Comments on: across the universe in a lifetime. with a catch. http://worldofweirdthings.com/2009/09/29/across-the-universe-in-a-lifetime-with-a-catch/ exploring science, the strange and the unknown Thu, 11 Mar 2010 03:56:00 -0800 http://wordpress.org/?v=2.9.2 hourly 1 By: Jim Gagnon http://worldofweirdthings.com/2009/09/29/across-the-universe-in-a-lifetime-with-a-catch/#comment-7330 Jim Gagnon Sat, 24 Oct 2009 04:45:34 +0000 http://worldofweirdthings.com/?p=7949#comment-7330 To KGB: We are on the verge of uncovering our latent abilities to hibernate. Turns out that breathing a dilute mixture of hydrogen sulfide triggers a hibernation mechanism in humans. There's a lot of effort to learn how to control it going on now, but if they find technology alone isn't enough then the bioengineers could grab a few bear genes and slice then into humans. That means sleeper ships are possible. Also on the table are realistic engines that will allow a craft to reach about 5% of the speed of light (fission fragment engines, look it up in Wikipedia). The part that's missing is a way to handle interstellar dust; it's a real problem and all the proposed solutions only work if the dust is charged. However, we are tricky apes; we might not find the answer this century, but I'm sure there's a way. We'll have more answers once we truly understand the nature of the matter field(s). We aren't the penguins that want to fly. We are the penguins that do fly. To KGB: We are on the verge of uncovering our latent abilities to hibernate. Turns out that breathing a dilute mixture of hydrogen sulfide triggers a hibernation mechanism in humans. There’s a lot of effort to learn how to control it going on now, but if they find technology alone isn’t enough then the bioengineers could grab a few bear genes and slice then into humans. That means sleeper ships are possible. Also on the table are realistic engines that will allow a craft to reach about 5% of the speed of light (fission fragment engines, look it up in Wikipedia). The part that’s missing is a way to handle interstellar dust; it’s a real problem and all the proposed solutions only work if the dust is charged. However, we are tricky apes; we might not find the answer this century, but I’m sure there’s a way. We’ll have more answers once we truly understand the nature of the matter field(s).

We aren’t the penguins that want to fly. We are the penguins that do fly.

]]> By: ResearchBlogging.org News » Blog Archive » Editor’s selections: water on the moon, telescopes in history, seeing through other people’s eyes, and space travel http://worldofweirdthings.com/2009/09/29/across-the-universe-in-a-lifetime-with-a-catch/#comment-6802 ResearchBlogging.org News » Blog Archive » Editor’s selections: water on the moon, telescopes in history, seeing through other people’s eyes, and space travel Mon, 05 Oct 2009 15:32:25 +0000 http://worldofweirdthings.com/?p=7949#comment-6802 [...] across the universe in a lifetime. with a catch. At weird things, Greg Fish talks about relativity and what it implies for future space exploration. [...] [...] across the universe in a lifetime. with a catch. At weird things, Greg Fish talks about relativity and what it implies for future space exploration. [...]

]]> By: Michael http://worldofweirdthings.com/2009/09/29/across-the-universe-in-a-lifetime-with-a-catch/#comment-6721 Michael Thu, 01 Oct 2009 20:32:31 +0000 http://worldofweirdthings.com/?p=7949#comment-6721 What is amusing to me is that anyone doubts that this is ever going to be possible to do. Half a century is easily doable without even engineering our own bodies. We've only just begun to try that. What is amusing to me is that anyone doubts that this is ever going to be possible to do. Half a century is easily doable without even engineering our own bodies. We’ve only just begun to try that.

]]> By: jab49 http://worldofweirdthings.com/2009/09/29/across-the-universe-in-a-lifetime-with-a-catch/#comment-6702 jab49 Thu, 01 Oct 2009 04:49:20 +0000 http://worldofweirdthings.com/?p=7949#comment-6702 You could use a high energy laser grid around the spacecraft to vapourise down to component atoms all interstellar dust, at atomic levels it would be possible to armour the ship accordingly You could use a high energy laser grid around the spacecraft to vapourise down to component atoms all interstellar dust, at atomic levels it would be possible to armour the ship accordingly

]]> By: gfish http://worldofweirdthings.com/2009/09/29/across-the-universe-in-a-lifetime-with-a-catch/#comment-6701 gfish Thu, 01 Oct 2009 04:33:09 +0000 http://worldofweirdthings.com/?p=7949#comment-6701 Victor, These comments were just random spam that got past the filter but was flagged. I try to clean those up as fast as I can but sometimes they do hang around for a bit before they get deleted. Victor,

These comments were just random spam that got past the filter but was flagged. I try to clean those up as fast as I can but sometimes they do hang around for a bit before they get deleted.

]]> By: Victor http://worldofweirdthings.com/2009/09/29/across-the-universe-in-a-lifetime-with-a-catch/#comment-6700 Victor Thu, 01 Oct 2009 03:38:44 +0000 http://worldofweirdthings.com/?p=7949#comment-6700 Wow. his/her comments were deleted right after I posted. what a coinkidink. Wow. his/her comments were deleted right after I posted. what a coinkidink.

