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What's the next step?


Old Man

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So it seems very likely that we will locate several Earthlike worlds around other stars in the next 5-10 years, some of which could be only a few dozen light years away. The question on my mind is... what happens after that? Should we send a robotic probe and wait centuries for it to send back information? Should we attempt to send a multigenerational starship to colonize the world? What if the world has liquid water but no evidence of life? What if it does show evidence of life? What if the Chinese or Iranians start to build a colony ship? What should be included on such a colony ship? How do you set up a society and ecosystem on such a ship so that its occupants (or their descendants, anyway) will make it?

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Re: What's the next step?

 

Well, you certainly need to get started now if you want to be done by 2020 ahead of the NPC races(and launch by next year to get the maximum number of VPPs). Remember that they can launch at any point up to 2016, and even if there's no sign of a programme now, all they need is a few spies, as they tend to have pretty awesome production capabilities. It's almost like there's some AI adjusting the way the world works to allow them to finish their spaceship on time.

 

The other option is that you build lots of howitzers and blitz them a year or so before they launch.

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Re: What's the next step?

 

I have to agree with The Weapon -- the next step is pinning down our definition of 'earth-like.' For some astronomers, earth-like means anything that falls in between air-less balls of rock (or nearly air-less, like Mars) and gas giant worlds. For the general public, OTOH, earth-like means something resembling the back lot of a Hollywood movie studio -- they're expecting exo-planets that look a lot like southern California.

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Re: What's the next step?

 

The problem is, with our current resolutions we can see something is the right size, and in the right place, but have no idea of atmospheric density or composition. The BEST thing to do would be to wait - build the next generation of space telescopes, Very Large Interferometers and super sensitive spectroscopic arrays. There is absolutely NO point to sending even automated probes if they'll take two hundred years to tell us what we'll have discovered anyway in twenty. And if Iran starts building a generation ship to go to Eta Bootis, let them - it's a near-certain death sentence for the crew and bankruptcy for a regime we don't like.

We have, barely, the tech to colonize Mars. Venus and the outer worlds are going to have to wait awhile. Once we're done there, have some idea of what we're doing and what's out there, THEN will be the time to set sail for the interstellar void.

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Re: What's the next step?

 

I have to agree with The Weapon -- the next step is pinning down our definition of 'earth-like.' For some astronomers' date=' [i']earth-like[/i] means anything that falls in between air-less balls of rock (or nearly air-less, like Mars) and gas giant worlds. For the general public, OTOH, earth-like means something resembling the back lot of a Hollywood movie studio -- they're expecting exo-planets that look a lot like southern California.

 

Specifically, Vasquez Rocks, near Aqua Dulce. Maybe with a blue filter.

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Re: What's the next step?

 

Taking what we can do now as a guide, I'm going to go with waiting until we have the best remotely-obtained information that we're likely to get, followed by a generation ship.

 

Why? Space is big, and blah blah like that. We have to go as fast as we can, unless we're content to wait for millennia for results. (Though if we are, we can go very efficiently, since we can use solar sails to decelerate as well as accelerating in the first place.) And at the moment it looks like the fastest (or, to put it another way, the most energetic thrust reaction available) is h-bomb rockets. And h-bombs don't scale down. You can do the "Project Orion" nuclear thrust with tactical nukes pushing little robot probes, but there is only so much uranium in the solar system, and using it like that doesn't get us to the fusion part of the fission-fusion-fission reaction that gives h-bombs their zingy fresh taste.

 

So, unless we develop a more compact means of producing fusion, it looks like a gigantic generation ship is the most cost effective way of doing that. But before we launch one of those, we need to be very clear about what we're launching it at. And do some engineering --about, I'd say, 150 years worth.

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Re: What's the next step?

 

So it seems very likely that we will locate several Earthlike worlds around other stars in the next 5-10 years' date=' some of which could be only a few dozen light years away. The question on my mind is... what happens after that? Should we send a robotic probe and wait centuries for it to send back information? Should we attempt to send a multigenerational starship to colonize the world? What if the world has liquid water but no evidence of life? What if it does show evidence of life? What if the Chinese or Iranians start to build a colony ship? What should be included on such a colony ship? How do you set up a society and ecosystem on such a ship so that its occupants (or their descendants, anyway) will make it?[/quote']

Call me skeptical. I doubt that we will get multi-generation colony ships right the first time. So let's set up a few O'Neil habitats as trial ships where we can evacuate any survivors if things go pear shaped.

