Is interstellar travel possible?

[Enthalpy]

No physics here. Did you botch Wiki's article yourself?

[Airbrush]

No physics here. Did you botch Wiki's article yourself?

 

You mean did I copy and past? Yes.

 

No physics there at all? Well, that's the best I can do right now. Did you go to the Wiki article and read it all, and you discovered there was no physics there at all? Well, it may be a hundred years before there is physics related to this.

 

Other than the physics, does it not address the opening question? I think it does the best that can be done in 2013.

 

"....Given sufficient travel time and engineering work, both unmanned and sleeper ship interstellar travel requires no break-through physics to be achieved, but considerable technological and economic challenges need to be met. NASA, ESA and other space agencies have been engaging in research into these topics for decades, and have accumulated a number of theoretical approaches....."

 

Wiki disagrees with you. How can NASA and ESA research this for decades and no physics involved?

Edited October 22, 2013 by Airbrush

[swansont]

 

Wiki disagrees with you. How can NASA and ESA research this for decades and no physics involved?

 

NASA and ESA do physics. But there was essentially none in the copy/paste from the wikipedia article. It reads like a bad press release.

[Persius]

If you guys are just going to use wikipedia then why are you on here?

[EdEarl]

If you guys are just going to use wikipedia then why are you on here?

There aren't experts in every subject, and using Wikipedia requires knowledge of key words to find things. Thus, many people ask questions either because they have not looked into Wikipedia or they have looked but have not found what they need and want. Thus, a few experts and some wanna-be helpers like me can answer a wide variety of questions. Experts often focus on a very narrowly defined subject, which means you may not find the one you want on SFN.

[Enthalpy]

The part of Wiki's article was obviously written as propaganda in favour of the project. It contains no physical basis, but uses the standard techniques of propaganda. That's why I asked if Airbrush, who develops very similar arguments in this thread, is also the author of the regrettable section at Wiki.

 

Botched articles at Wiki do exist, for instance the one that claims cyclopropane to detonate when liquid or compressed, despite all safety data sheets ignore this, and Wiki's suggestions there (tungsten wool to brake the cyclopropane molecules...) are meaningless. Apparently, the article was botched when Esa considered to develop of a rocket engine burning cyclopropane.

 

As an other example, French articles describing nuclear (quasi-) accidents in France have been cut, and only their English translation is still available.

 

So, yes, use Wiki - but keep in mind it can be false, and sometimes intentionally.

 

----------

 

Nasa and Esa do physics. As any human enterprise, they sometimes err, and they also need to catch the public's interest. As spenders of public budget, they also depend on decisions by politicians.

 

From time to time, you can read about worm fossiles in Martian stones before the story is fully assessed, or airships to reach orbit, or superconducting magnetic shields for interplanetary travellers that have clearly indentifyable weaknesses. But I've seen much worse in several companies.

[Endercreeper01]

We could use relativity to be able to travel large distances

[Enthalpy]

We could use relativity to be able to travel large distances

How?

[Airbrush]

Then this means that scientists currently don't have a clue WHEN unmanned missions may be launched to nearby stars. Maybe within a few hundred years from now? Only when the cost of such missions comes down enough. Then I would suppose multiple similar unmanned missions would be sent over a period of years to all the nearby stars with Earth-like planets that were discovered by the next generations of space telescopes.

Edited October 24, 2013 by Airbrush

[Endercreeper01]

How?

Because of time dilation, then time slows down the closer you are to the speed of light. This means that it will take less time for you to get there. There is also length contraction. The length contracts the faster you are to the speed of light. You multiply the original length or time by (1-v²/c²)^1/2 to find the relative time or length. Because of this effect, if we get something to travel close to the speed of light, then time and length will greatly shrink, making it take less time to get there.

[Airbrush]

Because of time dilation, then time slows down the closer you are to the speed of light. This means that it will take less time for you to get there. There is also length contraction. The length contracts the faster you are to the speed of light. You multiply the original length or time by (1-v²/c²)^1/2 to find the relative time or length. Because of this effect, if we get something to travel close to the speed of light, then time and length will greatly shrink, making it take less time to get there.

 

Enthalpy knows this already. His question is (I believe) "HOW do you get to relativistic speed?" Right Enthalpy? Currently scientists don't know how.

