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Interstellar Flight: Perspectives and Patience

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Re: Interstellar Flight: Perspectives and Patience

#41

Post by ge96 »

os2warpman wrote: post #6

>To get around thousand-year generation ships, we are examining some beamed energy solutions that could drive a small sail to Proxima in 20 years. The odds of a spacecraft hitting a single particle of dust while in space are 100%. A spacecraft hitting a single particle of dust at 0.2c will impart tens of millions of joules into the body of the spacecraft, the equivalent of getting hit with hundreds of pulses from the…

scifi answer (the particle warps with space around the vehicle)

the other thought is a space ram jet sucking in particles heard of some idea like this

Re: Interstellar Flight: Perspectives and Patience

#42

Post by carpdiem »

JumpCrisscross wrote: post #39
d_silin wrote: post #32

Developing propulsion technology to reach 0.1c velocity will move the needle on interstellar propulsion from impossible to just barely feasible. Although that is at least 100-200 years away, we can absolutely start expanding into our Solar System, starting with nearby bodies, like Moon and Mars.

> Developing propulsion technology to reach 0.1c velocity will move the needle on interstellar propulsion from impossible to just barely feasible More than barely. "A 40-year one-way interstellar flyby mission to the nearest stars will require a relativistic spacecraft speed in excess of 6000 AU/yr ( i.e. , > 0.1c)" [1]. That means, practically speaking, nuclear-fusion, antimatter-annihilation and directed-energy pro…

1 AU is about 8.3 light minutes. So 6k AU is about 50k light minutes. with ~525k minutes in a year, that means that 6k AU/yr is almost exactly 0.1c.

Re: Interstellar Flight: Perspectives and Patience

#43

Post by NoMoreNicksLeft »

kibwen wrote: post #27
NoMoreNicksLeft wrote: post #8

Earlier quoted context omitted.

>Humanity has never been content with staying put, why would we start now? For whatever reason, humanity's attitude in this regard has changed drastically in the last century. We can't even bother to make the next generations, and a shrinking population eventually (quite quickly, really) shrinks to zero. Not only do they want to "stay put", they want to lay down and die.

The steelman counterargument is that focusing resources on extraplanetary colonies at the expense of the one habitable planet within reach will hasten humanity's destruction. How are you going to make an Eden on Mars if we can't even make an Eden on Earth? The only large-scale planetary engineering in humanity's history is Veniforming its home world.

>The steelman counterargument is that focusing resources on extraplanetary colonies at the expense of the one habitable planet within reach will hasten humanity's destruction.

That doesn't seem like a strong argument to me. It seems like a distraction from the crowd that would save the planet by extinguishing humanity if that's what it took. Though what value the planet might have with all of us gone I leave as an exercise for the reader.

The first priority of any society that wants to continue to exist into the future must always be to make the next generation. If you do not do this, or if you just leave the task to others hoping that someone else will do it, then you are behaving in a way that will in all probability lead towards there being no next generation sooner or later. The "global warming is the apocalypse" movement constantly talks about how the best way to reduce your carbon footprint is to have no children.

>The only large-scale planetary engineering in humanity's history is Veniforming its home world.

So it is claimed, but from my point of view it looks very much as if it's intent on making itself extinct through fertility decline. But at least carbon dioxide levels will return to normal, eh?

Re: Interstellar Flight: Perspectives and Patience

#44

Post by JumpCrisscross »

sorcerer-mar wrote: post #40
trhway wrote: post #30

Earlier quoted context omitted.

Our civilization has been driven by expansion. Without it we'd probably collapse into a neurally-connected well-organized ant colony without need for further technological/social/economic progress (which would naturally select/cull out corresponding features in our brain). And, i'd guess that is possible one of the forms of the Great Filter stopping many civilizations. At 53 and good health, i'm contemplating that my…

That's a truly awful way to die (all your fluids and gases suddenly surging through your tissue). Seems much easier to reframe the "chains" of earth into acceptance of a remarkable cycle that we're privileged to get a glimpse of from the inside and just die happily here with your loved ones.

> Seems much easier to reframe the "chains" of earth into acceptance of a remarkable cycle that we're privileged to get a glimpse of from the inside and just die happily here with your loved ones

This works for most people. Most humans didn't leave Africa or Mesopotamia or the Old World, either originally or in the Age of Exploration, and most Americans today don't have a passpport.

Re: Interstellar Flight: Perspectives and Patience

#45

Post by JumpCrisscross »

carpdiem wrote: post #42
JumpCrisscross wrote: post #39

Earlier quoted context omitted.

> Developing propulsion technology to reach 0.1c velocity will move the needle on interstellar propulsion from impossible to just barely feasible More than barely. "A 40-year one-way interstellar flyby mission to the nearest stars will require a relativistic spacecraft speed in excess of 6000 AU/yr ( i.e. , > 0.1c)" [1]. That means, practically speaking, nuclear-fusion, antimatter-annihilation and directed-energy pro…

1 AU is about 8.3 light minutes. So 6k AU is about 50k light minutes. with ~525k minutes in a year, that means that 6k AU/yr is almost exactly 0.1c.

