(I initially wrote this in the comment section, but it’s important enough that I’ll post it as an article)

There are several factors about radiation that are generally unknown, so I’ll elaborate.
First, one needs to understand that human body, and other animals and plants that evolved here on Earth, have a built-in mechanism for dealing with radiation damage. If not, they wouldn’t have lasted very long, since radiation is a way of life here. My dosimeter “clicks” frequently enough that I had to turn off sound, and every click means that its small, coin-sized sensor has been hit by a high-energy photon. This means that every piece of our body that is the size of that small sensor gets hit with the same frequency, which means that we are getting constantly pierced by gamma rays. Obviously, this level of radiation is not a problem since our bodies can deal with it. So, how do they deal with it? Gamma rays basically eject electrons from atoms, which in case of atoms that share an electron in their highest orbital means that the molecular bond is broken. I think the cells know how to fix minor damage of this kind, but if it gets too much, something in the cell’s chemistry changes sufficiently that the immune cells recognize it as damaged/foreign, and start attacking it. The cell then dies and its content is disposed as any other waste.
This gives us three corollaries: first, that cancer should never happen if the immune response is healthy, which means that cancer is basically disease of the immune system, which does not perform its normal function of recognizing and attacking damaged cells. The second corollary is that radiation sickness is basically a state when the body is overwhelmed by garbage disposal from all the damaged/destroyed cells. This is why acute radiation damage is so dangerous, and why it’s a rule of the thumb: if enough cells die to overwhelm your kidneys, liver and other organs, you die. If not, you just get very sick during the garbage disposal phase, which, incidentally, is the same thing one suffers when they take antibiotics that are very effective against bacteria: all the garbage from the dead bacteria overwhelms the body. If the antibiotics don’t work, you won’t feel anything at all. The third corollary is that body will deal with radiation damage in a matter of days and weeks; basically, everything that is damaged will be killed off and disposed, except if your immune system is suppressed, in which case you will get cancer. Also, one should absolutely never have sex during this phase, because that’s when the genetically damaged children get conceived. After the body had the time to purge the damaged cells, it’s safe. The disclaimer is that this is empirical data obtained from irradiated men. I don’t know irradiated women handle the damaged ova, because it’s the men who statistically got irradiated and thus were unfortunate enough to provide me with a statistical sample.
Also, and this is not really recognized by science at this point, but I have the empirical data from Chernobyl, the initial burst of high radiation is absolutely deadly, and does exactly what you would expect. However, the long-term elevated doses of radiation seem to be more-less harmless, and this is a shocking datapoint, because there are carp merrily swimming in the super-radioactive lake near the exploded reactor, and they are fine. They are radioactive as all fuck, to the point that their bones make the Geiger-counter scream, but eagles that are supposed to be highly sensitive to the accumulation of heavy metals on top of the food chain are also fine; they eat radioactive carp from the radioactive lake and they are fine. The wolves, also the top of the food chain, are similarly fine, and they have a very healthy population there. Old people who refused to evacuate from the exclusion zone eat radioactive cheese and milk from their radioactive cows, and they are all fine. For the animals, the radioactive exclusion zone is heaven on Earth. As for the mutations, that’s another funny thing – there aren’t any. Radiation doesn’t increase the speed of mutation, because the mutated DNA is recognized as damaged, and is routinely destroyed by the immune system. There was an evolutionary preference for black frogs over the normal ones, because apparently melanin stops gamma rays the same way it stops UV light, and increases survival rate; since those frogs live in the super-radioactive lake, the initial deadly radiation probably preferentially killed the low-melanin frogs. The corollary of this is that one should hide from the initial strong radiation immediately and effectively, but later on the body seems to adapt to the higher amounts of ionizing radiation and is able to cope even with the doses that would be expected to be deadly.
Cancer is actually the least of the problems; cataract, sterility and lethal stress are much more probable, because the population from Chernobyl exclusion zone showed that almost all elderly people who evacuated quickly died from stress-related conditions, while those who remained had no issues whatsoever and lived to very old age. Also, among the highly-irradiated engineers in the station itself the main causes of death are myocardial and cerebral infarctions; I would guess that radiation damages the inner linings of their blood vessels, which likely promotes clotting. That’s the weird thing – nobody seems to get cancer from radiation. However, stress will really fuck you up, especially if you believe all the hype about radiation and if you have to evacuate from your home and basically restart your life.

