Debunking Interstellar Travel: Separating Fact from Fiction

[anorlunda]

Here's a question. Are there any kinds of "launching" devices that could provide an initial burst of acceleration instead of having to rely solely on the ship's engines? Something like a very, very large electromagnetic "catapult" similar to the ones proposed for facilitating launches from Earth.

Since we're talking about fanciful future technology, how about an elastic tether that we could attach to a passing asteroid? The name of the ship could be the USS Bungee.

 

[Drakkith]

Let's see.
With assisted 1g acceleration for 3600 seconds, you'd get 36 km/s and the accelerating track structure needs to be 64800 kilometers long (somewhat smaller than Jupiter radius).
At 2g, you get 72 km/s and track length is also x2 - 129600 km.
At 2g and 1800 seconds, you get 36 km/s and track length is smaller: 32400 km.
At 10g and 1200 seconds, you get 120 km/s and track length is 72000 km.

Oh my. Those are some big accelerators...

 

[nikkkom]

Another datapoint:
If 0.1% of mass is converted to kinetic energy with no losses (0.1% conversion is the ballpark of fission) the attainable velocity is ~13000 km/s.
If 1% of mass is converted (fusion ballpark), the velocity is ~42000km/s.

 

[Rubidium_71]

marcus "send frozen zygotes"

One question would be how do the zygotes become fully functioning adult humans? Having holograms and robots raise children didn't work out so well in Lexx... ;) How are they educated to survive in their new environment? Has the environment changed significantly during the long journey?

I wonder if the ultimate feat will be to send just our intelligence to another world via machine. Rather than take extreme measures to preserve such a delicate biological form for an interstellar voyage and then further try to protect or modify our biology for an alien world, a machine intelligence is the most likely winner here. AI is widely believed to be achievable, indeed inevitable. It is a project that can be worked on right here at home and when it's ready we can boot it out into the interstellar medium to make trouble/explore space. If it is self aware and contains a large quotient of human knowledge, in a sense "we" will have a presence beyond the Solar system in time. In a way, the crude prototypes are already being sent out. The further a probe goes, the more it has to look after itself. Remote control only stretches so far,increasing the probability of a sentient interstellar machine. It's probably just a question of when.

 

[rootone]

The best AI's we have so far produced are very good at performing a specific task which they have been programmed for.
They can also 'learn' new strategies within the context of their defined task
We are however nowhere remotely near self-aware machines yet, which could assess any arbitrary situation and determine an appropriate response.
That kind of AI if it's ever achieved would I guess have a personality and emotions as humans do, which would play a part in decisions.
So one such AI would probably respond differently to another, and who knows, maybe they could even fall in love with each other or do stupid things because another AI had made them angry.

 

[mfb]

Since we're talking about fanciful future technology, how about an elastic tether that we could attach to a passing asteroid? The name of the ship could be the USS Bungee.

Current materials limit the tip speed of untapered tethers to ~1 km/s. A reasonable tapering of 1:50 gives 4km/s. And that is just a tether without any load. Carbon nanotubes can achieve higher speeds, but attaching a spacecraft to it? You would not get any relevant speed from it.

That kind of AI if it's ever achieved would I guess have a personality and emotions as humans do, which would play a part in decisions.
So one such AI would probably respond differently to another, and who knows, maybe they could even fall in love with each other or do stupid things because another AI had made them angry.

Same problem with humans. In the future it could also be possible to scan a human brain and simulate it in a computer. Then you can run your spacecraft by a human-like thing without biological life support.

Could a human passenger survive that?, experiencing something like 50G?

10g in the direction "eyeballs in" are sort of tolerable, if they are not too long. Submerged in water and with some liquid breathing technique, more should be possible.

 

[Rubidium_71]

rootone - "We are however nowhere remotely near self-aware machines yet, which could assess any arbitrary situation and determine an appropriate response."

Well, we are talking about the future here (some of the posts on this thread contemplate events that are very far in the future.) Given that progress in space probes is ongoing (we've gone from Sputnik to New Horizons at this point) and that real AI projects are active and funded world wide (as opposed to other suggestions like generation ships or warp drives that have zero active support or funding at this time) I still think an AI extra-solar presence is the most likely scenario. It just might be as close as a human-constructed (or human-like) intelligence may get to leaving the Solar System. The knowledge and experience does the traveling while the weak biological vehicle is left behind.

