geordief

Journey to Alpha Centauri

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geordief    47

I have just  been watching a documentary on BBC2 

 

"The Search for a New Earth"

http://www.tvguide.co.uk/detail/2790044/131126240/the-search-for-a-new-earth

 

about the possibilities of  sending a manned mission to Alpha Centauri ( can I say "don't laugh" ?)

 Along with Hawkin's   warnings that many of us are no doubt familiar (in my case sympathetically so) with, the  subjects of  possible suitable  destinations and methods of transport were addressed.

 

I was left  dissatisfied  since ,although it appears technically possible to cut the time of journey to Alpha Centauri  and its posited Goldolocks zone planet (all 4 light years distant from Earth)  by means of ground based laser propulsion the crucial  question of how to land on a planet was not addressed.

 

If a theoretical manned craft can be sent to  the neighbourhood of Alpha Centaur  by  accelerating it to relativistic speeds  (10-20% of the speed of light by the looks of it) how can this craft be decelerated? A fly past is of no use whatsoever (not a problem for a fleet of mini craft equipped  with sensing  tools but useless for a manned expedition)

 

I cannot see the point of a programme like this that does not address  this point. And I cannot really see the point of  even discussing this putative manned mission /colonization of Alpha Centauri  unless there is  consideration given to this (it seems to me) intractable problem.

 

Has anyone a clue as to how  any craft can be  decelerated from   such high speeds? Are there any possible methods? 

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Ken Fabian    28

I haven't seen the doco but it looks like hypothetical technologies to reach an impossible goal - but dressing up the primitive urge to hit the road when life gets difficult as supremacy of rational foresight to garner popular support. And would a society capable of living in a self reliant and sustainable way in space even need planets?

I have real doubts that we can establish any kind of self reliant colonies in space without a long and sustained history of successful exploitation of space resources by an Earth economy that extends itself into space. A large, broadly capable and successful space economy is needed before any kind of genuine self reliance can emerge. And it will be an emergent property, not a primary objective. "Higher" objectives like providing a lifeboat for humanity might be popular but it is successful economics that make and break all these visions of the future.

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geordief    47
22 minutes ago, Ken Fabian said:

I haven't seen the doco but it looks like hypothetical technologies to reach an impossible goal - but dressing up the primitive urge to hit the road when life gets difficult as supremacy of rational foresight to garner popular support. And would a society capable of living in a self reliant and sustainable way in space even need planets?

I have real doubts that we can establish any kind of self reliant colonies in space without a long and sustained history of successful exploitation of space resources by an Earth economy that extends itself into space. A large, broadly capable and successful space economy is needed before any kind of genuine self reliance can emerge. And it will be an emergent property, not a primary objective. "Higher" objectives like providing a lifeboat for humanity might be popular but it is successful economics that make and break all these visions of the future.

If lifeboats ever became remotely feasible the danger might perhaps  that they will only be for a few  and policies might be followed   which effectively set the Earth adrift as the motivation for making the hard choices  on "terra firma" would be undermined.

But I cannot see "lifeboats" ever becoming realistic  (in a relevant timeframe) and I think  if we do not manage our shrinking world we may  all go down with the ship one way or the other.

That  discussion reminds me of the so called technological fixes to climate change that  supposedly allow us to  pollute the planet and emerge consequence free.

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beecee    77

Naturally if we as a human race, are given the time, and can avoid any catastrophic disaster, either man-made or natural, such as a meteor/asteroid hit, or any other civilization altering/destroying event, we should be able to reach the stars..either and probably firstly, in generation type space ships travelling at sub relativistic speeds, that may be overtaken by later spaceships as advanced humans are able to harness the technology to warp spacetime and travel at relativistic speeds. It's all a matter of progress and avoiding the disasters I speak of.

The following are some orginizations already working towards that end.....

https://100yss.org/mission/team

https://tauzero.aero/

https://tauzero.aero/who-we-are/

 

NB: Both these companies are headed by experienced  NASA people including DR Mae Jamison ( engineer, physician and NASA astronaut. ) and Marc Millis (Aerospace Engineer NASA Glenn Research Center)

 

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Ken Fabian    28

Beecee - sorry but I think it's 99.999% fantasy to believe we will reach the stars, especially via any kind of direct flights. Should full self reliant space communities ever develop - reliant entirely on deep space resources without solar power - then perhaps growth and expansion, leap frogging from deep space object to deep space object could happen and some far future generations might reach another star. I think that level of self reliance is only possible with large, comprehensive industrial economies that only large populations can achieve; optimised down to bare essentials, the technology required is still likely to require more than an advanced Earth nation, depending on technologies that still exceed our combined capacities to perfect, like fusion power. There is nothing inevitable about it.

