How difficult is interstellar travel?

[Complexity]

To the OP: I've always found it to be rather peaceful.

Of course, I always bring plenty of reading and make sure the other passengers are frozen.

 

[Corsair 115]

Meh, who needs interstellar travel? We've got an entire solar system of our own to play around in, and we've only barely scratched the surface of what it has to offer. It'll be enough to keep us busy for a one or two hundred years at least.

 

[Cuddles]

Alpha Centauri is a three star system consisting of two sun like stars orbiting each other and a third red dwarf at great distance. The names for the three stars are Rigil Kentaurus A, Rigil Kentaurus B and Proxima (the red dwarf). Proxima happens to be on our side of the system at the moment so it is our closest neighbor at the moment.

Although it is still not certain that Proxima is actually part of the system and not just passing through. It moves slowly enough that the observations so far aren't enough to confirm it is definately in an orbit.
http://www.newscientist.com/article/mg16221820.700

 

[Schneibster]

Well, to be pedantically correct, it is in an orbit, the question is whether it's a closed orbit. It might still be a parabola or hyperbola.

 

[MilwaukeeMike]

What do you mean by "Running out of resources"? Could I see some evidence for this?

Where are these "resources" going? Unless they are being sent out into space, past earth orbit, they still should be here.

It may sound difficult to recapture the carbon in the atmosphere and resynthasize it back into usable materials, or to mine old landfills for metal and then seperate and re-smelt it.

It's a hell of a lot easier than going to the stars though. As things stand now, there is little chance we'll be running out of matter to synthasize stuff out of any time soon. (Again... difficult but much easier than going to a star)

But how does it help humanity to move to other planets? If we go to, say, mars, we'll need to bring massive amounts of technology from earth and keep ourselves alive artificially for hundreds, possibly thousands of years, before even the slightest hope that the planet could form a naturally sustainable enviornment fit for higher life forms. (and it very well may never)

And the stars? Again, spend hundreds and hundreds of years just to get to some of the extremely nearby stars? The couple dozen systems that we have even the slightest hope of getting to within less than a million years?

And then arive and find there are no suitable planets? Then what? Keep going for thousands more years?

The spacecraft required would possibly require more than all the world resources. And the idea that life could be sustained with artificial technology reliably for generation after generation after generation is not very realistic.

Yes, maybe getting to another star is possible, but not in my lifetime. Not in your lifetime, not in your childrens' childrens' childrens' lifetime. I realize that it's dangerous to limit the possibilities in the future, but it won't happen in any forseable future, unless there is some dramatic discovery which expands the laws of physics beyond what we currently think is possible.

There's no technology that could do this. There's no technology under development to do this. There's no extension of technology being considered for development for this. There's no technology which could possibly lead to a future technology which could be expanded to do this. It is many many many orders of magnitude beyond what we are even capable of considering.

The best we might be able to do is maybe, in a few cneturies, hope to send a small group of humans to alpha centauri and have them return to say "yeah. no planets. Not a very good star for habitation. We came back because we saw no other place to go"

Don't underestimate the speed of tech advance. Think of it this way; in 1900 we could not fly. Yet, by 1969 we landed a man on the moon. In just 69 years we went from no flight to landing on the moon.

70 years from now we could be living on the moons of Jupiter if the pace of tech advancement continues to exponentially accelerate.

 

[Paulhoff]

Don't underestimate the speed of tech advance. Think of it this way; in 1900 we could not fly. Yet, by 1969 we landed a man on the moon. In just 69 years we went from no flight to landing on the moon.

70 years from now we could be living on the moons of Jupiter if the pace of tech advancement continues to exponentially accelerate.

It still will take a hell of a lot of energy no matter what the advance tech is. To get your spaceship going to 86.6% of the speed of light it would take as much energy by weight as the spaceship weights and that only if you have 100% efficiency in getting it to that speed.

Paul

 

[mhaze]

No doubt for me: robotic interstellar.

However, it seems unlikely they would be the same price. It seems to me almost certain that the interstellar mission would be much, much, more expensive than a manned Mars mission.

Not so sure about the relative pricing.... Both projects would yield massive spinoffs, and profitable side benefits of various sorts.

One would think that the manned mission would become political football, be subject to the usual ridiculous cost overruns and the like.