I’ve seen several articles commenting the fact that for the last 5 MY or so, the solar system has been traversing the so called “local bubble“:The obvious explanation of this structure is a supernova remnant, something similar to the Crab nebula, only bigger; orders of magnitude bigger, in fact:

The thing I personally find puzzling is that absolutely nobody mentioned the first thing that crossed my mind when I found out about this. You see, when you see a structure that has a stellar nursery on its gaseous outer perimeter, and empty space inside the perimeter, the first thing that comes to mind is to expect at least one black hole somewhere in the center of this structure; more precisely, there have probably been several supernovae of the population 2 stars in the center of this, and considering how big the structure is, I would expect them to have produced black holes, rather than neutron stars, and we are going right through this area.

Is this a danger? That’s hard to tell, but a black hole is not more dangerous than an ordinary star of its mass; it doesn’t just go around and suck things in. You need to get fairly close, and then the most likely outcome would be the disruption of the Oort cloud, with the likely result of multiple intrusions of comets into the inner solar system, and in the worst case, if we pass really close, it can disrupt the solar system, or cause the Sun to start misbehaving quite dramatically due to tidal effects, which could create extreme coronal mass ejections. As I said, it’s hard to tell – it all depends on how close we are to something we won’t necessarily even see unless we get dangerously close; if you can see it producing relativistic distortions of space on the night sky, you are basically fucked. It’s a very old black hole, and probably not of the kind that advertises itself by chewing up new matter and producing lots of radiation along its axis of rotation, or we would have seen it on a radio telescope by now. What is basically certain is that there is at least one, it is expected to be around the center of the local bubble, and we are basically there.

However, considering how big this structure is, we could miss it by a parsec or so, which is the distance to Alpha Centauri, and relative to this structure’s size I would still say we’re basically right on top of it, and it wouldn’t affect us at all, so it is what it is.

There’s one thing people obsess over with some regularity: aliens. By “aliens” I don’t mean existence of extraterrestrial life in general, but, specifically, flying saucers or UFOs being alien spacecraft secretly monitoring us, and, as a step further, American government having access to alien technology, either by having recovered wrecked alien craft, or by secretly cooperating with aliens in secret facilities. As “evidence” for that, American stealth aircraft are usually presented – originally, the fighter jets looked nothing like that, and then “something” happened and the Americans suddenly started developing “invisible” aeroplanes. It is strongly hinted that this happened because they gained access to alien technology, and incorporated it into their new weapons designs.

Well, “something” happened alright; a Soviet scientist by the name of Pyotr Yakovlevich Ufimtsev developed the theory behind it and published it in a Soviet scientific journal, but the Soviet military saw no utility in it, unlike the Americans, who promptly translated his work and developed upon it further. To quote Wikipedia:

“Pyotr Yakovlevich Ufimtsev (sometimes also Petr; Russian: Пётр Яковлевич Уфимцев) (born 1931 in Ust-Charyshskaya Pristan, West Siberian Krai, now Altai Krai) is a Soviet/Russian physicist and mathematician, considered the seminal force behind modern stealth aircraft technology. In the 1960s he began developing equations for predicting the reflection of electromagnetic waves from simple two-dimensional and three-dimensional objects.
Much of Ufimtsev’s work was translated into English, and in the 1970s American Lockheed engineers began to expand upon some of his theories to create the concept of aircraft with reduced radar signatures.”

Basically, attributing obscure technology to aliens seems to be a popular thing among the fake sources, but it’s also something that makes it quite easy to debunk said fakes once you learn the truth. It’s similar to claiming to have learned some secret shit in Tibet or India from a secret guru or in a secret monastery. It worked best while those places were unknown by most and thought to be the end of the Earth, but less so today.

