# SETI a pipe dream? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [July 12, 2014, 6:20pm UTC](https://boards.straightdope.com/t/seti-a-pipe-dream/692941 "2014-07-12T18:20:40Z")\ **Posts on this page:** 5\ **Page:** 2
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [July 13, 2014, 10:18pm UTC](https://boards.straightdope.com/t/seti-a-pipe-dream/692941/21 "2014-07-13T22:18:14Z")
> [@Habeed](#): > > The starship would have to be mostly antimatter fuel. Containing it would be quite tricky, but it’s probably doable. The antimatter fuel would be used to decelerate the starship when it reaches the destination. This was addressed in another thread. Antimatter is all but unusable as a fuel, most of the reaction product is neutrinos, which you simply cannot control (they exit in all directions, ignoring almost everything around them. You simply could not contain an adequate mass of antimatter fuel to be useful. But space is just loaded with free energy, and no matter whether you carry automatons or wetware, you basically _have_ to use it. Your vessel would have a really, really large magnetic field to capture the energy of cosmic rays through deceleration, which not only protects your payload but also supplies you with additional matter, which could possibly be fused for more energy or collected for thrust-out. The drive/nav system is a tech we are not close to developing, but it would apply force by creating an imbalance in the local vacuum energy density. Captured space energy would provide power for the drive, which would probably not work as well close to large bodies or systems, but in the end, the idea that a starship would need to be, or even that it _could_ be mostly fuel is a bit questionable. In any case, it is not at all obvious what could be expected of interstellar travelers, their abilities and their motivations. We cannot just project what we know of social behavior outside the bounds of where we have been able to observe social behavior. But I am pretty confident that interstellar society would not look like the Klingon Empire, the Sith Empire, the Saurdukar Empire or any other kind of structure that would look familiar to us. ---
**Author:** ![Absinthe\_Anecdote](https://avatars.discourse-cdn.com/v4/letter/a/f6c823/32.png) [@Absinthe\_Anecdote](https://boards.straightdope.com/u/Absinthe_Anecdote)\ **Post date:** [July 13, 2014, 10:36pm UTC](https://boards.straightdope.com/t/seti-a-pipe-dream/692941/22 "2014-07-13T22:36:23Z")
> [@Mangetout](#): > > I don’t believe that _not doing SETI_ significantly mitigates any of these risks. I think you meant to say active SETI as opposed to passive SETI, but I get your drift. I think SETI has been listen only, except for one or two short experiments that they did broadcast a signal. In that video that I linked above, Seth Shostak briefly mentions an intense debate over the dangers of an active SETI program. From a few of his comments in the video, I get the strong impression that the SETI administrators shy away from discussing alien “sociology.” What is the point anyway, we don’t even know they exist yet. ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [July 14, 2014, 12:42am UTC](https://boards.straightdope.com/t/seti-a-pipe-dream/692941/23 "2014-07-14T00:42:25Z")
I believe “active SETI” is known as “METI” (the “M” stands for “Messaging”, or something like that). ---
**Author:** ![DingoelGringo](https://avatars.discourse-cdn.com/v4/letter/d/9d8465/32.png) [@DingoelGringo](https://boards.straightdope.com/u/DingoelGringo)\ **Post date:** [July 14, 2014, 12:45am UTC](https://boards.straightdope.com/t/seti-a-pipe-dream/692941/24 "2014-07-14T00:45:56Z")
> [@Absinthe\_Anecdote](#): > > Do you think it is safe for us or any other civilization to deliberately broadcast signals to another star system? > > Aren’t there inherent dangers in that? What fear factor do you think the government should put out? Red alert The Martians are coming!! ---
**Author:** ![Absinthe\_Anecdote](https://avatars.discourse-cdn.com/v4/letter/a/f6c823/32.png) [@Absinthe\_Anecdote](https://boards.straightdope.com/u/Absinthe_Anecdote)\ **Post date:** [July 14, 2014, 1:19am UTC](https://boards.straightdope.com/t/seti-a-pipe-dream/692941/25 "2014-07-14T01:19:47Z")
> [@DingoelGringo](#): > > What fear factor do you think the government should put out? Red alert The Martians are coming!! Not trying to say we should panic. I brought that up in the context of why should the administrators SETI automatically assume that other civilizations would be actively signaling us. Also, I’m not 100 percent certain that we should beam signals at other stars. [Previous page](https://boards.straightdope.com/t/seti-a-pipe-dream/692941.md?page=1)