# Would you shoot out DNA onto baby planets if you planned to visit it someday?

The question popped into my mind when I read this.

Since we know our scientists are searching for planets which might be capable of supporting life; most of them many light-years away, could the reverse be possible? ie: Some advanced civilization discovered the secrets of creating life, then looked into space and saw a bunch of planets that could in a few million years become habitable, and then shot out vials of DNA or some life-forming-tech toward those planets (one being Earth) so that by the time they could build spacecraft and reach Earth, the Earth (and other planets) would have got populated with life and become habitable? (if this sounds like a nice story idea, please do take and write about it or make a movie. It'll be nice if the credit could be shared with me and the person who asked about the DNA vial :-) ).

So the question is would a civilization find it viable to do that? Perhaps even our civilization. We've obviously populated Mars with micro-organisms from Earth already. Would it be practical for us to shoot out life-forms into other planets and a million years later actually travel there? (Ideas for NASA and ISRO).

EDIT: For those of you mentioning the fact that equipments sent to Mars were sterilized. Well, think about it. Could you really remove each and every one of those bacteria and viruses from every nook and cranny of those highly complex scientific equipments? If the organisms ended up on Mars and died because of the atmosphere, that's another thing, but they also do tend to form cysts to protect themselves.

• Comments are not for extended discussion; this conversation has been moved to chat. – Serban Tanasa Sep 15 '16 at 18:11
• This question has a really awkward title, especially if you remove the word "planet"... – Durakken Sep 15 '16 at 19:39
• What??? Mars is contaminated?? – Ovi Sep 15 '16 at 19:59
• Yes, they can and did clean every "nook and cranny", unless you have evidence to say otherwise? – Tim B Apr 4 '18 at 17:42
• "if this sounds like a nice story idea, please do take and write about it or make a movie" a) you are very definitely not the first to come up with this idea, not by a long chalk, by many decades, possibly longer b) they already did, both in books many many times over & in film a fair few times, if you didn't know this you need to get out less (spend more time reading or watching movies) or maybe just climb out from under that rock once in a while, the most recent iteration that springs to mind is Prometheus. – Pelinore Apr 5 '18 at 23:24

I'm going to throw my hat in the ring with an answer different than the others. Simply, yes... there are some reasons. I think the tag makes this a tougher argument, but you also inquired as to whether ANY civilization (presuming intelligent life on other planets) might want to do this. And, of course, there's plenty of reason.

### Prime Directive

First, let's counter this. We have something akin to a prime directive when it comes to launching spacecraft and considering life on other planets, but even that doesn't encompass all of Earth. Russia, for instance, does not always hold the same beliefs that Americans do, and if North Korea were to truly get in the space exploration game, there's no telling what their motives may be. With a country like that, they could simply do something like this for the glory of saying that they had. If we throw in the possibility of intelligent life elsewhere in the universe, an intelligent and evolved species is only marginally likely to have the same mindset we do with things like this. A warlike people, or a strictly intellectual people may simply not have the same ideas about compassion for other life that we do, or may value spreading life more than surveying it.

### Feasibility

Surely it's been stated that DNA itself is simply programming. But, given enough vessels shot out in enough directions (obviously trying to hit planets in a Goldilocks zone of other stars), it's entirely plausible that life could take a foothold on an otherwise uninhabited planet. It's still incredibly unlikely, and even if it did, we would likely send bacteria and other microorganisms, so the resulting millions of years of evolution may not look at all Earth-like anyhow.

### Cost

While in contemporary Terran terms, this would be cost-prohibitive, what's to say that society may not come to a point where cost isn't really a thing. Or, again in the case of North Korea, cost isn't a factor so much since the government just takes what it wants/needs from the people. So really even in modern Earthly terms, cost may not be such a big issue in the long run given the right circumstances. A self-contained economy in a totalitarian state can "fund" many, many things given time and resources.

So, it's extremely unlikely, bordering impossible, but yes - there are feasible ways to make this plausible in a very remote way.

