PAART | ARCHEAN EON | BORING BILLIONS

ARCHEAN EON

The Archean's main features are the appearance of life and the establishment of the early local geography and atmosphere.

EOARCHEAN

By the end of the Hadean - at 550Myo, Paart's oceans were starting to form, submerging the hammered surface in water.

Large impacts on the planets crust will either thicken or totally crack the crust in it's surroundings, the counter-movement of the mantle to these events is to form a vortex of new material to the surface, and this molten material will squeeze itself into the cracks of the crust and spill out in the bottom of the ocean, which is pressing over these fragile places, those are the start of oceanic ridges...

Oceanic ridges are found in between plates that are drifting away from each other

Around those oceanic ridges, as the seawater penetrate into the rock as the lava flows out, it excavates little tunnels as it boils and oxidize the rock components, as it reaches a certain temperature it comes back to the surface, spilling boiling chemicals, those hydrothermal vents and it's chemical soup, might been a key ingredient for life in the sea - as sunlight would probably be still impossible to access in a constant flux as the dense cloud cover of the early ecumenical storms would be raging across the surface for some more millions of years.

Paart might not have the initial 5~6 hour day length as Earth is believed to have in this early stages - but with a gravitational field not as strong as Earth's, Paartian winds can still acquire quite some velocity, yet Earth had a much more violent start than this alien world.

A view of the Archean sunrise on Paart; Art by me

Is pretty much possible that RNA/DNA appeared by the end of this period, as those reactions would not only happen in the depths of the oceans, but sunlight would have also contributed for these same reactions to happen into the puddles of water from the first continents, so maybe Earth life appeared not only or twice, but hundreds or thousands of times, being mixed together as the high tides introduce new chemicals and water (or remove them) to the isolated systems.

PALEOARCHEAN

Finally, dry land...

The first continents emerge, and the first simple prokaryotic life appear, on Earth, we have rocks dating back from this period whose composition presents chemicals that could be only be found in such concentration that points towards to life as Early as the very end of the Hadean, though some are still unsure about life this early and prefer pointing out to the start of the Archean, though I personally believe life could be present in the end of the Hadean, is safer to recognize early prokaryotic life certainly appeared during the Paleoarchean.

MESOARCHEAN

In the warm waters of the Mesoarchean Paart, emerges the first supercontinent, as the volcanic fallout increases, the soil darkens, because the little oxygen present in the atmosphere reacts with the rock vapor to oxidize it, when the oxygen is on near-zero levels, rock can't oxidize and the soil of Paart comes to present it's natural color.

By this time, the shallow oceans near volcanic lava are teeming with microbial life, some building entire reefs of it's biology byproducts, is the ascension of chemosynthetic reefs...

NEOARCHEAN

The discovery of photosynthesis was a great breakthrough in obtaining energy, although the volcanic smoke didn't allowed the light of Vol to fully shine on the surface, it's ultraviolet light could still be easily scattered in the water vapor of the warm atmosphere, so photosynthetic bacteria used purple pigments to reflect blue and purple light, while absorbing green and red light from Vol, the release of oxygen initially reacted with the dissolved metals in the seawater - those released over millions of years so far by thermal vents.

This was Paart's little Oxygenation event, and gave origin to banded iron, cassiterite and bismuthinite rocks in the bottom of the ocean, marking the periods of high and low oxygenic activity over time.

But when the oceanic metals weren't enough to capture it, the oxygen ascended to the atmosphere...

- M.O. Valent, 29/02/2020
 

PAART | HADEAN EON | BIRTH OF PAART

IN THE BEGINNING THERE WAS NOTHING BUT THE SILENCE OF ETERNAL DARKNESS...

Creation of the Universe from the film Noah (2014)

HADEAN EON

On the geological time scale, Hadean is the oldest eon, which started with the formation of the Volar System and Paart, and ended when the first rocks and the Archean eon emerged from the depths. 

Its name derives from Hades, the land of the dead in Greek mythology, a reference to the hellish conditions of the planet during its first hundreds of millions of years.

The star's leftover materials like, rock, gas and ice, coalesces, and over time, form the clumps of rock we call proto-planets, this first 100 million years of existence is believed to be very turbulent and chaotic, and in between the Hadean and the Archean eons the impacts can take enormous proportions - as the planetesimals are now accreted into the planetary mass, and now all we have are couple dozen or about a hundred Mars-sized planets "competing" for the most stable orbits.