Our machines are simply tougher than we are, with fewer requirements for ongoing survival and comfort. Pioneer and Voyager are already heading out of the system and can serve as relics to our ingenuity long after people are extinct. They have been followed by other, smarter, longer functioning machines like New Horizons. Even smarter machines with greater longevity will very likely follow New Horizons. If this trend continues and we move into areas like quantum computing to achieve further breakthroughs in computing, an AI arriving in another star system some time in the future is not out of reach.
Not really sure about the necessity of "emotions and personality" aspects you mention. In theory an alien entity could play back the Brandenburg Concerto from one of the Voyager golden records and have an emotional response to it, so even a non-functioning non-AI machine could (theoretically), in a sense, transmit something on an emotional level to another life form.
But we're not really postulating an encounter with aliens here, just some sort of human presence outside the Solar System. I think an AI (in this case) would really only need to be a scientist, not a diplomat. Personality and emotions are usually considered for an AI to make the interface more warm and friendly to humans. I wouldn't see a need for it where the AI is traveling alone to another star system. In that scenario it won't interact with a human or anything else for probably hundreds of thousands of years. Emotions would be detrimental in that situation, I think, consider how bored the poor thing would get. It's primary task would be gathering and relaying information, it doesn't need to be happy or sad to accomplish that.

 

[anorlunda]

Ships filled with zygotes or artificial intelligence don't sound very appealing. I would rather put my money on interstellar communication to transmit the genome or the AI program at light speed to an alien host.

But interstellar light communications are impractical or impossible you say? Ditto for interstellar ships. It would be a simple race in technologies.

 

[ebos]

I'm just thinking about the fuel requirements to keep an acceleration of about 10m/sec^2 (which is 'G' approximately) in order to get even close to relativistic speeds. And you'd have to double that for the deceleration at the other end. The dust problem could be resolved by welding the bumpers from a '56 Cadillac to the front of the ship.

 

[mfb]

Our machines are simply tougher than we are, with fewer requirements for ongoing survival and comfort. Pioneer and Voyager are already heading out of the system and can serve as relics to our ingenuity long after people are extinct. They have been followed by other, smarter, longer functioning machines like New Horizons.

New Horizons is slower than the Voyager probes, and will (probably) not last as long as those. We might even lose contact to New Horizons earlier than contact to the Voyager probes, launched decades earlier.

And you'd have to double that for the deceleration at the other end.

You have to square it. The rocket equation can be cruel.

 

[Astronuc]

assuming we have the technology

That too is a fantasy. There are only so many ways to achieve propulsion. Somewhere mass must be ejected from an object in order to achieve high velocity. The mass must be carried, and the power (energy production) system my produce considerable power to provide some substantial thrust. Putting such mass in orbit would be rather expensive, and constructing a system from resources on the moon or asteroids would be similarly expensive.

I think there have been scenarios proposed to use the gas planets as jumping off points for interstellar travel, but those are rather fanciful. Infrastructure would need to be in place, and that means colonizing the outer planets in some fashion, i.e., orbiting space stations.

Besides interstellar dust, there is the matter of galactic cosmic radiation.

 

[enorbet]

I truly wish I wasn't forced by logic to be such a wet blanket on this subject but currently there are so many seemingly insurmountable difficulties so far beyond us for which only vast amounts of time (combined with effort) can solve, I can't help but conclude that odds are greatly against ever achieving the most primitive of Interstellar travel, let alone some Star Trek vision.

It seems to me this wiki came from another thread here but I think it useful here since a number of responses depend on human civilization having vast amounts of time to discover new, affordable technologies. If you look at

https://en.wikipedia.org/wiki/Timeline_of_the_far_future#Future_of_humanity

you will see that using The Drake Equation the odds are 95% against human civilization surviving beyond 10K years. We likely don't have even 10s of thousands of years let alone millions or billions. Since mere velocity as we think of it now has very bad odds of making Interstellar travel practical or even possible, the only remaining possibility is some manner of Warp Drive that probably folds spacetime and the likely energy costs of that surely make Interstellar Travel a subject fit for dreamers only. We need dreamers but we are presently so far behind in this area that this is likely the subject of "pipe dreamers" as sad as I am to say it.

