Looking to Lasers, Microwaves and Anti-Matter for Space Travel

Space.com ^ | 11/26/03 | Leonard David

[RadioAstronomer]

Thanks! I do not have this book. I will order it :-)

What an interesting concept huh. :-)

[boris]

"I still don't see the advantage. Here is anothe rub. Would you, as an advance civilization, send a probe (that would probably mutate out inot the universe which may harm another species? Heck, even now, we ensure our probes are as microbial free as we can get them when we launch an interplanetary now."

Explain how hardware--backed up and redundant--can "mutate". In "Star trek" it evidently happens when one probe collides with another(!). Robots are far more immune (potentially) to 'genetic mutation' during reproduction than we are.

Secondly, I can tell you how to sterilize spacecraft now. Firstly, it is probably not a big concern. A probe could launch smaller, sterile probes even if it itself were not sterile.

To sterilize:

(1) Expose all parts which will not be harmed to ethelyne oxide gas or some other anti-biotic, anti-spore agent;
(2) Expose all parts which will not be harmed to GAMMA RADIATION at levels high enough to kill everything on board.

Rinse. Repeat.

Sterilization is NOT that hard--if conducted in space, away from Earth contamination.

--Boris

[donh]

I don't see a race squandering the precious resources of its own solar system with no practical benefit.

Huh. You mean like that oh so useful painting on the ceiling of the Sistine Chapel? And you think we will cavil at handful of Von Neumann's self-replicating probes?

Your deponent has a good point, and Von Neumann probes will not likely have the capacity to "evolve". Just fail, or replicate like gangbusters.

I think it a very good argument for our being isolated-- either by being alone, or by fiat--that we aren't teeming with extra-solar visitors. However, I can think of at least two other explanations: 1) they are here, we just don't notice much. Ants probably don't notice humans very much, even when their anthills are near bus stops. 2) Earth is owned, cultivated property, and there is a big NO TRESPASSING sign out.

The other rub, is how do these probes replicate? Where is the energy to not only do this but to get back out of the gravity well of either the star or object it used to make the replication?

You don't drop down to a planetary surface to replicate. You do it in interplanetary space using space debris. If you are a nanobot, and you have a virtually infinite supply of ambient energy, of any magnetude at all, and all the time in the world, you don't need to drag a bessemer oven, a forge, and a lathe across interstellar voids.

[onedoug]

The trash can lid I'd flung into the air and Poloroid photographed when I was 14, is still the best UFO pic ever! --©

[RadioAstronomer]

I still don't see the point of creating these. Two other observations:

1) Since they are made of "stuff", they would be subject to GR just like we are. So the velocity would always be sublight.

2) If they replicate and they are complex enough to record and do "useful" stuff, IMHO, evolution (or replication error) would be inevitable.

[RadioAstronomer]

You don't drop down to a planetary surface to replicate. You do it in interplanetary space using space debris. If you are a nanobot, and you have a virtually infinite supply of ambient energy, of any magnetude at all, and all the time in the world, you don't need to drag a bessemer oven, a forge, and a lathe across interstellar voids.

So where is the return for the investment?

[RadioAstronomer]

Sterilization was not my point. Sending replicating probes to unknown destinations with unknown consequences are. The sterilization was an analogy for what we do with our interplanetary probes now.

[RadioAstronomer]

There would be, then, the possibility of advanced technology from another 2nd or 3rd generation star elsewhere.

Agreed. However, it still does not resolve the distance and "c" problem. :-)

I suspect we are not alone, however, I do not think we have been visited.

[js1138]

Star Trek explain this away by not using the word conversion (at least early on). They used the words "A Dirac Jump" instead. As Scotty put it (in the early books I am talking now) "a conversion would blow up the ship".

The best bet is the infinite improbability transporter. Simply sift through all the possible universes for the one in which all the molecules of your body instantaneously tunnel their way to the desired location in the proper order. No energy required, merely a small problem of programming.

