I have been in one. Its just a room with an air flow rating and slight positive pressure vs ambient. There's no entry control, no special clothing, no hair nets. There was visible dust on top of the equipment and no one seemed to care, not even the people who you think should. I honestly think its there for a check mark on the paperwork.
Honestly that might be ok for class 10000 (ISO class 7). HEPA filters do good work! At my work we use gowns, hair nets, booties, the works. However, we also changed cleaning companies once and didn't realize they were no longer sweeping the floor for a few months until visible dust bunnies started appearing in corners. Addressed that quick but not before we ran a few tests, still in spec! We also have local controls (flow hoods) over particularly sensitive operations.
We have class 100 (ISO class 5) space that's a lot more stringent, but even that is less sensitive than you might expect. Our semicon customers have a bad habit of taking our carefully bagged product out in their uncontrolled warehouse to check the serial numbers, but I'm not aware of any issues that arose from this.
Things get a lot more interesting when you start working with DUV and EUV wavelengths, as now you care about more than dust. We're adding an advanced molecular contamination cleanroom (AMC) where we'll need to start restricting perfume, deodorant, and cigarette use.
I've been in higher than 10,000 cleanrooms and it's not the dust on the desks they care about.
There are entry protocols around what you can take in, how you swab it, and so on. Also, specific instructions around how often to go from sitting to standing, clothing materials under your smocks, and everything else.
I absolutely love how once things get down to 1 AWG they realized they had a problem and just started adding zeros. Then that got a bit silly, so when they reached 4/0 AWG they switched to KCMIL measurements and the numbers start going up.
It's not clear to me that the phys.org restatement of that article (which is what it's discussing) adds anything new to the story, which would be HN's criterion for non-dupe status.
This argument from the article meshes with my own thinking:
The reason there have not been new forms of life originating on Earth, evolving alongside our microbial cousins, could be that there is simply no room for a newcomer. In a system where every niche is filled with more advanced life looking for a next meal, even if a new form of life got started, it would not last long.
There are a number of related issues regarding life, including LUCA and the emergence of mitochondria in eukaryotic cells, which suggest to me less that a single ancestor existed at that time than that that ancestor's descendents out-competed (or out-lucked) all other comers, and that once established other contenders for life simply couldn't find an available niche.
Oh, and bad news for the fans of LGM / panspermia, at least in the "absence of evidence" sense:
Population statistics indicate that the microorganisms originated from terrestrial contamination during the sample preparation stage rather than being indigenous to the asteroid.
> which suggest to me less that a single ancestor existed at that time than that that ancestor's descendents out-competed
I’m not smart enough to get this. Why would it decrease the emphasis on a single ancestor? The suggestion of competition among descendants isn’t contrary to that, neither does one take from or add to the other.
The distinction: there's a frequent understanding or expression that a single common ancestor means that that was the only individual alive at a time, or that its ultimate dominance was evident immediately or very shortly afterwards.
Neither of these is the case.
Nor, strictly, is the notion that the individual (or its descendants) were necessarily evolutionarily fitter than others.
In the first instance, a common ancestor may have come long before some evolutionary chokepoint or contest in which their gene line ultimately survived whilst others died out. And in some cases (mitochondria), the alternative gene lines didnt' die out. Non-mitochondrial organisms are the prokaryotes, and they have continued (for many hundreds of millions of years) to live alongside their mitochondrial-bearing eukaryotic cousins. Bacteria are AFAIU largely prokaryotic. Even some eukaryotes have lost their mitochondria, though it seems that all eukaryotes had mitochondria at some point in their evolution. But where it comes to complex organisms, overwhelmingly mitochndria-bearing cell forms out-compete those which lack same.
As for evolution, that which is expressed in genomes requires a threefold process: variation, selection, and inheritance. That is, whatever leads to the eventual survival of a particular line of descendants must be based on an inheritable characteristic: stronger muscles, lower metabolism, superior coordination, robustness to environmental variance, faster development within a given niche, mate-selection advantage, etc., etc. (And note that what works in one selective environment may well not be suited to another.)
Other selection events are not directly heritable, or are far less heritable. Getting smacked by an asteroid is an example, though there are features (e.g., being an aquatic life-form, small body size) which may increase survival odds after a major impact. Other natural disasters (earthquakes, tsunamis, volcanoes, wildfires) etc., are to an extent random and arbitrary in what they kill, though there may be specific adaptations which increase survival odds after such events. Even given this, many species will see a fairly arbitrary selection of extinction and survival, often with little prediction for a future repeat of such an event. Which individuals survive, or don't, is pretty much a wash. Those are still selection events, but don't convey any heritable advantage.
The possibility that some common ancestor or LUCA is at least in part arbitrarily determined seems high to me.
