[Calaban]

No, not tyranid, and not space bugs like you'd normally think. The bugs I'm talking about are bugs like the common cold. Viruses, and maybe bacteria.

I'm just going to present two anecdotes that I dont think have ever been considered side by side before. Now, as anecdotal remembrances, the details may be fuzzy, so any numbers or dates I present are rough guesses.. But the point of it all remains.
[hr]
The Lunar surveyors common cold:
Before the Apollo missions to the moon, a moon probe was sent to land and do its experiments... after say a few weeks, its batteries died, and it became a relic on the exposed lunar surface, its job complete.

Then, on a later Apollo moon landing, one of the experiments they decided to do was to retrieve the surveyor probe, and return it to earth, for study. The purpose was to see how the different materials held up in the harsh environment of space over a long period of time. This probe sat on the moon for like 4 years, and alternates froze/cooked as the 2 week days and nights passed.

One very suprising thing that they found that held up quite well to 4 years in space was the common cold virus, that the detected in on of the subassemblies that they studied! From what they figured out, back in the parts' factory where it was made, some worker with the common cold sneezed on it, without a face mask [shame shame!]. That virus remained [whats the word?] viable even after its life out there on the moon... in fact it remained viable much longer than it normally would BECAUSE it was in the pristine environment of hard vacuum. The virus was put to the test and rapidly infected test batch cells like it normally would.

This came as a complete suprise to NASA engineers, as they felt certain the radiation from the sun and the van Allen belts would instantly destroy any microbes or other DNA based life that happened to make it to outer space. But this proved them wrong. A virus, at least, with minimal radiation shieldinf provided by the probe hull, survived just fine.

Its because of this that biological contamination procedures became so strict, and why now extreme effort is put into ensure that NOT earth life is on any probes we send to other planets. Its a thing that NASA knows now, but that isn't really common knowledge: we can infect other worlds with our own bugs from space.

[hr]

The 1918 flu

The 1918 flu is the common flu bug we get every year [influenza], but of a chromosomal makeup that proved far far deadlier than the common annual flu. That was the flu that killed millions. But the odd thing was: it sprang up instantaneously around the world... this was a time before widespread air travel, so HOW it spread in a matter of days around the world remains a big mystery. Actually, a HUGE mystery!

One of the odder possibilities was that the flu was alien in nature (not sentient alien, just off-world alien), and its virus dusting was 'salted' across the earths upper atmosphere as it spun through the infested portion of space. While highly odd and improbable, it would explain the worldwide simultaneous outbreak.. and is about the ONLY theory that offers a reason to explain it.
[hr]

So there ya go: Space bugs!

To clear up the question "WHERE would earth compatible DNA come from out there?", I'll add a third anecdotal story:

Cometary seeding of life on earth:
Life sprung up early in earths' planetary development... like... incredibly early.

Earth is 4.5 billion years old... much of the beginning of that life was full of collisions and other natural planet forming mechanics... and the earth in its early days was a hot, molten, meteor showered hell for the first billion or so years. As it gradually cooled [the meteor showers were tapering off by now], the occasional comet impacted, and gifted the earth with its water... at some point, that is still a bit hard to determine, things stabilized, and the earth became a water covered world what we may begin to recognize, about 3.8 billion years ago.. by our best guess.

... Simple life forms are found off Australia's west coast [oldest surviving coastal crust] that are.. you guessed it: 3.8 billion years old.. so as SOON as such bacterial life COULD take root in the local conditions, it DID.

It seems as though life just couldn't wait to spring up in this favorable locale of a planet, and did so right away. One explanation for this is that the DNA was being introduced, ready made, continually, most likely within the comets, and their soup of complex amino acids. And that the DNA based Space Bug was continually trying to live wherever it happened to find itself, and only in Earths oceans at that certain day did it finally find a place to grow.

The implications for this is staggering: the life didn't actually originate here on earth, but was merely seeded here, and left to grow! Some other ecosystem evolved the DNA style of life, and possibly when its system went supernova, the few surviving seeds of life incubated in the remaining dust cloud, and waited out the eons as a new star system gathered and formed, globbing up as cometary halo object that may have helped to support its survival, that luckily one day hit our Earth with its warm and inviting oceans, successfully 'seeding' life on another world! In its day, our star system will also go nova, and we pay participate our own 'petri dish cultured' viral live out in our local galactic dust clouds, to continue this reeaally long gestation period. Its really kinda mind blowing.

I guess we will know if this planetary seeding thing is true when we study the first alien life we find.. be it a little green man on the white house lawn, or a microbe in Europa's under ice sea... if they are also DNA based, then this theory cannot be denied!