 

[mfb]

I truly wish I wasn't forced by logic to be such a wet blanket on this subject but currently there are so many seemingly insurmountable difficulties so far beyond us for which only vast amounts of time (combined with effort) can solve, I can't help but conclude that odds are greatly against ever achieving the most primitive of Interstellar travel

How would you have evaluated the chances to go to Moon in 1900, or heavier-than-air flight in 1800? Both got realized, due to "dreamers".

you will see that using The Drake Equation the odds are 95% against human civilization surviving beyond 10K years

If you apply statistics in a completely wrong way (it is also not the Drake equation). By exactly the same argument, you would have a 5% chance to get 20 times as old as you are today. How realistic is that?

 

[enorbet]

ping mfb - I recognize that it is true that amazing things get accomplished exactly because the people responsible "didn't know it was (nearly) impossible" so I am somewhat at emotional odds within myself posting in this thread because I have no desire to dampen anyone's dreams. That said I will try to answer your questions and not assume they are merely rhetorical.

Allow me to take "heavier-than-air flight in 1800" first. It seems to me that the desire to fly had a serious "leg up" long before 1800 because any fool could see it was theoretically possible since birds, insects and a few mammals did it. All of the basics were in place long before Orville and Wilbur came along. It just took someone with the desire, money and time and an experimental mind to make each small step required to put it all together and achieve flight.

The Moon by 1900 is an order of magnitude more difficult since AFAIK Jules Verne was the most known person to imagine how that could be accomplished yet anyone familiar with Newton could easily prove Man could not withstand the Gs of a cannon. Granted there were fanciful stories of moon travel back as far as ~80 AD and something somewhat resembling a rocket was imagined by Cyrano de Bergerac but by and large they weren't considered serious because most depended on what amounts to magic ie anti-gravity paint, etc. This is not anywhere near as convincing as seeing heavier-than-air things fly every day. So it is likely that I would have bet against flight to the moon in 1900. Thankfully I would have been wrong and I sincerely hope I am wrong about Interstellar Travel as well.

However, it seems to me the progression follows, that Interstellar Travel is currently many orders of magnitude beyond Moon Travel with no examples to follow yet. Also the financial requirements are similarly aligned with the progression of difficulty. Two men could afford a plane. Millions were required for Moon flight. Just how much power must one (or how many men) have at one's disposal (and at what cost?) to generate and control sufficient power to achieve it when we can't even calculate if it is really possible to get to a fraction of c? let alone fold spacetime?

I'm not assuming it is impossible ever... just that presently, given what we know or even can "see", it is far, far beyond our reach even in imagination of anything remotely realistic. I do understand that Drake was lacking in evidence sufficiently to cast doubt on how likely his conclusions can be, making them "best guesstimate" at best. Game changers do occur but until they do we are stuck with what we have, where we are.

If I am overly pessimistic please do enlighten me. I'd welcome the hope.

 

[B Levenson]

The history of the Alcubierre drive is that in 1994, M.A. published his article showing that, with the right metric, you could propel a ship locally slower than light but globally faster, by compressing the space ahead and expanding it behind. In 1997, another article (I forget the authors) said you would need more energy than was available in the universe for this to work. In 1998 or '99, a third article said it could be done with a lot less energy, but you'd need some matter with negative mass, and nobody knows how to produce that or even just what it is. So warp drives are in limbo for the moment.

 

[mfb]

I recognize that it is true that amazing things get accomplished exactly because the people responsible "didn't know it was (nearly) impossible"

Most of the things get done by people knowing exactly that it is "impossible".

1800 didn't have internal combustion engines, 1900 didn't have de Laval nozzles used in rocketry, which are crucial for high exhaust speeds.

A (relatively) slow colony ship doesn't require unknown physics. It requires a lot of engineering, more research in independent habitats and tons of other fields, but all those things are not completely new. They are mainly things we have already, on a much larger scale. Sure, cost is a huge issue, but if that is the only issue, things tend to get done over time.