[R. Scott]

Whenever I read on this topic – and the replies – I am reminded how accepted reality changes.
Long ago it was deemed impossible to cross the oceans – the distance was just too great.
In the Nineteenth Century some scientists deemed it impossible to travel over 35 (?) mph in a steam powered train because it would be impossible for us to breathe at that speed.
In the Twentieth Century it was deemed impossible for many to travel faster than sound.
Also in the Twentieth Century many deemed space travel impossible because there is no atmosphere for a rocket exhaust to push against – which ignored Newton.
The common wisdom now is that intergalactic distance is too great to traverse. With today’s technology and scientific understanding that is true – but who knows what the 21st or 22nd Century will bring?

[boris]

Is it your supposition that all advanced ET technological civilizations will follow the Prime Directive?

Would we...had we the means?

Ask the Amerinds.

--Boris

[RadioAstronomer]

Is it your supposition that all advanced ET technological civilizations will follow the Prime Directive?

Not at all. However, a race sufficiently advanced to build these replicating probes would have at least a passing thought to this problem.

I still think that building better local instrumentation is a far better utilization of time, expense, and resources.

[boris]

"So where is the return for the investment?"

If a technological civilization has lasted 10⁴ or more years, it has developed patience. As I said, every so often, a probe will wander home and spill its guts--the collected knowledge of all of its ancestors. INFORMATION is the zeroth-order return.

The payoff is tremendous in proportion to the (tiny) investment [as I mentioned, building 100 0.05c probes will not be a big effort for such an advanced culture].

Such civilizations will not think in the short term--especially if they've a proven ability to persist for many orders of magnitude longer than our technological civilization has managed.

--Boris

[donh]

So where is the return for the investment?

The probes you drop down on the surface aren't the probes that replicate and move on. You sure it isn't worth a few nickels to get a camera lens down on the surface of a planet around Alpha Centauri?

[donh]

1) Since they are made of "stuff", they would be subject to GR just like we are. So the velocity would always be sublight.

I didn't say it wasn't a long-term investment.

2) If they replicate and they are complex enough to record and do "useful" stuff, IMHO, evolution (or replication error) would be inevitable.

Poleroid cameras and radio transmitters don't have to replicate to be useful. Evolution is not at issue, just failure of replication. Failed replicants won't move on, valid copies will. Evolution requires a basin of opimizable variations--this is not happening in the Von Neumann scenario. Ribosomes have been operating on multiple redundancy for a very long time without much change.

[RadioAstronomer]

The final rub is does an advanced race really expand outward or inward? We are all shooting in the dark here. What if we are the most advanced, or another race does not hold exploration of the physical to be supreme, etc.

This is all pure speculation. However, just because we have not seen other machines in our solar system, does not mean we are the only intelligent life forms in the universe. It also does not mean we are not either. I do not "believe" in either position. There is not enough data to posit a position on this.

That being said, SETI is still, IMHO, a good (even grand) endeavor. Either of the two results from this leads to a profound conclusion about our place in the universe.

[PatrickHenry]

As I said, every so often, a probe will wander home and spill its guts--the collected knowledge of all of its ancestors. INFORMATION is the zeroth-order return.

I don't think we'd need to wait for one to stagger home. If they had sufficient energy, they could transmit their observations to us, as our unmanned probes do today. Solar power might be sufficient, and it would trigger a call home each time one of them approaches a star. With enough of them out there, we'd "soon" be deluged with information. That's a fair return on what will, to some future generation, be a small investment.

[RadioAstronomer]

Such civilizations will not think in the short term--especially if they've a proven ability to persist for many orders of magnitude longer than our technological civilization has managed.

Fair enough. :-) But to believe or disbelieve either exist and you are postulating a "faith" instead of a speculation.

[RadioAstronomer]

Evolution is not at issue, just failure of replication.

But that is a tenant of evolution. Tiny replication errors that still allow functionality or survivability.

[hosepipe]

Anti-matter....
Ummm, finger to temple....
Whats a pound of anti-matter weigh ?
or if its anti-matter does it exist at all ?...