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Looking to Lasers, Microwaves and Anti-Matter for Space Travel
Space.com ^ | 11/26/03 | Leonard David

Posted on 11/28/2003 1:49:27 PM PST by LibWhacker

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To: donh
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?

I agree with a probe to a specific location. However, shotgunning them thru the galaxy is not very practical IMHO.

61 posted on 11/30/2003 11:12:08 AM PST by RadioAstronomer
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To: PatrickHenry
Think of what it took to receive the data from the Voyager spacecraft for Neptune encounter. These are tiny machines. I don't think they would stand a chance of sending even a signature over interstellar distances.
62 posted on 11/30/2003 11:14:41 AM PST by RadioAstronomer
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To: RadioAstronomer
Well, I guess we'll need relay stations. (A good job for SETI burnout cases.)
63 posted on 11/30/2003 11:18:03 AM PST by PatrickHenry (Hic amor, haec patria est.)
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To: PatrickHenry
A good job for SETI burnout cases

:-)

64 posted on 11/30/2003 11:20:55 AM PST by RadioAstronomer
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To: RadioAstronomer; boris
Remember out Sun is either a second or third generation star

Most likely a third-generation star. Hard to imagine a first-generation star consisting mostly of H and He manufacturing enough heavier elements to complete the Periodic Table and give us our terrestrial composition...an issue which speaks to the heart of this debate.

No matter how intelligent and dexterious the life-form, without sufficient raw materials, they're not going into space. Thus, a metallic-rich planet orbiting a third-generation star may be essential. If this is so, then perhaps all life in Universe is at about the same stage of development that we are...with interstellar space travel as yet impossible.

65 posted on 11/30/2003 11:47:08 AM PST by Aracelis
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To: RadioAstronomer
So there may be hundreds or even thousands or intelligent species, however, there would not be an interstellar civilization/galactic federation.

If they are using 'empire time' there can be

66 posted on 11/30/2003 11:53:31 AM PST by Centurion2000 (Resolve to perform what you ought, perform without fail what you resolve.)
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To: Centurion2000
If they are using 'empire time' there can be

Fair enough :-)

67 posted on 11/30/2003 12:08:33 PM PST by RadioAstronomer
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To: Piltdown_Woman
Most likely a third-generation star.

More than likely, however, a second generation star is not out of the question.

This is just one site of many that postulates either: :-)

http://www.rwc.uc.edu/koehler/biophys/7b.html

I do agree with your assessment. We just don't have enough data to make an informed proclamation about ET and/or ET exploration.

68 posted on 11/30/2003 12:19:19 PM PST by RadioAstronomer
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To: hosepipe
"Whats a pound of anti-matter weigh ?"

A pound.

Anti-matter falls down, not up. This is a consequence of the Principle of Equivalence of Inertial Frames which is part of General Relativity. Indeed, GR was once tested by checking that anti-particles fall down.

Any brand of "matter" that fell UP would destroy the Equivalence Principle and hence GR. 'Negative' matter (upsidasium) is thus highly improbable.

--Boris

69 posted on 11/30/2003 12:42:47 PM PST by boris (The deadliest Weapon of Mass Destruction in History is a Leftist With a Word Processor)
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To: boris
upsidasium... Lol..
Had some of that once, but swore off, that stuff with make you ignert...
70 posted on 11/30/2003 12:58:37 PM PST by hosepipe
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To: boris
upsidasium

We call it Viagrium.

71 posted on 11/30/2003 1:46:00 PM PST by PatrickHenry (Hic amor, haec patria est.)
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To: RadioAstronomer
I agree with a probe to a specific location. However, shotgunning them thru the galaxy is not very practical IMHO.

Quite practical, and rather the point of the exercise. After the first one that works gets moving, all the rest are free, from our point of view, here on this mudball. It costs us nothing to build and randomly vector another few million self-replicating nanobots from junk circling alpha centauri.

72 posted on 11/30/2003 5:55:46 PM PST by donh
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To: RadioAstronomer
I still don't see the point of creating these. Two other observations:

It is an investment for future generations to reap the harvest of. Kind of like when you build a huge campus building on your alma mater by bequest.

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

Right. So it takes a long time until payback. Already conceded.

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

Not playing in the right ballpark. This is not biological engineering, it is factory robotics reduced to a tiny scale. Sure there will be transcription failures. That's why we're sending replicators instead of straightforward probes. We can tolerate lots of replication failure when producing a multitude of offpring. Ask any bacterium. The laws of evolution apply to competition for finite resources where there is both variation, and selection. Where there is effectively no such competition, there is not going to be evolution, even if you have variation. The failures drop by the wayside, and the accurate copies continue on shipping out copies to distant regions.

73 posted on 11/30/2003 5:58:51 PM PST by donh
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To: Ichneumon
CODE OF THE LIFEMAKER

Thanks for the book recommendation. Just added that one to my holiday Amazon wish list. FR is a great place for book tips ;-)

74 posted on 11/30/2003 8:37:23 PM PST by Prodigal Son
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To: RadioAstronomer
Thank you so much for your insight and the ping!
75 posted on 11/30/2003 10:15:00 PM PST by Alamo-Girl
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To: boris; RadioAstronomer
I shall not let this thread die! Muwahahaha!

Anyhoo, I had some more questions, if you have the time (and patience).

I have read layman texts regarding speed limitations, and the consequences that has on manned inter-stellar travel. However, as one of you stated earlier, with less mass we can enjoy higher speeds. Would it be possible to propel a massless object faster than light? Sort of like the propogation of gravity (1.4 C or something)?

Also, what if our biological evolution steers us into sentient computers? If humans wound up producing conscious computers, or even more fantastically, implanting human consciousness into a computer, wouldn't that eliminate all these time problems?

76 posted on 12/01/2003 7:04:05 AM PST by Shryke
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To: Shryke
"I have read layman texts regarding speed limitations, and the consequences that has on manned inter-stellar travel. However, as one of you stated earlier, with less mass we can enjoy higher speeds. Would it be possible to propel a massless object faster than light? Sort of like the propogation of gravity (1.4 C or something)?"

As "Doc" Smith pointed out, if you can nullify inertia, an infinitesimal force will result in a velocity of "c" in zero time. Velocities greater than "c" involve imaginary quantities and lots of juicy paradoxes.

You might want to read up on Mach's Principle, if you want your mind bent. I understand it on Monday, Wednesday, and Friday; it is lucidly clear. On other days I am completely bamboozled; it is ludicrously opaque.

--Boris

77 posted on 12/01/2003 8:07:37 AM PST by boris (The deadliest Weapon of Mass Destruction in History is a Leftist With a Word Processor)
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To: boris
Velocities greater than "c" involve imaginary quantities and lots of juicy paradoxes.

What about gravity? It propagates faster than light, no?

78 posted on 12/01/2003 9:26:46 AM PST by Shryke
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To: Shryke
What about gravity? It propagates faster than light, no?

Brief article on this: HERE.

79 posted on 12/01/2003 10:35:50 AM PST by PatrickHenry (Hic amor, haec patria est.)
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To: PatrickHenry
The experiment I am referring to involved Jupiter and a quasar that it eclipsed. Although debated, some scientists are concluding that the rate of propagation is faster than light speed.
80 posted on 12/01/2003 10:58:59 AM PST by Shryke
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