This creates a new doomsday scenario for alien bacteria. Not that it could infect us, but that it could be much more efficient than existing life in some fundamental way that can’t be stopped.
So it's all the more amazing than we can't find life anywhere.
We grab a sample of asteroid "soil", try to keep it in conditions as hostile to life as possible, and yet within days it's teeming with (terrestrial) life.
Life formed quickly on earth, but earth has so much special going on: iron core, habitable zone, lots of water, three phases of water, good distribution of elements and minerals, oxygenated atmosphere, magnetosphere, lunar shield, lunar tides, Jupiter to clear out junk, etc. etc. We hit the lottery.
And intelligence is an even harder step given how much absurdly longer it took to evolve than basic life.
And technology is probably also a hard step where we had tailwinds like massive oil deposits, smallish gravity well, etc.
But it's also kind of crazy to assume that we should be able to detect the techno signatures of advanced aliens or AIs given our small and limited understanding of the universe.
The only thing I find truly special about our place is the moon.
The moon is really weird. Same geological material as earth, huge size for a natural satellite, appears the same size as the sun.
It's an unusual set of coincidences that (as far as I know) our solar system formation models, so far, can only explain using an extraordinary event (Theia collision, etc).
>So it's all the more amazing than we can't find life anywhere.
Maybe because it destroys itself, then gets blasted out into such far reaches the two races are never within a distance (in terms of space or time) they could communicate?
> gets blasted out into such far reaches the two races are never within a distance (in terms of space or time) they could communicate?
I know this is not directly related to what you say, but we do have right here and now whales to talk to. And elephants too! There is this idea that to find alien minds to communicate with one has to reach out to the far cosmos. But we can't even talk to the alien minds right on our doorsteps. Maybe we should try that before we theorise that communication between two races is impossible due to distance.
Atmospheric pressure of Mount Everest is about 1/3 of that of average at sea level on earth.
The Martian average is 2% of Earth's atmospheric density, or about 0.6% pressure- very nearly hard vacuum, especially considering how little oxygen is present.
Any earth life left behind is almost certainly dead or in hibernation type stasis. There's not much noteworthy about it unless Mars somehow develops a thicker atmosphere, better radiation shielding and warms up a fair bit... And if that miracle occurs, it's probably because far future humans have terraformed Mars to be habitable by humans, and we'll have already brought a whole bunch of algae and fungus and plants with us.
While yes, conditions are incredibly harsh, we've found life in such a variety of places on Earth I can't imagine there's absolutely nothing here that couldn't survive there - it's just it probably didn't hitch the ride to Mars. We've found bacteria(alive!) deep in polar ice, miles under the ground, on radioactive waste and in geothermal vents with no oxygen and in hundreds degrees celcius.
I imagined that the space stations have the equipment to take all measurements and record evidence so you aren't having to return samples to earth except for a neat souvenir.
Readit News
Then I decided to look it up.
Turns out, the larger that number is, the LESS clean it is!
https://www.mecart-cleanrooms.com/learning-center/cleanroom-...
From above site: "Class 10,000 cleanrooms are one of the most common, if not the most common, level of cleanliness across the industry."
The bulk of the article's message is still valid, but less astonishing.
https://www.nature.com/articles/s41550-021-01550-6
Here you can read that, in fact, a class 1.000 cleanroom was used.
This is also consistent with the description of the facility:
https://en.wikipedia.org/wiki/Extraterrestrial_Sample_Curati...
According to the paper, five different chambers were used. You can read the entire procedure down to materials of cleaning spatulas.
We have class 100 (ISO class 5) space that's a lot more stringent, but even that is less sensitive than you might expect. Our semicon customers have a bad habit of taking our carefully bagged product out in their uncontrolled warehouse to check the serial numbers, but I'm not aware of any issues that arose from this.
Things get a lot more interesting when you start working with DUV and EUV wavelengths, as now you care about more than dust. We're adding an advanced molecular contamination cleanroom (AMC) where we'll need to start restricting perfume, deodorant, and cigarette use.
There are entry protocols around what you can take in, how you swab it, and so on. Also, specific instructions around how often to go from sitting to standing, clothing materials under your smocks, and everything else.
The fun backwards measurement is always AWG. Smaller number means thicker wire. Larger number means thinner wire.
<https://news.ycombinator.com/item?id=42238603>
3 days ago, 59 comments.
It's not clear to me that the phys.org restatement of that article (which is what it's discussing) adds anything new to the story, which would be HN's criterion for non-dupe status.
The reason there have not been new forms of life originating on Earth, evolving alongside our microbial cousins, could be that there is simply no room for a newcomer. In a system where every niche is filled with more advanced life looking for a next meal, even if a new form of life got started, it would not last long.
