Von
Neumann probe is a name given to a theoretical type of spacecraft with the
unique feature of being able to produce and send its copies to other places.
For example, the probe is sent from earth to any planet, where from basic
elements available two copies are produced and sent to two new different
planets.
It may seem like a very advanced
device and indeed it is, but wouldn’t we be able to build them today?
Artificial intelligence systems and humanoid robots are getting more and more
effective. Very soon we should be able to make a robot that can construct its
copy from spare parts and, if programmed accordingly, it could perform any
mechanical task that humans can. We have nuclear sources of power that can work
for hundreds of years.
I think that economy is a much
more limiting factor here today than technology. Technologically,
we are very close to creating the von Neumann probe and if we united our
efforts, we would probably build one.
So, what about the travel time?
With huge distances it would take extremely long for such a probe to get
anywhere. Or maybe not really that long? In the 50s scientist designed
something called a nuclear propulsion system (project Orion) using current
technology. It is the type of space ‘engine’ using detonations of miniature
nuclear warheads to propel the spacecraft. This type of propulsion could
achieve constant acceleration of 1 g over many years. For example, sending such
a type of spaceship to the nearest star – Proxima Centauri - would take around
40 years (with the average speed being around 10% of the speed of light).
But even if we assumed the average
speed of just 1% of the speed of light we could get to tens of thousands other
systems in less than 100 thousand years (1000 lightyears distance). This for sure
seems like a lot of time but if we consider life on earth has existed for at
least 3.8 billion years it does not look that long anymore.
Now consider the exponential
growth of von Neumann probe operations. Let’s assume that the probe travels for
an average time of 500 years before it lands on a new planet. It then requires
500 years to build and send two of its copies. Excluding accidents and failures
(their effects can be reduced by sending more than 1 probe at the beginning)
number of probes (and visited planets) doubles every 1000 years. So after about
10 000 years we have over 1000 probes and planets visited. Considering
very low average speed (worst case scenario: no development of better
propulsions) and a very long time for each probe to make its copies, it is still possible to visit every
single planet in the galaxy in 5 million years. 5 million years is a blink of
an eye compared to the age of the galaxy.
We can take it further. By
nature of the exponential growth (next powers of 2 every 1000 years in this
example) it wouldn’t take much more time for von Neumann probes to convert all
of the planets in the galaxy to its copies.
During many billion years of our
galaxy’s existence if any civilization had developed von Neumann probes (and we
are currently not that far from it) they would have had enough time (hundreds of thousands times over)
to ‘be’ everywhere. Then why don’t we see our galaxy filled with such
constructs? I consider at least two interesting possible explanations:
- Every civilization destroys itself with its own technology (imagine printing thermonuclear weapons on 3D printer in your garage in 50 years from now) just before they are able to develop and build von Neumann probes.
- We would not exist in a galaxy where such a probe had been built, because probes would turn everything into its copies and we couldn’t ever appear. Therefore, according to the anthropic principle, it looks like we live in a galaxy where von Neumann probes haven’t been created yet, regardless of the very high probability that it should happen in any given galaxy.
Drawing 1: Example simulation of von Neumann colonization
compared to the galactic timeline; source: http://abyss.uoregon.edu/~js/cosmo/lectures/lec28.html
(October 2016)
Comments
The whole concept of space and it's exploring is very interesting, but considering we explored a super small tiny percent of it makes me wonder if we ever discover any new life out there, be it with this method or another one.
They are part of the plot in many science fiction books and movies. For example the replicators from the Stargate tv series, are by far most dangerous enemy encountered during 10 seasons.
Ion egines are diffrent technology and they are already used in probes. They are very efficient. Tha main reason why poject orion type drive hasn't been developed further is huge risk of nucelar contamination when sending nuclear fueal to outer space. And also nuclear weapons are banned in space.
As the life shows when you try sth once, you will try it another times. Combining chemistry and physics is very fascinating buy it could be deadly.
Same as with your "other life forms" article, I think it's safe to assume that we didn't find those probes because there is no such awesome civilisation like ours in Milky way yet.
However, the time seems to be the key factor here. Even the smallest network of discovered planets is going to appear after 2000 years of probing. A decent network after 3500 years. What are the chances humanity exists in its current form after that time? Seriously, it was like 300 years ago that we burned people alive for being witches. It's safe to assume a lot is going to change in 2000 years, with high possibility of humanity destroying itself.
One more thought. We have a robot that is sent on a planet, eats a part of it, creates two more robots that are sent on other planets to eat a part of it and multiply. You know what you created? A space parasite that feasts on planets and keeps multiplying. Let's not do that.
I agree with you, that Von Neumann probes might be a good way to find out planets with good conditions and maybe also find other civilizations. However, there need to be cooperation between nations to create for example Von Neumann probes, new, faster engines and as we see from current world situation, this might be the biggest problem we are facing.
Things listed there are really amazing and I belive that there are people trying to make this come true, what is unbelievable: what people can do, what they want to do. But at the same time there is a fear, how it could be used? I think, that such technology and achievements can make someone really powerfull, and there is a question: What this person would do with this?
Yes, if our ancestors would have built it - we would have much more information about other plants now. I think that NASA or SpaceX should think about the concept of such machines.
Correct me if I’m wrong, but maybe the other reason why the space industry isn’t developing so fast is because it isn’t so profitable and it’s not a number one priority for all countries.
In the future when I’d have more experience in software development - I’d like to contribute to such project as a volunteer by writing a software for gathering data about planets in our galaxy.
Thanks for sharing this interesting and complex concept. Great food for a brain :)
I think it is in our reach to actually send first people to Mars in order to begin the exploration of the planet so that in some years it may be our civilization's second home. However, it would require enormous preparation for both the people as well as the equipment, examinations, environment, dangers, opportunities etc.
Also, I agree that it seems that the space industry has slowed down a bit, in comparison to the actions it has been taking many decades ago. Therefore I think that it should continue working on the machines, technology and plans of going forward with the space missions development. We are talking about different planets here, different world which is still unknown for us humans. Even if the technology would enable it for us to visit or move there, it would have to be people which would adjust to the conditions which they would face.
First of all, the idea. 50 years ago, people didn't even think about such inventions. Not only because of technology, but also the way of thinking. I mean there was a lot to do here, on Earth.
Second, increase of technology is huge. It's not linear growth, but much more. Cubic? I'm not sure. It's truly amazing that such a thing is happening literally before our eyes. I know (as IT guy) I contribute to it directly, but it amazes me all the time.
Finally, interests. Apart from capabilities, people were always interested in exploring the Galaxy (as Agnieszka told). Referring to your second article, I think another life will be discovered faster than we suppose.
To sum up, von Neumann probe is invention that gives us a lot of possibilities. I think it will contribute to even stronger technological growth, but I'm not sure if humanity is ready for this.
i mean now you can’t even teleport a coin from one place to another let say in the same room :),
so to make Von Neumann probe happen in my opinion not possible at least now a days.
Or maybe our Earth life is some sort of alien self-replicating "probe"?
Anyway, I lean towards the explanation based on economic and organizational problems. For sure, it is not technology what is stopping us from building and sending von Neumann probes. It would be a huge project, costing a lot of money and involving lots of people. In my opinion it is the human factor what would be the greatest weakness here. Similarly, this may be true for other civilizations also.
As we all know there is no software without bugs so there is a huge chance that there will be glitch in this machines and they will annihilate us because of it.
I think it is not possible for now, maybe in a few years.