]]> By: DaveM http://worldofweirdthings.com/2009/09/29/across-the-universe-in-a-lifetime-with-a-catch/#comment-6699 DaveM Thu, 01 Oct 2009 03:31:38 +0000 http://worldofweirdthings.com/?p=7949#comment-6699 Interesting idea, but I don't think people tend to think of all the implications in terms of physical laws. For example, you can calculate from the Lorentz Factor described (15 billion light years traveled in 50 years of ship's time) that the ship speed would have to be 0.99999999999999999444 c, where c is the speed of light. At this speed, the relativistic kinetic energy would be 2.7 * 10^25 Joules per kilo. This is about 300 million times as much energy as is present in the mass, if you were to convert the entire mass directly into energy as per Einstein's formula. We're not even considering reaction mass here, obviously this would be some propulsion system that doesn't rely on ejecting mass out of the rear, a reactionless drive. And we're talking about converting the entire rest mass of the ship into energy, including the astronaut and the engines. And even then, the energy is short by a factor of 300 million. Obviously, the solution would be to pick up more mass along the way, picking up interstellar dust like a Bussard Ramjet. According to Wikipedia, the density of interstellar dust is about 1 gram per 10^18 cubic meters. So if you had a scoop that was a square kilometer in cross section, you'd have to move through 700 million light years of space to even collect the mass needed to drive our 1 kilo spaceship. Of course, if you want a bigger spaceship, you need even more mass. I do not think this will ever happen. We better find wormholes or some other means to travel large distances, because light speed is going to be a bummer. Interesting idea, but I don’t think people tend to think of all the implications in terms of physical laws.

For example, you can calculate from the Lorentz Factor described (15 billion light years traveled in 50 years of ship’s time) that the ship speed would have to be 0.99999999999999999444 c, where c is the speed of light.

At this speed, the relativistic kinetic energy would be 2.7 * 10^25 Joules per kilo. This is about 300 million times as much energy as is present in the mass, if you were to convert the entire mass directly into energy as per Einstein’s formula. We’re not even considering reaction mass here, obviously this would be some propulsion system that doesn’t rely on ejecting mass out of the rear, a reactionless drive. And we’re talking about converting the entire rest mass of the ship into energy, including the astronaut and the engines. And even then, the energy is short by a factor of 300 million.

Obviously, the solution would be to pick up more mass along the way, picking up interstellar dust like a Bussard Ramjet. According to Wikipedia, the density of interstellar dust is about 1 gram per 10^18 cubic meters. So if you had a scoop that was a square kilometer in cross section, you’d have to move through 700 million light years of space to even collect the mass needed to drive our 1 kilo spaceship. Of course, if you want a bigger spaceship, you need even more mass.

I do not think this will ever happen. We better find wormholes or some other means to travel large distances, because light speed is going to be a bummer.

]]> By: Victor http://worldofweirdthings.com/2009/09/29/across-the-universe-in-a-lifetime-with-a-catch/#comment-6698 Victor Thu, 01 Oct 2009 03:06:37 +0000 http://worldofweirdthings.com/?p=7949#comment-6698 @website And I suppose your statement isn't ignorance masquerading as "thoughtful contribution". Yes, thought experiments are vague, and maybe viewed as unconventional, but it allows the mind to do what machines cannot. Considering what thought experiments have been shown to accomplish (Galileo, anyone?), I'd say they're a bit more than just "personal bias". @website

And I suppose your statement isn’t ignorance masquerading as “thoughtful contribution”.

Yes, thought experiments are vague, and maybe viewed as unconventional, but it allows the mind to do what machines cannot.
Considering what thought experiments have been shown to accomplish (Galileo, anyone?), I’d say they’re a bit more than just “personal bias”.

]]> By: Thorne http://worldofweirdthings.com/2009/09/29/across-the-universe-in-a-lifetime-with-a-catch/#comment-6682 Thorne Wed, 30 Sep 2009 12:05:01 +0000 http://worldofweirdthings.com/?p=7949#comment-6682 Poul Anderson dealt with this problem in his classic scifi novel, "Tau Zero" (http://en.wikipedia.org/wiki/Tau_Zero). He proposed using a "Bussard ram jet" which used the interstellar dust and gas to provide thrust for the ship. It's become cosmologically outdated, but still a good read and interesting science. Poul Anderson dealt with this problem in his classic scifi novel, “Tau Zero” (http://en.wikipedia.org/wiki/Tau_Zero). He proposed using a “Bussard ram jet” which used the interstellar dust and gas to provide thrust for the ship. It’s become cosmologically outdated, but still a good read and interesting science.

]]> By: gfish http://worldofweirdthings.com/2009/09/29/across-the-universe-in-a-lifetime-with-a-catch/#comment-6669 gfish Wed, 30 Sep 2009 00:23:51 +0000 http://worldofweirdthings.com/?p=7949#comment-6669 <i>"There was one significant advantage to the fictional ‘inertialess drive’ of E.E. Smith..."</i> Unfortunately, a spacecraft without inertia would be permanently stationary. It would violate Newton's 3rd Law which is impossible as far as we know. And Hank, while the scoop concepts are great, they would encounter so much friction from the interstellar medium that the craft would come screeching to a halt after a certain velocity. “There was one significant advantage to the fictional ‘inertialess drive’ of E.E. Smith…”

Unfortunately, a spacecraft without inertia would be permanently stationary. It would violate Newton’s 3rd Law which is impossible as far as we know.

And Hank, while the scoop concepts are great, they would encounter so much friction from the interstellar medium that the craft would come screeching to a halt after a certain velocity.

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