[Persius]

There aren't experts in every subject, and using Wikipedia requires knowledge of key words to find things. Thus, many people ask questions either because they have not looked into Wikipedia or they have looked but have not found what they need and want. Thus, a few experts and some wanna-be helpers like me can answer a wide variety of questions. Experts often focus on a very narrowly defined subject, which means you may not find the one you want on SFN.

I just don't think using wiki in an argument is good. I know that most of everything on wiki is true because they have people checking quality constantly. Thank you, by the way, for giving me those links to other topics. I would like to hear about any of your ideas on the topic.

[Mr Monkeybat]

Because of time dilation, then time slows down the closer you are to the speed of light. This means that it will take less time for you to get there. There is also length contraction. The length contracts the faster you are to the speed of light. You multiply the original length or time by (1-v²/c²)^1/2 to find the relative time or length. Because of this effect, if we get something to travel close to the speed of light, then time and length will greatly shrink, making it take less time to get there.

 

Time dilation does not make it any quicker or slower for the astronaut than if you had simply ignored Einstein and calculated the travel time with Newtons physics. Even if you include the Earths reference frame Relativity does not make interstellar travel any more or less practical because the amount of energy, and reaction mass required to reach speeds where time dilation etc are significant is immense.

 

I doubt you can hybernate humans for more than a few years without reducing there lifespan so even on a sleeper ship I don't think maned interstellar travel is practical unless you have an antimatter powered ship like the one in the pandorapedia. At such speeds though the tiniest speck of space dust becomes a major problem, probably need some kind of powerful laser to detect and vaporize incoming space dust or some kind of magnetized plasma bubble cushion or something.

 

Its a long shot but considering all the difficulties and expense of any conventional method of reaching stars even if you have antimatter. Perhaps you best hope is that those people researching aclubiere warp mange to pull something out the hat. Or how about macro quantum tunneling at light speed, quantum tunnel through that space dust haha.

[EdEarl]

I just don't think using wiki in an argument is good. I know that most of everything on wiki is true because they have people checking quality constantly. Thank you, by the way, for giving me those links to other topics. I would like to hear about any of your ideas on the topic.

I do not argue often. But, many of my posts have links to elsewhere, including Wiki.

[imatfaal]

 

Time dilation does not make it any quicker or slower for the astronaut than if you had simply ignored Einstein and calculated the travel time with Newtons physics. Even if you include the Earths reference frame Relativity does not make interstellar travel any more or less practical because the amount of energy, and reaction mass required to reach speeds where time dilation etc are significant is immense.

If I am travelling at a fair pecentage of c relative to the earth and alpha centauri - then the frame of the earth, alpha centauri and the distance between is travelling at a fair percentage of c relative to me. Frames travelling at a relative velocity are length contracted.

 

This is the nub of the explanation of why muons survive their trip through our atmosphere; from our frame they are moving at such a velocity that they are time dilated and their short life time is stretched enough to allow them to travel the few kilometres before hitting the surface. But they cannot be dilated in their own frame; in their frame they see the earth and its atmosphere travelling at such a velocity that the atmosphere is length contracted and even their short life is enough to cross this reduced distance. This is not expected before str.

 

Regarding energy needed, safety and practicality agree entirely.

[Persius]

I do not argue often. But, many of my posts have links to elsewhere, including Wiki.

Links to other sites are fine but I don't care for wiki as a source. It is just my opinion. I'm sorry if i offended you in any way.

[Awesomebenc99]

I heard something about having a disk that spins at light speed in the center thus forth faster than light farther from the center.

This would be really cool.

[Janus]

I heard something about having a disk that spins at light speed in the center thus forth faster than light farther from the center.

This would be really cool.

Impossible.

 

For one thing there is no material that could withstand the strain. For the other, it is not possible to spin the disk so that any part of it can travel at the speed of light. No matter how hard you try, you will never get the outer edge o fthe disk even up to the speed of light.

[hoola]

interstellar travel should not be attempted until a method of propulsion can be developed that will not leave a residue trail such as chemical propellants. Other than voyager, we should wait and remain within the solar system, even with robot craft. Seems there is plenty to do locally, such as fixing the mess we are creating here. At any rate, one possible propulsion system I can imagine is using the dark energy force to provide a "green" propulsion in the next century. A manipulation (shielding?) of the natural dark energy forces in space ahead of a craft would cause it to move forward. And likewise, manipulations at the sides of a craft would allow steering in the other two axis. An actual generation of synthetic dark energy force aimed out the rear of the craft would create an extra amount of acceleration, pushing against space itself. If the universe and everything in it, including dark energy is information, then that same information might be generated and then manipulated by computers, and the only energy input to the drive/steering system is the energy to run the computers.

