Talk:Interstellar travel/Archive for 2015

Deleted Relativistic effects only work for ship, not for earth

Apologies, the section was on faster than light travel, which is fine for making it faster for everyone. 71.198.169.64 (talk) 23:59, 7 March 2015 (UTC)

Error in the "Ion engine" section

Dawn was not the first spacecraft to use an ion thruster. Russia has been using them since the 1970s. Cheers, BatteryIncluded (talk) 16:03, 13 March 2015 (UTC)

Corrected. Dawn was the first ion drive powered craft to carry out research on other objects in the solar system, but it wasn't the first time it was used. Goddard did research in the 1910's, NASA did research in the 60's, and it has been used occasionally for placement of satellites in high orbit, but wasn't tried beyond Earth Orbit until Deep Space 1. Nerfer (talk) 18:29, 17 April 2015 (UTC)

What a horrible article.

This article is a patchwork of very poorly linked concepts. Its composed of mostly wishful thinking, a few facts, and the rest fantasy. There are so many things wrong with it, I don't know where to begin or what to include. Lets see, the two egregious specific claims made here are 1) General Relativity, "theoretically" allows faster-than-light travel. No, it doesn't. Any claims to the contrary are based on SPECULATIONS about unknown Physics or hypothetical scenarioes which are not known to be possible (eg, an infinitely dense spinning rod). The editors confuse the words "theoretically" with "hypothetically", and here the difference matters. The other claim that is just plain wrong is that constant acceleration is the quickest way to get there. No, it isn't. If it were all we'd need is a light and a window, and let 1 photon per second escape (conferring a constant acceleration). This constant acceleration would get us nowhere fast, regardless of how long you sat there. Since v = at, if I double acceleration, I can be at the same v after any given time by coasting for half the time - if I triple it, and coast half the time, I will get there quicker than a constant acceleration (of 1/3 the magnitude). This article is a mish-mash of wild speculation and nonsense. It simply isn't credible to claim that it will take 100 years before we have "the technology" or before we've figured out how to "do it". Of course, no one is too worried that in 100 years they'll be criticized for their "estimate", they'll (probably) be dead. There are reliable authoratative sources on what is currently technologically feasible. There are authoratative sources on what may be feasible in 10 or 20 years, but there simply are NO authoratative credible sources on what "will be" beyond that. Its been 22 years since Nakamura invented bright, blue LED technology and who would have guessed 25 years ago what would happen to signs and flashlights because of this technology? Anyway, just because you find some "scientist" willing to SPECULATE about future innovations and inventions, does not make him/her an authority on it. History should guide us here, any speculation is most likely wrong. Such speculation should be placed in a separate "Speculations on the Future" section. I here distinguish between engineering not yet done and science not yet established. Its valid to speculate that we can land on one of Jupiter's moons, since current technology "could" take us there (at enormous expense, and pretty much ignoring the radiation from Jupiter), its NOT valid to speculate that we will "invent" some (magic) technology enabling us to convert energy to momentum with near perfect efficiency. There just isn't any established science to justify it; that is its speculation and mostly just wishful thinking. A great example is Fusion Power. We've been "20 years away" from (sustained) break-even for literally the last 60 years. Maybe it will happen tomorrow, maybe never. All of the speculative propulsion schemes are no better. We just have no reason to believe we can attain even 50% efficiency of Energy to velocity. On the web page The Relativistic Rocket, the calculation is made about how much mass would be necessary, IF we could convert it all into energy, to carry along on an interstellar voyage in order to maintain a constant 1g acceleration/decceleration. Apparently nobody here thinks that the acceleration of the INITIAL mass of the craft and fuel is significantly different from the final acceleration of just the craft (with fuel exhausted). Apparently, nobody thinks mentioning that none of our (relevant) technology has been shown to be durable enough to function for 40 or even 20 years is relevant. Apparently, nobody thinks that our demonstrated INABILITY to establish a closed (in the thermodynamic sense) ecology is relevant when discussing "generation" ships or multi-year voyages. Apparently, no one thinks that the fact that there has never been any suggestion that any current technology can shield a craft or probe from damage from gas and dust is relevant. Its always "might". Apparently, their aren't any questions about violation of human rights in subjecting children to robotic up-bringing (or even incarceration in a generation ship). Apparently the fact that we can not predict mental state 20 years in the future is irrelevant in the belief that we can "pick" a crew that will successfully endure 20 or 40 years together. Even in the most firmly established areas, which are energy requirements, there's almost nothing here that fully informs the reader about the huge chasm between what we can do, and what we'd need to do. As of today, the most efficient means of propulsion in chemical. Why isn't that scenario fleshed out here. Take a, say, 2000 kg probe with an ability to pick-up fuel pods along the way. Start launching fuel pods into space (you'd need fuel pods picking up fuel pods in order to match velocity of the probe as it passes by at the way-points). So, how much fuel, assuming current say, Space Shuttle type tanks (or next gen) along with state of the art engines? Its a easy calculation to do, why hasn't it been done? (I expect it has been done, and published, but I haven't run across it yet.) Poorly structured, incomplete, and full of fantasy and wild speculation, with no effort to distinguish between what is known and the speculative.216.96.76.79 (talk) 10:45, 30 August 2015 (UTC)

If you give it a go, I'll buy you a pint or three. Wikipedia:Blow it up and start over. Cheers, BatteryIncluded (talk) 14:37, 30 August 2015 (UTC)

Some article attract lots of speculation and hypothetical stuff. I'm in favor of removing or greatly condensing it when ever possible and appropriate. Isambard Kingdom (talk) 14:56, 30 August 2015 (UTC)

Odenwald's article

This single (non-peer-reviewed) article from the Huffington Post<r[1] is cited as the reason why exploring nearby stars would be fruitless.

The truth is that, if we were on Alpha Centauri today with our current planet-detection technologies, we would not be able to see our own Earth. Kortoso (talk) 17:29, 26 October 2015 (UTC)