Technological advancement is not exponential, it is an S-curve, no matter that at some points along that curve it can look that way.

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Area54    103
12 hours ago, geordief said:

I have just  been watching a documentary on BBC2  "The Search for a New Earth"

http://www.tvguide.co.uk/detail/2790044/131126240/the-search-for-a-new-earth

about the possibilities of  sending a manned mission to Alpha Centauri ( can I say "don't laugh" ?)

You must have been the only person on the planet to see this documentary. The rest of us were watching one about sending a manned mission to Proxima Centauri.

12 hours ago, geordief said:

the crucial  question of how to land on a planet was not addressed.

In a program as brief as this many aspects of the journey need to be overlooked. For this issue we currently have multiple ways of landing on planets so it, arguably, merited little or no consideration in the program.

 

12 hours ago, geordief said:

If a theoretical manned craft can be sent to  the neighbourhood of Alpha Centaur  by  accelerating it to relativistic speeds  (10-20% of the speed of light by the looks of it) how can this craft be decelerated? A fly past is of no use whatsoever (not a problem for a fleet of mini craft equipped  with sensing  tools but useless for a manned expedition)

We were definitely watching different programs. The laser was for the mini-robot surveyors you mentioned. The proposed propulsion for the explorer's craft was a plasma drive. So your insurmountable problem is not the issue you think it is.

 

11 hours ago, Ken Fabian said:

I have real doubts that we can establish any kind of self reliant colonies in space without a long and sustained history of successful exploitation of space resources by an Earth economy that extends itself into space.

I believe I have encountered your skeptical views on this topic before. Perhaps they are correct, yet individuals and companies are spending real money towards these goals. And that investment is increasing, not decreasing.

 

32 minutes ago, Ken Fabian said:

Beecee - sorry but I think it's 99.999% fantasy to believe we will reach the stars, especially via any kind of direct flights.

If you furnish me with your particulars I shall arrange for my great-great grandchildren to tell your great-great-grandchildren, "I told you so!"

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geordief    47
25 minutes ago, Area54 said:

You must have been the only person on the planet to see this documentary. The rest of us were watching one about sending a manned mission to Proxima Centauri.

In a program as brief as this many aspects of the journey need to be overlooked. For this issue we currently have multiple ways of landing on planets so it, arguably, merited little or no consideration in the program.

 

We were definitely watching different programs. The laser was for the mini-robot surveyors you mentioned. The proposed propulsion for the explorer's craft was a plasma drive. So your insurmountable problem is not the issue you think it is.

 

 

Yes I wan't sure of the name of the star (but I think we all know that I was referring to our nearest star that may have a planet around it in the Goldilocks zone)

 

Arriving at P Centauri in any acceptable(?) timeframe  will require relativistic speeds imo and how can such a craft be decelerated in order in make a landing?

 

Any idea at all?

 

The plasma drive  would take an absurd  20,000 years (as I recall ) and so the question of deceleration/landing does not even arise.

Edited by geordief

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Area54    103

The plasma drive offered a one way  trip of 20 years, not 20,000 years. You decelerate as you approach the star the same way as you accelerate when you leave the solar system. The plasma drive is a rocket.

I'm not sure that speeds of only 20% the speed of light, as envisaged in the program, are considered relativistic. Obviously there is some effect, but that is true of riding on a bicycle.

One critical factor not considered was the damage caused by impact with debris a 0.2c. Large abrasion pads at the front of the craft for small particles and lasers to zap anything more substantial have been proposed by others. (The program dealt only with protection from radiation, via the thoroughly unproven suggestion of hibernation. One researcher believes he has demonstrated protection of DNA from ionising radiation during hibernation )

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geordief    47
10 minutes ago, Area54 said:

The plasma drive offered a one way  trip of 20 years, not 20,000 years. You decelerate as you approach the star the same way as you accelerate when you leave the solar system. The plasma drive is a rocket.