There are a number of related issues regarding life, including LUCA and the emergence of mitochondria in eukaryotic cells, which suggest to me less that a single ancestor existed at that time than that that ancestor's descendents out-competed (or out-lucked) all other comers, and that once established other contenders for life simply couldn't find an available niche.
Oh, and bad news for the fans of LGM / panspermia, at least in the "absence of evidence" sense:
Population statistics indicate that the microorganisms originated from terrestrial contamination during the sample preparation stage rather than being indigenous to the asteroid.
I’m not smart enough to get this. Why would it decrease the emphasis on a single ancestor? The suggestion of competition among descendants isn’t contrary to that, neither does one take from or add to the other.
Neither of these is the case.
Nor, strictly, is the notion that the individual (or its descendants) were necessarily evolutionarily fitter than others.
In the first instance, a common ancestor may have come long before some evolutionary chokepoint or contest in which their gene line ultimately survived whilst others died out. And in some cases (mitochondria), the alternative gene lines didnt' die out. Non-mitochondrial organisms are the prokaryotes, and they have continued (for many hundreds of millions of years) to live alongside their mitochondrial-bearing eukaryotic cousins. Bacteria are AFAIU largely prokaryotic. Even some eukaryotes have lost their mitochondria, though it seems that all eukaryotes had mitochondria at some point in their evolution. But where it comes to complex organisms, overwhelmingly mitochndria-bearing cell forms out-compete those which lack same.
As for evolution, that which is expressed in genomes requires a threefold process: variation, selection, and inheritance. That is, whatever leads to the eventual survival of a particular line of descendants must be based on an inheritable characteristic: stronger muscles, lower metabolism, superior coordination, robustness to environmental variance, faster development within a given niche, mate-selection advantage, etc., etc. (And note that what works in one selective environment may well not be suited to another.)
Other selection events are not directly heritable, or are far less heritable. Getting smacked by an asteroid is an example, though there are features (e.g., being an aquatic life-form, small body size) which may increase survival odds after a major impact. Other natural disasters (earthquakes, tsunamis, volcanoes, wildfires) etc., are to an extent random and arbitrary in what they kill, though there may be specific adaptations which increase survival odds after such events. Even given this, many species will see a fairly arbitrary selection of extinction and survival, often with little prediction for a future repeat of such an event. Which individuals survive, or don't, is pretty much a wash. Those are still selection events, but don't convey any heritable advantage.
The possibility that some common ancestor or LUCA is at least in part arbitrarily determined seems high to me.
Deleted Comment
We grab a sample of asteroid "soil", try to keep it in conditions as hostile to life as possible, and yet within days it's teeming with (terrestrial) life.
So where is everyone?
And intelligence is an even harder step given how much absurdly longer it took to evolve than basic life.
And technology is probably also a hard step where we had tailwinds like massive oil deposits, smallish gravity well, etc.
But it's also kind of crazy to assume that we should be able to detect the techno signatures of advanced aliens or AIs given our small and limited understanding of the universe.
Of course, the oxygenated atmosphere only exists due to life. Otherwise, it would just rapidly oxidize everything else.
The only thing I find truly special about our place is the moon.
The moon is really weird. Same geological material as earth, huge size for a natural satellite, appears the same size as the sun.
It's an unusual set of coincidences that (as far as I know) our solar system formation models, so far, can only explain using an extraordinary event (Theia collision, etc).
It happened 2.4 billion years ago, and wiped out most of the existing life: https://en.wikipedia.org/wiki/Great_Oxidation_Event
Maybe because it destroys itself, then gets blasted out into such far reaches the two races are never within a distance (in terms of space or time) they could communicate?
https://en.wikipedia.org/wiki/Panspermia
Doesn't solve the origin of life question, but it would explain the emptiness -- life is rare, and reseeds itself every few very long stretches.
I know this is not directly related to what you say, but we do have right here and now whales to talk to. And elephants too! There is this idea that to find alien minds to communicate with one has to reach out to the far cosmos. But we can't even talk to the alien minds right on our doorsteps. Maybe we should try that before we theorise that communication between two races is impossible due to distance.
[0] https://www.nationalgeographic.com/environment/article/soils...
Evidently, there are places (mountain ranges in Antarctica) on Earth that cannot sustain life at all.
So, life is possibly already multiplanetary?
The Martian average is 2% of Earth's atmospheric density, or about 0.6% pressure- very nearly hard vacuum, especially considering how little oxygen is present.
Any earth life left behind is almost certainly dead or in hibernation type stasis. There's not much noteworthy about it unless Mars somehow develops a thicker atmosphere, better radiation shielding and warms up a fair bit... And if that miracle occurs, it's probably because far future humans have terraformed Mars to be habitable by humans, and we'll have already brought a whole bunch of algae and fungus and plants with us.