The rocky planets are more likely to form between the star and the Frost Line, a certain distance at which methane and ammonia freeze, and beyond this boundary, planets will accrete leftover hydrogen, water, methane and ammonia from the molecular cloud.

Paart during the first half of the Hadean like the other planets was struck by several planetesimals, which composition make up the planet's final structure, though, being surrounded by large gas giants whose cores bear 5 to 8 times the mass of Earth - at the time - all it was left for Paart and her brother Hool were a couple dozen planetesimals, which were in course to either Veek or Seey.

 

 Paart at 160 million years old

Being in this crossfire was quite intense, leaving permanent marks on it's geology that would still be visible billions of years later (if you dig deep enough) - this intense bombardment with Moon-size objects often occurred within direct trajectory, and thus Paart's moon didn't formed due an impact between Paart and another body at an angle - Like Earth did, but by the nearby shock between two of these bodies, whose the impossible product of vectors put the material into the orbit of Paart, and while Paart's soil is usually dark due it's carbides and bismuth rich mantle, Taaf's surface is white from titanium and aluminum rocks.

how it would have happened

The Upper Hadean is characterized by the late strikes of de-orbiting moons, product of the large body forming in it's surroundings - Taaf. And also, the appearance of liquid water.

The other minor moons that formed de-orbited into the planet after a couple centuries, notice the polar arrangement of craters, that void is created by the accretion of equatorial material into Taaf's body.

Paart has a relatively weak magnetosphere because it more or less retained it's original structure for a long period of time, although the impacts following the start of the Upper Hadean provided the extra iron and rotational speed needed for a decent dynamo (about 0,5Gs).

The Upper Hadean in Paart's history ends with the first rainstorms, and the rapid cooling of those initial lava flows, bringing the quadrillions of tons of water down to the surface, as the water that initially was present at the surface by the end of the Lower Hadean was due to sheer pressure of the thick hydrogen and water atmosphere above, unable to fully condense until further cooling.

- M.O. Valent, 28/02/2020
 

OTHER CONCEPTS | LOCATION NAMES

WHAT'S OUR PLANET'S NAME?

 Columbus fleet arrive at the Americas, circa 1492, colorized.

Probably 地球 (Dì qiú) if you're looking for what most native speakers call it, or Земля (Zemlya) - if you're looking for where is most likely for them to land.

Now we have a problem, we don't even know what to call our planet, sorta - one may argue that most languages call our planet with the capitalized word analogous to ground or soil - that being inherited from the Holy Roman Empire, where various dialects of German along with other languages were spoken, from the word Erde - meaning Earth was used, and as French, Italian, Polish, Czechs and Dutch got apart they kind of kept it that way.

The Greeks and Romans had Gaia and Tellus (hence where we got Telluric planets) to represent the Earth, but also the well known Terra.

While looking for answers I stumbled upon some rather interesting suggestions, some already well known (not including the opening of this post):

Terra
Latin, as well how Italian and Portuguese currently name it.

Domus
Latin, meaning home.

Sol III
Indicates the Latin name of our star and the position from it our planet finds itself.

Origin
Quite poetic, I mean, is where we've born.

Dhéǵhōm 
Proto-Indo-European, meaning the Broad One, Mother Earth, or House of the Mortals depending on who you ask.


Pangea
Greek, meaning All of Earth.

EArth
500,99 USD to check this translation.

Earth... Is though thing to resolve, because, it is a name from a time the world resumed itself to the ground, and anything above were deemed supernatural, not that any of us at that time could have figured out that early we were in a rock floating in space around a star, and that other stars had Earth's of their own - when we were too busy finding food or waging war.

Personally, I find the idea of renaming our planet quite silly. The same way we dubbed a planet light years away Kepler 22b or Trappist-1 e, alien astronomers and explorers would already have a catchy name for our little blue planet - references to their great persons and their own gods, and pop culture.

However, the question stands out if the alien explorers DO CARE about what we call our planet.
If both give each other time to study each other's language, maybe we could arrive at a consensus about it.
Ex; like they would refer to our among them as Blue Planet, and we would refer to theirs as Green Moon, until we have properly figured out each other.

None of those words will make any sense if they do speak musical notes, or sign language, or worse, it could mean something obscene for them - just imagine telling them our place is called Pangea, and it actually means Rape to them (if they do have such a concept).
Or the contrary, if an alien homeplanet is called Nostrils or Lemon.