We could get a lot of good data from a crude intersteller probe regardless of whether it completed its mission. (Already got one going out there, sort of.....). Data on the oort cloud would be interesting.

 

[Meadmaker]

Not so sure about the relative pricing.... Both projects would yield massive spinoffs, and profitable side benefits of various sorts.

I always thought the "spinoff" argument was not a very good one.

Spinoffs occur whenever scientists and engineers are doing anything, whether it's useful or not. If your project is new and useless, there will be spinoffs. If your project is new and useful, there will be spinoffs. Which one is better?

If it's a good idea to do something, it's good regardless of the spinoffs. At best, spinoffs turn a marginally good idea into a very good idea. If it's a waste of effort, it's a waste of effort witht the spinoffs as well.

 

[Ziggurat]

To the OP: I've always found it to be rather peaceful.

Of course, I always bring plenty of reading and make sure the other passengers are frozen.

That way they don't spoil. If they go bad, you'll be hungry for a very long trip.

 

[DRBUZZ0]

To the OP: I've always found it to be rather peaceful.

Of course, I always bring plenty of reading and make sure the other passengers are frozen.

My advice: Don't take Hal with you. He could mess up those plans...

(that's everyone's cue for the massive groan)

 

[Davo]

Until we can development the technology to travel to a planet and set up a self sufficient environment for humans interstellar isn`t practical (at least for humans anyway).

The moon or Mars would be the first places to colonise, but I don`t see that happening in the near future.

 

[RecoveringYuppy]

No. Near Earth orbit will have a hotel fairly soon.

 

[RecoveringYuppy]

In just 69 years we went from no flight to landing on the moon.

That's an impressive stat. But the moon landings were a tour de force experienced by a dozen people. The statistics that impress me more are the fact that the everyday average American flies an average of twice a year now and the less well known fact that North America's domestic airlines have enough capacity to completely evacuate North America to any other continent in about ten years. I expect that in 150 years we'll have enough capacity to evacuate the planet, but, like our domestic airline fleet, that won't be what we'll be using it for.

 

[Davo]

No. Near Earth orbit will have a hotel fairly soon.

This would help make small advances but would rely 100 % on resources and equipment being brought up from Earth.

Until we can make planets habitable which are completely self sufficient, there won` t be any further human expansion in our galaxy.

To be self sufficient in fuel, materials ,growing of food is a highly complex activity when you look into the finer details. Can`t see it happening but would be good if we could advance ourselves this way.

 

[Bodhi Dharma Zen]

I bet new natural "laws" will be discovered.

I bet that the power requirements that seem impossible now will be piece of cake when those new "laws" are discovered.

I bet that interstellar travel will be accomplished more or less at the same time we find out how to "transfer" what we call "consciousness" to a longer lasting structure.

 

[Jimbo07]

I bet new natural "laws" will be discovered.

I bet that the power requirements that seem impossible now will be piece of cake when those new "laws" are discovered.

That's a different form of a bet I've made before:

If we don't have some sort of viable theory, upon which some kind of FTL device could eventually be developed, within 150 years... we never will.

 

[RecoveringYuppy]

I bet that the power requirements that seem impossible now will be piece of cake when those new "laws" are discovered.

I'm kind of baffled by people who think the power requirements seem impossible.

Back in post 74 someone provided a link to a piece that shows how "difficult" it would be to send a probe to another star system in a single human lifetime (a time requirement I would point out is not necessary for colonization or exploration). Speaking of the power required he then said this:

To put this figure in perspective, the total conversion of one kilogram of mass into energy yields 9 x 10[SIZE=-1]16[/SIZE] Joules. (Which one of my sources informs me, is about equivalent to 21.6 megatons in thermonuclear explosive yield). So we require the equivalent energy output to 400 megatons of nuclear armageddon in order to move a capsule of about the gross weight of a fully loaded Volvo V70 automobile to Proxima Centauri in less than a human lifetime. That's the same as the yield of the entire US Minuteman III ICBM force.
For a less explosive reference point, our entire planetary economy runs on roughly 4 terawatts of electricity (4 x 10[SIZE=-1]12[/SIZE] watts). So it would take our total planetary electricity production for a period of half a million seconds — roughly 5 days — to supply the necessary va-va-voom

So this is an outrageous amount of energy? Yet it's something we can do now? Including one method (ICBM warheads) that has been around so long that it's already past it's original expected obsolence date? And it sat around unused for it's entire lifetime?