I'm not sure that speeds of only 20% the speed of light, as envisaged in the program, are considered relativistic. Obviously there is some effect, but that is true of riding on a bicycle.

One critical factor not considered was the damage caused by impact with debris a 0.2c. Large abrasion pads at the front of the craft for small particles and lasers to zap anything more substantial have been proposed by others. (The program dealt only with protection from radiation, via the thoroughly unproven suggestion of hibernation. One researcher believes he has demonstrated protection of DNA from ionising radiation during hibernation )

The Plasma drive only does 100,00 mph (kph? ) according to that programme. So only about 5 times faster than present day speeds.

 

Here is something I found (that I cannot vouch for) They are discussing the Plasma Drive.

 

https://www.universetoday.com/15403/how-long-would-it-take-to-travel-to-the-nearest-star/

 

"But adjusted for a one-way journey to Proxima Centauri, a nuclear rocket would still take centuries to accelerate to the point where it was flying a fraction of the speed of light. It would then require several decades of travel time, followed by many more centuries of deceleration before reaching it destination. All told, were still talking about 1000 yearsbefore it reaches its destination. Good for interplanetary missions, not so good for interstellar ones."

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Ken Fabian    28
9 hours ago, Area54 said:

I believe I have encountered your skeptical views on this topic before. Perhaps they are correct, yet individuals and companies are spending real money towards these goals. And that investment is increasing, not decreasing.

BeeCee, I had an explorer great uncle in the early 1900's - he did okay out of it, doing expeditions into central Australia. The hype at the time about undiscovered gold and other riches prompted plenty of popular interest. He never found anything of significant value but he did okay, because investors were willing to hand him money to fund his explorations in a "share in the discovery" arrangement. I see real similarities - and differences; my uncle did raise enough that way to fund real expeditions. Not conducted with expensive, unproven, cutting edge tech but with camels.

 

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beecee    77
11 hours ago, Ken Fabian said:

Beecee - sorry but I think it's 99.999% fantasy to believe we will reach the stars, especially via any kind of direct flights. Should full self reliant space communities ever develop - reliant entirely on deep space resources without solar power - then perhaps growth and expansion, leap frogging from deep space object to deep space object could happen and some far future generations might reach another star. I think that level of self reliance is only possible with large, comprehensive industrial economies that only large populations can achieve; optimised down to bare essentials, the technology required is still likely to require more than an advanced Earth nation, depending on technologies that still exceed our combined capacities to perfect, like fusion power. There is nothing inevitable about it.

Technological advancement is not exponential, it is an S-curve, no matter that at some points along that curve it can look that way.

And there was also a time when humans thought that if they sailed onwards to the horizen, they would fall off the edge of the Earth, and we believed the Earth was flat and that it was the center of the universe, and we would never fly...In fact an otherwise great scientist named Lord Kelvin poo pooed manned flight only 9 or 10 years before the Wright Brothers.

And of course I have always encouched my more realistic predictions, with "in the course of time" and "if we survive any future catastrophic event" We will mine asteroids in time: We will return to the Moon in time: We will establish out posts on the Moon in time, much as we do in Antarctica: We will put man on Mars: We will leave our solar system and go to distant stars in time: Given the time, we can accomplish anything that is allowed by the laws of physics and GR: 

We were not born to stagnate on this fart arse little blue orb we call earth. 

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Ken Fabian    28

beecee, those ancient history examples of underestimating what is achievable don't really apply; we are far more capable now to figure out what is realistically feasible within the real universe, because we have a much better understanding of it's fundamental physics. And that fundamental understanding is an S-curve that we are much further along. Missions to other stars are not feasible.

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beecee    77
23 hours ago, geordief said:

I have just  been watching a documentary on BBC2 

 

"The Search for a New Earth"

http://www.tvguide.co.uk/detail/2790044/131126240/the-search-for-a-new-earth

 

about the possibilities of  sending a manned mission to Alpha Centauri ( can I say "don't laugh" ?)

 

Let me add, that yes indeed, inter-stellar travel is in reality far beyond anything we can ever hop for at this present time. As mentioned the time factor alone, [10s of thousands of years] is daunting. But at the risk of repeating myself, the time factor will also benfit humanity. In 500 years we will certainly have put men on Mars and established Moon out posts and other outposts throughout our system.Perhaps we will have sent a "generation"type star ship to another extra solar planet that is suitable for life...Now lets look at a 1000 years...5000 years....damn, let's look at humanity in a 100,000 years: If we are still around, does anyone really believe that we will not have the technology to reach the stars, either through generation type ships or advanced relativistic  ships.