[SaganWannaBeWannaBe]

Great thread, nice discussion. But this topic strikes me as one where a little different perspective might be in order. Most of the proposed solutions I've read here are variations on "how to make a faster horse". (Maybe the ones involving wormholes aren't.) Is it possible to speculate about means other than a faster horse? A nice analogy is solving the problem of getting a message from one town to another. That's where the faster horse example comes in. Way back (say 500 years), all the thinkers could do was think in terms they were already used to like horses, maybe better horse feed, etc. No one would ever, COULD ever, think about email for example, or just the telegraph. Are we doing the same thing here when we talk about propulsion sources, fuel, even "speeds" and generation ships? Is it possible to speculate on some wholly different means to travel between stars? Sometimes I think it's useless. Then again, we'd never get anywhere if there weren't those thinking totally out of the box.

 

Thoughts? Speculations?

[hoola]

no problem with thinking about using worm-holes or teleportation devices....but the next step in the "faster horse" idea is going to be literally, a faster horse....as a step such as the automobile being faster than the horse, plane being faster than a car...etc. If we want a technological evolution, we must go through all the steps, it seems..and teleportation seems several steps away before we can eliminate "the horse" and simply appear somewhere else, with perhaps a super-entanglement transceivers set up at various points within the universe, which seems the most likely scenario of getting rid of "the horse". In my thinking, we would still need the horse to set up the send-receive stations, say from earth to various points in the solar system, and once established, could transport quickly around....so if we wanted to transport to a distant interstellar point, then we would have to ride our fastest horse to get there, then once an entanglement transceiver is established, could pop in and out of and established system at will, from earth to alpha centauri, if desired. Unless some sort of communications could be established with an intelligence at remote distances, then an entanglement transceiver could be built in cooperation with the other intelligence, in both locations,and we wouldn't have to go there in a fast horse first, not they to ours.

[SaganWannaBeWannaBe]

Excellent points. And doh! to me for not thinking about the scenarios you outlined. Can you say "Contact" or "Stargate" anyone And that's really a good way to think about things too...in stages.

[hoola]

never saw contact or stargate.....too busy, nor the matrix for that matter....trailer seemed superficial. I suppose most of what I said was said years ago in these movies...as to entanglement, the first use in practical a sense would be communications, as that seems fairly straightforward....like the "sub-space" comm system on star trek....much later with the movement of material objects.

[Enthalpy]

as to entanglement, the first use in practical a sense would be communications, as that seems fairly straightforward.

Already used in telecomm demos, nothing straightforward, and only to ensure that the data link has not been tampered.

[...] getting a message from one town to another. [...] 500 years back, all the thinkers could do was think in terms they were already used to like horses, maybe better horse feed, etc. No one would ever, COULD ever, think about email for example, or just the telegraph. Are we doing the same thing here when we talk about propulsion sources, fuel, even speed ?

 

Thoughts? Speculations?

Exactly, you're encouraging speculation instead of development in physics or technology.

The resulting answers would bring exactly nothing. Only buzzwords like "wormhole", "dark energy", "metamaterial" used improperly by people ignoring them.

 

The constructive approach - but it's lengthy and not spectacular, and gives less the illusion of a brilliant brain - is to describe work on your disruptive technology, make it feasible, and show or explain how it is feasible.

 

If not, search for a less disruptive improvement - a faster horse if you wish - and tell how your ideas have made it possible. That's already very difficult, and finding one from time to time is an accomplishment.

 

By the way: the people who made disruptive inventions or discoveries also made faster horses. Einstein patented some apparatus of common use.

[seriously disabled]

Interstellar travel is just not possible for humans in my opinion.

 

Interstellar travel is just too difficult and there are too many dangers for such a project to be safely accomplished.

 

My source for this is:

 

https://www.scientificamerican.com/article/interstellar-travel-as-delusional-fantasy-excerpt/#

Edited May 31, 2017 by seriously disabled