When thinking about that, is way simpler to stick with the concept of Us and Them, the Terrans, Klingons and Vulcans, like we do separate countries, when actually their societies may and would be as complex as ours, with their own Nazi Germanies, and Russias, and Canadas.
We as humans never been a monocultural species, and the last century until today is the closest everybody in this planet got to ever be united in someway, and there is still native populations not contacted for half a millennia since Europeans landed in the New World...

We still wage wars against each other, we steal land, we have political parties and different religions and worldviews all around, that just won't let us to be mono cultural as far humanity is concerned, in many scenarios is way more easy to just accept your workers can't eat pork and go on with life and building stuff than starting a thousand year war to absorb their people - and that's still not accounting for racism and xenophobic people.

One funny (or not) thought experiment you can do is to try imagine the world if aliens had come in WWII and helped Nazi Germany to win and 'unify' the world, or helped USSR to spread communism - if they did recognize the world's major powers at the time as rulers of the world, what would modern day Earth look like? What if this occurred back in the 1800s when Europe divided Africa?

Now, what if the Klingon we love to see as the enemy is only one of a dozen or even hundred klingon peoples that got into space, knowing their society is as much varied as ours, would you blow their planet up to help the Federation?.

The Cold War is a good demonstration that the world doesn't exactly need to be united as a planet to explore space.

Again, into the consensus, I think names should be given in neutral territory, I mean, doesn't mean something utterly mundane or obscene for one or both main languages of the parts - or, one must accept the other's culture regardless of sounding, at least, to a certain extent.

A PLACE CALLED EARTH
Or maybe we don't need to worry much about it, because if hundreds of civilizations and peoples isolated from one another have told us is Regression to the Mean, maybe there would be a huge tendency to call the world "soil" in some manner. And if that is true out of mankind, it means that if an alien could answer in perfect English what's their homeplanet's name - they would answer, Earth.

SAMPLE PIECE OF LORE

The protagonists find themselves in a barren alien planet the natives call Hokushoku, later on, they find out that is not the actual name of their planet, but a nick given in an ancient dead language so their alien friends could call them by - the Place of all Hoku. It's like Earth was called Domuhominum or Anthropédaphos.

- M.O Valent, 25/02/2020

PLANETARY MODEL | PART 5 | PLATE TECTONICS IN 10 MINUTES

PLATE MOVEMENT SIMULATION

Last time I wrote about Paart's geography, I came up with this:

Now, I see how messy and hard it can be to get away with plate tectonics - as I had to move, and redraw each new map for the planet, account distortions by latitude and keep track of plate movement to keep it on track - a mess I believe no one may want to go through, myself included gave up on the fourth map of Paart's plate tectonics. I'm not saying you should give up on stuff, but it is rather silly to do certain things manually when you have the appropriate tools lying around.

While looking for solutions for my problem, I had stumbled across a website called Tectonics.js, it's purpose is to reproduce plate tectonics over time, and you can watch it evolve with a random seed, or import a heightmap as a starter for the process to take place. What is great for us, as we can provide a Pangea-analogue map and evolve it over time in a natural looking way - apart from what we would usually do by hand or using fractals, every ocean, every mountain, and coastline has it's own history behind it's shape.

Main page of Tectonics.js

So, I did loaded a map of Paart at age 4,2Gyr old, and watched it evolve over 600 million years - printing the screen every 25 million years - this process took about 10 minutes at 1Myr per second - and this was the result.

According to the simulation, the closest to the next super-continent it will get is 600Myr in the future (frame 21), when most of the landmass is shared by 3 neighboring plates.

Using this evolution of the landmasses, we can track where ancient rain forests lived and determine coal and oil rich points, and by that later determine which future countries or people around the world would be industrial powers due to the availability of those resources, what is a great starter for realistic geopolitics.

Here a + sign mark the place of a certain coal deposit through time:

I have chosen an interval of 420 million years to work with - by that I mean, that Paart's civilization will arise when the planet is roughly 4,62 billion years old.

Then working in 100Myr million year intervals, we get those climates (roughly):

Color code:
Rainforests
Savannas and humid regions
Hot regions, probably deserts
Dry regions
Tundras
Mountains
Ice

Then, most of the landmasses will be on the southern hemisphere of the planet, what makes most of the continents to have similar temperature ranges, it will be an era of greenness and warmth compared to previous eons.

As well, I marked sections of landmass that contained previous rainforests for long periods of time to mark fossil fuel rich places.

RED = OIL

With continental drift tracking, we can as well map the spread of fauna and flora over time, the same way some dinosaur species can be found on both South America and the west coast of Africa, or North America and Europe.