 

Studying an extra-solar planet has been compared to studying a firefly perched on the rim of a searchlight. Cancer can correct me if I am wrong, but I believe the instrument for this is called an interferometer. Build a honking big one, preferably outside Earth atmosphere. I'm thinking Luna?

 

Next a radio telescope. One on Luna that can work with ones on Earth will give us an array a quarter of a million miles across. Build bigger ones even further from Earth. I'm thinking the Trojans. Gives us an array from 4 to 6 AU across.

 

Go throttle to the firewall on clanking replicators. When we launch the robot probes, the one thing we can count on is that we'll think of something better as soon as we launch. Make them able to reconfigure /upgrade themselves in response to instructions from the ground.

 

This will be the best we can do to collect data and run simulations before we launch.

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Re: What's the next step?

 

I think the best thing we could do would be to start increasing the focus in the direction of such worlds with projects like S.E.T.I. Likewise we should consider what it's like to be on the other end of such a project and setup sustainable (as in something that could potentially go on operating for millennia) solar-powered broadcasters beaming in the direction of such worlds, sending signals like the first 100 prime numbers or elements of the Fibonacci series or something. If intelligent life is out there, we're not likely to be able to meet it personally or even hold a discussion with it for a very, very long time, but just the discovery that it is out there would provide a HELL of a stimulus to kick us into high gear for scientific advancement, and that's what we need right now more than anything.

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Re: What's the next step?

 

So, unless we develop a more compact means of producing fusion, it looks like a gigantic generation ship is the most cost effective way of doing that. But before we launch one of those, we need to be very clear about what we're launching it at. And do some engineering --about, I'd say, 150 years worth.

 

IIRC solar sails may actually be faster than fusion, simply because sails don't have to carry a fuel source, and could be propelled from the launching system using lasers.

 

Either way though, we're definitely talking multigeneration even for the nearest likely candidates. How would you go about setting up the society of such a ship so that its crew doesn't kill itself off halfway to the destination? How do you prepare the landing descendants, twelve or so generations ahead of time?

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Re: What's the next step?

 

IIRC solar sails may actually be faster than fusion' date=' simply because sails don't have to carry a fuel source, and could be propelled from the launching system using lasers.[/quote']

Solar sails may not work beyond the heliopause, at least not without laser pumping. Also the question of slowing down at the other end. Do we have clanking replicators build lasers at the destination?

 

Solar sails or ion engines have a small but constant accelleration, vs the massive but brief pulses from the Orion drive. We need to find the preformance limits of all of them then do the math.

 

Either way though' date=' we're definitely talking multigeneration even for the nearest likely candidates. How would you go about setting up the society of such a ship so that its crew doesn't kill itself off halfway to the destination? How do you prepare the landing descendants, twelve or so generations ahead of time?[/quote']

Beats me. I'm still working on the social dynamics of a crewed Mars mission. "Six people share an efficency apartment they can't leave for three years." Sounds like a Reality Show from Hell.

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Re: What's the next step?

 

I'm still working on the social dynamics of a crewed Mars mission. "Six people share an efficency apartment they can't leave for three years." Sounds like a Reality Show from Hell.

 

I would totally watch Survivor: Mars! "You've been voted off the space-ship. You have 5 minutes to report to the airlock...."

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Re: What's the next step?

 

Not to sound like a jerk, (because it's a very good question) but I think we should continue working on saving our own planet first. You might say that we might need to relocate if things are going down that path, but with timelines of 150 years, or longer for radio signals sending us information, we probably won't be around to even attempt anything like that.

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Re: What's the next step?

 

Not to sound like a jerk' date=' (because it's a very good question) but I think we should continue working on saving our own planet first. You might say that we might need to relocate if things are going down that path, but with timelines of 150 years, or longer for radio signals sending us information, we probably won't be around to even attempt anything like that.[/quote']

 

Always have a backup plan. If it turns out we've done too much damage to Earth, let's make sure we can do without.

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Re: What's the next step?