> that means that 6k AU/yr is almost exactly 0.1c

Nobody debates this. The point is that 0.1c propulsion is not necessarily 100+ years away. And its 40-year transit time is not "barely feasible," it's comparable to present deep-space mission timelines [1].

[1] https://science.nasa.gov/mission/voyager/

Re: Interstellar Flight: Perspectives and Patience

#46

Post by bilbo0s »

zppln wrote: post #36
ta1243 wrote: post #23

Earlier quoted context omitted.

To quote Babylon 5 Ask ten different scientists about the environment, population control, genetics, and you'll get ten different answers, but there's one thing every scientist on the planet agrees on. Whether it happens in a hundred years or a thousand years or a million years, eventually our Sun will grow cold and go out. When that happens, it won't just take us. It'll take Marilyn Monroe, and Lao-Tzu, and Einstein…

And those stars will go out as well.

Well true.

That's the fallacy in the given argument.

Re: Interstellar Flight: Perspectives and Patience

#47

Post by JumpCrisscross »

awongh wrote: post #31
os2warpman wrote: post #6

>To get around thousand-year generation ships, we are examining some beamed energy solutions that could drive a small sail to Proxima in 20 years. The odds of a spacecraft hitting a single particle of dust while in space are 100%. A spacecraft hitting a single particle of dust at 0.2c will impart tens of millions of joules into the body of the spacecraft, the equivalent of getting hit with hundreds of pulses from the…

Are there any real proposals that deal with this issue for a vehicle that would carry humans and go fast? Something that's not "energy shields". Edit to add: we basically understand the physics of accelerating something to a high speed, what it would need to be made from, etc., afaik all within the realm of possibility- if we could gather and direct that much energy and then wait long enough to decelerate at the othe…

> Are there any real proposals that deal with this issue for a vehicle that would carry humans and go fast?

Whipple shields [1].

> Something that's not "energy shields"

The interstellar medium contains lots of charged particles [2]. Electromagnetic deflection is perfectly realistic.

[1] https://en.wikipedia.org/wiki/Whipple_shield

[2] https://www.space.com/interstellar-space-definition-explanat...

Re: Interstellar Flight: Perspectives and Patience

#48

Post by JumpCrisscross »

agentultra wrote: post #12
cryptoz wrote: post #4

Earlier quoted context omitted.

All life on Earth is going die. Humanity has never been content with staying put, why would we start now? And what do you mean "literally nothing there"? The universe has a loooooot of stuff in it.

It's mostly empty, isn't it? By "literally nothing there," I mean there's literally nothing for us. Three stars and a few Earth-sized planets in the habitable zone that are, more than likely, uninhabitable by humans. There's nothing there worth going all that way for. I like sci-fi as much as the next person but the reality of the situation, it seems to me, is that the universe is mostly empty, vast, and inhospitable…

> It's mostly empty, isn't it?

So is the Pacific Ocean for practical definitions of emptiness. You don't got to the empty places.

Re: Interstellar Flight: Perspectives and Patience

#49

Post by tejtm »

sorcerer-mar wrote: post #20
krunck wrote: post #16

The comment by Benjamin Stockton on the article page is spot-on: >I just wonder if humanity’s adventurous nature is leading us away from a proper focus on the sustainability of our civilization, our specie, and our fragile planetary environment? But we still need spaceflight at least for planetary defense against asteroids, mining asteroids(so we don't have to mine Earth), etc.

What resources are on asteroids that justify the energy expenditure to get from space and back? Can't be many of them...

"What resources are on asteroids that justify the energy expenditure to get from space and back? Can't be many of them..."

I suggest re-framing the the question as the cost of preserving the objectively limited and to the best of our knowledge singularly unique in the Universe resource, which is the surface of Earth.

Acquiring resources that do not deplete or spoil the future of life on this planet should be in everyone's best interest.

Re: Interstellar Flight: Perspectives and Patience

#50

Post by JumpCrisscross »

trhway wrote: post #15
os2warpman wrote: post #6

>To get around thousand-year generation ships, we are examining some beamed energy solutions that could drive a small sail to Proxima in 20 years. The odds of a spacecraft hitting a single particle of dust while in space are 100%. A spacecraft hitting a single particle of dust at 0.2c will impart tens of millions of joules into the body of the spacecraft, the equivalent of getting hit with hundreds of pulses from the…

alternatively you ionize that particle, may be make in into plasma by laser for ease of "digestion" down in the engine, direct in into the engine where it is used as working mass for your ion thruster, kind of similar to scramjet. As far as i see with today's tech - like Starlink's ion thruster + classic nuclear reactor - we can get to 300km/s in about 4 stages. Straightforward improvement of ion thrusters - mainly v…

> alternatively you ionize that particle, may be make in into plasma by laser for ease of "digestion" down in the engine, direct in into the engine where it is used as working mass for your ion thruster, kind of similar to scramjet

This is a Bussard ramjet [1]. The interstellar medium is too thin to make it work. (Maybe we'll find the husk of an ancient ramjet from an earlier era of the universe floating around one day...)

[1] https://en.wikipedia.org/wiki/Bussard_ramjet

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