• Few centuries ago, people wouldn't even have been able to conceptualize the concept of software. I believe un-thinkable concepts and cultural practices are yet to come. In their own time; in their own way. – Nav Sep 14 '16 at 14:40
• Cost, in terms of "your civilization, with all of its resources, could not do it" can be prohibative even in a "NK" like situation. And the costs here are ... large. – Yakk Sep 14 '16 at 16:48
• In addition, some alien cultures could simply leave their DNA on a planet for the same reason dogs pee on things, they just want to mark the planet and say "This is mine" – Flotolk Sep 15 '16 at 0:04
• @Flotolk - Some human cultures would be happy to do much the same. – Jesse Williams Sep 15 '16 at 12:18
• @Flotolk not as much "this is mine" than "ZoltarOmicron wuz here" – Mindwin Sep 15 '16 at 16:51

Bearing in mind that the only reason DNA exists is through Amino Acids and a nitrogen-rich atmosphere that allowed it to exist; I'd say the answer to your question is:

## Not Likely

DNA in and of itself is just information. It contains the coding for cellular machinery, it is not that machinery itself.

Secondly, and here's a big kicker.

## Space is BIG

Unimaginably big! The nearest star to the Earth other than our Sun is Proxima Centauri, and even that is still 4.2 Light Years away.

If anyone's interested in maths:

the speed of light = $299\,792\,458\ m/s$

multiplied by $3600\ (60\times60) = 1\,079\,252\,848\,800\ (\approx 1.08 \text{ trillion})\ m/h$ (metres/hour)

multiplied by $24 = 25\,902\,068\,371\,200\ (\approx 25.9 \text{ trillion})\ m/d$ (metres/day)

multiplied by $\approx 365.25 = 9\,460\,730\,472\,580\,800\ (\approx 9.5 \text{ quadrillion})\ m/y$ (metres/year)

And that's just the distance light would take in the time it took the Earth to complete one rotation about the sun, it's got to do that 4.2 times.

Even with our fastest currently active spacecraft (Voyager 1 at some 17050 m / s) it would take well over 70,000 years to reach Alpha Centauri, even if it were pointed in that direction.

Put bluntly, by the time any kind of probe containing genetic information would make it to Earth from another star system, it would probably have been overhauled by colonizers in faster ships expecting to find a populated world and ending up finding that they'd beaten the genetic pod to the destination by some margin.

Then there's the little thing I mentioned at the start of my answer. You have no way of knowing if the target planet even has the right conditions for "life" as you know it to exist on its surface. Even with our technology, we can only guess at distant planets' compositions and need to send probes to make closer analysis of the planets' surfaces. (see New Horizons / Juno / OSIRIS-REx)

## Intelligent Life

How can we define intelligent life? Is it something resembling humanoids? Is it Homo Sapiens Sapiens? (Us?) Either way, life, you'll find takes a rather long time to take hold on any planet, even one such as Earth.

I'm ignoring the first 500 million years, approximately, of Earth's life as it was too inhospitable for life to form.

On Earth, for approximately 600 MILLION YEARS the most complex life found was single-celled life (Hadean Era)

For approximately 1 BILLION YEARS (1 thousand Million, not 1 million million) after that you had algae and photosynthesis, but still no multi-cellular life.

Then, for the next, approximately, 1 BILLION YEARS Eukaryotes dominated the early Earth.

Finally, 1.5 billion years ago, multi-cellular life began to form; they were still simple algae, but now they had multiple cells, and it stayed this way for another 1 BILLION YEARS approximately.

Now, we're at 500 Million Years Ago and finally we enter the Cambrian Explosion, where the largest amount of land animals and plantae evolved rapidly (20-35 million years is pretty rapid in planetary terms) Now things are really heating up!

Swiftly following the Cambrian era (541–485.4 million years ago) are as follows:

• Ordovician Era (485.4–443.8 million years ago)
• Ordovician - Silurian Exinction Event
• Silurian Era (443.8–419.2 million years ago)
• Devonian Era (419.2–358.9 million years ago)
• Late Devonian Extinction Event
• Carboniferous Era (358.9–298.9 million years ago)
• Permian Era (298.9–252.17 million years ago)
• Permian Extinction Event
• Triassic Era (First dinosaurs as we know them - 252.17–201.3 million years ago)
• Triassic - Jurassic Extinction Event
• Jurassic Era (201.3–145 million years ago)
• Cretaceous Era (145–66 million years ago)
• Cretaceous - Paleogene Extinction Event (Extinction of the dinosaurs)
• Paleogene Era (66–23.03 million years ago - Mammals evolved mostly here, but still no humans)
• Neogene Era (23.03–2.58 million years ago) - Finally! at 2.58 MILLION YEARS AGO, more than 4.5 BILLION YEARS after the formation of the earth, we have the first, true hominids, early humans coming out of Africa.