Image result for optimistic quotes about going to the stars

6 minutes ago, Ken Fabian said:

beecee, those ancient history examples of underestimating what is achievable don't really apply; we are far more capable now to figure out what is realistically feasible within the real universe, because we have a much better understanding of it's fundamental physics. And that fundamental understanding is an S-curve that we are much further along. Missions to other stars are not feasible.

I suggest you talk to Marc Millis, or Dr Mae Jamison. Or even to the applicants that applied to Mars One, for a proposed one way trip to Mars: http://www.mars-one.com/

To say missions to other stars is not feasible, at this time, is true: But given the time, say 500, 1000, 10,000 years, to still say it will be not feasible is totally unrealistic despite any of your projected fabricated S curves..

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Area54    103
12 hours ago, Ken Fabian said:

BeeCee, I had an explorer great uncle in the early 1900's - he did okay out of it, doing expeditions into central Australia. The hype at the time about undiscovered gold and other riches prompted plenty of popular interest. He never found anything of significant value but he did okay, because investors were willing to hand him money to fund his explorations in a "share in the discovery" arrangement. I see real similarities - and differences; my uncle did raise enough that way to fund real expeditions. Not conducted with expensive, unproven, cutting edge tech but with camels.

Camels are not native to Australia, which, unlike all the other continents, they were not native too. Use of any technology, in this case domesticated camels, in a novel environment is expensive, unproven and cutting edge. As we move into space permanently much of it will be achieved through the reapplication of existing "camels".

Forgive my directnesss, but you are too narrow-minded on this one. (Please don't take the hump.)

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DrKrettin    209
4 hours ago, Area54 said:

Camels are not native to Australia, which, unlike all the other continents, they were not native too.

It sound like you are saying that camels are also native to the Antarctic . (My turn to be pedantic)

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Area54    103
9 minutes ago, DrKrettin said:

It sound like you are saying that camels are also native to the Antarctic . (My turn to be pedantic)

Good one. I missed that. I'm now frantically and pointlessly searching google to find if camels evolved before Antarctica split and moved too far south!

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Ken Fabian    28

The quality of the 'camels were leading edge tech' argument leaves much to be desired, besides missing the essential point I made about hype supporting unviable enterprises. Should I bother countering it? There is so much wrong with it that I don't believe anyone here even believes it; not even pedantry but factually false. Amuse yourselves with it if you like but it's pure distraction.

There is optimism and there is unfounded and excessive optimism. There are the developmental leaps that may overcome the obstacles in front of us, for which we may feel justifiably optimistic - but when the following ones are dependent upon the prior ones, in ongoing iterations it rapidly becomes fantasy, like homeopaths mixing a drop of something real and diluting it, over and over until it becomes pure optimism.

True leading edge technologies - and this problem goes well beyond actual leading edge technologies - don't come cheap and whilst optimism may be essential, so are realistic expectations.

Edited by Ken Fabian

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beecee    77
25 minutes ago, Ken Fabian said:

The quality of the 'camels were leading edge tech' argument leaves much to be desired, besides missing the essential point I made about hype supporting unviable enterprises. Should I bother countering it? There is so much wrong with it that I don't believe anyone here even believes it; not even pedantry but factually false. Amuse yourselves with it if you like but it's pure distraction.

There is optimism and there is unfounded and excessive optimism. There are the developmental leaps that may overcome the obstacles in front of us, for which we may feel justifiably optimistic - but when the following ones are dependent upon the prior ones, in ongoing iterations it rapidly becomes fantasy, like homeopaths mixing a drop of something real and diluting it, over and over until it becomes pure optimism.

True leading edge technologies - and this problem goes well beyond actual leading edge technologies - don't come cheap and whilst optimism may be essential, so are realistic expectations.

You keep repeating your rhetoric: Again, talk to reputable people, like Marc Millis and Dr Mae Jamison,  far more in the know then you or I, and of course with that essential quality called reasonable progressive optimism that humanity mostly always has, and which you seem to totally lack.

