Two potentially life-friendly planets found orbiting a nearby star • Hacker News Board

Re: Two potentially life-friendly planets found orbiting a nearby star

#321

Post by michaelmrose » Wed, Jun 19, 2019, 12:47 AM UTC

fastball wrote: post #116

sulam wrote: post #73

Earlier quoted context omitted.

There are holes wide enough to fit a solar system through that argument. Reductio ad absurdum. Here, I'll construct an argument in a similar form. People don't like mosquitos, for various reasons including that they transfer deadly diseases. Therefore the presence of mosquitos says there's a high probability that the planet isn't actually inhabited by us, because we would have killed them by now. After all, we have t…

To be honest, I've never really understood how a Dyson sphere would be superior to many nuclear fusion reactors that you can move around / turn off and on / build more of / etc

The sun is 99.9% of the mass in the solar system. Most of the rest of the mass is in Jupiter.

If you are ultimately bounded by energy requirements then solar is where most of the available energy is even if you literally cannibalize the gas giants.

Re: Two potentially life-friendly planets found orbiting a nearby star

#322

Post by jacobush » Wed, Jun 19, 2019, 12:55 AM UTC

blotter_paper wrote: post #307

kevin_thibedeau wrote: post #304

Earlier quoted context omitted.

We should be colonizing the moon first, then Phobos or Deimos. Then, once established, we can conquer the martian gravity well with local resources.

I like Musk's plan of using Mars as a fuel-planet, I just don't expect a self-sufficient colony for some time. Mars is like an oil rig or a mineshaft; no place for children.

In fact it's cold as hell.

And there's no one there to raise them if you did.

Re: Two potentially life-friendly planets found orbiting a nearby star

#323

Post by codesushi42 » Wed, Jun 19, 2019, 1:04 AM UTC

abtinf wrote: post #289

codesushi42 wrote: post #272

Earlier quoted context omitted.

You consider 12 light years to be within shooting range? Good luck with that.

Well, that’s just a matter of time. But I was referring to the parent comment’s system.

It's also a matter of space. Maybe you are unfamiliar with the concept of space-time and what a light year really measures.

Re: Two potentially life-friendly planets found orbiting a nearby star

#324

Post by Tuna-Fish » Wed, Jun 19, 2019, 1:09 AM UTC

cced wrote: post #320

joshuahedlund wrote: post #98

Earlier quoted context omitted.

Yes 12 ly is amazingly close! > If we presume there's nothing special about our little corner of the universe, then the distance to the nearest potentially habitable planets gives us an estimate of how many habitable planets are out there I would put a slight caveat to this - I would argue we do know there's something "special" about our little corner of the galaxy , at least - we are in the continuously habitable zo…

I often hear about the LY unit of distance. Why is it that we are still discovering things which are close to us in LY units? Wouldn’t we discover things at a distance of 5xLY before discovering things at a distance of 100xLY?

Things that are very luminous can be seen much further away than things that are very dim.

This particular star is a tiny red dwarf, which is so dim we only just found the star itself in 2003.

Our best planet-finding methods depend on finding signals in the light output of the host star. This is relatively insensitive to distance, but very sensitive to the properties of the star.

Re: Two potentially life-friendly planets found orbiting a nearby star

#325

Post by abledon » Wed, Jun 19, 2019, 1:50 AM UTC

blotter_paper wrote: post #292

jl6 wrote: post #266

Earlier quoted context omitted.

Harder, I think. We have the technology to live on Mars (not to terraform it, just to survive on it). We have some ideas from physics about how to get to a planet 12 ly away, but not the technology. Nor, I would argue, do we have the social and political setup required for such a project, which would most likely take hundreds of years to get to a basic colony.

> We have the technology to live on Mars (not to terraform it, just to survive on it). I'm not convinced this is true intergenerationally without a maternity ward in a centrifuge; the low gravity mouse embryo experiments don't look promising. Maybe 1/3rd earth gravity is enough, but I'm doubtful. If we're granting centrifugal habitats as something doable with current technology, an Orion/Daedalus style nuke-propelled…

mouse embyro zero-G experiments being referred to: https://www.wired.com/2009/08/spacebabies/

Re: Two potentially life-friendly planets found orbiting a nearby star

#326

Post by snowwrestler » Wed, Jun 19, 2019, 2:21 AM UTC

soulofmischief wrote: post #178

akiselev wrote: post #174

Earlier quoted context omitted.