I find it hard to believe the future generations are going to find these numbers daunting when we've got that amount of energy "sitting on the shelf" unused at the moment.*

To give a different perspective on those numbers, his power requirement works out to about 1.5 gigawatts when the energy is spread over the duration of the mission he is describing. A solar power stations based near the orbit of Mercury would need under a square kilometer to catch that energy.

The energy isn't even outrageous, let alone impossible.

* BTW the design for the rocket capable of using that energy source has been sitting around unused for 40 years also.

 

[Paulhoff]

I'm kind of baffled by people who think the power requirements seem impossible.

Back in post 74 someone provided a link to a piece that shows how "difficult" it would be to send a probe to another star system in a single human lifetime (a time requirement I would point out is not necessary for colonization or exploration). Speaking of the power required he then said this:

So this is an outrageous amount of energy? Yet it's something we can do now? Including one method (ICBM warheads) that has been around so long that it's already past it's original expected obsolence date? And it sat around unused for it's entire lifetime?

I find it hard to believe the future generations are going to find these numbers daunting when we've got that amount of energy "sitting on the shelf" unused at the moment.*

To give a different perspective on those numbers, his power requirement works out to about 1.5 gigawatts when the energy is spread over the duration of the mission he is describing. A solar power stations based near the orbit of Mercury would need under a square kilometer to catch that energy.

To put this figure in perspective, the total conversion of one kilogram of mass into energy yields 9 x 10[SIZE=-1]16[/SIZE] Joules. (Which one of my sources informs me, is about equivalent to 21.6 megatons in thermonuclear explosive yield). So we require the equivalent energy output to 400 megatons of nuclear armageddon in order to move a capsule of about the gross weight of a fully loaded Volvo V70 automobile to Proxima Centauri in less than a human lifetime. That's the same as the yield of the entire US Minuteman III ICBM force.
For a less explosive reference point, our entire planetary economy runs on roughly 4 terawatts of electricity (4 x 10[SIZE=-1]12[/SIZE] watts). So it would take our total planetary electricity production for a period of half a million seconds — roughly 5 days — to supply the necessary va-va-voom

The energy isn't even outrageous, let alone impossible.

* BTW the design for the rocket capable of using that energy source has been sitting around unused for 40 years also.

For the fun of it, we have a 2000 kilogram car, we convert 20 kilograms of matter into energy using a power plant with 100% efficiency, and we get the car to go to 14% of the speed of light. But we have not figured in the power plant’s weight, we will have less then 100 efficiency, we will need shielding for the power plant and food needed for a 60 year round trip, we’ll need more space then just a car for 60 years, the list will go on and on and of course more weight and more energy……

I am not saying that it can’t be done, but there is much more to logistic then meets the eye.

Paul

 

[Paulhoff]

Geeeeeeeeeeee.

 

[Hellbound]

Just to second Paul:

Using the energy in the form we have "sitting on the shelf" is prohibative, as well. That entire stock of minuteman missles has to be carried, as well...so already (just with fuel) you're significantly heavier than a Volvo of any stripe (for that matter, you have more mass than a Volvo factory or two). And we haven't even added the engine (pusher plate for an Orion vehicle, which is going to be on the order of tens of thousands of kilograms).

Yeah, we may have the nergy now, if we could cut off every other energy requirement in the world for a while, get every country to cooperate fully, store this energy somehow in a 100% efficient storage mechanism that weighs next to nothing, find a way to convert this storage to thrust (over a long term), and get multiply-redundant computer guidance that will still work to correctly position and move the spacecraft without any human input whatsoever. We can't give commands with a four year plus time lag...the craft has to find anything interesting on it's own, manuever to observe it, and know what to report wihtout intervention. It'll have to make judgements on what to study...we wouldn't want to go to Alpha Centauri, say, and study the star for a year, to find out there's a very interesting planet there that we can't tell the spacecraft to look at. Not to mention, it'll have to react to any emergencies on it's own, such as possible impacts with any debris in the Oort cloud of the target system, or just any random impact, solar flar, or malfunction that might occur.

It's a bit more difficult than "stuff it full of nukes and let's go!"