.. and possibly the entire galaxy is seeded this way, and ALL life is one common universal one, and that we are ALL very very distantly related! And who knows WHERE the originator life started, or when.



Hehe so there, just something to chew on.

[compubrains]

The problem with the theory that life came from other worlds is how it got here. Space is big. It would take a really long time for anything to get here. Not to mention the probability of something randomly hitting us is astronomical. They'd have to be aiming. In which case, they'd be sentient, and we'd be their slaves or something. If this was true, then I guess maybe a rival faction of space alien could've sent the spanish flu at us to kill off their rival's labor supply. Or, as it did not threaten to wipe out mankind, it could've just been our alien overlords testing our resistance to a certain contagion. Maybe they're vulnerable to it, and are looking for some resistant bodies to inhabit.

More likely is that life did not come here from another world, and as soon as life could form, it did. The 'ol primordial soup theory. Plus, 700,000,000 years is a really long time. Like, it's really really long. Really. In that case, even if some extraterrestrial disease did come to get us, it would be unable to interact with our systems due to the different formatting it most likely evolved under. We wouldn't know it existed. The 1918 flu was just one of those "oopses" of genetics. (Diseases really aren't supposed to kill their hosts, just spread to other victims, disappear from the original host, and evolve. That way, their descendants can use the same host again once they've evolved around the host's immunity.)

[VerjigormDeExile]

Comets are essentially similar to that "primodial soup" you describe in composition, and are all over the place, taking long trips in and out of system. A comet passing by earth at the right time could leave a great deal of interesting things in it's wake.

[ForbiddenKnowledge]

There's quite a lot of support for the seeded earth theory in the scientific community, from what I;ve read - not saying its definate, but that it is a very valid theory. Not to mention, we are colliding with another galazy.

[Solourus]

Originally Posted by Calaban

The 1918 flu
But the odd thing was: it sprang up instantaneously around the world... this was a time before widespread air travel, so HOW it spread in a matter of days around the world remains a big mystery. Actually, a HUGE mystery!

The Spanish flu lasted from March 1918 to June 1920, the disease was first noticed in March 1918 in the USA, a more virulent strain of it appeared in in Sierra Leone and France around August 1918. Before spreading to the rest of the world over a period of 2 years.

That's hardly an instantaneously appearance around the world, nor did it spread as quickly as you claim. It did however spread fairly quickly but there is a good reason for this, World War 1 ended in 1918. That means all the foreign soldiers fighting in Europe could very well have taken the flu with them back to their home countries.

Originally Posted by Calaban

One of the odder possibilities was that the flu was alien in nature (not sentient alien, just off-world alien), and its virus dusting was 'salted' across the earths upper atmosphere as it spun through the infested portion of space. While highly odd and improbable, it would explain the worldwide simultaneous outbreak.. and is about the ONLY theory that offers a reason to explain it.

This isent a possibility, we have a samples of the 1918 flu virus. It is just that a flu virus, in most respects nearly identical to the ones that infect the human population today. Even if an "alien" virus were to fall to earth it couldn't infect us, for the same reason virus that attack plants or bacteria are harmless to humans.

Originally Posted by Calaban

Cometary seeding of life on earth:
Life sprung up early in earths' planetary development... like... incredibly early.

Earth is 4.5 billion years old... much of the beginning of that life was full of collisions and other natural planet forming mechanics... and the earth in its early days was a hot, molten, meteor showered hell for the first billion or so years. As it gradually cooled [the meteor showers were tapering off by now], the occasional comet impacted, and gifted the earth with its water... at some point, that is still a bit hard to determine, things stabilized, and the earth became a water covered world what we may begin to recognize, about 3.8 billion years ago.. by our best guess.

... Simple life forms are found off Australia's west coast [oldest surviving coastal crust] that are.. you guessed it: 3.8 billion years old.. so as SOON as such bacterial life COULD take root in the local conditions, it DID.

Your right about the age of the earth, your other dates are off by a bit. Most textbooks say the earth had cooled enough to have liquid oceans by 4 billion years ago, although recent evidence suggests that liquid oceans existed as much as 4.3 billion years ago.

The first evidence of life appeared around 3.7 billion years ago. So that's ~500 million years in which life had a chance to evolve. For reference 500 million years ago plants, let alone animals had yet to colonise the land masses.

We have a good theory on how life could have evolved in earths early history there is no need to go inventing alien microbes, infact our D.N.A itself shows that we all came from a single ancestor because the D.N.A language all living things use is exactly the same. If D.N.A seeding was common you would expect to see different sets of organisms using different D.N.A language sets.

[Genmotty]

I agree with everything Solourus has just said. The 'Doomsday Flu' took years to spread across the world and it is widely documented who feel ill, where and when. Soldiers and the families of soldiers in the working classes with lowers standards of living were the ones most harshly affected by the virus.