It's not the density of the star but the density of stars. Dense clusters like those found in the center of our galaxy create a lot of secondary effects like bigger stars pulling matter away from smaller stars (creating lots of background radiation and matter floating around) and then stars plow through those interstellar clouds, creating deadly bursts capable of cooking entire planets, stripping away their atmospher…

I'm talking about the local solar density, not an individual star's density. Obviously that has little effect on the habitable zone of a planet. My question was about the ability of a system's star's own radiation to ward off extra-solar radiation and what kind of limitations we are aware of.

Electromagnetic radiation from one star does not repel electromagnetic radiation from other stars. If it did, we wouldn’t be able to see stars at night from the Earth.

Re: Two potentially life-friendly planets found orbiting a nearby star

#327

Post by JauntTrooper » Wed, Jun 19, 2019, 2:27 AM UTC

kevin_thibedeau wrote: post #304

blotter_paper wrote: post #292

Earlier quoted context omitted.

> We have the technology to live on Mars (not to terraform it, just to survive on it). I'm not convinced this is true intergenerationally without a maternity ward in a centrifuge; the low gravity mouse embryo experiments don't look promising. Maybe 1/3rd earth gravity is enough, but I'm doubtful. If we're granting centrifugal habitats as something doable with current technology, an Orion/Daedalus style nuke-propelled…

We should be colonizing the moon first, then Phobos or Deimos. Then, once established, we can conquer the martian gravity well with local resources.

Phobos and Deimos are very, very tiny.

The diameter of the Moon is 2,160 miles. The diameter of Phobos is 14 miles. Deimos is 8 miles.

(For scale, Mars' diameter is 4,200 miles).

Re: Two potentially life-friendly planets found orbiting a nearby star

#328

Post by svd4anything » Wed, Jun 19, 2019, 2:30 AM UTC

corodra wrote: post #100

onemoresoop wrote: post #62

Earlier quoted context omitted.

And imagine you're the first ship to arrive only to find out a) that the planet is not habitable and there were some wrong assumptions about it b) that the planet is already occupied by a different form of life and there's no warm welcome to us

This is also assuming A) Human engineering can create something that can last 200+ years of space travel. We don't even build houses anymore that can feasibly last 100 years. 2) People don't go mad and kill each other or do a mutiny III) Any number of stray objects from asteroids to rogue planets that just slams into the ship and causes major malfunctions d) Food and life support sustainability I mean... there are SO…

> d) Food and life support sustainability

Could we just send frozen embryos of humans and then have the ship auto thaw and gestate them 16 years to arrival?

With another 2-300 years of technological progress this doesn’t seem outlandish mission at all.

Re: Two potentially life-friendly planets found orbiting a nearby star

#329

Post by aaronax » Wed, Jun 19, 2019, 2:34 AM UTC

brianbreslin wrote: post #284

Moxdi wrote: post #268

Earlier quoted context omitted.

I bet there's a science fiction novel about that

If there isn't someone should write it.

I have read one. Many years ago, don't remember much about it. But I'm pretty sure it also discussed how all of the "future folk" were disgusted with the smell of the ones that had been traveling in cryo for 200 years. Too much perfume/deodorant...they didn't like the flower smells anymore as I believe they had engineered themselves to not perspire any more.

Re: Two potentially life-friendly planets found orbiting a nearby star

#330

Post by aaronax » Wed, Jun 19, 2019, 2:42 AM UTC

Teever wrote: post #301

bdamm wrote: post #213

Earlier quoted context omitted.

However, a transmitter with enough power to signal earth would be too massive to get fast with a solar sail, given today's technology. Maybe a chipsat gets to 20% c, but no way a dish does.

What if the chipsat sends the signal to the chipsat behind it which sends the signal to the chipsat behind it which.... So that the signal can be relayed by a bunch of short range transmitters all the way back to earth

Probably requires a surprising amount of short range transmitters to be launched then. I wonder if a formula could be developed that relates the energy needed to place one large transceiver at a given distance versus the energy needed to place small transceivers all along that given distance.