 

False dilemma. Let's do both.
Funny thing: I have the same conclusion for close to the opposite reason. :)
Always have a backup plan. If it turns out we've done too much damage to Earth' date=' let's make sure we can do without.[/quote']There are always other threats besides the damage we've done, like killer pulsars and nearby supernovas. Hence my above conclusion.
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Re: What's the next step?

 

There is a proposed instrument which in principle could discern the presence of atmospheric O2 in an extrasolar planet.

 

You need an orbiting optical interferometer array ... half-dozen telescopes separated by ~> 10 meters ... ganged to a low-resolution spectrometer. The absorption bands of molecular oxygen (the Fraunhofer lines, in particular the A and B bands at the red edge of the visible spectrum) are remarkably easy to detect, as long as you aren't trying to see through them (as you are here on Earth, peering through our atmosphere).

 

That interferometer instrument is probably 10-15 years (two technical generations) away, if it could be given steady funding.

 

Interstellar travel is something else.

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Re: What's the next step?

 

Pssh. Interstellar travel is easy. As long as you're not in a hurry, you can walk to the next solar system over. It's getting there in less than 50,000 years or so that's the trick.

 

Consider: we've been able to get chunks of metal going at ~1 km/sec for five centuries now. That's 1/300,000th of light speed right there. And we've been putting reaction engines in those chunks for almost as long. We admittedly don't use those engines to get additional velocity so much as to blow up foreigners at the moment, but used properly, the charge will push them considerably faster once they're lit.

 

We've also got some keen gravity tricks that'll push the speed of the payloads up quite considerably. That's good, because we really can't talk about going to the stars until we exceed solar escape velocity. But consider: if you reach solar escape, your vehicle will be travelling at about 7km/sec when it exits the heliopause --something that we've already done. That's good, because you'll get to Alpha Centauri 7 times faster, and we're down from 1.4 million years to 200,000 -less time than it's taken our species to live fast and die young.

 

Truth is, we want to go a lot faster, get there a great deal quicker. (On the other hand, the faster you go, the more provision you have to make for braking. On the third hand, a lot of worthwhile targets have significant velocities with respect to Earth that we'll have to catch up with.) Stupid gravity tricks pushed Voyager 1 up so fast that it could reach Proxima Centauri in 76,000 years, if we'd aimed it in that direction!

As I've already said, we can go a lot faster with alternatives to rockets. The ion drive, as currently operating, can get to Centauri in 81,000 years --and that's with no gravity tricks. Not bad, considering that we're talking the SMART car of space.

 

I don't know that we'll want to go that route, though. The Centaurians will think that we're hippies, and pretend not to be home when we get there, so as to avoid having to fill out some stupid petition and hear about how a raw food vegan diet can change their lives. The obvious alternative is that we take Project Orion, the Hummer of space, which, admittedly, makes us look like a bunch of jerks, but if we prep 'em right, they'll just say, "it could have been worse," and welcome us!

 

The best part? The Orion boosters think that their boat could hit 15,000 bleeding km/s, enough to reach Proxima in 81 years! Now, on the one hand, I usually discount tech boosters by 90%. On the other, according to the well known strategic theorem H-bomb>>muzzle loading cannon, I'd say that that's basically not implausible.

 

And, best of all, Orion works better the bigger the thing is (again, Hummers in space!), so there'll be room for us human losers aboard. And it's not even the biggest source of radiation pollution out there. When the space cops pull us over, we can truthfully say, "Just trying to keep up with that pulsar, officer." Then we'll slip him our license in a billfold with a fifty, because even if we get our asses hauled up to Vega on remand, we'll still be making this interstellar exploration thing work!

 

And, yes, we've got a lot to learn about plumbing in space. I'm not denying that. But before we launch Project Orion, we need asteroid uranium refineries. By the time we have those, we'll have, oh, I don't know, servers in orbit and a moonbase mining polar ice, and, overall, plenty of chances to figure out how to unplug the space crappers when the facility repair budget's already been blown for the quarter.

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Re: What's the next step?

 

Yeah' date=' but you can't get out of the solar system at that launch velocity. So we can't hit Epsilon Eridani with cannon balls.[/quote']

 

Well, 1 km/s may be the velocity "at infinity", after you've paid the velocity price of escaping Solar orbit.

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