 

[newjerseyrunner]

I think the analogy about heavier than air travel in the 1800s vs FTL travel now is invalid because in the 1800s, they didn't know how to do it mechanically, but they understood how to do it mathematically since the publication of the Principia: f = ma, if you push against the air harder than the Earth pulls you back, you'll fly, any science-literate person would have known that, it was only considered impossible then by the ignorant masses. FTL travel violates causality, and it's the scientists who believe that it's impossible.

I also agree that FTL travel is not required to colonize. Species that travel through space will continue to find more efficient ways of doing it, and for a colonizing species. Colonists tend to be a one way trip anyway so time is of little consequence, especially if you can be put in stasis during the flight. If you're leaving your planet behind for some reason, would you care if you were put to sleep for 4 years, 40 years, 4 thousand, 4 million? It'd be instantaneous to you.

 

[GeorgeDishman]

It seems to me that nobody would set out on a voyage to another star system without first being sure that there was a habitable planet there. That means sending unmanned probes first (and the problems in doing that are quite different from those in the article). If you have succeeded in getting an autonomous probe gravitationally captured by the target system, then soft-landed on the planet, then received its analysis saying that the flora and fauna are suitable, all you need is to have some form of 3D biological reconstruction system on the probe, a "teleport" receiver in a sense, and you can be scanned here and rebuilt there with the only delay being highly robust data communication at the speed of light. That sort of technology is currently in its infancy but there is huge financial potential in the medical industry so it will certainly develop. The idea of sending manned ships will be laughably obsolete long before it becomes feasible, but that doesn't mean interstellar travel won't happen.

https://en.wikipedia.org/wiki/3D_bioprinting

 

[nikkkom]

I'm just thinking about the fuel requirements to keep an acceleration of about 10m/sec^2 (which is 'G' approximately) in order to get even close to relativistic speeds.

Please do not be fixated at 1g acceleration (or any other fixed number). It is unimportant.

In fact, gentler acceleration in many cases is better. Say, if you have a fusion-powered engine, you probably need to carry a lot of deuterium. Deuterium is bulky. With gentler acceleration, your engine is smaller and lighter, and your tanks are less sturdy and therefore lighter, therefore mass fraction is better.

If you plan on a 100 year journey at 0.05c, you can accelerate at just 0.01g and it still takes only 5 years, a small fraction out of total flight time, to attain your cruise speed.

 

[ebos]

Please do not be fixated at 1g acceleration (or any other fixed number). It is unimportant.

In fact, gentler acceleration in many cases is better. Say, if you have a fusion-powered engine, you probably need to carry a lot of deuterium. Deuterium is bulky. With gentler acceleration, your engine is smaller and lighter, and your tanks are less sturdy and therefore lighter, therefore mass fraction is better.

If you plan on a 100 year journey at 0.05c, you can accelerate at just 0.01g and it still takes only 5 years, a small fraction out of total flight time, to attain your cruise speed.

True, but the humans on board will have turned to Jello.

 

[nikkkom]

What are you talking about?

 

[mfb]

The conclusion about the fuel needed is independent of the acceleration, it only depends on the final speed (and engineering details).

1g is convenient because you don't need other methods to produce artificial gravity then.

 

[phinds]

What are you talking about?

He is talking about the fact that in free fall or microgravity for many many many years, human muscles will atrophy to uselessness and bones will have serious problems as well. Kelly's recent year in space will provide more hard data on that but I believe it is inescapable that the human body cannot sustain year and years of free fall or micro-gravity.

 

[mfb]

Valeri Polyakov spend 437 days in space, Sergei Avdeyev 380 days, Vladimir Titov and Musa Manarov both 365 days in a joint mission.
Mikhail Korniyenko and Scott Kelly with 340 days are just rank 5/6.
Valeri Polyakov appears again in this list on rank 9, 240 days a few years before his record-length spaceflight.
All numbers are for a single continuous mission, of course.
Full list

Artificial gravity on a spacecraft is not magic. We simply don't have it because it is not necessary for current mission profiles.

 

[DrStupid]

He is talking about the fact that in free fall or microgravity for many many many years, human muscles will atrophy to uselessness and bones will have serious problems as well.