This brings us to the reason why I don’t care about the aliens: they don’t matter. If the aliens did in fact influence technological development in some country on Earth, and this changed the geopolitical situation here to their advantage, that would be a serious matter and I would change my opinion, but from what I can see, nothing of the sort exists. Furthermore, if the aliens indeed are behind the flying saucer phenomenon, and they monitor us for the better part of a century, and they never revealed themselves to us, this is not very different from the situation we would have if the aliens didn’t exist at all – they have zero effect on us. If something doesn’t have any effect on anything, I honestly couldn’t care about it. It’s like bacteria found in core samples from some extremely deep bore hole; yes, they exist, but they don’t influence absolutely anything I care about, and as a result I don’t care about them. They exist, they don’t do anything important, and I don’t care. Likewise, the aliens might not exist, or they exist and they don’t influence anything I care about. In both cases, I don’t care. If they revealed themselves and started influencing things I care about, my position might change, but until then, I don’t really give even a slightest bit of fuck.

Now someone will start about the Drake equation and the immensely low probability that we’re alone in the Universe, and I’ll just roll my eyes and ask what that has to do with anything. Furthermore, when I was younger I firmly believed in the existence of alien visits to Earth, based mostly on what seemed to be ancient cargo cults influenced by the aliens. My position changed with time, mostly due to my better understanding of the evolution of life. I used to think that the main problem with life was the development of DNA and cellular replication, and that this took billions of years, and after that point, everything was easy. It turned out that life on Earth started merrily replicating while the core wasn’t even properly solidified. It took basically no time to develop, which means it came here on comets or other interstellar debris, and complex molecules that form the basis of life were indeed found there, so it’s more of a case of “mix this with water and wait five minutes”, rather than waiting for electric discharge, chemistry in the primordial oceans and what not causing random combinations of molecules. The problem is, the life that was originally created was much simpler that what we have today; basically, you had single-cell replication, but it took enormously huge amounts of time, and a very few singular cases of what appears to be incredible luck, in order for life to get past the phase of self-replicating molecules, and into the phase where a eukaryote cell has a separate core, mitochondria, ribosomes and chloroplasts. Basically, the earliest fossils are 4 billion years old, right at the upper edge of Hadean epoch, when the Earth’s crust was still smoking orange. It took two billion years of vibrant evolution of life to create the first multicellular life, and only after that the things start conforming to my expectations of what evolution looked like – basically, it took another billion and a half years for life to develop to the point of the Cambrian explosion, and that’s the part of the history of life everybody seems to be familiar with.

