into something that seems compatible with the new information.
Maybe this is not quite the right way to look at it, but it seems to me that, taken together, these religious faiths have already survived many, many highly traumatic historical and informational challenges and persecutions (e.g. invasion of the "sea peoples" in the Eastern Mediterranean, rise and fall of the Greek Empire, rise of the Roman Empire, destruction of the temple in Jerusalem, Constantine's conversion, religious councils which redefined Jesus, fall of the Roman Empire, Galileo, Copernicus, Reformation, Magellan, Enlightenment, British Empire, Darwin/Evolution, Napoleon, Hubble–Lemaître and modern cosmology, the Holocaust, etc ...)
For example, it seems to me like modern astronomy has drastically challenged and damaged the very notion of a saintly or holy figure "ascending into heaven," but believers whose holy books explicitly describe such an event have not abandoned their faiths in large numbers because of it.
Another example is modern biology and theories about the origin of humanity. That didn't stop religions based on the book of Genesis.
IMHO, hard evidence of extra terrestrial life will be just one more speed bump in the history of these faiths.