• Lastly, the Quarternary Era (2.58–0 million years ago) somewhere in here, modern humans come into being, we invent the wheel, electricity, plumbing, the internet, computers, cell phones, cars, planes, buses, trains, cities, skyscrapers, buildings, etc, etc, etc.

• Add the time it takes for that 'life' to gain a foothold on the planet. – Jan Doggen Sep 14 '16 at 9:51
• @JanDoggen - Good point. Will do – Raisus Sep 14 '16 at 10:06
• The DNA molecule does not depend on amino acids at all! Granted, existing chromosomes are made of DNA and certain proteins and the proteins are made of amino acids, but DNA itself has nothing to do with amino acids. It codes for amino acids, but doesn't depend on them. Not directly anyway. – terdon Sep 14 '16 at 13:37
• there are plans to reach proxima in a few decades with laser sails accelerated micro-probes. A few more decades in the future and we will be able to actually do it. – njzk2 Sep 14 '16 at 13:46
• @BruceWayne - True. it's kinda where I got my inspiration for that part of the answer :P – Raisus Sep 14 '16 at 14:23

If by "DNA and life-forming technology" you mean single cell microorganisms, then there are reasons. Idea to terraform Mars by engineering algae that can live and prosper (and pump oxygen) isn't new. Example articles about it:

Reasons? To make planet hospitable if / when we need it. Even if it takes time.

So yes, in reality this was considered, on much smaller scale than you ask for, but it was.

• The idea was that the microorganisms would in a few million years evolve into larger animals like on Earth. By that time at least we might actually have the technology and time to reach the planet. – Nav Sep 14 '16 at 8:49
• @Nav this was not considered. You can't reliably predict evolution. Best you can hope for is atmosphere better suited for your needs and some ecosystem that uses the same dna and amino-acids you do. That's a lot, anyway! – Mołot Sep 14 '16 at 8:54
• it's not much different than von Neumann probe, just biological instead of mechanical. And harder to control. Likely to come back at you with warships after several million years : ) – Agent_L Sep 14 '16 at 14:46
• @Nav If we take a few million years to send humans to Mars then I'm going to be very upset with NASA and SpaceX. – TylerH Sep 14 '16 at 17:56
• The few million years thingy was for planets that are light years away. My reference to Mars was just that we might have already populated it with a few bacteria and viruses from Earth. – Nav Sep 15 '16 at 5:10

With your tag on this question, I would say "No".

There's going to be a huge cost in resources creating multiple craft pointing at multiple planets without any guarantee that they'd land.

Then you factor on top of that whether the conditions on the planet are in a fit state to use the DNA by that time (assuming they hit the planet intact and deploy their loads).

On top of that, you have the "why", when it would take thousands of years for the vials to hit their target.

And you have the moral "Prime Directive" aspect. If the planet has already evolved life by that point and then your tailored, aggressive, DNA comes along and wipes out the dominant species - is this an ethical thing to do?

• +1 for Prime Directive. Regardless of cost or feasibility, we do NOT want to terraform a planet before we know if it is inhabited. – Stig Hemmer Sep 14 '16 at 10:04
• @StigHemmer Unless of course, we're an evil empire, where this scatter-gun approach is an entirely appropriate way of spreading evilness... – Snow Sep 14 '16 at 10:07
• @Pete and taint the immaculate history of mankind? As a species we have spent too many years without committing any morally questionable action to indulge in that kind of behavior? – SJuan76 Sep 14 '16 at 12:25
• @SJuan76 You want morally questionable? How about permanently raising air temperatures through global warming, and polluting the world's oceans with plastic garbage? If I were the Earth's creator, I'd want to initiate a 'The Day The Earth Stood Still' scenario before humanity screws this planet up more. Not to mention we live in the business world, where EVERYTHING has to make economic sense - there will be no "charities" toward the environment. – cst1992 Sep 15 '16 at 8:13

According to RNA-world hypothesis, the abiogenesis involved RNA molecules as original self-replicating molecules. RNA can act as both catalyst, like other enzymes, and data-store, like DNA. RNA-world hypothesizes that DNA and specialized enzymes (and everything else) evolved later as specializations.

So if you wanted to populate a remote planet with living chemistry, to make sure that there were "raw materials" of some sort when you got there, you probably wouldn't send DNA. You would probably send RNA, and amino acids if they weren't there already.

You could no more bootstrap an ecosystem by sending a vial of DNA than you could bootstrap a robotic civilization by sending a printout of the blueprints of a computer.