Again, we were/are not born to stagnate on this fart arse little blue orb, with a great big wide wonderous universe waiting out there...but hey! You go ahead and knock yourself out repeating your own dismal unrealistic pessimistic qualities.

Edited by beecee

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beecee    77

Let me add some more...Humans have always explored, and while the least of the reasons scientifically speaking is "because its there" answer, it is without doubt part of our make-up.

Let me also say that there probably has always been those that have dismally decried exploration for whatever purposes including scientific. I wonder where we would be had the Wright Brothers listed to Lord Kelvin? Or had NASA listed to the fabricated reasonings why they should not have sent Alan Shepard aloft into orbit...and John Glenn in those heady early days of space exploration...I wonder where we would be if NASA had of listened  to the "bleeding hearts"  that probably suggested the end of the space missions when Grissom, White and Chaffee died tragically in Apollo 1...or when 14 astronauts were lost in the Columbia and Challenger space shuttle disasters? 

Sure, since those days, economic and political arguments have seen a slow down and a hiatus in going back to the Moon. But as I said before, those are variable quantities and do change, sometimes for the better and sometimes for the worst. But neither will halt our inevitable progress and technological advancement, and that obviously includes going back to the Moon, creating out posts, putting man on Mars and in the distant future, heading towards the stars in any of a variety of possible methods. Given the time of course. 

The likes of Marc Millis of Tau Zero, and Dr Mae Jamison of the 100 year Starship company, and Planetary resourses and Elon Musk and Space X, and many many other visionary, optimistic, realistic and hard working people are leading the way and making sure that continued journey takes place, despite the isolated pockets of those that would seek, for whatever reasons to curtail and/or halt such proceedings.

I have of course forgotten to mention the late Gene Roddenberry and his efforts...and of course sci/fi writers like Arthur C Clark and Andrei Asimov.

Today's Science Fiction, is tomorrows science fact:

 

 

ps: A question: Does today's modern mobile phone, surpass the Star Trek communicator of Star Trek fame? :) (Accepted the Star Trek communicator did not need Satellites)

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Ken Fabian    28

Who is trying to prevent these grand project? I've even suggested a means by which humanity might reach another star - even if I think the many steps along the way must be economically viable in their own right for it to occur and it hasn't been demonstrated convincingly that they are likely to be.

I do think some devil's advocacy isn't out of place in these discussions although I could hope for better, more content filled responses than "camels were cutting edge tech". Or "exploring is what humans do" for that matter. Exploring also finds places that are uninhabitable and resources that are not economically viable to exploit - which is about the stage we are at with space.

Edited by Ken Fabian

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beecee    77
48 minutes ago, Ken Fabian said:

 

 

48 minutes ago, Ken Fabian said:

Who is trying to prevent these grand project? I've even suggested a means by which humanity might reach another star - even if I think the many steps along the way must be economically viable in their own right for it to occur and it hasn't been demonstrated convincingly that they are likely to be.

There are a few ways we will attempt inter stellar travel, the first and probably the most likely at this time of our understanding would be a generation type of starship. And as I have said many times, economics is a variable, and of course while no one can predict that it will be viable at any particular stage, neither has anyone demonstrated that it can never be. 

Quote

I do think some devil's advocacy isn't out of place in these discussions although I could hope for better, more content filled responses than "camels were cutting edge tech". Or "exploring is what humans do" for that matter. Exploring also finds places that are uninhabitable and resources that are not economically viable to exploit - which is about the stage we are at with space.

While a certain amount of "devil's advocacy" can certainly be helpful in many respects, it needs to be associated with desire , willingness, and of course a realistic approach to the problem. I can't comment on camels, nor do I see it relevant in any way, but facts are facts....and exploring and going where no man has gone before, is part of the human makeup, and although as I did infer as the least of our reasons for pursuing the inevitable, it i still that part of the human makeup that no one will ever extinguish. But again, only part of the reason we will in time venture out there.

Edited by beecee

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Ken Fabian    28

Beecee - Generation ships face effectively the same problems that genuinely self reliant space colonies do; having an internal population and infrastructure - aka economy/society - of sufficient size and complexity to be capable of remaking every bit of tech that it uses and continue that capability through multiple generations - generations who won't necessarily come with the same levels of ability. With the added constraint of doing so without any outside resources, simultaneously with carrying the least possible mass.

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