# At least 3 planets in habital zone, one star:

sonhouse
Science 22 Feb '17 20:16
1. sonhouse
Fast and Curious
22 Feb '17 20:16

It's a dwarf star putting out about 1/2000th the intensity of our sun.

So the habital zone is very close to the star and these planets are orbiting in times measured in days! 9 days, one week, that kind of thing.

But it is only 39 light years away, about ten times further than Alpha Centauri but still pretty local as interstellar distances goes.

If a propulsion system could get to 1/10th c, it would be about 400 years to get there and even at half c would run 80 years so any way you slice it it is still far away in time for us. But it is the closest to finding possible life outside our solar system.
2. Soothfast
0,1,1,2,3,5,8,13,21,
22 Feb '17 20:50
Originally posted by sonhouse
If a propulsion system could get to 1/10th c, it would be about 400 years to get there and even at half c would run 80 years so any way you slice it it is still far away in time for us. But it is the closest to finding possible life outside our solar system.
If we fly there at around 88% the speed of light it'll take around 45 years for the observer at rest, but under 23 years for the ship's crew. ðŸ˜‰
3. sonhouse
Fast and Curious
22 Feb '17 22:303 edits
Originally posted by Soothfast
If we fly there at around 88% the speed of light it'll take around 45 years for the observer at rest, but under 23 years for the ship's crew. ðŸ˜‰
Yeah, the equation goes to 2.3 X at 0.9c. 0.99c gets you there about 7 times faster, ship time but we can forget about that in THIS century for sure. 0.999c does about 23 times faster ship time, so maybe 4 years to get there and back ship time of course, 80 years goes by on Earth for the round trip even at 0.999c. My guess is if ever, about the year 2300 or so. At 0.999c you are about 300,000 meters per second slower than c. c is 299,792,458 meters per second.
4. Soothfast
0,1,1,2,3,5,8,13,21,
23 Feb '17 04:05
Originally posted by sonhouse
Yeah, the equation goes to 2.3 X at 0.9c. 0.99c gets you there about 7 times faster, ship time but we can forget about that in THIS century for sure. 0.999c does about 23 times faster ship time, so maybe 4 years to get there and back ship time of course, 80 years goes by on Earth for the round trip even at 0.999c. My guess is if ever, about the year 2300 ...[text shortened]... .999c you are about 300,000 meters per second slower than c. c is 299,792,458 meters per second.
Curiously it looks like it takes almost exactly a year to attain a "near c" velocity at a rate of acceleration equal to gravity on the surface of Earth (about 9.8 m/s^2). Decelerating to a relative stop would be another year. Presumably that would be the limit for a multigenerational interstellar ship. I don't think a human crew could tolerate living in a 2 g environment for weeks or months.

We need us some new physics, with navigable wormholes.
5. 23 Feb '17 07:44
I personally see no real benefits to us travelling to a nearby star. Sending robots there, sure, but there is no need to send humans. When we have developed enough to travel such distances we will probably have large enough spaceships that we can live in them permanently. If we need resources, then merely send the robots to go mine them and bring them back.
As for g-forces, we will probably evolve into 100% couch potatoes so living in a 2G environment might not be so difficult.
6. sonhouse
Fast and Curious
23 Feb '17 08:28
I personally see no real benefits to us travelling to a nearby star. Sending robots there, sure, but there is no need to send humans. When we have developed enough to travel such distances we will probably have large enough spaceships that we can live in them permanently. If we need resources, then merely send the robots to go mine them and bring them bac ...[text shortened]... robably evolve into 100% couch potatoes so living in a 2G environment might not be so difficult.
I think they won't need generational ships to get to these stars if we decide to do that.

I think the advances in DNA sciences will allow the ship to be run only by robots, and even if the trip takes a thousand years, instead of humans on board, they have frozen embryo's or even earlier, eggs and sperm ready to make embryo's in some kind of reactor. That way, no resources are used, no air, no water, no food, only enough energy to run the robots which run the ships. Then say 40 years before they get to the destination, they start decanting eggs and sperm or embryo's, whatever, grow them in a tank and then start taking care of babies when at that time, that is when you need the human elements, air, food, water and so forth. All the knowledge of humanity would be in memory chips and by that time I imagine memory technology would allow exabyte storage that lasts thousands of years before deterioration so all our knowledge from the time the voyage starts would be encoded, all the math, physics, human history, and so forth, and of course along with humans there would be the same storage of as many life forms as we could stuff into the ship, a real live ark capable of finding a world, and even if it took some terraforming, the ship could do all that before even decanting humans.

I think that is the way we go interstellar, way before we get to the point of inventing faster than light drives or some kind of wormhole tech.