You need something capable of creating life. Luckily life is really good at self-replication. A vial of bacteria might do the trick but you'd need to be sure of a hospitable environment (a planet in the goldilocks zone with liquid water, a magnetosphere and an atmosphere) and a lot could go wrong. Your fridge and your stove are basically bacteria killing machines and they operate on a scale dwarfed by the conditions of space. You might need to put some thought into the process but a single automated mission could probably bootstrap an ecosystem. This could be replicated on a vast number of planets.

Of course Faster Than Light travel is impossible given our current understanding of physics, so visiting any of these places would be impossible, also it would take thousands of years for the missions to get where they're going and billions of years to bootstrap interesting ecosystems so I'm not sure what's in it for you.

Space is big. And space travel is slow.

Fast space travel runs into the problem that the insterstellar medium becomes rather nasty radiation at significant fractions of c, and into the problem that the energy budget gets ridiculous.

A K1 or K2 civilization can afford to do interstellar travel with at least small ships. Large ships (that carry actual people) is far beyond any reasonable reality check: there is every reason to believe that storing instructions on how to rebuild a person with a given personality at the other end is far easier than transmitting live people (not that rebuilding is easy, just easier than the quite ridiculous idea of generation ships).

Live crew on something faster than a generation ship is very, very ridiculous.

You could imagine a K1 civilization being able to send out micro-probes which could (A) land on a planet, (B) analyze the conditions, and (C) build a set of a microorganisms that could possibly survive there.

Such a task would be preceeded by solar-system sized telescopes that resolve the target planet down to a scale they can see the markers of life and get a good idea asto the conditions.

The star wisp would be accellerated, then maybe brake and navigate in the target system using a solar sail. An energy source capable of lasting 10,000+ years would have to be included somehow, and some reason to think it could survive and function after that long a period. Navigation would be ... challenging ... as at reasonable speeds, stars move, and galactic gravity is rough, and propulsion is impractical.

The "later" ship would be larger, even slower, and would intend to exploit the biosphere to build its economy up from scratch. It wouldn't carry "people" (definitely not organics), but planet-wide "terraforming" would somehow help its mission (at the least, it would have more organics to work with).

That ship could be designed to modify existing organics to surve its purposes. Maybe accellerate evolution towards macroscopic life.

Actually getting organic people there is hard. You could send encoded people, and somehow bootstrap an entire industrial machine civilization, and then build people-builders, and then build the people. But at that point, being "incarnate" in organic form would probably be a strange quirk.

A biosphere is probably still useful. But at the level of difficulty of insterstellar colonization, it seems like not that important an act. Maybe as an act of philanthropy to other systems.

• I was asked to provide reason, not for to argue but : Large ships (that carry actual people) is far beyond any reasonable reality check - statement is wrong. – MolbOrg Sep 14 '16 at 18:28
• @MolbOrg citation? I am talking about sending a large ship carrying one or more living biological humans to another star, at least 4 light years away. Doing so within a human lifetime requires a K1 or 2 civilization and magic materials to shield from radiation and "magic" brakes. Which leaves generation ships. Sending Ceres to prox over 10k years is E30J, or a 1 million year+ project for a K1 civilization. So this is a K2 civilization problem. Now they just have to make a 10,000 year biosphere in a tiny rock and store 5E5 K1-energy-output to slow it down. Your argument is? – Yakk Sep 14 '16 at 19:11
• I know that this topic is subject of long discussions, which leaves both sides equally unsatisfied, I try to avoid it and not interested in. You might consider to post that as question here on wb or maybe space. Make sure it was not answered before. As glue's: project orion; we are not K1 by any means; arguing by theoretical subjects as K1,K2 this statements is moved from particular situation where it might be true, to theoretical one where it is not. Ceres as ship I consider as a joke. How deep is my insanity here worldbuilding.stackexchange.com/a/45273/20315 project of this century. – MolbOrg Sep 14 '16 at 19:46

No one has yet mentioned that DNA has a half life of about 512 years.

Based on their calculations, the team predicted that even under perfect conditions for DNA preservation, it would take a maximum of 6.8 million years for every bond to be destroyed. And even before that time—after around 1.5 million years—the remaining strands of DNA would be too short to be readable.

So even before the questions of motive or the practicality of hitting a planet with your DNA payload or how you get the DNA to fertilize the planet, (rather than burning up on entry or impact, etc.), you have the problem that DNA degrades too quickly to survive an interstellar voyage... unless you have the technology to travel there anyway.

So a definite no. You can't seed life across the cosmos, at least not with DNA, because DNA degrades too quickly.

