Debunking Interstellar Travel: Separating Fact from Fiction

[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.

 

[AgentCachat]

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.

I was thinking of people so rich they could afford to risk much of their capital on projects that interest them. What more can Bill Gates do with 75 billion dollars? He gives away a few million to charity each year, big deal, pocket change to him.

 

[anorlunda]

I was thinking of people so rich they could afford to risk much of their capital on projects that interest them. What more can Bill Gates do with 75 billion dollars? He gives away a few million to charity each year, big deal, pocket change to him.

Can I interest you in investing your pocket change in a project whose result will not be known for 10000 years? If yes, maybe I can start a kickstart. I'll soon be as rich as Gates.

 

[AgentCachat]

Can I interest you in investing your pocket change in a project whose result will not be known for 10000 years? If yes, maybe I can start a kickstart. I'll soon be as rich as Gates.

LOL. My pocket change wouldn't get you very far. I was not implying that rich folks could finance interstellar travel with pocket change. But with $ 75 billion, you could afford to "only" have say $25 billion and still live comfortably. Carlos Slim could afford $10 billion, etc, And there must be lots of people who could afford millions. Add many billions of money stolen from taxpayers.

 

[anorlunda]

My pocket change wouldn't get you very far. I was not implying that rich folks could finance interstellar travel with pocket change. But with $ 75 billion, you could afford to "only" have say $25 billion and still live comfortably. Carlos Slim could afford $10 billion, etc, And there must be lots of people who could afford millions. Add many billions of money stolen from taxpayers.

You completely missed my point. I was trying to compare a 10000 year project to selling the Brooklyn Bridge.

 

[AgentCachat]

You completely missed my point. I was trying to compare a 10000 year project to selling the Brooklyn Bridge.

Oh I got it. But you don't invest in projects like this with the ROI being a concern.

We've about exhausted this topic. Think I'll go on to how to make politicians honest, or another easy subject.