For the very unlikely case that we will be able to build interstellar ships but not to adapt humans to microgravity we can simulate gravity with rotating habitats.

 

[phinds]

For the very unlikely case that we will be able to build interstellar ships but not to adapt humans to microgravity we can simulate gravity with rotating habitats.

Of course but that severely complicates the design. It IS "just" an engineering challange but could be done. I was simply responding to a specific question.

 

[DrStupid]

but that severely complicates the design

Simulated gravity is not even a minor challenge compared to other problems to be solved for an interstellar spaceship. We could easily do that with current technology.

 

[1oldman2]

For the very unlikely case that we will be able to build interstellar ships but not to adapt humans to microgravity we can simulate gravity with rotating habitats.

Like in 2001 a space odyssey ?

 

[DrStupid]

Like in 2001 a space odyssey ?

No, with a cable and a counterweight.

 

[1oldman2]

No, with a cable and a counterweight.

That would also work, I kind of liked the doughnut approach VS. the nunchuck effect but there are many different ways to approach the artificial gravity question. That is a very minor issue compared to the other problems mentioned.

 

[ebos]

I remember reading the Foundation and Empire series by Isaac Asimov (still my favorite sci-fi book just ahead of Heinlein's A Time For Love) and one of the main quests throughout the plot was to discover who the "Master Race" was. They were the ones who controlled basically everything and everyone in the galaxy while still keeping it a peaceful place . Spoiler alert, but when they were finally discovered they were a civilization of peasant who lived in small humble homes, grew their own vegetables and never fought. Kind of like a planet full of Mahatmas.
In other words, we just got down from the trees not too long ago. We have a long time to go. Even the Sun has at least 4 billion years left. Why don't we forget about outer space for now. Our technology has a lot to learn before we go way out there and/or try to colonize. We still haven't learned from any of the mistakes from our past yet. Look at the US this year and last. And we want to send that out to space? Let's slow down. Most of the new inventions we celebrate these days is usually just ego-driven anyways. Or it tries to fill a bottom-less hole in our hearts. Nothing wrong with keeping a hand in. Good telescopes and other powerful sensory devices are OK for now. But most of our energy needs to be spent right here learning about universal love, about not jumping to hatred or war at the least provocation, learning how to feed everyone, making sure everyone has enough instead of just 1%.. My goodness, I would turn down any ship that was fully guaranteed to go to a proven inhabited star if I was asked today because I would be too embarrassed when I got there. Or worse, when they got here.

 

[1oldman2]

And we want to send that out to space? Let's slow down.

Wow, great taste in authors and common sense. I wish they would allow more than one like per post, you would get your fair share from me.

 

[nikkkom]

Our technology has a lot to learn before we go way out there and/or try to colonize. We still haven't learned from any of the mistakes from our past yet. Look at the US this year and last. And we want to send that out to space? Let's slow down. Most of the new inventions we celebrate these days is usually just ego-driven anyways.

We still haven't learned from any of the mistakes? Really?

We (humanity) invented, after several iterations, more efficient systems of government. Namely, we removed from power people who would keep population superstitious and uneducated, suppress science just in order to cling to power. We removed from power people who pass their ruling position to their children, with no regard to their ability to rule well. We made it illegal to seize power for life (term limits). We made it illegal to suppress dissenting opinions (freedom of press). Etc etc etc.

We understood that environment should be protected, and all our activities (industrial and domestic) need to limit its damage to environment. No more uncontrolled discharge of nasty stuff into the rivers.

Scientific and engineering advances we made... I can't list even most important of those here, that would require several pages. And we are not showing any sign of slowing down.

 

[rootone]

We still haven't learned from any of the mistakes? Really?

We (humanity) invented, after several iterations, more efficient systems of government. Namely, we removed from power people who would keep population superstitious and uneducated, suppress science just in order to cling to power. We removed from power people who pass their ruling position to their children, with no regard to their ability to rule well. We made it illegal to seize power for life (term limits). We made it illegal to suppress dissenting opinions (freedom of press). Etc etc etc.

We understood that environment should be protected, and all our activities (industrial and domestic) need to limit its damage to environment. No more uncontrolled discharge of nasty stuff into the rivers.