• I also mentioned "or some life forming tech". It could also be some kind of a machine or semi-machine-semi-dormant-organism that knows how to assemble molecules and create fresh DNA or RNA or whatever. Basically, the point is that life eventually gets to the planet. It's not about discussing the nuances, because that would involve tech which we have no clue about because we are a very backward civilization, given that there is so much more about the universe to discover. – Nav Sep 16 '16 at 4:50

Microorganisms are the key to terraforming. Machines require maintenance and when they break on another planet, it is probably unfeasible to send a tech. I think your question as to whether or not we would send out DNA is actually a fruitful way to frame the question because DNA itself is a set of instructions for replication of organic machines.

The key to these precursor injections of simple organic life is to identify the current elemental and chemical composition of the planet and craft a cocktail of organisms that can leverage the most commonly available molecules into other molecules which will be necessary for organisms in all other directions of the nascent ecosystem of the planet. Notice, this isn't really about a "food chain" at this point. You could pre-emptively send small amounts of predatory organisms that will feed on the base level converters, or you could simply create a mutually beneficial non-predatory circulation of byproducts and just stockpile.

To accomplish any kind of time-delay in the introduction of novel organisms you'd have to package the delayed organisms in either a state of simple cryostasis, dehydration, or hibernation, or have a technologically advanced and robust "seeding station" equipped with field-containment technology that creates a true anti-entropic field. (Hey, its sci-fi, right?!) However, again, that's a machine, and you're crossing your fingers exponentially with each layer of complexity/delicacy.

I would like to dig one level deeper from the answer of Jesse Williams and to go against all other answers.

We are life. You cannot even say that we are obliged to do this; or that we need to think of reasons; we are this. If we don't shoot life to other planets at one point or another, we are not life; we demote ourselves to level of rocks.

Let me elaborate on this. A gedanken experiment: you have a universe with a star (high entropy source). You put rocks and some other unspecified matter there, you wait some time. What do you have? Rocks of equal mass, right? Instead you place the chlorella there, wait some time, you get more chlorella. You wait some time, the mass of chlorella increases even further. That's it. This is how life differs from non-living mechanisms. If you talk yourself into not acting like chlorella acts, you have talked yourself into being non-life like a rock. You have showed that all the evolution and all the brainpower, drove you to act similarly to a rock and to be possibly overridden by chlorella. You can "duck" temporarily, to hide yourself as a civilization; or maybe to conserve the environment until you learn what it is to learn from it. This is what we do for Mars today, I think. But ultimately (and I mean in a short time) you do colonize every damn planet you can.

I wouldn't colonize the inhabited planets, because diversity is important. It's not a strong argument. Chlorella would beg to differ, maybe future humans would decide otherwise, too.

## Reality-check tag, part 1

The first topic to reality-check is that other civilization planted us. We don't have data that would support or deny it. Occam's razor doesn't cut away planting hypothesis. If it's normal for life to emerge, there should be more of it nearby. If life is extremely unlikely to emerge, the first civilization shot at very large distances (better to shoot large distance and good environment than to shoot nearby for many crappy environments, the life will spread itself further if it has room). Sounds familiar?

## Reality-check tag, part 2

The second topic to reality-check is: can we shoot DNA. At this point, not. Trough recent history, we set our civilization to have today one primary goal. The goal is to childishly consume more and more stuff, have more gadgets, see more nice moving pictures. Until we come to set our civilization to act maturely, we would have "economic" (or rather, systematic) problem to plant ourselves.

# Disease

Sending out something, which is meant to evolve, to be DNA life-compatible and letting it stay in unknown environment under varying conditions - is just asking for trouble, and may be long-term fatal.

At least, a secure-contain outpost should be set on any planet with a possibility to sterilize the whole planet complete if something goes out of control. Or the "evolution" should be actually preprogrammed to result in providing a terraformed environment with totally safe lifeforms.

This is similar to European sailors dumping coconuts, pigs and goats on tropical islands, as a depot for when they came past again. They could only do this because there was already earth and greenery there. (One presumes there are cases where the animals did not survive.)

Shooting vials of stuff isn't enough. There has to be infrastructure to make sure your DNA will survive, maybe with some tailoring to local conditions, and covering all climate zones, not just one.

Then pop them in the right place (temperature, humidity). To achieve simulated and accelerated evolution the process would need constant monitoring and adjustment. You'd need not just a backup ship in orbit, but probes on the ground, zipping around and gardening.