Reply
 
Thread Tools Display Modes
  #251  
Old 03-27-2015, 07:01 PM
Lumpy's Avatar
Lumpy is offline
Charter Member
 
Join Date: Aug 1999
Location: Minneapolis, Minnesota US
Posts: 16,654
Quote:
Originally Posted by levdrakon View Post
I say we wait for the next rogue star to pass by our Oort Cloud, build some colonies around it and ride it wherever it's going. That would count, wouldn't it?
A generation ship to Tau Ceti would actually be faster.
  #252  
Old 03-27-2015, 07:20 PM
levdrakon is offline
Guest
 
Join Date: Apr 2002
Location: USA
Posts: 17,348
Quote:
Originally Posted by Lumpy View Post
A generation ship to Tau Ceti would actually be faster.
Yeah, but I think a cluster of large colonies around a star would be safer and more stable than a gen-ship that is Lord of the Flies just waiting to happen.
  #253  
Old 03-27-2015, 09:04 PM
Left Hand of Dorkness's Avatar
Left Hand of Dorkness is online now
Charter Member
 
Join Date: May 1999
Location: at the right hand of cool
Posts: 41,533
Quote:
Originally Posted by Askthepizzaguy View Post
For the purposes of the thought experiment, which I admit is just a hasty metaphor, you'd have to also suggest that they can't slowly damage the glass over time with a pebble by scraping the glass over and over. The glass is meant to represent the barrier that near-light speed represents, not an actual physical barrier you can scratch away.
Sure--but for the purposes of your thought experiment, the pebble represents the way that future ants figure out to get past the barrier that near-light-speed represents.

I go back to what I said last time this thread was up. Ask Archimedes the greatest distance over which a human voice can be heard, and he's likely to imagine a massive megaphone. He might be able to build something that amplifies a voice to be heard, I dunno, let's spitball it, ten miles away. Shit, let's make it 50 miles, Archimedes was a goddamned genius.

Ask him if it's possible to create a device that allows a speaker in Athens to speak and be heard by an audience in Gaul, and he'll pull out immensely intricate math to prove to you why that's physically impossible.

What he won't do is posit the telephone.

You're looking at today's Archimedes in order to show why tomorrow's inventors won't solve problems. I say that's unjustified.
  #254  
Old 08-20-2015, 08:40 PM
sweat209 is offline
Guest
 
Join Date: Nov 2012
Posts: 1,522
You can forget about warp drive or Alcubierre drive!!

The Alcubierre warp drive is only one of the theoretical propulsion systems NASA is speculating about ( http://www.nasa.gov/centers/glenn/te...eachev_prt.htm ), and it has many problems. It would require negative mass (not the same thing as antimatter), which we have no reason to suppose exists, and it's thought that, although the Alcubierre metric is a Lorentzian manifold (allowed by General Relativity), it would not be allowed by a quantum theory of gravity. Another objection is that it would need to be powered by a ridiculous amount of negative energy (which may not be something which can exist), equivalent (-E = -mc^2) to more negative mass than the equivalent positive mass of the entire Universe.

But, supposing there was a way round the various problems, what effect would the AWD have on the space around it? The warp bubble boundary would generate enormous tidal forces which would be catastrophic for any nearby body, and it's also thought that it would create a shockwave of highly energetic particles in front of it which would destroy whatever was at its destination.
  #255  
Old 08-20-2015, 08:47 PM
sweat209 is offline
Guest
 
Join Date: Nov 2012
Posts: 1,522
Quote:
Originally Posted by jackdavinci View Post
This.

I mean, I agree that interstellar travel that looks anything like Star Trek will require a bigger breakthrough than simple extrapolation. But considering the ridiculous acceleration in technology in just the past hundred years, this seems pretty likely. It's not like we know enough about the principles involved to rule it out.
But there are problems with warp drive so don't think by the year 2050 or 2090 we will have warp drive.