However if your going to look at flu strains the Spanish Flu is nothing like the influenza strains around today. The influenza virus is highly unstable and mutates at a very fast rate. As such this is why we fall ill to it quite often (except I've never ever had the flu even when all my friends and family have been struck down but it). Because each strain is different. Comparing the 1918 flu to todays strains is like saying H5N1 is the same as H1N1 which it's not. That's why they have different names, because they have different features even though they might be the same family of influenza.

[hr]

Organic Matter and Radiation

Ionising radiation is the most damaging radiation to matter, the sun is a major source of charged particles which can damage cells, but much of the 'electron winds' will be deflected by the magnetic fields of planets. Furthermore even the outer skins of spacecraft will absorb this type of radiation.

This leaves gamma, x-rays and other high energy photons to ionise the atoms in matter. These photons I believe have to be of discrete energy levels to 'liberate' electrons from the electron shells of an atom. When an atom loses one of its electrons it becomes an ion and therefore the chemical reactions which rely on those atoms can't take place to such a degree.

For instance if a atom in a strand of DNA is ionised it makes a small break in the DNA causing the cell to undergo a mutation when it tries to replicate it's DNA.

These ions manly cause damage in the DNA or Mitochondria/cytoplasm um in cells, however the cell membrane can also be perforated, but this won't be damaging the cell greatly in space.

These are typically stochastic effects to cells because the chance of damage to the cell increases with the random number of interactions with a photon. Of course a single photon could cause major damage if it interacts with the wrong atom, but many photons might pass straight through the cell never interacting at all.

When a cell is dividing it is at its most vulnerable to ionsing radiation as it might create an imperfect copy of itself. In space where there is a vacuum and the temperature is very very low and there is little for a cell to feed on, it will go into a period of hibernation until conditions allow for it to replicate. Therefore because it isn't 'living' and dividing it is less vulnerable to the effects of radiation than if it was beening one of the reasons we think bacteria can withstand the environment of space much better than we thought.

At least I think that's the theory,
Genmotty

[icer190]

Originally Posted by Rafe

There's quite a lot of support for the seeded earth theory in the scientific community, from what I;ve read - not saying its definate, but that it is a very valid theory. Not to mention, we are colliding with another galazy.

Actually, its two... and its more like eating them...

Not really colliding, but its not merging, its just absorbing them.

[chi3sa]

Interesting, wonder if in the harsh environments the cold could mutate to become more, less powerful or of some human importance.

[VerjigormDeExile]

Originally Posted by Solourus

The Spanish flu lasted from March 1918 to June 1920, the disease was first noticed in March 1918 in the USA, a more virulent strain of it appeared in in Sierra Leone and France around August 1918. Before spreading to the rest of the world over a period of 2 years.

That's hardly an instantaneously appearance around the world, nor did it spread as quickly as you claim. It did however spread fairly quickly but there is a good reason for this, World War 1 ended in 1918. That means all the foreign soldiers fighting in Europe could very well have taken the flu with them back to their home countries.

This isent a possibility, we have a samples of the 1918 flu virus. It is just that a flu virus, in most respects nearly identical to the ones that infect the human population today. Even if an "alien" virus were to fall to earth it couldn't infect us, for the same reason virus that attack plants or bacteria are harmless to humans.

Your right about the age of the earth, your other dates are off by a bit. Most textbooks say the earth had cooled enough to have liquid oceans by 4 billion years ago, although recent evidence suggests that liquid oceans existed as much as 4.3 billion years ago.

The first evidence of life appeared around 3.7 billion years ago. So that's ~500 million years in which life had a chance to evolve. For reference 500 million years ago plants, let alone animals had yet to colonise the land masses.

We have a good theory on how life could have evolved in earths early history there is no need to go inventing alien microbes, infact our D.N.A itself shows that we all came from a single ancestor because the D.N.A language all living things use is exactly the same. If D.N.A seeding was common you would expect to see different sets of organisms using different D.N.A language sets.

What if there's only one basic D.N.A. Language set? Which is what the idea is. Not that there's all kindsa alien life out there, but that it's all the same origin. Well, atleast, it's one theory

[Genmotty]

Originally Posted by VerjigormDeExile

What if there's only one basic D.N.A. Language set? Which is what the idea is. Not that there's all kindsa alien life out there, but that it's all the same origin. Well, atleast, it's one theory

It's a bad theory. As a physicist I except there is no 'specail place' in the universe. Therefore there is no 'specail place' life has originated, therefore either life can form independently, or some law of physics allows the future to become the past.

Therefore I don't think it's a good theory.

Genmotty