And looking back at our simulation, species from most of continents will have their ancestry either dating back ~50 million years, or as early 400 million years due isolation. What is not so bad, given that Pangea existed for about 340 million years, some creatures from Earth can be traced back to 250 million years ago.

As example, animals and plants from South America, Africa, and Australia had between 150 and 100 million years to diversify once they split apart.

So, our timescales seems reasonable so far...
 

Names in sanskrit based on their shape

I also named the continents for further reference when worldbuilding in the future.

Good modeling for everyone...

- M.O. Valent, 25/02/2020

OTHER CONCEPTS | SPACESHIP DESIGN & SPACE WARFARE

TIPS ON SPACESHIP DESIGN: a
SCI-FANTANSY WRITERS:

I'm not some Science-Nazi, but yea, there is some impracticalities in space that ships should be able to overcome, mainly battleships, as most blockbusters depict, such as Star Trek - so we will be talking about that today...

"Are you sure this design makes sense?"

Okay, as a good engineer would do, the problems we will face will shape our ship design along the way.

The first thing we should be concerned about space warfare is directionality.

Unless the ship is a heavy carrier that is planned to follow a well defined path through long distances, it should be able to maneuver in as many directions as possible in order to evade enemy fire or pursuit - so, big back facing engines OUT, they make up for a very easy and big fragile target, as well, it makes your ship's axis of rotation to be just into the engine, and unless all of your mass and cargo are located very close to the engine, that will put a large amount of stress onto unloaded parts of the structure and make the overall process of steering, hard and slow.

As an example of how this works, you could pick a plank and experiment with some weight on different locations, if the axis of rotation is closest if not just on the center of mass, so expect the cargo or the engine itself to be your axis of rotation in a ship.
Burning the engine at the just the right amount is a problem because you don't want your ship to turn too much while aiming or evading, so a board computer is just enough to make these calculations for the crew, when inserted the angle it needs to turn in each axis - manual steering would be highly reserved for tasks that need close visual contact.

SPACE IS NOT THE SEA

Rule 1
There is no water to counter your impulse, as well, each turn and maneuver might put your ship into an undesired course, for as slow as it may be, having your ship de-orbiting while you explore the ground is not cool.
Again, rear located propulsion is highly inefficient in doing that unless you dock vertically with your propulsion pointing at the surface of the planet or moon.
Having at least 6 rockets along the X and -X, Y and -Y, Z and -Z axis will grant your ship a minimum decent steering in any of the 3 axes.

The main axes of a cube

So far our ship would more likely look as compact as possible, like a sphere or cube, with free and stable movement.

Rule 2
Windows, are a weak spot, no matter what they're made of, what worries is not that they could break, is that they do expose the interior to dangerous radiation, as explained in FTL DEPICTION, near light-speed and faster-than-light travel expose the ship hull to dangerous UV, X-rays and Gamma radiation.
As well, in cruisers and aircraft carriers, is fairly natural that the majority of the crew do not see the sun for the entirety of the mission - nothing too strange so far.
So, little to no windows across the hull, if there is windows, make sure they are slim and can be shielded at any moment.

Star Wars: A New N o p e

Rule 3
We don't need an external horizon sense, I mean - Up or Down sides of a ship, we would want to make it cylindrical or with as many symmetry axes as we can, to make steering and defense evenly possible.

Rule 4
Heat is a serious problem. On Earth, vehicles, weapons and people can exchange heat with the environment. In space, we need to deal with irradiation of heat, the ship needs to get rid of extra heat from it's functioning and exposure to the sun, the problem is to balance the compactness of space ship with the large area needed to irradiate it away at a decent rate.
The ISS uses several heat plates to irradiate waste heat energy away from the ship, so computers, and people inside work properly.

We may want to use plates or several fins to irradiate the heat away, and as we would want to move this ship around, it should be able to control how much of that is actually irradiating heat away as we wouldn't want to freeze beyond the frost line or cook around Mercury.
An array of fins that run a fluid like oil or water as medium to carry heat away like a freezer's heating coil. Or we could design some part of our hull entirely dedicated to heat irradiation using the same principle, though using it's surface to do it.

In this case, we could use heat against our enemies, lasers or weapons designed to induce heat onto the hull or critical points like life support systems, can cook their equipment down and even kill them inside without necessarily breaching through the ship.

For this, we would never want to coat our ship in black paint or use dark materials to construct it's hull. Make it visually as bright as possible is the way to go, or at least as reflexive into the UV and Infrared as possible.