An Alcubierre Drive or warp drive is potentially quite dangerous, and could even blow up planets and star systems like the Death Star could

If you activate a 'warp' drive in space, you may think you're not bringing along any hitch-hikers, but in reality a lot high energy particles are whizzing past your spacecraft. When you activate the drive it expands the space behind you and contracts space in front, and the spacecraft is in a stable position in a kind of 'bubble', this bubble is the problem. It traps the high-energy particles mentioned earlier, and on a long trip the particles can build up enough energy that when the Alcubierre Drive is disengaged the particles will shoot out in front of the ship, easily capable of obliterating planets and even stars! Thankfully the high-energy particles won't interfere with space travel, only when it stops traveling.

For more info look at this website
http://www.extremetech.com/extreme/1...hen-you-arrive

Also, it's probably dangerous to use an alcubierre drive in close proximity to large amounts of matter because, much like the particles, can get trapped in the bubble and cause damage to the ship.
  #256  
Old 08-20-2015, 08:59 PM
levdrakon is offline
Guest
 
Join Date: Apr 2002
Location: USA
Posts: 17,348
I thought virtual particle pairs with negative mass/energy had something to do with Hawking radiation. All you need is a spinning event horizon or something, right?
  #257  
Old 08-21-2015, 01:24 AM
mistymage's Avatar
mistymage is offline
Member
 
Join Date: Apr 2012
Posts: 912
I'll throw my 2 cubic zircons into this zombie thread: assuming we figure a way to propel ourselves across the vast distances (using robots, harvesting comets, or anti-matter whatever)... I think I read something about using water to shield/diffuse radiation.

My "big" contribution to this thread: we grow ships. We are on the threshold of growing skin, organs etc. A ship that can regrow its skin could have a mile deep skin that continuously regrows itself as teeny sand-like bits of matter wear them down. Throw in non-skin layers. Bigger holes would be first closed over with a "scab" and then filled in over time.

We just have to figure out a way to convert common asteroid/comets/space debris into a layer between the "skin".
  #258  
Old 08-21-2015, 01:32 AM
Senegoid is offline
Guest
 
Join Date: Sep 2011
Location: Sunny California
Posts: 14,843
Quote:
Originally Posted by sweat209 View Post
But, supposing there was a way round the various problems, what effect would the AWD have on the space around it? The warp bubble boundary would generate enormous tidal forces which would be catastrophic for any nearby body, and it's also thought that it would create a shockwave of highly energetic particles in front of it which would destroy whatever was at its destination.
Maybe we shouldn't do that, then.
  #259  
Old 08-21-2015, 08:56 AM
Lumpy's Avatar
Lumpy is offline
Charter Member
 
Join Date: Aug 1999
Location: Minneapolis, Minnesota US
Posts: 16,654
Quote:
Originally Posted by sweat209 View Post
Another objection is that it would need to be powered by a ridiculous amount of negative energy (which may not be something which can exist), equivalent (-E = -mc^2) to more negative mass than the equivalent positive mass of the entire Universe.
I thought the "enormous mass" objection had been refuted by later formulations:
https://en.wikipedia.org/wiki/Alcubi...gy_requirement
  #260  
Old 08-21-2015, 08:58 AM
ralph124c is offline
Suspended
 
Join Date: Mar 2002
Posts: 18,476
Once we get the dilithium crystals, we can have a warp drive.
  #261  
Old 08-23-2015, 06:23 PM
sweat209 is offline
Guest
 
Join Date: Nov 2012
Posts: 1,522
Quote:
Originally Posted by mistymage View Post
I'll throw my 2 cubic zircons into this zombie thread: assuming we figure a way to propel ourselves across the vast distances (using robots, harvesting comets, or anti-matter whatever)... I think I read something about using water to shield/diffuse radiation.

My "big" contribution to this thread: we grow ships. We are on the threshold of growing skin, organs etc. A ship that can regrow its skin could have a mile deep skin that continuously regrows itself as teeny sand-like bits of matter wear them down. Throw in non-skin layers. Bigger holes would be first closed over with a "scab" and then filled in over time.

We just have to figure out a way to convert common asteroid/comets/space debris into a layer between the "skin".
That may be one way to deal with radiation and space debris. Using a organic spaceship.
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 03:38 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.

Send questions for Cecil Adams to: cecil@straightdope.com

Send comments about this website to: webmaster@straightdope.com

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Copyright 2019 STM Reader, LLC.

 
Copyright © 2017