Scientific and engineering advances we made... I can't list even most important of those here, that would require several pages. And we are not showing any sign of slowing down.

I admire your optimism.

 

[Drakkith]

I admire your optimism.

Yes, it's a nice change from the pessimism so many people have.

Why don't we forget about outer space for now.

I can think of at least one reason. Having the ability to save our species from extinction in the event of a global catastrophe, whether man-made or natural. I'm sure there are plenty of others.

We still haven't learned from any of the mistakes from our past yet. Look at the US this year and last. And we want to send that out to space? Let's slow down. Most of the new inventions we celebrate these days is usually just ego-driven anyways. Or it tries to fill a bottom-less hole in our hearts. Nothing wrong with keeping a hand in. Good telescopes and other powerful sensory devices are OK for now. But most of our energy needs to be spent right here learning about universal love, about not jumping to hatred or war at the least provocation, learning how to feed everyone, making sure everyone has enough instead of just 1%.

In my opinion you're operating under the assumption that if we just spend more time and effort we'll overcome all of those difficulties. That may not be true. We could very well never solve them. In addition, I doubt you could ever get everyone to agree on what "universal love" even means, or which system of government and/or economics is best for everyone.

 

[DrStupid]

Look at the US this year and last. And we want to send that out to space?

Look at the US and the Russians in cold war. Did they sent that into space? Manned spaceflight originally was a side product of intercontinental nuclear weapons and only intended to demonstrate technological superiority. But once in space the super powers started to cooperate there (e.g. with the Apollo-Soyuz Test Project). Things on Earth and in Space will always be different.

But most of our energy needs to be spent right here learning about universal love, about not jumping to hatred or war at the least provocation, learning how to feed everyone, making sure everyone has enough instead of just 1%.

Changing the nature of humans is problematic from an ethical point of view - even when done for the best. Preventing humans from "jumping to hatred or war at the least provocation" would require general mental modifications. There is no doubt that humans will be modified both physically and mentally in the future - especially if we colonise space. But that will happen for a minority only and it will result in additional problems (e.g. conflicts between different post-human species).

Solving our problems on Earth first is a popular idea but out of touch with reality. There will always be problems.

 

[anorlunda]

There's another assumption beneath all this fantasy-full discussion of future advancements. Namely that evolution stops with homo sapiens.

If we are projecting thousands or millions of years into the future, then any inhabitants of Earth will presumably be a post-human species.

Listening to some, machines or AI will be the successor, and darn soon.

Think of Kurzweil's "The Singularity is Near" (He says the year is 2043).

Think of Arthur Clarke's classic story, Childhood's End, where he portrays biological evolution (rather than Kurzweil's AI evolution), but leading the the same end result as Kurzweil's.

Think also of the recent doomsaying by Bill Gates, Elton Musk, and Stephen Hawking on the same subject saying that we should fear AI.

I like to think of software advancements as just the next step in evolution, and to think of the Gates/Musk/Hawking types as just a new flavor of Creationists, who believe that homo sapiens should be immune to being overtaken, that the status quo is sacred, and that evolution is constrained to DNA driven biological processes.

So, if we want to discuss Interstellar travel by humans, shouldn't we confine the discussion to the next 2043-2016 = 27 years.

 

[1oldman2]

So, if we want to discuss Interstellar travel by humans, shouldn't we confine the discussion to the next 2043-2016 = 27 years.

A point well taken, your post is likely the most relevant "interstellar travel" concept mentioned thus far.

 

[nikkkom]

But most of our energy needs to be spent right here learning about universal love, about not jumping to hatred or war at the least provocation, learning how to feed everyone, making sure everyone has enough instead of just 1%.

I find it questionable to have "universal love", whatever that is. People sometimes behave aggressive and even go to war not because they are inherently evil. They do it because it is an *evolutionary necessity*. "Fight or flight". Both reactions make sense. If you see a rockfall upon you, it makes sense to flee. But someone who always runs from any danger, loses. If you run away, you lose everything you left behind - stockpiled food, shelter, territory, children.