So, the issue isn’t whether there’s life somewhere. I expect there to be some kind of life on at least five solar system bodies; basically, if life could develop on the early Earth, which was by all accounts the most terrible hellhole one can imagine, it can develop almost anywhere. However, I expect it to be of the kind we had during the first two billion of years of development of life on Earth, because it still would have been there if not for several very lucky events one wouldn’t have the time for if, for instance, his planet lost its magnetic field and its oceans evaporated into space. Life on such a planet would have quite an opportunity to continue developing underground, like it does deep in the Earth’s crust, and evolve into very resistant extremophiles, but you would never have anything like the Cambrian explosion, or even the eukaryotes. But let’s imagine you indeed get multi-cellular life somewhere, but there’s no ozone layer, or the land is for some reason perfectly hostile to life; for instance, life develops around the hydrothermal vents in the deep ocean, on some cold moon of Saturn. Let’s imagine life developing to the point of some octopus, which is quite intelligent, but remains an evolutionary dead end forever. This is not at all a far-fetched conclusion; in fact, this is how most successful Earth animals exist; they become very successful in their evolutionary niche, and change very little for millions or even hundreds of millions of years. In fact, some single-celled organisms probably didn’t change for billions of years, and I don’t really see why they would, if they are extremely successful in their environment. Furthermore, the more stable the environment, the less reason and opportunity one would have to evolve, for the evolutionary niches are inhabited by super-successful organisms that make it impossible for anything new to evolve, because evolution implies half-assed attempts stumbling along for long enough to eventually mutate into something that can resist even the slightest bit of pressure, which precludes functional competition, and this explains why new forms of life on Earth flourished only when some disaster wiped out the masters of the previously established evolutionary niches. We had human evolution in the Pleistocene, where the climate is so chaotic that it routinely wiped out anything static, and started disproportionally favouring adaptability and intelligence. Basically, the birds had to evolve seasonal migration, the mammals needed to evolve hibernation, and the humans needed to evolve enough of a brain to start using tools, making fire, wearing clothes and building shelters in order to survive the seasonal extremes. However, when we add the incredible length of time necessary for life to evolve from replicating RNA to eukaryotes, and I mean incredible as in “enough time for a star to grow old”, and that’s with Universe giving you a head start by providing the almost-living chemicals on comets, probably created in the aftermath of a supernova, it is not unreasonable to assume that in most places where life managed to take hold, it either found the conditions too unfavourable to continue, it evolved at a slower pace because of the conditions (for instance, being limited to a narrow space around a hydrothermal vent on Europa, and then having the hydrothermal vent move and everything freeze every now and then, or oceans on Mars evaporating, or soil containing reactive chemicals that inhibit life past the extremophile phase, or radiation inhibiting complexity past the tardigrade phase), or it just died out, or reached one of a billion possible dead ends. When you combine the likelihood of bad luck, such as having an asteroid wipe everything out every now and then, or having a very active star that produces a CMA of great power every now and then and sterilizes the planets around it, with necessity of having several instances of extremely good luck that were necessary to create the Earth as we know it, for instance the Theia impact that created the Moon, which is responsible for Earth’s incredibly strong magnetic shield, and also for stability of its axis of rotation and probably several other important things, or hundreds of other things that could’ve gone the slightest bit of a margin differently and we wouldn’t be here, the fact that our star has been incredibly well behaved for immense percentage of its life, and so on; earlier, I thought that the Universe was just too big for us to be the only intelligent species, but with everything I now know, it might be that the Universe is too small for this to be repeated anywhere else. I don’t know if that is indeed the case, but for all we know, Jupiter, Venus and Mars might be the rule for how the planets turn out. Basically, they either don’t develop a magnetic field, or they lose it, and then it’s all over; or they have a significant magnetic field, but they are gas giants, and maybe the conditions on their moons are more favourable for the development of life than on the inner planets, because of the tidal forces influencing the moons’ cores and creating geothermal activity that favours life – maybe, but we have no evidence yet, and we especially have no evidence that this life isn’t permanently stunted by its environment. In any case, the Universe outside Earth looks like a barren wasteland, incredibly hostile to life. The conditions on Earth look like something that required too much luck for it to be a normal or expected thing, and perhaps too much luck not to have been created backwards, by setting the desired outcome and then creating the conditions that allow that to work, which is basically what I think happened.

In any case, my current opinion about the existence of aliens, in the sense of an intelligent space-faring extraterrestrial species that visited Earth in the past and does so in the present, without revealing themselves to our public, is that something that doesn’t reveal itself and doesn’t influence anything for all intents and purposes doesn’t matter, and might as well not exist for the degree of importance it has to all the things that matter to me in any way or form. Will aliens help me in any way? No. Will they hinder my plans in any way? No. In any case, I already spent an inordinate amount of time and effort thinking about the implications and probabilities, and there’s obviously a limit as to what resources I will dedicate to completely impractical matters.

Sure, you can define aliens in ways that include non-physical beings, such as God, angels and demons, and re-define “other worlds” to mean non-physical realms, but that’s not what most people mean by aliens – beings that occupy and have originated in this physical Universe, only on places other than Earth. If you need to enter the sphere of theology and redefine aliens in order to make them relevant, you basically accept my reasoning as to why aliens don’t matter, you just phrase it as “physical aliens don’t matter”.