For now, our ship might look like a plain white cube-sat, with large panels to irradiate heat.

Now, we can't scale up our ship and make it a white Borg Cube, it is a ridiculously large target.

We would need to reduce our ship's silhouette in order to make it difficult to shoot down, making it an elongated bar would do well, we have a small circular silhouette along one axis, and a relatively thin bar on the other two.

The ISD, checks for rule 4 only

SPACE WARFARE
We would probably want or need to engage our enemy from a fairly long range - a couple thousand kilometers, if not light-seconds away, so light-based weapons are ineffective, and sub-light projectiles can be tracked and counter-measured with a maneuver set.

In this case, to create an untraceable cloud of high velocity debris or projectiles is the most effective way to engage the enemy, basically, use a space-shotgun to create a cone of debris at a distance that is virtually impossible for them to evade.
If your enemy can travel sub-light at 8km/s, create a cone with a base radius of 9~10km on their end, so you still get a hit if they try to evade.
If they do that to us, the most efficient way to get over it would be to have a thick hull at the extremes of our ship and turn parallel to the firing direction minimizing our silhouette as the cone passes.

Another viable solution we can learn from WWII, inclined plane of armor, makes it's effective thickness increase, as well it decreases the probability of penetration by deflecting projectiles, this is efficient as long as the incoming fire is nearly parallel to plane of your plate - that is what makes high-ground fire and mortars a good weapon against tank armor since you're shooting where the armor is thinner.

So, some extra armor plating in some angle on the extremes and we can create a wide safe pocket behind our ship where debris and projectiles won't reach our fleet comrades.
On the side we can dedicate a central line of weapon bays and more plating on the upper and lower part of the line.

Again, a good steering capability is necessary to maintain your orientation parallel to the direction of fire. In this case, guided missiles or curved trajectory missiles (doesn't have a tracking system, it is made in such a way it does describe an arch in space within a certain range, if the target is too close or too far away it becomes rather useless) might be a good way to overcome your enemy maneuvering speed, again, that can be dealt with via anti-missile and turret systems - but that's defined by how good both attackers and defenders are on each (and who has more Plot Armor).

Space warfare would be boring and slow in ideal conditions (access to the same degree of equipment and strategy use):

Ships have no real reason to be within visual distances from one another, unless you want to worry about debris from nearby dead allies.

 Scenes like this would be rare, and willing to be avoided by both sides

Being hundreds, thousands of kilometers or even light-seconds away from one another means that if you are able to even track your enemy, it is still a shoot and wait game.

For instance, if your artillery is 10x as fast as the WWII 40.6 cm SK C/34, ie, have a muzzle velocity between 8 and 10km/s, it would take 40~44 seconds to reach a target as distant as the ISS usually is from the ground (400km). What gives plenty of time for the enemy to react. Creative solutions such as dummy rockets or projectiles to accompany the real shell or radio / luminous flashbangs may come in hand.

The closest of visual contact with the enemy would be something like this...

...or this.

Unless one or both sides have access to Relativistic Weapons - weapons that fire projectiles at near light-speed, and thus deliver ludicrous amounts of energy upon impact.

Here is a clear and more mathematical approach to:
Kinetic Energy of RW [LINK]
Relativistic projectiles and moving spaceships [LINK]
And the full playlist on Relativity [LINK]

Overall, your ship design might resemble some of Mark Poe's work, a fellow artist that allowed me to showcase his designs here, those pretty much follow along the guidelines established previously.

As, well I recommend visiting the YouTube channel Isaac Arthur for more in depth approach to science and futuristic topics.

Val, out.

- M.O. Valent, 09/02/2020

THIS POST HAS A PART 2
SPACESHIP DESIGN & SPACE WARFARE | PART 2

BIOLOGY | PART 6 | DON'T TAKE OFF YOUR HELMET YET

EARTH-LIKE PLANETS MIGHT BE PLACES YOU WOULD NEVER WANT TO VISIT...

The air composition is similar to that of Earth's, the sea-level pressure is that of +90 meters, temperature is stable near 16°C... So far, humanity could thrive here...
                                                                                        ...Or is it? ô-0 *cue music*

Michael Stevens, VSauce YT channel

See, there's very much of an appeal to Earth-like conditions on other planets, in principle that would make easier for humans to settle around, like, it's way easier to move from Washington to Tokyo, than say move from Washington to somewhere in the mid Antarctic.

