Philosophy Discussion Forums

There has been some recent mainstream interest in the idea of exploring other star systems by sending very small very fast space probes. The most recent proposal is a lightweight probe, perhaps no bigger than a sheet of paper, which would be accelerated very rapidly up to perhaps one fifth of the speed of light using a very powerful Earth-based laser. This probe could then reach our nearest stellar neighbour, the Alpha Centauri system, within a couple of decades.

See articles like this for more information:

universetoday.com/128416/ac-best-place- ... e-look-et/

blogs.scientificamerican.com/guest-blog ... i-or-bust/

I think it might be interesting to discuss the technical limitations of this idea, to squeeze the idea to its logical limits and see if any philosophy drips out.

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Obviously there are very many technical issues. Among them are:

1. How could the probe send information back to Earth? Would we send multiple probes, one at a time, and use them to relay information back?

2. Would the probe need to slow down when it reaches its destination? If so, how?

3. Given the fact that we cannot practicably communicate commands to them, what level of AI would they need? Would a system of many probes perhaps have a collective, networked AI?

4. Given that they're travelling at a large fraction of the speed of light, how do we protect them from collisions by interstellar particles? Would the large initial acceleration (about 60000g) tear them apart?

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Finally, I'll start off the process of squeezing this idea to its logical limits:

What if we make smaller and smaller probes, in larger and larger numbers, travelling closer and closer to the speed of light? Ultimately, the idea converges with the idea of sending EM (e.g. radio) signals to other star systems - i.e. sending probes the size of photons at the speed of light.

That'll do for starters.

At 90% light speed, the mass of an object will have roughly doubled as compared with its rest mass, but trying to move faster than that would seem a waste of effort due to the exponential mass increases and concomitant fuel requirements.

I think a small object would have to be terribly unlucky to be hit in interstellar space but there are asteroid belts and Oort cloud objects to contend with along with way. I guess if the craft beams back a constant stream of information, we might be getting the info increasingly late but at least there's either learning to be done or a long stream of zeroes from interstellar space - or maybe there's more "out there" than we realise?

Speaking of surprise discoveries, it will also be interesting to send another object to further explore the giant magnetic bubbles found by Voyager at the edge of the solar system. Apparently this region is called the "foam zone".

Steve3007 wrote:There has been some recent mainstream interest in the idea of exploring other star systems by sending very small very fast space probes.

I cast my vote against spending money and brain power on projects like this.

Humanity wakes up every morning with a loaded gun (nuclear weapons) in it's mouth. Global warming is here. The knowledge explosion is sure to bring more existential threats that could crash civilization. It's actually literally insane for us not to be making such matters the highest priority.

A plan to explore other star systems, and other such research which doesn't address our most pressing needs, would seem to prove that intelligent life has not yet been discovered anywhere in the universe, including here.

Ormond wrote:

Steve3007 wrote:There has been some recent mainstream interest in the idea of exploring other star systems by sending very small very fast space probes.

I cast my vote against spending money and brain power on projects like this.

Humanity wakes up every morning with a loaded gun (nuclear weapons) in it's mouth. Global warming is here. The knowledge explosion is sure to bring more existential threats that could crash civilization. It's actually literally insane for us not to be making such matters the highest priority.

A plan to explore other star systems, and other such research which doesn't address our most pressing needs, would seem to prove that intelligent life has not yet been discovered anywhere in the universe, including here.

The technology developed in this project will no doubt find useful applications here on Earth.

More broadly, if we don't keep progressing technologically there is ultimately no future. Humans will die out and the next most intelligent and dexterous animal standing will take over our dominant role and most likely follow a similar path. In evolutionary terms, there's plenty of time for other species to follow us if we fall. If humans are so callous and unthinking that we wipe ourselves out then perhaps it's for the best, just another evolutionary cul-de-sac. Aside from asteroids, quakes and supervolcanoes we will reap what we sow.

So the space program would be amongst the last areas I would cut because in it lies the only feasible future for humankind and the biosphere (not to mention technological and strategic advantages). By exploring space we are laying the groundwork for future generations to be able to preserve something of the biosphere's journey. The Earth's surface will be uninhabitable in less than a billion years' time and then it's game over unless bacteria ejected into space by asteroid impacts and space exploration finds a place to live.

Further, if space technology improves enough - and for this we need a voracious approach to gathering more information about and understanding of space - then we may even be able to alter the Earth's orbit into optimal zones based on the Sun's future development, or build outposts on the moons of gas giants as they move into the habitable zone? We may be able to terraform other worlds.

So I'd rather focus on filling tax loopholes exploited by billionaires and multinationals, cutting excessive perks for politicians, cracking down on government collusion with multinationals, cutting subsidies and spending on big sports, cutting tax exemptions for religions, cutting military adventurism, reducing duplication between federal and state jurisdictions, ending the costly war on drugs, place strict limits on political advertising and politically motivated panels and inquiries - and so on.

The technology developed in this project will no doubt find useful applications here on Earth.

