Water found on a potentially life-friendly alien planet • Hacker News Board

Re: Water found on a potentially life-friendly alien planet

#321

Post by healsjnr1 » Thu, Sep 12, 2019, 9:16 AM UTC

tunesmith wrote: post #264

dylan604 wrote: post #221

Earlier quoted context omitted.

does this take into consideration that you would need to start slowing down halfway there?

No, it assumes you start and end at whatever that maximum velocity is that we've been able to achieve. That'd be fun to add, though. I'm not really sure what human-safe acceleration is - people here assume it's in the 1g-3g range. (That seems like a lot to me though, particularly for a long period of time - I think anything more than a fraction of g would be wildly uncomfortable.)

1G would be great as it would remove any unexpected physiological impacts of living in zero or low gravity.

Having said that, the distance and duration means that only a small portion of this journey would be under acceleration, the rest would be in zero g.

Spending a century in zero g would probably have a bunch of strange side effects and almost certainly mean that the people alive when they arrived wouldn't be able to stand the planets gravity.

This exact topic is what about 80% of The Expanse is about.

Re: Water found on a potentially life-friendly alien planet

#322

Post by bakuninsbart » Thu, Sep 12, 2019, 9:25 AM UTC

adrianN wrote: post #295

s_kilk wrote: post #292

Earlier quoted context omitted.

Isn't it always 30 years away?

No. It's mostly a number of Euros away and we haven't been funding it very well.

Could you give some sources for that or explaing where exactly the problems in fusion technology lie and how it could be solved by throwing money at it?

Re: Water found on a potentially life-friendly alien planet

#323

Post by bakuninsbart » Thu, Sep 12, 2019, 9:25 AM UTC

nannal wrote: post #296

mk89 wrote: post #294

Earlier quoted context omitted.

So our only hope to see a planet different from ours is that some advanced alien population comes to "see" us, with all the implications this has...

History does not favour the civilization which is visited.

Our history doesn't.

Re: Water found on a potentially life-friendly alien planet

#324

Post by ygmelnikova » Thu, Sep 12, 2019, 9:32 AM UTC

So many comments, so many dreams. As Peterson would say, "If you can't clean up your own room, who the hell are you to think you could travel to other worlds?"

Re: Water found on a potentially life-friendly alien planet

#325

Post by tontonius » Thu, Sep 12, 2019, 9:35 AM UTC

cryptoz wrote: post #67

Lots of discussion on the possibility of going or communicating, but for me the excitement is the narrowing of uncertainties in the Drake equation and the focusing of discovery of alien life, intelligent or otherwise. Discoveries like this improve our understanding of likelihood of extraterrestrial life, which has direct Earthly implications. It also enables better estimates and searches for planets that are closer,…

After reading Liu Cixin's Three body Problem, let's just say I'm less super interested in communicating :)

Re: Water found on a potentially life-friendly alien planet

#326

Post by mesid » Thu, Sep 12, 2019, 9:37 AM UTC

vermilingua wrote: post #246

gisely wrote: post #242

Earlier quoted context omitted.

The speed of light is just a compute constraint imposed on the physics simulation that is our universe. If we can just get the gods who are running that simulation to give us a little extra compute time in our neck of to woods then we can all be galactic explorers.

Just for the sake of argument, let's run with that. If we're in a physics simulation, we don't experience at the rate that the simulation is processed. One "tick" of the simulation could be processed in one second of the host universe, or one hour: and we wouldn't feel the difference. We are processed at the same tickrate as the rest of the universe, so we experience the passage of time at the same rate that the simu…

What does speed of causality mean? And how is light so close to that?

Re: Water found on a potentially life-friendly alien planet

#327

Post by gmueckl » Thu, Sep 12, 2019, 9:39 AM UTC

luxuryballs wrote: post #270

manicdee wrote: post #134

Some caveats per Marina Koren https://twitter.com/marinakoren/status/1171873631808438273 1. This planet probably doesn’t have a solid surface 2. Being in the “habitable zone” doesn’t mean a planet is habitable 3. The detection is of water molecules, chances are the water only exists as vapour in the atmosphere of this small gas giant. 4. If you ask 10 astronomers about this you will get 11 opinions

Also it just seems to be water, they’re obviously not 100% sure it’s not something else that’s reading as water.

How easy is it to have different mixtures of substances that lead to similar enough absorption apectra that they are indistinguishable with the available resolution and sensitivity?

Re: Water found on a potentially life-friendly alien planet

#328

Post by wazoox » Thu, Sep 12, 2019, 9:46 AM UTC

tunesmith wrote: post #204

I got into the Wait Calculation[1] a few weeks back and made a Jupyter notebook out of it. At our current max speed (692,000 km/hr, stated max speed of Parker Space Probe), it would take about 173,000 years to get to that planet. We could instead choose to Wait and grow our tech. By picking a constant annual growth rate and then doing some calculus to find the minimum, we can calculate the shortest possible time it w…

Yeah. Well. That's a fun math game and not much more. Other view on "energy growth rate": https://dothemath.ucsd.edu/2011/07/galactic-scale-energy/

Energy growth is due to end sooner or later.

First, in the real world, any long term exponential growth is actually the upward branch of an S (that plateau at some point) or of a bell curve (that falls down after a peak).

Second, with such an energy growth rate we'll boil the ocean from heat dissipation long before we reach the stars.

Re: Water found on a potentially life-friendly alien planet

#329

Post by dkersten » Thu, Sep 12, 2019, 10:22 AM UTC

username90 wrote: post #308

vermilingua wrote: post #246

Earlier quoted context omitted.

Just for the sake of argument, let's run with that. If we're in a physics simulation, we don't experience at the rate that the simulation is processed. One "tick" of the simulation could be processed in one second of the host universe, or one hour: and we wouldn't feel the difference. We are processed at the same tickrate as the rest of the universe, so we experience the passage of time at the same rate that the simu…

We could ask the host to update their algorithm to let c be a property of objects and then just do spaceship.c = 1000 * c. Would probably be a heck of a refactor to get it working without bugs though.

Just leave the bugs in for the speedrunners to use.

Re: Water found on a potentially life-friendly alien planet

#330

Post by amelius » Thu, Sep 12, 2019, 10:23 AM UTC

narrator wrote: post #230

tunesmith wrote: post #204

I got into the Wait Calculation[1] a few weeks back and made a Jupyter notebook out of it. At our current max speed (692,000 km/hr, stated max speed of Parker Space Probe), it would take about 173,000 years to get to that planet. We could instead choose to Wait and grow our tech. By picking a constant annual growth rate and then doing some calculus to find the minimum, we can calculate the shortest possible time it w…

Progress in physics was much faster in the early 20th century when it wasn't so fascinated with deep space. Yes, you needed to observe eclipses to verify relativity, but that was a tool, not the end in itself. Cosmology involves distances that are so great that it seems like it's pouring a whole bunch of smart people's efforts down the drain in an ultimately futile waste of brain power that will never amount to anyth…

> it seems like it's pouring a whole bunch of smart people's efforts down the drain in an ultimately futile waste of brain power that will never amount to anything much at all.

Well, at least they're not making people click ads ...