Using ships like that, we could make thousands of such trips and humans would spread throughout the galaxy on a thousand worlds.
7. 23 Feb '17 12:04
Originally posted by sonhouse
Then say 40 years before they get to the destination, they start decanting eggs and sperm or embryo's, whatever, grow them in a tank and then start taking care of babies when at that time,.....
Why 40 years before? It makes far more sense to get there, establish the necessary colony on the planet and only then introduce humans. Even better, have an advance spaceship take various life forms and go and terraform the planet long before sending the humans.
8. 23 Feb '17 12:06

at 13:47 they show an image that they claim is 'scientifically accurate' showing some of the planets as seen in the sky of one of them. They look far too large to me - larger than our moon does. Surely if they were that close they would be orbiting each other not the star?
9. sonhouse
Fast and Curious
23 Feb '17 15:37
Why 40 years before? It makes far more sense to get there, establish the necessary colony on the planet and only then introduce humans. Even better, have an advance spaceship take various life forms and go and terraform the planet long before sending the humans.
I was just thinking the first ones decanted and grown by robots would be 40 odd years old when they arrive and could make better decisions as to the hability of the planet, do we have to terraform it, is there already life there, issues that perhaps robots would not be able to deal with. Hey, look, it's already a done deal, I already spoke to Trumpf about it, it's ready to flyðŸ™‚
10. 23 Feb '17 18:20
Originally posted by sonhouse
I think they won't need generational ships to get to these stars if we decide to do that.

I think the advances in DNA sciences will allow the ship to be run only by robots, and even if the trip takes a thousand years, instead of humans on board, they have frozen embryo's or even earlier, eggs and sperm ready to make embryo's in some kind of reactor. That ...[text shortened]... make thousands of such trips and humans would spread throughout the galaxy on a thousand worlds.
Even if you made the long trip you might get there and find a Venus like planet.

I think it is amusing that news reporters leave out the word "may" and say they are Earth like planets just because they are of similar size. Odds are they are Venus like planets.
11. 23 Feb '17 18:481 edit
Originally posted by sonhouse
I was just thinking the first ones decanted and grown by robots would be 40 odd years old when they arrive and could make better decisions as to the hability of the planet, do we have to terraform it, is there already life there, issues that perhaps robots would not be able to deal with.
And if it turns out its not suitable, you just kill off that group and move on to the next star?
12. Soothfast
0,1,1,2,3,5,8,13,21,
23 Feb '17 20:55
I personally see no real benefits to us travelling to a nearby star. Sending robots there, sure, but there is no need to send humans. When we have developed enough to travel such distances we will probably have large enough spaceships that we can live in them permanently. If we need resources, then merely send the robots to go mine them and bring them bac ...[text shortened]... robably evolve into 100% couch potatoes so living in a 2G environment might not be so difficult.
I think robots would need to go first, anyway, to assess nearby exoplanets to determine whether they would be at all suitable for human habitation. Certainly, if our sun were on the verge of dying and there were no other options within our solar system, then colonizing another world would be the way to go. But then, if our civilization is still around in a billion years, humans would likely have evolved into robots themselves, or perhaps something else entirely like a hive mind living in the Cloud.

That last thought about a hive gets me thinking of another motivation for colonizing other worlds: the mode of living on Earth may evolve in such as way that is intolerable for a sizable fraction of the population. Crowdfunded interstellar expeditions would perhaps take away millions of people at a time to various destinations where they can preserve a way of life that is no longer possible on Earth. As long as humans are humans there will be tribalism and diversity in lifestyles.

And yes, many if not most such expeditions would likely be on large ships that can go on indefinitely and be worlds unto themselves, so that reaching a final destination, while perhaps desired, is not an absolute necessity. Many such ships say simply stick with orbiting the sun for awhile.
13. 23 Feb '17 22:35
Originally posted by Soothfast
I think robots would need to go first, anyway, to assess nearby exoplanets to determine whether they would be at all suitable for human habitation. .
So do I.
I think it would be completely insane to send humans to a planet before robots are sent to it to both determine whether it is suitable for human life and, if necessary which I am sure it is likely to be, terraform it to make it more suitable.
14. DeepThought
23 Feb '17 22:36
Originally posted by Soothfast
Curiously it looks like it takes almost exactly a year to attain a "near c" velocity at a rate of acceleration equal to gravity on the surface of Earth (about 9.8 m/s^2). Decelerating to a relative stop would be another year. Presumably that would be the limit for a multigenerational interstellar ship. I don't think a human crew could tolerate living i ...[text shortened]... a 2 g environment for weeks or months.

We need us some new physics, with navigable wormholes.
Why would the crew need to put up with a 2g acceleration? The difficulty with this is that it ignores the interstellar medium, which is pretty tenuous in its rest frame, but in the frame of reference of your interstellar spaceship it will be relatively dense and very hot. Also there is a problem with fuel mass, keeping up an acceleration of 1g for a round trip of 2 years ship time is going to present an engineering challenge. I doubt that this is viable. I agree with your last sentence, we need to put an order in for some new physics, preferably by return of post.
15. Soothfast
0,1,1,2,3,5,8,13,21,
23 Feb '17 23:05
Originally posted by DeepThought
Why would the crew need to put up with a 2g acceleration? The difficulty with this is that it ignores the interstellar medium, which is pretty tenuous in its rest frame, but in the frame of reference of your interstellar spaceship it will be relatively dense and very hot. Also there is a problem with fuel mass, keeping up an acceleration of 1g f ...[text shortened]... ur last sentence, we need to put an order in for some new physics, preferably by return of post.
I'm ignoring the practical issues involved in sustaining a 1g acceleration for a year, which would indeed be astronomical. I don't seriously propose such an endeavor. Getting up to 0.1c or 0.2c would be, I think, about the best that we could hope for for a ship with a human crew.

I wasn't aware of the issues with the interstellar medium, though. You have reminded me of the ramjet proposals of old, which would use the medium for fuel en route.