Re: SETI How many fingers does ETI have?


Larry Klaes (lklaes@bbn.com)
Wed, 09 Jun 1999 14:49:46 -0400


>From the Warp Drive When? Web site: http://www.lerc.nasa.gov/WWW/PAO/html/warp/ideachev.htm#alcub Alcubierre’s "Warp Drive" Here’s the premise behind the Alcubierre "warp drive": Although Special Relativity forbids objects to move faster than light within spacetime, it is unknown how fast spacetime itself can move. To use an analogy, imagine you are on one of those moving sidewalks that can be found in some airports. The Alcubierre warp drive is like one of those moving sidewalks. Although there may be a limit to how fast one can walk across the floor (analogous to the light speed limit), what about if you are on a moving section of floor that moves faster than you can walk (analogous to a moving section of spacetime)? In the case of the Alcubierre warp drive, this moving section of spacetime is created by expanding spacetime behind the ship (analogous to where the sidewalk emerges from underneath the floor), and by contracting spacetime in front of the ship (analogous to where the sidewalk goes back into the floor). The idea of expanding spacetime is not new. Using the "Inflationary Universe" perspective, for example, it is thought that spacetime expanded faster than the speed of light during the early moments of the Big Bang. So if spacetime can expand faster than the speed of light during the Big Bang, why not for our warp drive? These theories are too new to have either been discounted or proven viable. Any other sticky issues? Yes... First, to create this effect, you’ll need a ring of negative energy wrapped around the ship, and lots of it too. It is still debated in physics whether negative energy can exist. Classical physics tends toward a "no," while quantum physics leans to a "maybe, yes." Second, you’ll need a way to control this effect to turn it on and off at will. This will be especially tricky since this warp effect is a separate effect from the ship. Third, all this assumes that this whole "warp" would indeed move faster than the speed of light. This is a big unknown. And fourth, if all the previous issues weren’t tough enough, these concepts evoke the same time-travel paradoxes as the wormhole concepts. [Our gratitude to Michael Pfenning for pointing out an error in our older explanation of the Alcubierre warp drive.] Larry At 10:36 AM 06/09/1999 +0200, Elisabeth Piotelat wrote: >Ron wrote: > >> How many fingers does ETI have? > >I can imagine something like a gaussian curve : most ETI have 6 fingers on each hand (20%), others have 5 or 7 (15%), very few have only 2 fingers (1%). > >Now, the other question is how many hands will have an ETI ? >What about the radial or axial symetry ? > > >Zeus wrote: > >> If such things as Alcubierre warps are possible, why not use "interstellar >> posting" by sending and receiving small Alcubierre bubbles containing data >> inside? > >A web link on Alcubierre warps or bubbles would help. What's that ? > > >Elisabeth



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