We would look for matching temperatures, atmosphere, mass and size to that of Earth's, that's what we've been doing so far.
Is rather fun to see weird creatures interacting in a world like Star Wars, a dozen species sharing the same bar and maybe a hundred sharing the same planet in the great Z Empire or X Republic. BUT there is something rather overlooked that is an interesting point to include sometimes - microbes.

The problem with a place just like Earth around another star, is ironically the same very thing that attracted us there in the first place - it's just so friendly to life, it becomes too dangerous to ever go beyond low orbit.

When the astronauts from Apollo 11 returned to Earth, they were in quarantine for 21 days, just to make sure they hadn't come back carrying harmful lunar microbes that might live on the Moon, later on it was found that the Moon was sterile, and following lunar expeditions were safe to come home back right away.
But differently from the Moon which is cosmically just kissing Earth, we cannot be sure of life on other planets from here, if not via very strong signals like atmospheric pollution spectral analysis.

Samplings and tests against known antibiotics and development of vaccines against the local microorganisms might be the very first step into colonizing another planet.

Knowing with certainty that life is present on such a place, decades or even centuries of microbial research would be required before the first civil settlement is established.

A planet may be totally devoid of plant and animal life, but it's air and water might be teeming with bacterial films and viruses.
For Earth, the amount of bacteria (source1, source2) floating in air is between ~800 thousand bacterial and ~1.2 million viral spores per cubic meter, fungi about 1K spores per cubic meter. Or if you examine a square meter of soil after a day it will be under 800 million airborne viral spores. That's not even mentioning aeroplankton.

If a planet present similar numbers to ours, an astronaut taking a single breath would be exposed to about (a human breathes 7~8L of air per minute, giving us ~125mL per breath) ~100K bacterial, ~150K viral and ~125 fungi spores, foreign lifeforms that our bodies haven't evolved to counter or even chemically detect. Imagine taking a 1 second breath and catching a thing similar to syphilis down your throat and lungs, you wouldn't want that to happen.

Entire native-American populations of humans were vanished from the map in a couple decades via diseases brought by European explorers - which despite never having previous contact with still evolved stranded to the same biological machinery the pathogens were used to explore.

In some cases, one may argue that we as 'superior' beings, would be immune to most primitive alien biospheres. What does make sense as we are continuously dealing with viruses and bacteria in our own planet that may happen to be way more dangerous than what we would ever found in an alien planet and thus our major concern would be Forward Contamination - to carry our pathogens to this place.
And you're right to a certain point, but what do you mean by humans as "superior"? Your body may have powerful antibodies compared to those tiny viruses and protozoans in this alien atmosphere, so we are safe... Right?

WЯÖNG!
Actually, your body as 100% human matter does pretty well against most pathogens, but you should be concerned about Immunodeficiency-causing pathogens, the ones that don't directly target your cells like skin and muscle, but target your local microbiota, we humans depend on chemicals and vitamins extracted from food by microbes that live within our tissues and guts. Just imagine the physiological catastrophe that would be if a virus happens to prey on our Mitochondria, or the bacteria that syntheses vitamin B and K, that's sensible machinery, that may even trigger our immune system to destroy our own cells while trying to stop the spread of the virus or infection.

Viruses raiding a cell

There will be worlds without penicillin, that on Earth is naturally produced by fungi, and those worlds may have natural chemicals we would consider synthetic because our fauna or flora isn't able to produce it, and many infectious diseases are so harmful because the pathogen releases a dangerous chemical as byproduct of it's life-cycle or in response to the immune system attacks, now imagine an alien infection cause it's host to die via an overdose of aspirin, or Benzylpenicillin, not exactly a lethal dose to our nervous and lymphatic system, but enough so the lack of our microscopic comrades, or even the spread of local bacteria due to change in the gut chemistry would cause severe injury if not death.

Even if viruses are not able to use our DNA machinery, they would still trigger over-allergic reactions from the body, or worse - to just destroy the cell without being able to properly use it.

It would be quite ironic if that image was inverted to a heat-ray lifting a dead human hand instead. War of the Worlds (2005)

If we are including other friendly aliens or alien food, we must also be concerned about their pathogens and their resistance against ours, unless one or both of us have to wear hazmat or space suits during reunions and visits.

Maybe everybody should have their helmets on...

Nature is force, a force that drives creatures forward in competing with others, and either theirs or our own pathogens will out-compete one another in some areas given time and exposure, in a manner that, if equilibrium is possible, any, and every outworld colony should be in constant quarantine - for the security of their own citizens and the security of the rest of humanity.

- M.O. Valent, 06/02/2020