We don't need to stop fighting. We need to stop fighting *when it can be avoided with diplomacy, economic pressure, etc*. When we do fight, we need to do it cleverly, not letting our natural animalistic emotions turn the conflict into slaughter.

As to "learning how to feed everyone", I don't see starving people in Western countries. If anything, *obesity* is a problem here, not starvation. "Making sure everyone has enough instead of just 1%"? What is "enough"? Having food, shelter, and health care is enough? I am not in richest 1%, and I have all of that, and much more. Looks like these two problems are solved.

 

[1oldman2]

We seem to be wandering away from the main thread topic and more towards current events.

 

[Drakkith]

We seem to be wandering away from the main thread topic and more towards current events.

I've got my eye on the thread, but if you think it gets out of hand just report one of the posts so it can be brought up to the other mentors.

 

[1oldman2]

I've got my eye on the thread, but if you think it gets out of hand just report one of the posts so it can be brought up to the other mentors.

Just trying to nudge things back on track, thanks.

 

[Ssnow]

For me it is fantasy we need a lot of technologies before to think about the interstellar travel. I think we must to start to visit our solar system for example a travel on Mars ( in a summer day ) ... but also for this I believe we need a lot of time (I cannot realize for an ''interstellar travel'')

 

[ogg]

I've always thought it would be fun to write a sci-fi (short) story about a race of beings who invent force fields which revolutionizes their technology. The zinger would be that these "force fields" are what we know as "matter". (or perhaps now that I think about it, perhaps solids would be more plausible then at least I could have gaseous or liquid beings...) This thread's arguments seems to break down three ways, why the 4th is being avoided, I don't know. The three are: 1. Physics will evolve but it will not mutate, so intestellar travel is extremely implausible 2. Known Physics has changed in the past, therefore we should expect profound changes to the Laws of Physics in the future (aka magical thinking) 3. We should consider AI or genetically space adapted beings and their ability to travel between the stars. The 4th category is (imho) so what if it takes one of our ships 10,000 (or 1,000,000) years to get to its destination? Is there any reason (that we know about) we can't do that?

 

[mfb]

Known physics has changed in the past, but the previous laws have always stayed good approximations.
Newtonian gravity is not correct, but a really good approximation if you want to build a house. If you want an accurate GPS system, you better add some small correction terms.
Solid-state physics today is based on quantum mechanics, but you don't have to consider quantum mechanics to build a house, because you can use the approximations of classical physics there. If you want to study objects on the nanometer scale, you better use quantum mechanics.

There are certainly amazing new things yet to be discovered, especially on the microscopic scales, but things like conservation of momentum are unlikely to go away - or only with extremely tiny deviations.

The 4th category is (imho) so what if it takes one of our ships 10,000 (or 1,000,000) years to get to its destination? Is there any reason (that we know about) we can't do that?

That concept is widely used as idea for interstellar travel.

 

[AgentCachat]

True, but the humans on board will have turned to Jello.

Hmm, you must have misread some numbers. Very high acceleration is needed to turn people into jello. A dv/dt of 0.05 c is too small for long trips.

 

[AgentCachat]

Humans will not be satisfied to sit here on earth, its not in our nature. We will find a way to the planets, then the stars. Its only a matter of will.. We may not be able to traverse the galaxy at warp speed, but getting to the nearest stars is possible, however difficult.

 

[rootone]

Humans will not be satisfied to sit here on earth, its not in our nature. We will find a way to the planets, then the stars. Its only a matter of will.. We may not be able to traverse the galaxy at warp speed, but getting to the nearest stars is possible, however difficult.

I agree, but it won't happen unless there is a collective wish to do it. Communism is out of fashion at the moment.

 

[AgentCachat]

I agree, but it won't happen unless there is a collective wish to do it. Communism is out of fashion at the moment.

I think it can happen if enough people want it to. It could be a private venture. The capitalist U.S. beat the communist U.S.S.R. to the moon. I mean, Lithuania has its own satellite now. Israel launches its own spy satellites, South Korea has launched a satellite. There is no sign of space exploration and utilization slowing down.

 

[rootone]

A private venture is possible, but I think not many people with serious financial means would invest in an interstellar exploration project with an unknown result.
They got rich anyway by investing in things of which the outcome would probably be profitable.