Like what? Like when? Nuclear weapons could end us this week. Global warming could over run a tipping point in decades. What technology are you thinking of which is more important than these threats. You have no idea, right? Why should we invest in maybe someday projects when we have very real very pressing needs right now?

Apologies, don't take it personally, but you're just singing memorized mantras from the science clergy hymnal.

More broadly, if we don't keep progressing technologically there is ultimately no future.

And yet, we lived for thousands of years with hardly any technology at all.

The Earth's surface will be uninhabitable in less than a billion years' time ....[/quote]

Ah, so this is the pressing crisis you are addressing!

So you would cut space programs before all those other issues I raised earlier?

The technology developed in this project will no doubt find useful applications here on Earth.

Ormond wrote:Like what? Like when? Nuclear weapons could end us this week. Global warming could over run a tipping point in decades. What technology are you thinking of which is more important than these threats. You have no idea, right? Why should we invest in maybe someday projects when we have very real very pressing needs right now?

Because if we don't then someone else will, and they will gain the technology advantages - which they will happily sell to us at premium price.

More broadly, if we don't keep progressing technologically there is ultimately no future.

Ormond wrote:And yet, we lived for thousands of years with hardly any technology at all.

The Earth's surface will be uninhabitable in less than a billion years' time ....

We know what happened to indigenous people when they encountered more modern peoples. The "noble savage" meme is a myth, a child's yearning to return to the security of mother's breast, but there is no going back. The only way humans are returning to the wild to live in "harmony" with nature is if we break everything and render the advances of the last thousand years pointless. Back to short lifespans, constant threats, high infant mortality, superstition, ignorance and brutality, riddled with parasites and other infections ...

Do you have evidence that the Earth will be uninhabitable before then? Uninhabitable for all species or just human civilisations? What is your timetable? Why do you think the Earth won't heal itself or maybe at some point in the future undergo another ice age?

Why pick on space programs when there's so many areas of outrageous waste that don't offer the potential societal and economic gains that space exploration does? Why not also immediately hit religiously-oriented threads with criticism of religions' tax free status?

Greta wrote:Why pick on space programs...

I'm not picking on space programs. Space programs are the topic of this thread.

when there's so many areas of outrageous waste that don't offer the potential societal and economic gains that space exploration does?

I'm open to near Earth orbit space projects if they can demonstrate that they can help us with pressing Earthly problems. I don't see how exploring distant star systems can do that. If someone can demonstrate such a benefit that doesn't come in the form of utterly vague maybe someday promises, I'll listen.

Greta wrote:Why not also immediately hit religiously-oriented threads with criticism of religions' tax free status?

Because not only do I not worship the science clergy, I don't worship the atheist clergy either.

This thread is about exploring other star systems, and I'm against that. With all your typing you've done nothing to demonstrate why I should change my view.

Ormond wrote:I'm open to near Earth orbit space projects if they can demonstrate that they can help us with pressing Earthly problems. I don't see how exploring distant star systems can do that. If someone can demonstrate such a benefit that doesn't come in the form of utterly vague maybe someday promises, I'll listen.

Often the greatest gains come from esoteric research.

Ormond wrote:With all your typing you've done nothing to demonstrate why I should change my view.

I have, actually.

Greta:

At 90% light speed, the mass of an object will have roughly doubled as compared with its rest mass, but trying to move faster than that would seem a waste of effort due to the exponential mass increases and concomitant fuel requirements.

True. Also, signals sent back from it will be increasingly red-shifted.

I think a small object would have to be terribly unlucky to be hit in interstellar space but there are asteroid belts and Oort cloud objects to contend with along with way. I guess if the craft beams back a constant stream of information, we might be getting the info increasingly late but at least there's either learning to be done or a long stream of zeroes from interstellar space - or maybe there's more "out there" than we realise?

I've read somewhere that the density of hydrogen in interstellar space is probably about one atom per 10 cm². I wonder if, travelling at this speed, these induced cosmic rays would be dangerous, even if that small.

Ormond:

I cast my vote against spending money and brain power on projects like this.

I don't know about this specific project but, generally, I cast my vote firmly in favour of such projects and I don't do it because of any argument that they might have some incidental technological benefit. I don't care about that. I support them purely because they're interesting. I would like to see such things as further exploration of Mars, probes to the sub-surface oceans of the Jovian and Saturnian moons, further exploration of our own ocean floors, investigation of the lakes under the antarctic ice, further experiments in particle physics at such places as CERN, etc. I would like to see all of these things and many more purely because they're interesting. Absolutely no other reason.

The reason I spend some of my spare time writing educational computer simulations and do not spend every spare moment striving to help the world become a better place is purely because I find it interesting.

I think the fact that we face various problems here on Earth is entirely irrelevant because it's not a zero-sum game. Placing an immediate stop on doing anything interesting will not suddenly make us more effective at solving our problems. We'll simply go from being a species with some problems to being a slightly more boring species with some problems.

-- Updated Tue Apr 19, 2016 9:15 pm to add the following --

Error: When I said 10 cm² I meant 10 cm³.

Must get these things right, eh.

I think this is somekind of scattering experiment, they simply want to calculate the S-matrix of the universe by accelerating small sheets very fast.