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.

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.

> oxygenated atmosphere

Of course, the oxygenated atmosphere only exists due to life. Otherwise, it would just rapidly oxidize everything else.

Have you heard of the anthropic principle?

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).

The oxygenated atmosphere is created by life, not a cause of it.

It happened 2.4 billion years ago, and wiped out most of the existing life: https://en.wikipedia.org/wiki/Great_Oxidation_Event

> 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.

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.

Dont you need a 3T type MRI machine strength magnetic generator in.the right place to give Mars its shield. Thats what I remember

> It is strictly less likely than Earth-bound abiogenesis

> all panspermia does is layer on an additional series of long-shot coincidences

Disagree. There is a lot more of not-Earth than Earth. I agree that the probability density (per unit volume of the universe) of life originating on Earth is much higher than anywhere else, but there's just so much more room out there for life to originate that the probabilistic cost of traveling to Earth is tiny in comparison.

All you need is a proto-life that's stable in an inert environment with sufficient radiation shielding. It could've originated billions of light years away and still have had enough time to arrive on Earth 4.2 billion years ago. That's a mind-boggling number of Earth-like environments.

In fact, proto-life doesn't even need to look like Earth life, so even environments that are hostile to current Earth life today could've been the cradle of origin (as a wise man once said, "life, uh, finds a way"). Additionally, environments that used to be Earth-like but eroded away are candidates too since all we need is for life to have escaped before the erosion.

In my opinion, panspermia is strictly more likely than Earth-bound abiogenesis.

Kurzgesagt teached me that at some point between Big Bang and now, the universe had an average temperature equalling comfortable room temperature. Having realized that, it feels likely life could have formed basically anywhere.

Check out the giraffe's cardiovascular system. It seems you're alluding to intelligent design and there's a lot of very unintelligent "design" everywhere.

Perhaps that's true of your body, but my body was manufactured in the Soviet Union, and it shows.

Tell that to the laryngeal nerve which loops around your aortic arch, for no good reason. And to our inferior eye compared to the octopus. Amongst other things.

I'd like to speak to life's manager. The human body is full of dumb shit. Who designed these shit ass joints!

> and put together with the finest art, in the shortest way, the best form, the lightest manner, and most practicable shape

Yeah nah. Ask any doctor or biologist. Humans and most other organisms are definitely not put together like that. It's pretty cool and it works very well, but many things are just... why? There's lots and lots of hacks, questionable cable management, backwards design, dead code, and leftovers from previous iterations.

Just because we're a pretty successful organism does not mean we are anywhere near the pinnacle of what can be achieved.

Look also at my ingrown toenail, which for some reason grows about three millimeters wider than the nailbed.

Omnipotence, indeed!

The complexity of current life could have still formed from incredibly simple means over time.

Lab and semiconductor grade iron isn't notably expensive or difficult compared to other materials. It's just that there are few reasons to purify it beyond what's commonly available from supply houses, unlike more interesting materials like silicon or cesium.

Unless panspermia is much more common than usually imagined.

If much of the thousands of tons of extraterrestrial debris that falls to earth every year was teeming with microbes we might not easily tell the difference.

But I very strongly suspect this is not the case.

They dismissed it as being from earth based on "Population statistics", not determining them to be known earth microbes.

I think maybe the first step in this scientific rigor is to read the article. On the other hand, maybe scientific rigor is primarily in the amount of repetition of ideas already dismissed. Perhaps the most rigorous scientists simply repeat the same hypothesis unchanged when another of them finds evidence to dismiss it.

I have heard tales of a truly scientific rigorous civilization. Every human there replicates every study. They’re currently confirming that using cutting rocks to tear flesh is advantageous to survival.