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Two potentially life-friendly planets found orbiting a nearby star

nationalgeographic.com

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

#271

Post by lioeters »

hesk wrote: post #207
CWuestefeld wrote: post #192

I saw a study recently, unfortunately I can't locate it now. It discussed the possibility of there having been past civilizations on Earth, hundreds of millions or even billions of years ago. The conclusion was that this can't be entirely ruled out. It noted how few actual fossil remains we have for what we know of dinosaurs, and that there's a lot of space left in those gaps for all the evidence to have been destroy…

Maybe it was this? Gavin A. Schmidt, Adam Frank: The Silurian Hypothesis: Would it be possible to detect an industrial civilization in the geological record?, https://arxiv.org/abs/1804.03748 I found it through an article in The Atlantic that may or may not have been linked on HN recently. https://www.theatlantic.com/science/archive/2018/04/are-we-e...

Indeed, there was a discussion about this article, about a year ago. As a fan (and amateur writer) of science fiction, I greatly enjoyed learning about this hypothesis.

Was there a civilization on Earth before humans?

https://news.ycombinator.com/item?id=16837120

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

#272

Post by codesushi42 »

abtinf wrote: post #270
cptaj wrote: post #128

And to think that there is likely an Easy Mode system out there. A habitable planet on the low end of the mass spectrum needed for a stable atmosphere with other habitable planets in-system. And all that close to another star with habitable planets, possibly in the sub-lightyear range. Basically everything ripe for a spacefaring civilization to grow without too much trouble and with plenty of motivation. The Earth is…

Or perhaps that’s ultra-hard mode. Multiple fantastically different independent intelligent species evolving on planets within shooting range of each other with basic industrial technology. If you’ve ever played civilization, it is a helluva lot harder to get started in Europe than in North America.

You consider 12 light years to be within shooting range?

Good luck with that.

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

#273

Post by jodrellblank »

MRD85 wrote: post #263
cptaj wrote: post #128

And to think that there is likely an Easy Mode system out there. A habitable planet on the low end of the mass spectrum needed for a stable atmosphere with other habitable planets in-system. And all that close to another star with habitable planets, possibly in the sub-lightyear range. Basically everything ripe for a spacefaring civilization to grow without too much trouble and with plenty of motivation. The Earth is…

Imagine an easy mode planet in a system with multiple habitable planets. Now that I've typed that I'm also considering how Mars would look from 12 light years away. Is establishing a colony 12 light years away easier than transforming mars into a habitable planet?

On interstellar travel realities: http://www.antipope.org/charlie/blog-static/2007/06/the-high... - aka it’s not happening soon.

And for terraforming Mars, Isaac Arthur’s YouTube channel has many related videos, and he posits that by the time your civilisation could do it, it would be a wasteful use of Mars when it could be better disassembled and turned into O’Neill cylinders or something.

But coming over a crater or valley on Mars and transforming it into something habitable would be enormously easier than travelling 12 ly.

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

#274

Post by reneberlin »

How long will it take until the next planet is overpopulated and resources are consumed?

I mean: birth control? Socialism? Rules to obey?

If it is a competitive race it will end up pretty much the same. The question is then only: how long will it take?

Over to the next one ...

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

#275

Post by ArnoVW »

neaden wrote: post #169
dheera wrote: post #110

Earlier quoted context omitted.

Meh. 200 years aro they would have called you insane for wanting to fly between continents, let alone to the moon.

They also would have called you crazy for saying you wanted to turn lead into gold with alchemy. Fact is, most of the time the people who say something can't be done are right.

Nitpick: we can actually transmute, either by fusion or fission. Sure it's not economically effective, but then neither was Apollo.

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

#276

Post by m3kw9 »

Why aren’t we discovered? Probably because an advanced civilization but barely reach for the first time would be wise not to fly in risk getting detected and captured. So they wait till they have overpowering cloaking ability before re attempting a sighting. Maybe by that time, we are no longer interesting because of their own advances

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

#277

Post by m3kw9 »

m3kw9 wrote: post #276

Why aren’t we discovered? Probably because an advanced civilization but barely reach for the first time would be wise not to fly in risk getting detected and captured. So they wait till they have overpowering cloaking ability before re attempting a sighting. Maybe by that time, we are no longer interesting because of their own advances

Also there is probably a super small probability where both civilizations are in similar advances that they can brave a encounter without worrying. If one is way more advanced, either one may not be interested, or the less advanced one chickens out/ gets destroyed because they want to hide their location.

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

#278

Post by civilian »

dheera wrote: post #211
joshuahedlund wrote: post #124

Earlier quoted context omitted.

I highly recommend the book The Equations of Life: How Physics Shapes Evolution[0] . While it's be foolhardy to rule out other dramatically different forms of life, there are only so many candidates in the periodic table and only so many of those in common concentrations throughout the universe. The universal laws of physics that continually converge on the same solutions on Earth, and the fact that life has apparent…

Why does life have to be chemical as we know it? Why can't a massive galactic-scale lifeform exist upon gravitational waves, radioactive particles, or even dark matter or things we don't know?

Some of the qualities of life is that it needs to: (1) be able to grow, (2) be able to reproduce (3) have hereditary traits.

I'll grant that there are probably galactic-scale patterns of light and gravity. My guess is that the amount of noise would make it impossible for any "life" to form. The unspecified type of wave would have to have an ability to store information in such a way that it would change the behavior of the waves.

As a tangent, these requirements of life is what makes the RNA world hypothesis so compelling. RNA is able to both store information _and_ act as an enzyme. 2-fer!

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

#279

Post by m3kw9 »

For those that wants to live on another planet, you will unlikely like how things look under another suns sunlight. It is hard to have a planet that will have day light like our sun and be habitable. Think of a yellow-reddish, or a light that is cold blue when you walk out. Human eyes evolved with earths lighting conditions.
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